Preliminary results from phase 2 of CC-92480- MM- 001: Mezigdomide plus dexamethasone in relapsed/refractory multiple myeloma (RRMM)

In phase 1 of CC-92480- MM- 001 (NCT03374085), the recommended phase 2 dose (RP2D) of mezigdomide plus dexamethasone (MEZI-d) was selected at 1 mg once daily for 21/28 days. Here we report preliminary results from the MEZI-d dose-expansion cohort in patients with heavily pretreated RRMM. Key eligibility criteria were: RRMM;>=3 prior lines of therapy;disease progression <=60 days of last myeloma therapy;refractoriness to lenalidomide/pomalidomide, a proteasome inhibitor, a glucocorticoid, and an anti-CD38 monoclonal antibody. Oral mezigdomide 1 mg was given on days 1-21 of each 28-day cycle, plus weekly dexamethasone (40 mg;20 mg if >75 years of age). Primary objective was to evaluate efficacy (overall response rate [ORR]);secondary objectives included safety/tolerability and additional efficacy assessments. Pharmacodynamics was an exploratory objective. As of 16/Sep/2022, 101 patients had received MEZI-d at the RP2D. Median age was 67 (range 42-85) years, median time since initial diagnosis was 7.4 (1.1-37.0) years;39.6% of patients had plasmacytomas and 37/101 patients had high-risk cytogenetics (56/101 not evaluable). Median number of prior regimens was 6 (3-15);prior therapies included stem cell transplantation (77.2%) and anti-BCMA therapy (29.7%). All patients were refractory to last myeloma regimen and triple-class refractory. Median follow-up was 7.5 (0.5-21.9) months, with a median of 4 (1-20) cycles;10.0% of patients continued treatment;progressive disease was the main reason for discontinuation (60.4%). ORR was 40.6% for all patients. Whilst data are not mature yet, median PFS was 4.4 (95% CI 3.0-5.5) months and median duration of response was 7.6 (95% CI 5.4-9.5) months. ORR was 30.0% in patients with plasmacytomas (N = 40) and 50.0% in patients with prior anti-BCMA therapy (N = 30). Ninety-one (91.1%) patients experienced a grade 3/4 treatment-emergent adverse event (TEAE). Most frequent hematologic grade 3/4 TEAEs were neutropenia (75.2%), anaemia (35.6%), and thrombocytopenia (27.7%);34.7% of patients had grade 3/4 infections, including grade 3/4 pneumonia (15.8%) and COVID-19 (7.0%). Occurrence of other grade 3/4 non-hematologic TEAEs was generally low. Due to TEAEs, 76.2% and 29.7% of patients had mezigdomide dose interruptions and reductions, respectively;90.1% of patients discontinued mezigdomide. Mezigdomide induced substrate degradation and increases in activated and proliferating T cells in patients, including those directly refractory to pomalidomide-based therapies. MEZI-d had a manageable safety profile with encouraging efficacy in patients with triple-class refractory RRMM, including patients with prior BCMA-targeted therapies. These results strongly support the continued development of mezigdomide in MM, and especially in combination.

Post-Transplantation Cyclophosphamide for the Prevention of Graft-Versus-Host Disease Should Not Limit Transplantation for Acute Lymphoblastic Leukemia in People with Trisomy 21

Introduction: Use of hematopoietic cell transplantation (HCT) in patients with trisomy 21 (+21) is infrequent given concerns about increased toxicity with cytotoxic chemotherapy.1 Due to increasing evidence of benefit from post-HCT cyclophosphamide (PTCy) for graft-vs.-host disease (GVHD) prophylaxis and lack of prior descriptions in patients with +21,2-4 we report on 2 patients with +21 and acute lymphoblastic leukemia (ALL) who underwent HCT with PTCy. Method(s): Retrospective data were collected from 2 patients with ALL and +21 who underwent allogeneic HCT with PTCybased GVHD prophylaxis from 2019 to 2021. Data collected included age, disease risk, HCT-CI, GVHD incidence, and survival. Result(s): Patient 1 is a 22-year-old male and patient 2 a 25-year-old female. Both had Ph-negative, B-cell ALL. Patient 1 had ETV6/RUNX1 rearrangement, del 12p, gain of X, and he had recurrence of measurable residual disease (MRD) after initial MRD-negative CR with two lines of therapy pre-HCT. Patient 2 had normal cytogenetics and relapsed disease with 4 prior lines of therapy. Both achieved MRD-negativity pre-HCT. Both received fludarabine and melphalan conditioning, and patient 1 also received thiotepa 2.5 mg/kg. PTCy was given on days +3 and 4 at 50 mg/kg with sirolimus and tacrolimus for GVHD prophylaxis. Patient 1 had a haploidentical donor and received one dose of rabbit ATG (1 mg/kg) on day +5. Patient 2 had a matched unrelated donor. There was no significant delay in engraftment of ANC (day 16-19) or platelets (day 15-16). Patient 2 developed acute GVHD at day 30 (stage I skin, stage II GI) that resolved with steroids which were tapered off by day 96 without recurrence. Sirolimus stopped at day 79 (pt 1) and 103 (pt 2) and tacrolimus was stopped at day 274 (pt 1) and 469 (pt 2). Patient 1 developed a sirolimus-induced pericardial effusion at day 84 which did not recur after sirolimus discontinuation. Patient 2 developed moyamoya 8 months post-HCT during tacrolimus taper without other GVHD symptoms. Response to steroids was noted, so tacrolimus was restarted for residual neurological deficit. Neither patient developed chronic GVHD or left ventricular ejection fraction decline, and neither patient had disease relapse at follow-up of 30 and 16 months respectively. Patient 2 developed COVID pneumonia 16 months post-HCT and died while in CR. Patient 1 remains alive, in CR, and off immunosuppression nearly 3 years post HCT. Conclusion(s): Allogeneic HCT with PTCy at standard doses did not appear prohibitively toxic in patients with +21 when administered after reduced-intensity conditioning. In this case series, GVHD rates seemed consistent with larger series in patients without +21. Moyamoya development is associated with autoimmunity in patients with +21 and hence may have been GVHD-related5. Trisomy 21 should not be a barrier to patients otherwise eligible for HCT, even with PTCy prophylaxis.Copyright © 2023 American Society for Transplantation and Cellular Therapy

Pathology Playground: An Interactive Web-Based System for Pathology Unknowns With Immunohistochemistry and Molecular Studies

(Arch Pathol Lab Med. 2023;147:492-495;doi: 10.5858/ arpa.2021 -0516-EP) Interactive, computer-based learning has been used in numerous areas of medicine, and more often than not is more effective than traditional teaching methods.1,2 Patient simulations are even used in the United States Medical Licensing Examination to assess diagnostic decision-making skills, therapeutic intervention skills, and patient management skills.3 Computer-aided learning in pathology has been used in the forms of virtual slides linked to additional content,4 games in which correctly answering questions results in saving a patient or earning virtual prizes,5 and programs that aid the user in following an algorithmic approach to histologic diagnosis.6 Additionally, in the COVID-19 era, Web-based learning is proving more valuable in replacing standard formats.7 Working through a difficult case in pathology typically involves the use of immunohistochemistry and other special studies, including molecular diagnostics, that either confirm a suspected diagnosis or narrow the differential diagnosis and guide further tests. Ideally, a trainee would be able to see the H&E slide, choose what to order, refine the diagnosis, and perhaps order further studies, which would be closer to clinical practice. Images were obtained from in-house cases as well as online sources, primarily the University of Michigan Virtual Slide Box.8 An interface was written in HTML, PHP (PHP Hypertext Preprocessor), and JavaScript. About 50 cases have been presented in this manner in total, such as carcinoid tumor of the pancreas (with synaptophysin and chromogranin), blastic mantle cell lymphoma (with immunohistochemistry, flow cytometry, and fluorescence in situ hybridization [FISH] results), synovial sarcoma (with immunohistochemistry and cytogenetics results), hemochromatosis (with special stains and molecular genetic results confirming the patient's mutation), and histiocytic sarcoma (with immunostains).

Virtual screening for uveal melanoma: A Princess Margaret cancer centre perspective during the COVID-19 pandemic

Princess Margaret Cancer Centre (PM) receives roughly 120 new patients (pts) per year with uveal melanoma (UM). Moderate to high-risk pts, based on AJCC staging and cytogenetics, undergo a strict surveillance program for metastases with liver MRI every 4-6 months and annual chest imaging. The importance of surveillance has been highlighted by new therapies which are likely more effective in pts with lower volume metastases. In this single center retrospective study, we assessed the effectiveness of a virtual surveillance model, by comparing UM pts on standard in-person surveillance (SS) pre-COVID (August 2018 to March 2020) with virtual surveillance (VS) after COVID onset (April 2020 to November 2021). Virtual visits were done through phone or MS Teams video calls, and images were done either locally or externally. We identified 106 pts who underwent SS and 107 pts who underwent VS. In the SS group, 10 pts were diagnosed with metastasis and of these 9 (90%) were staged as M1a disease and 1 (10%) was M1b. In the VS group, 20 pts were diagnosed with metastases, 2 (10%) of which had M1b disease and 18 (90%) with M1a disease. Fifteen (14%) pts in the SS group and 34 (20%) pts in the VS group lived out of province;13 (12%) of the SS pts and 36 (21%) of pts in the VS cohort had scans externally. With regards to surveillance adherence in the SS group, 70 (66%) of pts had their scans performed on time versus 127 (75%) of pts in the VS cohort. Virtual screening of pts with moderate to high-risk UM during the COVID 19 pandemic showed similar ability to detect low volume disease compared with our standard screening. There was a higher level of adherence to screening during the VS period. When implemented appropriately, VS appears to be an effective model to monitor UM pts.

Special Issue: Covid-19 molecular testing and clinical correlates. (Special Issue: Covid-19 molecular testing and clinical correlates.)

This special issue contains 17 articles that discuss clinical pathology on the latest trends in clinical laboratory management, providing a sound basis for creating and working in a highly effective clinical laboratory, focusing on pathology, including quality control in lab testing, coagulation, clinical microbiology, toxicology testing, clinical cytogenetics, mass spectrometry, and blood transfusion.

ADDITION OF IXAZOMIB TO POMALIDOMIDE AND DEXAMETHASONE IMPROVES PROGRESSION-FREE SURVIVAL FOR MULTIPLE MYELOMA PATIENTS PROGRESSING ON LENALIDOMIDE AS PART OF 1ST LINE THERAPY: ALLIANCE A061202

Background: Lenalidomide (LEN) maintenance and continuous LEN-based induction therapy until disease progression have become standard of care for frontline therapy of multiple myeloma (MM). As such, an increasing number of patients (pts) in need of 2nd line therapy have LEN-refractory disease. Optimal treatment in this setting has not been rigorously assessed in randomized studies. The phase I portion of Alliance A061202 demonstrated the safety of the ixazomib-pomalidomide-dexamethasone (IXA-POM-DEX) combination for the treatment of pts with LEN and proteasome inhibitor (PI)-refractory MM. Aims: In the randomized phase II portion, we evaluated the addition of IXA to POM-DEX for PI naïve / sensitive pts progressing on LEN as part of 1st line therapy. The primary endpoint was progression-free survival (PFS). Key secondary endpoints included overall response rate (ORR), depth of response, survival and safety. Methods: Pts were randomized 1:1 to IXA-POM-DEX or POM-DEX and stratified by prior bortezomib exposure, International Staging System stage (1 and 2 vs 3) and the presence of high-risk cytogenetics. POM was administered at 4 mg on days 1-21;IXA 4 mg on days 1, 8 and 15;and DEX 20 mg (>75 years (yrs)) or 40 mg (≤75 yrs) on days 1, 8, 15 and 22 of a 28-day cycle. Treatment was continued until disease progression, the emergence of unacceptable side effects or withdrawal of treatment consent. Results: 38 and 39 eligible pts were assigned to IXA-POM-DEX and POM-DEX, respectively. The median age was 66 yrs (range 41-83) and 64 yrs (range 52-85). A planned first interim analysis was conducted after 43 out of 57 required events had occurred. PFS favored the IXA-POM-DEX arm (one-sided log rank test value = 4.6345, p=0.03134 [< p-value boundary of 0.058]), yielding a hazard ratio of 0.528 (upper 90% bound = 0.777). A stratified log-rank test found that PFS was superior for the triplet after adjusting for stratification factors (one-sided stratified log rank test value = 5.8371;p=0.0157), adjusted hazard ratio 0.451 (upper 90% bound = 0.694). The ORR favored IXA-POM-DEX (63.2% vs 43.6%, p=0.0853), and the ≥very good partial response was 26.3% vs 5.1%, respectively (p=0.01). The clinical benefit rate (ORR + minimal response rate) was 73.7% and 56.4%. The most common grade 3/4 adverse events included lymphopenia, neutropenia, anemia, and fatigue in 40%, 37%, 16% and 16% of IXAPOM-DEX-treated pts and 26%, 21%, 13%, and 15% of POM-DEX-treated pts. Therapy was discontinued for disease progression in 47.4% of pts on IXA-POM-DEX and 76.9% of pts on POM-DEX and for adverse events in 7.9% and 7.7% of pts, respectively. Summary/Conclusion: The addition of IXA to the POM-DEX backbone improved the depth of response and PFS for pts relapsing on LEN as part of 1st line therapy. Hematologic toxicity was increased with the addition of IXA, but side effects were manageable. The ease of administration of this all-oral combination allowed for safer, uninterrupted treatment during the COVID pandemic. Our results should be confirmed in phase III trials but lend support for this regimen as part of 2nd line therapy for this patient population.

DREAMM-9: PHASE I STUDY OF BELANTAMAB MAFODOTIN PLUS STANDARD OF CARE IN PATIENTS WITH TRANSPLANT-INELIGIBLE NEWLY DIAGNOSED MULTIPLE MYELOMA

Background: The bortezomib, lenalidomide, and dexamethasone (VRd) regimen is a standard of care for newly diagnosed multiple myeloma (NDMM). Belantamab mafodotin (belamaf) is a B-cell maturation antigen-binding antibody-drug conjugate that eliminates myeloma cells by a multimodal mechanism: direct cell kill and anti-myeloma tumor immune response. Belamaf has demonstrated deep and durable responses as a monotherapy in the DREAMM-2 study of patients (pts) with relapsed/refractory multiple myeloma (RRMM). Preclinical evidence of belamaf in combination with bortezomib or lenalidomide suggests enhanced anti-myeloma activity, providing rationale for this treatment combination. Aims: To evaluate the safety and tolerability of this combination in adult pts with transplant-ineligible (TI) NDMM and establish the recommended Phase III dose. Methods: DREAMM-9 (NCT04091126) is an ongoing Phase I, open-label, randomized study of belamaf + VRd. The belamaf dose cohorts currently being evaluated are Cohort 1 (1.9 mg/kg Q3/4W), Cohort 2 (1.4 mg/kg Q6/8W), Cohort 3 (1.9 mg/kg Q6/8W), Cohort 4 (1.0 mg/kg Q3/4W), and Cohort 5 (1.4 mg/kg Q3/4W). Belamaf is given with VRd Q3W until Cycle 8, and with Rd Q4W thereafter. After evaluation of safety data for Cohort 1, Cohorts 2-5 were opened in parallel and enrolled pts were randomized 1:1:1:1. Primary endpoint is safety. Secondary endpoints include efficacy, tolerability, and pharmacokinetics (PK). Results: As of data cutoff (07 Dec 2021), 64 pts were analyzed across all cohorts. Median age (range) was 73.0 (51- 88) years, 55% were male, 80% were white, 8% had extramedullary disease, 59% were International Staging System stage II or III, 20% had amp1q, and 17% had high-risk cytogenetics (≥1 of: t(4;14), t(14;16), del17p). The median duration of follow-up varied: Cohort 1 (17.4 months [mo]), Cohort 2 (5.9 mo), Cohort 3 (6.1 mo), Cohort 4 (4.7 mo), Cohort 5 (5.8 mo). Median number of belamaf cycles were: Cohort 1 (6), Cohort 2 (3), Cohort 3 (3.5), Cohort 4 (4.5), and Cohort 5 (5). Most common adverse events (AEs) across cohorts included thrombocytopenia (49%), constipation (43%), diarrhea (32%), and peripheral sensory neuropathy (30%). AEs related to study treatment were experienced by 61 (97%) pts. Belamaf-related grade 3/4 AEs occurred in 24 (38%) pts. Belamaf dose reductions occurred in 11 (18%) pts, with dose delays in 10 (16%) pts. Three pts experienced a fatal severe AE (unrelated to study treatment);2 due to COVID-19 infection, 1 due to pancreatic adenocarcinoma. Early deep responses were observed;67-92% pts achieved ≥very good partial response (VGPR) (Table), with median time to VGPR of 2.1-2.9 months across cohorts. Of pts with ≥VGPR, 17 were minimal residual disease (MRD) negative, 10 in Cohort 1. As of data cutoff, 8-75% of pts achieved best response of complete response (CR) or stringent CR (sCR). Grade 3 corneal exam findings were reported in 25-58% of pts;grade 3 visual acuity changes were reported in 21-75% of pts. No grade 4 corneal exam findings or visual acuity changes were reported in pts receiving belamaf Q6/8W, compared with 0-17% and 0-8%, respectively, in the Q3/4W cohorts. Belamaf PK profile was similar to that in pts with RRMM, accounting for baseline characteristics. Image: Summary/Conclusion: Belamaf + VRd demonstrated high response rates in pts with TI NDMM, with a high rate of MRD negativity indicating deep responses. No new safety signals were observed relative to DREAMM-2. Study is ongoing to evaluate the safety and efficacy of variable dose intensities of belamaf in combination with VRd.

ARTERIAL THROMBOSIS AND ACUTE MYELOID LEUKEMIA - IS THERE A CONNECTION?

Background: Arterial thrombotic events (ATE) are important cause of noncancer-related deaths among patients with cancer. It is estimated that the prevalence of ATE among those patients is between 2-5%. However, data regarding acute myeloid leukemia (AML) related ATE are scarce and far less available than those related to venous thrombotic events. Aims: To determine the incidence of ATE in nonM3-AML patients and to underline the potential risk factors for ATE development. Methods: The single center, retrospective, cohort study was carried out in University Clinical Center of Serbia. Adult patients, who were diagnosed with nonM3-AML between January 2009. and December 2021. were included. In all patients the occurrence of ATE (e.g. a heart attack, a stroke, critical limb ischemia) was assessed during the active treatment and the three months following the last chemotherapy session. Diagnosis of ATE was established using clinical, laboratory and radiological methods. Patients who experienced venous thromboembolism during the treatment period were excluded. Demographic data, presence of obesity, smoking status, history of thrombosis, baseline laboratory findings (complete blood count, fibrinogen, D-dimer, PT, aPTT, LDH), leukemia-related parameters (cytogenetics (including ELN risk stratification), flow cytometry), Khorana score, ECOG PS, HCT CI score, concurrent COVID-19 were collected from patients' health records. The methods of descriptive (mean ± standard deviation, median (range), frequency (%)) and analytic statistics (Student's t-test, chi-squared test) were used. Results: A total of 545 patients (293 males (53.8%)) were included in the study. Median age of the study population was 58 (range: 18-81) years. ATE was noted in 18/545 (3.3%) subjects with following distribution: ischemic stroke 12/18 (66.7%), myocardial infarction 5/18 (27.8%), and acute lower extremity arterial thrombosis 1/18 (5.5%). ATE was diagnosed most commonly during the induction (8 (44.4%) patients), reinduction (3 (16.7%) patients) and consolidation (4 (22.2%) patients) cycles. However, cases of ATE were noted at diagnosis (1 (5.6%) patient), after transplantation (1 (5.6%) patient) or at relapse (1 (5.6%) patient) as well. ATE were significantly more frequent among patients with previous history of thromboembolic events (p = 0.016). Moreover, ATE were more common in patients with adverse cytogenetic abnormalities (p < 0.001). Other examined parameters did not significantly differ between those with and without ATE. Summary/Conclusion: The incidence of arterial thrombosis in our group was 3.3% which is in accordance with the previously published studies. Since the great number of already known risk factors for the arterial thrombosis are modifiable (e.g. smoking, diet, physical activity, excessive drinking?) it is important to actively work on the reduction on those risk factors, especially if the patient has the history of previous thromboembolic event and/or suffer from high risk AML. Prophylactic therapy with antiplatelet agents is aggravated due to the lack of firmer evidences and the presence of thrombocytopenia. Therefore further studies regarding this issue are needed.

PEDIATRIC-TYPE FOLLICULAR LYMPHOMA - A NEW PARADIGM IN DIAGNOSIS?

Background: Recognized as an entity in the 2016 WHO Classification of Tumors of Hematopoietic and Lymphoid Tissues, Pediatric-Type Follicular Lymphoma (PTFL) is a rare nodular follicular lymphoma that affects primarily children and young adults. The clinical presentation is characterized by the sudden appearance of an isolated lymphadenopathy, with a predilection for the head and neck region, without systemic symptoms. The incidence is higher in men. It has an excellent prognosis with the excision of the affected ganglion. By definition, diagnosis is histological, immunocytochemical and molecular. There are no known risk factors or any described association with immunodeficiency or viral infections. Aims: We report two clinical cases. Methods: Case 1 - a previously healthy 18-year-old boy with an isolated, non-painful, cervical lymphadenopathy of approximately 20 mm, which was incidentally found. Case 2 - a 13-year-old boy without relevant personal history, who, after the second dose of vaccination against COVID-19, developed multiple adenomegalies that spontaneously regressed. However, one month later, a right submandibular adenomegaly appeared. It was analysed by ultrasound and was described as suspicious. In both cases, a fine-needle lymph node biopsy was performed for cytological diagnosis and material was sent for immunophenotyping by flow cytometry and molecular cytogenetics by FISH. Results: Immunophenotyping suggested a large-cell B-lymphoma with a phenotype compatible with Burkitt's Lymphoma (BL). In the cytology of both cases, the population observed was more consistent with diffuse large B cell lymphoma (DLBCL) or possibly high-grade follicular lymphoma (FL). In the FISH study, no rearrangements in the MYC, BCL2, BCL6 or IRF4 genes were detected in the samples of the two cases. The lymphadenopathies were excised with a probable diagnosis of PTFL or DLBCL. Histological examination confirmed the PTFL diagnosis. Summary/Conclusion: We did not find in the literature any reference to clear causal relationship between vaccination against COVID-19 and the onset of lymphoproliferative diseases. The cytological/immunophenotypic/molecular approach of this entity in both cases seems to define a characteristic pattern, which may eventually allow, in a first approach, to suspect this diagnosis. More extensive studies will be needed to establish the role of these methodologies in the diagnosis of this pathology.

RISK AND PATTERN OF INFECTIONS IN NEWLY DIAGNOSED PATIENTS OF MULTIPLE MYELOMA VACCINATED UPFRONT AGAINST PNEUMOCOCCUS & INFLUENZA

Background: Infections contribute to an early mortality risk of 15 percent in newly diagnosed multiple myeloma(NDMM) cases. There is a limited literature on the type of infections in fully vaccinated NDMM patients. Aims: To study epidemiology, clinical profile and predictors of infection in NDMM who are immunised against pneumococci and influenza. Methods: NDMM patients were prospectively studied for 6 months for the pattern of infections . All patients were vaccinated with pneumococcal and Influenza vaccine at diagnosis. PJP prophylaxis and fluconazole prophylaxis was given for patients receiving high dose steroids while acyclovir was given to all. Infections were classified as microbiologically defined, clinically defined and fever of unknown focus according to definitions published by the International Immunocompromised Host Society. Severity of infections were graded according to the NCI CTCAE Ver5. Results: Forty-eight NDMM patients with a median age 55 years comprising of 26 males and 22 females were enrolled. Renal involvement was noted in 42% of enrolled patients and two third of them required renal replacement therapy. ISSIII and R-ISS III were 70.8 % and 62.5 % respectively. 85% had poor performance status(ECOG ≥2) at baseline. RVD was the most common regimen (37%)used. 6 patients received daratumumab based regimen. Treatment response of atleast VGPR was seen in 97 % of NDMM patients. A total of 19 episodes of infections were observed during 6 months. All episodes of infections were reported in the first 45 of myeloma diagnosis(Median 6 days;Range 0-45). Ten of these episodes of infection were diagnosed during the initial evaluation for myeloma defining events. Microbiological diagnosis was possible in 63 %. Commonest infectious agent was COVID 19(n=8) followed by Gram negative bacteria (n=5) viz E.coli and Klebsiella pneumoniae . None of the eight patients who developed COVID 19 infection had received COVID vaccine as they antedated the operationalisation of national guidelines for immunisation. Respiratory and the urinary tract were the most common focus of infection. All critically ill COVID patients succumbed to progressive respiratory failure and all patients with mild and moderate COVID illness recovered uneventfully. Early mortality in our cohort of forty eight patients was twenty percent(n=10). Three fourths of infections in our cohort were Grade≥3 severity. A total of seven deaths were attributable to infectious diseases in this cohort of NDMM patients. Imune paresis was seen in eighty four percent of patients at diagnosis. On follow up at 6 months;immune paresis had persisted in only thirty seven percent. Regression analysis of variables with odds of infection is shown in Table 1 Baseline BMI<18.5 kg/m2;albumin<3g/dl and ISS or R-ISS stage ≥ 2 was found to be have statistically significant odds of predicting infection risk in the cohort of patients. The choice of myeloma regimen, presence of high risk cytogenetics and response to therapy did not correlate with increased odds of infection in our cohort. Summary/Conclusion: Conclusion In this prospective study of NDMM patients vaccinated against pneumococci and influenza at baseline;infection attributable early mortality was 14.5 %. Advanced stage of presentation, hypoalbuminemia and baseline BMI < 18.5 kg/m2 correlated with increased odds of infection. COVID vaccination and COVID appropriate behavioural practices may mitigate COVID related outcomes including deaths in myeloma patients.

Efficacy of Oral Decitabine/Cedazuridine (ASTX727) in the CMML Subgroup from the Ascertain Phase 3 Study

text: Background/Introduction: Chronic Myelomonocytic Leukemia (CMML) is an uncommon MDS/MPN overlap syndrome that has historically been included under the umbrella of myelodysplastic syndromes (MDS) for clinical trial and treatment. As a result, DNA methyltransferase inhibitors (DNMTi) such as decitabine or azacitidine have been the established standard of care for the treatment of CMML. The oral bioavailability of these agents has been limited due to rapid degradation by cytidine deaminase (CDA) in the gut and liver so treatment has required intravenous infusion or subcutaneous injections daily for 5-7 days every month (m) adding significant burden to older cancer patients due to daily time commitment and travel to treatment centers. In the context of pandemic SARS-CoV-2, parenteral therapy also increases contact with medical settings with increased infection risk. Oral decitabine 35 mg/cedazuridine 100 mg (ASTX727) is an oral fixed dose combination of decitabine and the CDA inhibitor cedazuridine that produced equivalent exposure (99%;90% CI 93% to 106%) to IV decitabine 20 mg/m 2 in a randomized cross-over study (Garcia-Manero et al, ASH 2019), and Median overall survival (mOS) for the entire study population in the ASCERTAIN study was approximately 32 months (Savona, 2021). Here, we present outcome data for this study for the enrolled subpopulation of patients with CMML. Methods: We used a randomized cross over design in which patients were randomized in the first 2 cycles 1:1 to either Sequence A: (decitabine 35 mg/ cedazuridine 100 mg in Cycle 1 followed by IV decitabine at 20 mg/m 2 in Cycle 2), or Sequence B: (IV decitabine in Cycle 1 followed by oral decitabine/cedazuridine in Cycle 2). We conducted an intra-patient comparison of decitabine PK (primary PK endpoint: decitabine AUC equivalence over 5 days of dosing). Cycles were repeated every 28 days (unless delays were needed). All patients received oral decitabine/cedazuridine in Cycles 3 and above until disease progression or unacceptable toxicity. Patients were eligible per the FDA-approved label of IV decitabine (MDS patients by FAB classification including CMML, or MDS IPSS Intermediate-1, 2 or high-risk patients). Clinical endpoints were best response according to International Working Group (IWG) 2006 response criteria, transfusion independence for at least 8 or 16 consecutive weeks, overall survival, and safety. Adverse events (AEs) were graded by Common Terminology Criteria for Adverse Events (CTCAE) v 4.03. Results: Of the 133 patients enrolled and treated in ASCERTAIN, 16 (12%) had a diagnosis of CMML with demographics and as follows: median age 71.5 years, 69% Male/31% Female, median weight 87kg (range 65-124), 25% ECOG 0, 75% ECOG 1. Population disease characteristics were: 19% poor or intermediate risk cytogenetics, with median baseline hemoglobin 90 g/L, neutrophils 1.27 X 10 9/L, platelets 84 x 10 9/L, bone marrow blasts 5%, with 38% RBC transfusion dependent. Patients received a median of 7 cycles of therapy (range 3-24). Treatment-emergent adverse events of CTCAE Grade 3 or higher in > 10% of patients, independent of relationship to ASTX727, were cytopenias (neutropenia [69%], thrombocytopenia [63%], anemia [56%], leukopenia [19%]), febrile neutropenia (31%), fatigue (13%). Two patients (12.5%) had Complete Responses (CR), 8 (50%) had marrow CR ([mCR], including 3 (19%) with hematologic improvement (HI);Overall Response rate (ORR) [CR + PR+ mCR + HI] was 75%. Of six patients with baseline RBC transfusion dependence 3 (50%) became transfusion independent. Leukemia-free survival was 28.2 months and after a median follow up of more than 33 months, median overall survival had not been reached. Two patients (13%) went on to Hematopoietic Stem Cell Transplant (HCT). Conclusions: In the overall study, oral decitabine/cedazuridine delivered equivalent PK exposure to 5 days of IV decitabine 20mg/m 2 with a resultant clinical activity safety and efficacy profile in CMML patients consistent with the published literature (e.g Zeidan, et a 2017) and the Phase 2 experience. The use of oral decitabine/cedazuridine is a reasonable approach in CMML patients. References: Garcia-Manero, et al ASH 2019 Savona, et al, Int. MDS Symposium, 2021 Zeidan, et al, Cancer 2017: 3754-3762. [Formula presented] Disclosures: Savona: Geron: Consultancy, Membership on an entity's Board of Directors or advisory committees;CTI: Consultancy, Membership on an entity's Board of Directors or advisory committees;Karyopharm: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees;BMS-Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees;NOVARTIS: Consultancy, Membership on an entity's Board of Directors or advisory committees;Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees;Sierra Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees;Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees;TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding;Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding;ALX Oncology: Research Funding;Astex: Research Funding;Incyte: Research Funding. McCloskey: Pfizer: Consultancy;Takeda: Consultancy, Speakers Bureau;Incyte: Speakers Bureau;Novartis: Consultancy;COTA: Other: Equity Ownership;BMS: Honoraria, Speakers Bureau;Amgen: Speakers Bureau;Jazz: Consultancy, Speakers Bureau. Griffiths: Boston Biomedical: Consultancy;Celgene/Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding;Abbvie: Consultancy, Honoraria;Taiho Oncology: Consultancy, Honoraria;Genentech: Research Funding;Astex Pharmaceuticals: Honoraria, Research Funding;Takeda Oncology: Consultancy, Honoraria;Novartis: Honoraria;Apellis Pharmaceuticals: Research Funding;Alexion Pharmaceuticals: Consultancy, Research Funding. Yee: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Forma Therapeutics: Research Funding;Geron: Research Funding;Shattuck Labs: Membership on an entity's Board of Directors or advisory committees;Bristol-Myers Squibb/Celgene: Membership on an entity's Board of Directors or advisory committees;F. Hoffmann La Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding;AbbVie: Honoraria;Janssen: Research Funding;Onconova: Research Funding;Genentech: Research Funding;Otsuka: Membership on an entity's Board of Directors or advisory committees;MedImmune: Research Funding;Jazz: Research Funding;Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding;Tolero: Research Funding;Takeda: Membership on an entity's Board of Directors or advisory committees;TaiHo: Membership on an entity's Board of Directors or advisory committees;Pfizer: Membership on an entity's Board of Directors or advisory committees;Paladin: Membership on an entity's Board of Directors or advisory committees. Zeidan: BeyondSpring: Consultancy;Janssen: Consultancy;Boehringer Ingelheim: Consultancy, Research Funding;BioCryst: Other: Clinical Trial Committees;AstraZeneca: Consultancy;Pfizer: Other: Travel support, Research Funding;Kura: Consultancy, Other: Clinical Trial Committees;Incyte: Consultancy, Research Funding;Ionis: Consultancy;Daiichi Sankyo: Consultancy;Epizyme: Consultancy;Novartis: Consultancy, Other: Clinical Trial Committees, Travel support, Research Funding;Loxo Oncology: Consultancy, Other: Clinical Trial Committees;Genentech: Consultancy;Geron: Other: Clinical Trial Committees;Cardiff Oncology: Consultancy, Other: Travel support, Research Funding;BMS: Consultancy, Other: Clinical Trial Committees, Research Funding;Gilead: Consultancy, Other: Clinical Trial Committees;Aprea: Consultancy, Research Funding;Astellas: Consultancy;Astex: Research Funding;Jazz: Consultancy;Jasper: Consu tancy;Amgen: Consultancy, Research Funding;Agios: Consultancy;ADC Therapeutics: Research Funding;Acceleron: Consultancy, Research Funding;AbbVie: Consultancy, Other: Clinical Trial Committees, Research Funding. Al-Kali: Novartis: Research Funding;Astex: Other: Research support to institution. Patel: Agios: Membership on an entity's Board of Directors or advisory committees;Celgene-BMS: Membership on an entity's Board of Directors or advisory committees;PVI: Honoraria. Sabloff: Takeda: Membership on an entity's Board of Directors or advisory committees;BMS: Membership on an entity's Board of Directors or advisory committees;Astellas: Membership on an entity's Board of Directors or advisory committees;Novartis: Membership on an entity's Board of Directors or advisory committees;TaiHo: Membership on an entity's Board of Directors or advisory committees;Jaxx: Membership on an entity's Board of Directors or advisory committees;Abbvie: Membership on an entity's Board of Directors or advisory committees;Pfizer: Membership on an entity's Board of Directors or advisory committees;ROCHE: Membership on an entity's Board of Directors or advisory committees;Celgene: Membership on an entity's Board of Directors or advisory committees. Dao: Astex Pharmaceuticals, Inc.: Current Employment. Fazal: Janssen Oncology: Consultancy, Honoraria, Speakers Bureau;Taiho Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau;Gilead Sciences: Consultancy, Honoraria, Speakers Bureau;Novartis: Consultancy, Honoraria, Speakers Bureau;Agios: Consultancy, Honoraria, Speakers Bureau;Sanofi Genzyme: Consultancy, Honoraria, Speakers Bureau;Takeda: Consultancy, Honoraria, Speakers Bureau;Glaxo Smith Kline: Consultancy, Honoraria, Speakers Bureau;AMGEN: Consultancy, Honoraria, Speakers Bureau;Incyte: Consultancy, Honoraria, Speakers Bureau;Jazz Pharmaceuticals:Consultancy, Honoraria, Speakers Bureau;Bristol Myers Squibb: Consultancy, Honoraria, Speakers Bureau;Stemline Therapeutics: Consultancy, Honoraria, Speakers Bureau;Karyopharm Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau. Odenike: Celgene, Incyte, AstraZeneca, Astex, NS Pharma, AbbVie, Gilead, Janssen, Oncotherapy, Agios, CTI/Baxalta, Aprea: Research Funding;AbbVie, Celgene, Impact Biomedicines, Novartis, Taiho Oncology, Takeda: Consultancy. Kantarjian: Ipsen Pharmaceuticals: Honoraria;Astra Zeneca: Honoraria;Astellas Health: Honoraria;Aptitude Health: Honoraria;Pfizer: Honoraria, Research Funding;Novartis: Honoraria, Research Funding;Jazz: Research Funding;Immunogen: Research Funding;Daiichi-Sankyo: Research Funding;BMS: Research Funding;Ascentage: Research Funding;Amgen: Honoraria, Research Funding;AbbVie: Honoraria, Research Funding;KAHR Medical Ltd: Honoraria;NOVA Research: Honoraria;Precision Biosciences: Honoraria;Taiho Pharmaceutical Canada: Honoraria. DeZern: Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees;Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees;Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees;Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees. Roboz: Janssen: Research Funding;AbbVie: Consultancy;Actinium: Consultancy;Agios: Consultancy;Amgen: Consultancy;Astex: Consultancy;Astellas: Consultancy;AstraZeneca: Consultancy;Bayer: Consultancy;Blueprint Medicines: Consultancy;Bristol Myers Squibb: Consultancy;Celgene: Consultancy;Daiichi Sankyo: Consultancy;Glaxo SmithKline: Consultancy;Helsinn: Consultancy;Janssen: Consultancy;Jasper Therapeutics: Consultancy;Jazz: Consultancy;MEI Pharma - IDMC Chair: Consultancy;Mesoblast: Consultancy;Novartis: Consultancy;Otsuka: Consultancy;Pfizer: Consultancy;Roche/Genentech: Consultancy. Busque: Novartis: Consultancy. Leber: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Pfizer: Membership on an entity's Board of Directors or advisory committees, peakers Bureau;BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;AMGEN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;TaiHo: Honoraria, Membership on an entity's Board of Directors or advisory committees;Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Otsuka: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hao: Astex Pharmaceuticals, Inc.: Current Employment. Keer: Astex Pharmaceuticals, Inc.: Current Employment. Azab: Astex Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees.

Successful Treatment of Acute Myeloid Leukemia with CPX-351 in 2 Patients in the United Kingdom during the COVID-19 Pandemic

Introduction: The COVID-19 pandemic hit the United Kingdom in early 2020. High infection rates prompted concern for immunocompromised patients, including patients with AML receiving intensive chemotherapy. CPX-351 (Europe: Vyxeos ® Liposomal;US: Vyxeos ®), a dual-drug liposomal encapsulation of daunorubicin and cytarabine in a synergistic 1:5 molar ratio, is approved for the treatment of newly diagnosed therapy-related AML (t-AML) or AML with myelodysplasia-related changes (AML-MRC) in adults in Europe and in adults and pediatric patients aged ≥1 year in the United States. Despite concerns about intensive chemotherapy-related myelosuppression, the National Cancer Research Institute AML Working Group recommends that CPX-351 should continue to be administered in patients with adverse-risk cytogenetics and/or secondary AML during the pandemic. We report 2 patients with AML who were successfully treated with CPX-351 in the United Kingdom during the COVID-19 pandemic. Methods: The patients were diagnosed and managed per institutional guidelines. Two patients received CPX-351 induction (daunorubicin 44 mg/m 2 + cytarabine 100 mg/m 2) on Days 1, 3, and 5 (Days 1 and 3 for second induction) and CPX-351 consolidation (daunorubicin 29 mg/m 2 + cytarabine 65 mg/m 2) on Days 1 and 3, all by 90-minute IV infusion, during the pandemic. Results: The first patient was a 67-year-old male who presented with generalized fatigue in June 2020 with comorbidities of type 2 diabetes, diabetic nephropathy, and leg ulcers. Blood counts demonstrated a hemoglobin count of 79 g/L, white blood cell count of 0.7×10 9, platelet count of 58×10 9/L, and neutrophil count of 0.2×10 9/L. A bone marrow biopsy revealed AML-MRC with 40% blasts, and the patient had wild-type FLT3, NPM1, and SRSF2. The patient achieved morphologic and cytogenetic remission after 2 CPX-351 induction cycles. The patient then received 1 CPX-351 consolidation cycle but was not a candidate for transplant due to diabetic nephropathy. Tolerability improved with each cycle;the patient experienced neutropenic sepsis during the first induction, a flare up of leg ulcers and cellulitis during the second induction, and no tolerability concerns during the consolidation cycle. After the first induction, recovery of neutrophils and platelets occurred around Day 35 and Day 28, respectively (Figure 1), and counts recovered more quickly with each cycle. This patient was managed without contracting COVID-19 or experiencing any pandemic-related complications. The second patient was a 69-year-old female who presented with pancytopenia in February 2020 with no significant past medical or drug history. Her hemoglobin count was 66 g/L, white blood cell count was 0.6×10 9/L, platelet count was 17×10 9/L, and neutrophil count was 0.3×10 9/L. The patient was diagnosed with AML-MRC with mutated NPM1, SRSF2, IDH2, and JA2. During the first CPX-351 induction cycle, the patient contracted COVID-19. Some symptoms were present, but the patient did not become significantly unwell from COVID-19. Despite count recovery, the patient remained positive by nasal/oral PCR swab test for several weeks, delaying the delivery of the second CPX-351 induction cycle. After the second CPX-351 cycle began, the patient once again became positive for COVID-19 by PCR swab. The patient remained positive for longer than the first infection but was largely asymptomatic during the cycle (apart from a bout of sepsis). After a period of approximately 3 months from the previous CPX-351 cycle, the patient received a CPX-351 consolidation cycle and achieved complete remission with no measurable residual disease by NPM1 mutation in the bone marrow (Figure 2). The patient was eligible for transplant but declined. Conclusions: Two patients with AML-MRC were successfully treated with CPX-351 during the COVID-19 pandemic, despite one of the patients contracting and variably testing positive for the disease. During the pandemic, it is important to weigh the benefits of treating AML with curative intent versus the risks of immuno uppression and potential COVID-19 infection. Individualized decisions must be made for each patient based on disease, treatment, and COVID-19 risk factors through discussion with a multidisciplinary team. Although treating patients with AML with CPX-351 during the pandemic can be challenging, it remains an option for appropriate patients with newly diagnosed t-AML or AML-MRC. [Formula presented] Disclosures: Munisamy: Roche: Speakers Bureau;Jazz Pharmaceuticals: Speakers Bureau. Choudhuri: AstraZeneca, Bristol-Myers Squibb, Jazz Pharmaceuticals, and Pfizer: Consultancy.

THE EVOLVING WORLD OF LABORATORY MEDICINE

Christine Bruce Senior Director, Laboratory Medicine University Health Network, Ontario Automation Where No Automation Has Gone Before As an industry, we've worked through a tremendous amount of change over the past couple of decades. Dr. Michael Mengel Medical Director (North), Alberta Precision Laboratories Chair, Department of Laboratory Medicine and Pathology, University of Alberta Analyzing Big Data with A.I. One development that will transform our field over the next years is the digitization of health information and big data, and the resulting need for artificial intelligence-driven support tools for analysis. In Alberta, with the introduction of one uniform health record,4 large amounts of standardized or harmonized data will become accessible - to study them, to discover inter-relationships of processes and disease, for risk stratification of patients, and for informing health providers in decision-making in essentially all areas. Josh MacDonald Client & Support Services Program Manager Pathology and Laboratory Medicine Nova Scotia Health Authority Tinier, Higher-Tech Blood Tests I think phlebotomy is not only overdue for a widespread and drastic change, but is probably close to having that change.

What is beyond NPM1 and FLT3 ITD Mutationsas Prognostic Indicators in AML- Experiencefrom a Tertiary Care Centre

Introduction: Acute Myeloid Leukaemia (AML) is one of the mostcommon haematological malignancies in adults. Molecular mutationsin AML are major determinants of the patient's response to therapyand outcomes. Nucleophosmin 1 (NPM1) confers a good prognosiswhile fms-like tyrosine kinase-3 gene (FLT3-ITD) is associated witha poor prognosis.Aims &Objectives: To study the prognostic molecular markers andcytogenetics of all newly diagnosed and de novo AML cases andassess the impact of the same on treatment outcome.Materials &Methods: 23 patients with newly diagnosed (adult andpaediatric) de novo AML from Jan 2021 to Aug 2021 at GauhatiMedical College, Guwahati were included in this study. We analysedthe bone marrow aspirates, clinical significance of NPM1, CEBPA,FLT3 (by real time PCR) with disease progression. Cytogenetics bykaryotyping and immunophenotypic parameters were also documented and corelated with disease progression.Result: There were (12/23)52.2% males and (11/23)47.8% female. 2patients (8.7%) were positive for FLT3 and 4(17.4%) were positivefor NPM1. (7/23)30.4% patients had t(8,21) of which 3 had normalkaryotype while 2 patients (8.7%) had turner's genotype(45,X). 4patients (17.4%) expired while receiving Induction chemotherapy, ofwhich one had 45,X,t(8,21)genotype, one had NPM1 mutation andone expired during 3 rd cycle of consolidation due to covid 19pneumonia. 6(26.1%) patients had treatment failure following intensive induction therapy of which 2 had t(8,21) with normalkaryotype(40%) and one had NPM1 mutation with wildtype FLT3.All patients with NPM1 mutation were negative for CD34 andHLADR. All patients with NPM1 and FLT3 uniformly expressed CD33.Conclusions: 3/6 patients had failure of induction in spite of havingstandard risk cytogenetics. So, next generation sequencing (NGS) iswarranted upfront for all diagnosed AML cases. It should now beincorporated as a standard of care in the management of AML. Onepatient with turner's genotype and t(8,21) expired during inductiontherapy, hence, prognostic significance of 45,X needs to be furthervalidated in AML.

Oral Decitabine/Cedazuridine in Patients with Lower Risk Myelodysplastic Syndrome: A Longer-Term Follow-up of from the Ascertain Study

[Formula presented] Background/Introduction: Lower-risk (IPSS low risk and Int-1) myelodysplastic syndromes (MDS) are typically treated supportively to address cytopenias. DNA methyltransferase inhibitors (DNMTi) such as azacitidine and decitabine (DEC) are FDA-approved for higher risk MDS patients (pts), and while the DEC USPI includes IPSS Int-1 pts, it is not widely used in this population. Approved intravenous (IV) or subcutaneous (SC) regimens require 5-7 days of treatment every month burdening older cancer pts due to daily travel and treatment time and may increase potential risk from pandemic SARS-CoV-2 infection. Because DNMTis are rapidly degraded by cytidine deaminase (CDA) in the gut and liver, oral availability has only been recently possible. A randomized study with CC-486, an oral formulation of azacitidine, in the Int-1 population showed a median overall survival (mOS) of approximately 17 months for both placebo and treated patients (Garcia-Manero, 2021). Oral DEC 35 mg/cedazuridine 100 mg (ASTX727) or DEC-C, is an oral fixed dose combination (FDC) of DEC and the CDA inhibitor cedazuridine (CED) resulting in equivalent exposure (99%;90% CI 93% to 106%) to standard IV DEC 20 mg/m 2 for 5 days in an intra-patient randomized cross-over study (Garcia-Manero et al, ASH 2019). Here, we present data on patients with lower risk MDS from that study. Methods: We used a randomized cross over design with pts randomized 1:1 in the first 2 cycles to either Sequence A: (DEC 35 mg/ CED 100 mg in Cycle 1 and IV DEC at 20 mg/m 2 in Cycle 2), or Sequence B (IV DEC in Cycle 1 and oral DEC/CED in Cycle 2). Cycles were repeated every 28 days unless delays were needed, and all patients received oral DEC-C in Cycles 3+ until disease progression or unacceptable toxicity. We conducted an intra-patient comparison of DEC PK (DEC AUC equivalence over 5 days of dosing). Pts were eligible as per the FDA-approved label of IV DEC (MDS pts by FAB classification including CMML, or MDS IPSS Intermediate-1, 2 or high-risk pts). Clinical endpoints were best response as assessed by an independent expert panel according to IWG 2006 response criteria, transfusion independence (TI), overall survival (OS), and safety. Results: Of the 133 pts treated in ASCERTAIN, 69 had a diagnosis of lower-risk MDS (93% Int-1, 7% LR). Median age was 70.0 years (range 45-87), 65% were male, median weight was 84 kg (range 50-127), median baseline hematologic parameters were: hemoglobin 89 g/L (range 69.8-146.5), WBCs 1.50 X 10 9/L (range 0.11-7.1), platelets (plt) 86 x 10 9/L (range 5-703), bone marrow blasts 4% (range 0-18), cytogenetics: 7 (10.1%) poor-risk, 21 (30.4%) intermediate risk, 37 (53.6%) better-risk, 4 (5.7%) missing or not evaluable. 27(39%) of the pts were RBC transfusion dependent (TD) and 6 (9%) plt TD. 17 (25%) had received prior MDS treatment, 3% prior DNMTi. Pts received a median of 9 cycles of therapy (range 1-28). Treatment-emergent adverse events of CTCAE Gr 3 or higher in >10% of pts, independent of relationship to ASTX727, included cytopenias (neutropenia [59%], thrombocytopenia [58%], anemia [48%], leukopenia [26%]), febrile neutropenia (32%), and pneumonia (19%). Sixteen pts (23%) achieved Complete Response (CR), 18 (26%) had marrow CR (mCR), including 9 (13%) with hematologic improvement (HI). Overall Response rate (ORR;CR + PR+ mCR + HI) was 57%. Of those RBC or plt TD at baseline, 13 (48%) became RBC TI and 4 (67%) became plt TI. With approximately 32 months of median follow up, neither median leukemia-free survival (mLFS) nor mOS had been reached (Figure 1). Twelve pts (17%) went on to allogeneic stem cell transplant. Conclusions: Oral decitabine/cedazuridine given as a FDC in MDS pts produced equivalent PK exposure to 20 mg/m 2 IV DEC;in lower risk MDS pts with treatment indicated, the agent was generally well-tolerated with prolonged treatment and could result in mLFS and mOS which exceeds 32 months. This FDC and other dosing regimens of oral DEC-C should be further studied in this patient population. References: Garcia-Mane o, et al, ASH 2019 Savona, et al, Int. MDS Symp. 2021 Garcia-Manero, et al, Phase III, Randomized, Placebo-Controlled Trial of CC-486 (Oral Azacitidine) in Patients with Lower-Risk Myelodysplastic Syndromes. J.Clin.Onc. 2021 39:13, 1426-1436 [Formula presented] Disclosures: McCloskey: Pfizer: Consultancy;Jazz: Consultancy, Speakers Bureau;COTA: Other: Equity Ownership;Incyte: Speakers Bureau;Takeda: Consultancy, Speakers Bureau;Novartis: Consultancy;BMS: Honoraria, Speakers Bureau;Amgen: Speakers Bureau. Griffiths: Alexion Pharmaceuticals: Consultancy, Research Funding;Abbvie: Consultancy, Honoraria;Taiho Oncology: Consultancy, Honoraria;Genentech: Research Funding;Novartis: Honoraria;Takeda Oncology: Consultancy, Honoraria;Astex Pharmaceuticals: Honoraria, Research Funding;Celgene/Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding;Apellis Pharmaceuticals: Research Funding;Boston Biomedical: Consultancy. Yee: Paladin: Membership on an entity's Board of Directors or advisory committees;TaiHo: Membership on an entity's Board of Directors or advisory committees;Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Genentech: Research Funding;Geron: Research Funding;Janssen: Research Funding;Jazz: Research Funding;MedImmune: Research Funding;Onconova: Research Funding;Tolero: Research Funding;AbbVie: Honoraria;Bristol-Myers Squibb/Celgene: Membership on an entity's Board of Directors or advisory committees;Otsuka: Membership on an entity's Board of Directors or advisory committees;Shattuck Labs: Membership on an entity's Board of Directors or advisory committees;Pfizer: Membership on an entity's Board of Directors or advisory committees;Takeda: Membership on an entity's Board of Directors or advisory committees;F. Hoffmann La Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding;Forma Therapeutics: Research Funding;Astex: Membership on an entity's Board of Directors or advisory committees, Research Funding. Zeidan: Novartis: Consultancy, Other: Clinical Trial Committees, Travel support, Research Funding;Genentech: Consultancy;Ionis: Consultancy;Astellas: Consultancy;Epizyme: Consultancy;AbbVie: Consultancy, Other: Clinical Trial Committees, Research Funding;Jasper: Consultancy;Cardiff Oncology: Consultancy, Other: Travel support, Research Funding;BeyondSpring: Consultancy;Loxo Oncology: Consultancy, Other: Clinical Trial Committees;Janssen: Consultancy;Acceleron: Consultancy, Research Funding;AstraZeneca: Consultancy;Kura: Consultancy, Other: Clinical Trial Committees;Gilead: Consultancy, Other: Clinical Trial Committees;Agios: Consultancy;Daiichi Sankyo: Consultancy;Boehringer Ingelheim: Consultancy, Research Funding;Geron: Other: Clinical Trial Committees;BMS: Consultancy, Other: Clinical Trial Committees, Research Funding;BioCryst: Other: Clinical Trial Committees;Pfizer: Other: Travel support, Research Funding;Aprea: Consultancy, Research Funding;ADC Therapeutics: Research Funding;Jazz: Consultancy;Incyte: Consultancy, Research Funding;Amgen: Consultancy, Research Funding;Astex: Research Funding. Al-Kali: Astex: Other: Research support to institution;Novartis: Research Funding. Patel: Celgene-BMS: Membership on an entity's Board of Directors or advisory committees;PVI: Honoraria;Agios: Membership on an entity's Board of Directors or advisory committees. Sabloff: Pfizer: Membership on an entity's Board of Directors or advisory committees;Novartis: Membership on an entity's Board of Directors or advisory committees;Astellas: Membership on an entity's Board of Directors or advisory committees;Takeda: Membership on an entity's Board of Directors or advisory committees;ROCHE: Membership on an entity's Board of Directors or advisory committees;TaiHo: Membership on an entity's Board of Directors or advisory committees;Jaxx: Membership on an entity's Board of Directors or advisory committees;Celgene: Membership on an entity's Board of Directors or advisory ommittees;BMS: Membership on an entity's Board of Directors or advisory committees;Abbvie: Membership on an entity's Board of Directors or advisory committees. Dao: Astex Pharmaceuticals, Inc.: Current Employment. Fazal: Taiho Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau;Stemline Therapeutics: Consultancy, Honoraria, Speakers Bureau;Sanofi Genzyme: Consultancy, Honoraria, Speakers Bureau;Novartis: Consultancy, Honoraria, Speakers Bureau;Karyopharm Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau;Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau;Janssen Oncology: Consultancy, Honoraria, Speakers Bureau;Incyte: Consultancy, Honoraria, Speakers Bureau;Glaxo Smith Kline: Consultancy, Honoraria, Speakers Bureau;Gilead Sciences: Consultancy, Honoraria, Speakers Bureau;Bristol Myers Squibb: Consultancy, Honoraria, Speakers Bureau;AMGEN: Consultancy, Honoraria, Speakers Bureau;Agios: Consultancy, Honoraria, Speakers Bureau;Takeda: Consultancy, Honoraria, Speakers Bureau. Odenike: AbbVie, Celgene, Impact Biomedicines, Novartis, Taiho Oncology, Takeda: Consultancy;Celgene, Incyte, AstraZeneca, Astex, NS Pharma, AbbVie, Gilead, Janssen, Oncotherapy, Agios, CTI/Baxalta, Aprea: Research Funding. Kantarjian: AbbVie: Honoraria, Research Funding;Novartis: Honoraria, Research Funding;Ascentage: Research Funding;Pfizer: Honoraria, Research Funding;BMS: Research Funding;Daiichi-Sankyo: Research Funding;Amgen: Honoraria, Research Funding;Ipsen Pharmaceuticals: Honoraria;Jazz: Research Funding;Astellas Health: Honoraria;Immunogen: Research Funding;Astra Zeneca: Honoraria;Aptitude Health: Honoraria;KAHR Medical Ltd: Honoraria;NOVA Research: Honoraria;Precision Biosciences: Honoraria;Taiho Pharmaceutical Canada: Honoraria. DeZern: Takeda: Consultancy, Membership on an entity's Board of Directors or advisorycommittees;Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees;Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees;Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees. Roboz: Novartis: Consultancy;Mesoblast: Consultancy;Jasper Therapeutics: Consultancy;Jazz: Consultancy;MEI Pharma - IDMC Chair: Consultancy;Daiichi Sankyo: Consultancy;Otsuka: Consultancy;Bristol Myers Squibb: Consultancy;Blueprint Medicines: Consultancy;Bayer: Consultancy;AstraZeneca: Consultancy;Astellas: Consultancy;Astex: Consultancy;Amgen: Consultancy;Agios: Consultancy;Actinium: Consultancy;AbbVie: Consultancy;Janssen: Research Funding;Celgene: Consultancy;Glaxo SmithKline: Consultancy;Helsinn: Consultancy;Janssen: Consultancy;Pfizer: Consultancy;Roche/Genentech: Consultancy. Busque: Novartis: Consultancy. Leber: Astellas: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Otsuka: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;TaiHo: Honoraria, Membership on an entity's Board of Directors or advisory committees;AMGEN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hao: Astex Pharmaceuticals, Inc.: Current Employment. Keer: Astex Pharmaceuticals, Inc.: Current Employment. Azab: Astex Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees. Savona: Geron: Consultancy, Membership on an entity's Board of Directors or advisory committees;Karyopharm: Cons ltancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees;CTI: Consultancy, Membership on an entity's Board of Directors or advisory committees;BMS-Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees;NOVARTIS: Consultancy, Membership on an entity's Board of Directors or advisory committees;Ryvu: Consultancy, Membership on an entity's Board of Directors or advisory committees;Sierra Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees;Taiho: Consultancy, Membership on an entity's Board of Directors or advisory committees;TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding;Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding;ALX Oncology: Research Funding;Astex: Research Funding;Incyte: Research Funding.

Randomized, Phase III Study of Early Intervention with Venetoclax and Obinutuzumab Versus Delayed Therapy with Venetoclax and Obinutuzumab in Newly Diagnosed Asymptomatic High-Risk Patients with Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL): Evolve CLL/SLL Study (SWOG S1925;NCT#04269902)

Background: Currently, asymptomatic patients with CLL/SLL are observed without treatment until development of symptoms or cytopenias. Historically, early intervention studies in patients with CLL/SLL with non-specific chemoimmunotherapy agents have not resulted in an overall survival (OS) benefit and have resulted in toxicity. The introduction of targeted therapies, such as venetoclax (an oral BCL2 inhibitor;V) and obinutuzumab (an intravenous anti-CD20 monoclonal antibody;O), have provided tolerable/efficacious options for patients with CLL. In the CLL14 study, symptomatic patients with CLL receiving frontline therapy with VO had longer progression-free survival (PFS) and deeper remissions [more undetectable minimal residual disease (uMRD)] compared with those receiving chlorambucil and O (Fischer 2019). The CLL-International Prognostic Index (CLL-IPI;Table 1) is a validated prognostic model to predict which patients are at highest risk of a shorter time to first therapy and shorter OS. A score of ≥4 is considered high-risk on this scale. We aim to use VO as early intervention in asymptomatic, high-risk CLL patients, assessed by CLL-IPI, to potentially improve OS and thus alter the natural history of the disease. Methods: On 12/14/20, we activated the S1925 study (NCT#04269902 ) for adult patients with CLL or SLL, who were diagnosed within 12 months of enrollment. Eligible patients have a CLL-IPI score ≥4 (Table 1) or complex cytogenetics (≥3 cytogenetic abnormalities) and do not meet any criteria for initiation of treatment by the International Working Group for CLL (IWCLL;Hallek 2018) guidelines. Enrolled patients are randomized in a 2:1 manner to early versus delayed (at the time IWCLL indication for treatment is met) therapy with VO (Figure 1). VO is administered as previously described (Fischer 2019). The primary endpoint is OS. We hypothesize that early intervention with VO will improve the rate of 6-year OS from 60% to 80%. This design requires 222 eligible patients for 88% power (2-sided a=0.05) for the primary comparison. To allow for 10% ineligibility, we will enroll 247 patients. Estimated accrual time is 4 years. Secondary endpoints include: rates of response, PFS, and relapse-free survival;safety;time to second CLL-directed therapy;and quality of life (assessed by FACT-Leukemia). As COVID19 is an infection with particularly high morbidity and mortality in patients with CLL, incidence of this infection and complications including death will be recorded and compared between patients followed on the early versus delayed intervention arms. The primary translational objective is to evaluate the prognostic association between OS and peripheral blood MRD status at 15 months after treatment initiation by flow cytometry. Secondary translational objectives include describing the association of other clinical outcomes, baseline prognostic factors, and IWCLL-defined response with MRD status at multiple timepoints. Current Status: At the time of submission, 7 patients have been registered and randomized per protocol. Accrual is ongoing. [Formula presented] Disclosures: Stephens: Adaptive: Membership on an entity's Board of Directors or advisory committees;TG Therapeutics: Membership on an entity's Board of Directors or advisory committees;Epizyme: Membership on an entity's Board of Directors or advisory committees;Beigene: Membership on an entity's Board of Directors or advisory committees;Innate Pharma: Membership on an entity's Board of Directors or advisory committees;AstraZeneca: Consultancy;CSL Behring: Consultancy;Celgene: Consultancy;Novartis: Research Funding;Abbvie: Consultancy;JUNO: Research Funding;Arqule: Research Funding;Mingsight: Research Funding;Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Moseley: BioSight Ltd: Consultancy. Hill: AbbVie: Consultancy, Honoraria, Research Funding;Gentenech: Consultancy, Honoraria, Research Funding;Beigene: Consultancy, Honoraria, Research Funding;Pfizer: Consultancy, Honoraria;Kite, Gilead Company: Consultancy, Honoraria, Other: Travel Support, Research Funding;Karyopharm: Consultancy, Honoraria, Research Funding;AstraZenica: Consultancy, Honoraria;Celgene (BMS): Consultancy, Honoraria, Research Funding;Novartis: Consultancy, Honoraria, Research Funding;Epizyme: Consultancy, Honoraria;Incyte/Morphysis: Consultancy, Honoraria, Research Funding. Pagel: Pharmacyclics/AbbVie: Consultancy;Actinium Pharmaceuticals: Consultancy;Incyte/MorphoSys: Consultancy;BeiGene: Consultancy;Epizyme: Consultancy;Kite, a Gilead Company: Consultancy;AstraZeneca: Consultancy;Gilead: Consultancy;MEI Pharma: Consultancy. Shadman: Mustang Bio, Celgene, Bristol Myers Squibb, Pharmacyclics, Gilead, Genentech, Abbvie, TG Therapeutics, Beigene, AstraZeneca, Sunesis, Atara Biotherapeutics, GenMab: Research Funding;Abbvie, Genentech, AstraZeneca, Sound Biologics, Pharmacyclics, Beigene, Bristol Myers Squibb, Morphosys, TG Therapeutics, Innate Pharma, Kite Pharma, Adaptive Biotechnologies, Epizyme, Eli Lilly, Adaptimmune, Mustang Bio and Atara Biotherapeutics: Consultancy. Danilov: Genentech: Consultancy, Honoraria, Research Funding;Takeda Oncology: Research Funding;TG Therapeutics: Consultancy, Research Funding;Abbvie: Consultancy, Honoraria;Beigene: Consultancy, Honoraria;Pharmacyclics: Consultancy, Honoraria;Gilead Sciences: Research Funding;Bristol-Meyers-Squibb: Honoraria, Research Funding;Rigel Pharm: Honoraria;Bayer Oncology: Consultancy, Honoraria, Research Funding;SecuraBio: Research Funding;Astra Zeneca: Consultancy, Honoraria, Research Funding. Mato: Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding;DTRM BioPharma: Consultancy, Research Funding;Acerta/AstraZeneca: Consultancy, Research Funding;Sunesis: Consultancy, Research Funding;BeiGene: Consultancy, Research Funding;Johnson and Johnson: Consultancy, Research Funding;Genentech: Consultancy, Research Funding;AbbVie: Consultancy, Research Funding;Nurix: Research Funding;Genmab: Research Funding;LOXO: Consultancy, Research Funding;Janssen: Consultancy, Research Funding;AstraZeneca: Consultancy;Adaptive Biotechnologies: Consultancy, Research Funding;MSKCC: Current Employment;TG Therapeutics: Consultancy, Other: DSMB, Research Funding. Brander: Juno Therapeutics/Celgene/Bristol Myers Squibb: Research Funding;Pfizer: Consultancy, Other: Biosimilars outcomes research panel;TG Therapeutics: Consultancy, Research Funding;Novartis: Research Funding;ArQule/Merck: Consultancy;Verastem: Consultancy;BeiGene: Research Funding;ArQule: Research Funding;NCCN: Other: panel member;AstraZeneca: Research Funding;Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding;LOXO: Research Funding;Ascentage: Research Funding;Genentech: Consultancy, Research Funding;DTRM: Research Funding;MEI Pharma: Research Funding;AbbVie: Consultancy, Other: informCLL registry steering committee, Research Funding. Coutre: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding;AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees;Beigene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Data Safety Monitoring Committee, Research Funding;Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees;Acerta: Other: Data Safety Monitoring Committee, Research Funding. O'Brien: Kite, Regeneron, Acerta, Caribou, Gilead, Pharmacyclics, TG Therapeutics, Pfizer, Sunesis: Research Funding;Amgen, Astellas, Celgene, GlaxoSmithKline, Janssen Oncology, Aptose Biosciences Inc., Vaniam Group LLC, AbbVie, Alexion, Verastem, Juno Therapeutics, Vida Ventures, Autolus, Johnson and Johnson, Merck, Bristol Myers Squibb, NOVA Research Company, El Lill: Consultancy. Erba: AbbVie Inc;Agios Pharmaceuticals Inc;Bristol Myers Squibb;Celgene, a Bristol Myers Squibb company;Incyte Corporation;Jazz Pharmaceuticals Inc;Novartis: Speakers Bureau;AbbVie Inc: Other: Independent review committee;AbbVie Inc;Agios Pharmaceuticals Inc;ALX Oncology;Amgen Inc;Daiichi Sankyo Inc;FORMA Therapeutics;Forty Seven Inc;Gilead Sciences Inc;GlycoMimetics Inc;ImmunoGen Inc;Jazz Pharmaceuticals Inc;MacroGenics Inc;Novartis;PTC Therapeutics: Research Funding;AbbVie Inc;Agios Pharmaceuticals Inc;Astellas;Bristol Myers Squibb;Celgene, a Bristol Myers Squibb company;Daiichi Sankyo Inc;Genentech, a member of the Roche Group;GlycoMimetics Inc;Incyte Corporation;Jazz Pharmaceuticals Inc;Kura Oncology;Nov: Other: Advisory Committee. OffLabel Disclosure: The trial studies early intervention with venetoclax and obinutuzumab in patients with CLL/SLL who are asymptomatic and observation would be standardly recommended.

Low-Dose Weekly Decitabine and Venetoclax in TP53-Mutated Myeloid Malignancies

Decitabine (Dec) and Azacitidine (Aza) that target DNA methyltransferase 1 (DNMT1) are hypomethylating agents (HMAs) approved to treat acute myeloid leukemia (AML) in combination with Venetoclax (Ven). The combination is also used to treat high-risk myelodysplastic syndromes, especially TP53-mutated (TP53mut) cases in which responses to HMA alone are short-lived. In most patients (pts), however, myelosuppression from treatment leads to frequent Ven duration and/or dose-reductions, and/or cycle delays. An approach to decrease HMA-mediated myelosuppression but maintain S-phase dependent DNMT1-targeting, evaluated in a previous clinical trial (https://doi.org/10.1111/bjh.16281), is to administer noncytotoxic doses/concentrations of Dec (0.2 mg/kg;~5 mg/m 2) by a frequent-distributed schedule of 1X/week. An approach to decrease Ven mediated myelosuppression but maintain cooperation with HMA, shown in pre-clinical studies, is to administer a single-dose prior to HMA. Ven can depolarize mitochondrial membranes;mitochondrial membrane-potential is essential to function of the mitochondrial enzyme DHODH that produces cytidine/deoxycytidine that competes with HMA in cells. Thus, Ven prior to HMA dosing temporarily inhibits de novo pyrimidine synthesis, to counter a major mechanism of resistance to HMA in MDS/AML, without suppressing normal myelopoiesis (https://doi.org/10.1182/blood-2020-143200). We conducted a retrospective analysis of all pts with TP53mut MDS or AML treated with weekly Ven and low-dose subcutaneous Dec at our institution. We analyzed the characteristics of these pts, response to therapy, and outcomes using standard descriptive statistics. Mutational testing was performed using a commercial next-generation sequencing (NGS) panel. Five pts, 3 male and 2 female, with TP53mut MDS or AML were treated with weekly Ven 400 mg on D1 and subcutaneous Dec 0.2 mg/kg on D2, administered weekly in 28 day cycles. Two pts had MDS (1 de novo, 1 treatment related) and 3 pts had AML (1 de novo, 2 secondary from prior MDS). Four pts (80%) received the treatment in frontline, all with poor performance status (PS), and 1 pt (20%) had R/R disease. Median age at diagnosis was 79 years [41-82]. The only young pt had prolonged severe cytopenias after 1 cycle Dec standard dosing during the peak of COVID-19 pandemic so was switched to this regimen. Of the 4 frontline treated pts, 2 pts had high-risk MDS, and 2 pts had adverse risk AML. The R/R pt had high-risk MDS transformed to AML that was refractory to 2 prior lines of therapy: standard Aza/Ven x5 cycles, then standard Vyxeos. Disease cytogenetics were complex in all pts. 60% (3/5) pts had sole TP53mut on NGS, with median variant allelic frequency (VAF) 48% [28-79]. 80% (4/5) pts were transfusion dependent prior to treatment. Median time to initiating therapy was 7 days from initial or refractory diagnosis [3-59] and median follow-up was 7.8 months (mo) [2.9-11.4]. The overall response rate (ORR) was 100%: 4/4 frontline pts had complete remissions (CR), and the 1 R/R pt achieved morphologic leukemia-free state (MLFS). Median time to best response was 2.9 mo. 50% (2/4) pts became transfusion independent. 40% (2/5) pts lost their TP53mut at best response, and another 40% (2/5) pts had significant reductions (83% and 38%) in TP53 mut VAF. The regimen was well tolerated with no pts stopping therapy due to adverse effects (AE). AE included G3/G4 neutropenia (80%), G1 thrombocytopenia (40%), nausea (20%), fatigue (20%), lower extremity edema (20%), pneumonia (60%), and neutropenic fever (20%) with a median of 1 unplanned hospitalization per pt during follow-up. 60% (3/5) pts remain in CR on continued therapy for a median of 7.8 mo [7.2-9.4] thus far. One pt underwent allogeneic stem cell transplantation, however, died 11.4 mo after conditioning due to transplant related mortality. The R/R pt died after being lost to follow-up 2.9 mo after therapy initiation. No pt had measurable relapse during follow-up. Combination weekly Ven with subcutaneous low-dose Dec is well tolerated yielding igh rates of clinical and molecular response in pts with TP53mut MDS/AML. Although small, this case-series extends previous clinical trial proof-of-activity of non-cytotoxic DNMT1-targeting to a high-risk, poor PS, historically chemorefractory patient population. The regimen allowed frequent, sustained exposure to therapy often not possible with standard HMA/Ven regimens. [Formula presented] Disclosures: Shastri: Kymera Therapeutics: Research Funding;Guidepoint: Consultancy;GLC: Consultancy;Onclive: Honoraria. Gritsman: iOnctura: Research Funding. Feldman: Glycomimetics: Current Employment, Current holder of stock options in a privately-held company. Verma: Celgene: Consultancy;Acceleron: Consultancy;Novartis: Consultancy;Stelexis: Consultancy, Current equity holder in publicly-traded company;Eli Lilly: Research Funding;Curis: Research Funding;Medpacto: Research Funding;Incyte: Research Funding;GSK: Research Funding;BMS: Research Funding;Stelexis: Current equity holder in publicly-traded company;Throws Exception: Current equity holder in publicly-traded company. Saunthararajah: EpiDestiny: Consultancy, Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

Daratumumab, Bortezomib and Dexamethasone (DVd) at First Relapse for Patients with Relapsed/ Refractory Multiple Myeloma (RRMM): A UK Myeloma Research Alliance (UK-MRA) Real-World Multicentre Analysis

Introduction: Daratumumab in combination with bortezomib and dexamethasone (DVd) demonstrated a superior overall response rates (ORR) and progression free survival (PFS) compared to Vd in the CASTOR phase 3 trial for patients with RRMM. On this basis, DVd was recommended in March 2019 for UK patients with RRMM that had 1 prior line (PL). Discrepancies in outcomes between patients treated in clinical trials compared to routine practice is well recognised due to a combination of patient, disease and treatment-related factors. In addition, bortezomib is often administered once-weekly in routine practice to minimise neuropathy, while CASTOR used bi-weekly bortezomib dosing. As a result, the real-world outcomes of patients treated with DVd are yet to be determined. The primary aims of this analysis was to assess the ORR and PFS for patients with RRMM with 1PL treated with DVd in routine practice. Secondary aims were to assess OS, time to next treatment (TTNT), and efficacy in different sub-groups (high risk cytogenetics, previous proteasome inhibitor (PI) exposure, refractoriness of prior therapies, bi-weekly vs weekly bortezomib schedule, and previous treatment free interval (TFI)). Methods: This was a retrospective analysis from 14 centres (academic and community hospitals;7 within the West Midlands Research Consortium (WMRC)) treated with DVd between March 2019 and June 2021. Patients received daratumumab (IV and then SC from June 2020) weekly in cycles 1-3, on day 1 of a 3-week cycle during cycles 4-8, and then monthly from cycle 9 to progression. SC Bortezomib was predominantly given weekly for cycles 1-8 although 5 centres used bi-weekly dosing for selected patients with aggressive disease. Adverse events were graded as per CTCAE criteria. Results: 288 patients were included, with a median age of 69 years (range 20-88) (Table 1). Patients received a median of 1 PL (range 1-2) with 93% (269) 1PL, 7% (18) 2 PL (due to COVID-19 measures). The majority had an ECOG performance status of 0-2 (98%) and most received weekly bortezomib (n=201). This population differed from those with 1PL treated on CASTOR in being older, more were ISS 3 (31% vs 19%, p=0.0145), and more had prior bortezomib exposure (71% vs 51%, p=0.0003), 4% were PI refractory, 9% had a GFR of <30ml/min (<20ml/min was an exclusion from CASTOR), and 2% had an ECOG performance status of ≥3. The ORR was 76%, with >VGPR in 54% (Table 2), with no significant difference in response between patients receiving biweekly vs weekly bortezomib (85% vs 83%;p=0.71). The median time to response was 1.6m. With a median follow up of 15m, the median PFS was 14m (95% CI 11.6-16). High cytogenetic risk patients had inferior outcomes: median PFS 10m (95% CI 6-14) for high risk vs not reached for standard risk (p=0.043);as did those with advanced ISS: median PFS was not reached, 15 and 12m for stage I, II and III respectively (p=0.05). For 15 patients with extramedullary disease (EMD), the median PFS was 3m (95% CI 1-5). Median PFS for patients who were PI refractory was shorter (10m vs 15m for PI sensitive patients (p=0.006)). There was no difference in median PFS for patients with prior PI exposure vs no prior PI (15 vs 13m;p=0.75), or according to weekly or bi-weekly bortezomib schedule (11 vs 15m;p=0.14). The median TTNT was 21m (95% CI 17-25). Overall, the median duration of treatment was 8m and 25 patients (9%) stopped treatment to receive a second autologous stem cell transplant. Those that had a prior TFI of >12m had a longer median PFS of 21m vs 10m (p=0.0004). The median OS has not been reached, with an estimated 2-year OS of 74%. For patients with high risk cytogenetics the median OS was 16m (95% CI 9-23;vs not reached for standard risk;p=0.0006), with estimated 2-year OS in the high risk group of 36%. There was no difference in OS for patients treated with biweekly vs weekly bortezomib (not reached for either;p=0.38). DVd was generally well tolerated with 6% stopping due to adverse events (CASTOR 9.5%). Grade 3 or 4 toxicity occurred in 62 (22%) most comm nly neutropenia and thrombocytopenia, with any grade infusion reactions reported in 27 (9%). Conclusions: These real-world data of DVd at 1 st relapse demonstrated good tolerability and high response rates with a weekly bortezomib schedule despite a more heterogenous population. However, high risk patients by cytogenetics, ISS or EMD had inferior outcomes as did those treated within 12 months from first line treatment. [Formula presented] Disclosures: Cook: Karyopharm: Consultancy, Honoraria;Pfizer: Consultancy, Honoraria;Sanofi: Consultancy, Honoraria;Takeda: Consultancy, Honoraria, Research Funding;Amgen: Consultancy, Honoraria, Research Funding;BMS: Consultancy, Honoraria, Research Funding;Oncopeptides: Consultancy, Honoraria;Roche: Consultancy, Honoraria;Janssen: Consultancy, Honoraria, Research Funding. Pratt: Binding Site: Consultancy;BMS/Celgene: Consultancy;Gilead: Consultancy;Janssen: Consultancy;Takeda: Consultancy;Amgen: Consultancy. Kishore: Celgene: Other: Attending fees;Jannsen: Other: Attending fees;Sanofi: Other: Attending fees;Takeda: Other: Attending fees. Yong: Amgen: Honoraria;Autolus: Research Funding;BMS: Research Funding;Janssen: Honoraria, Research Funding;Sanofi: Honoraria, Research Funding;GSK: Honoraria;Takeda: Honoraria. Popat: Abbvie, Takeda, Janssen, and Celgene: Consultancy;Takeda: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES;GlaxoSmithKline: Consultancy, Honoraria, Research Funding;AbbVie, BMS, Janssen, Oncopeptides, and Amgen: Honoraria;Janssen and BMS: Other: travel expenses.

Iberdomide (IBER) in Combination with Dexamethasone (DEX) in Patients (pts) with Relapsed/Refractory Multiple Myeloma (RRMM): Results from the Dose-Expansion Phase of the CC-220-MM-001 Trial

Introduction: Despite recent advances, MM remains incurable and new therapeutic options are needed, particularly for pts with RRMM. IBER is a novel, potent oral cereblon E3 ligase modulator (CELMoD ®) compound with enhanced tumoricidal and immune-stimulatory effects compared with immunomodulatory (IMiD ®) agents. Preclinically, IBER demonstrated marked synergy with DEX and with other standard myeloma treatments. CC-220-MM-001 (NCT02773030) is an ongoing phase 1/2 study evaluating IBER with different treatment combinations in independent cohorts of pts with RRMM;in phase 1, the recommended phase 2 dose of IBER, when given in combination with DEX, was determined at 1.6 mg (Lonial S, et al. Blood 2019;134[suppl 1]:3119). Here we report results from the dose expansion of IBER + DEX in pts with heavily pretreated, triple-class exposed (including ≥ 1 IMiD agent, ≥ 1 proteasome inhibitor [PI], and ≥ 1 anti-CD38 monoclonal antibody [mAb]) RRMM. Methods: Eligible pts had RRMM;had received ≥ 3 prior lines of therapy, including lenalidomide (LEN), pomalidomide (POM), a PI, a glucocorticoid, and an anti-CD38 mAb;had experienced disease progression within 60 days of last myeloma therapy;and were refractory to an IMiD agent, a PI, a glucocorticoid, and an anti-CD38 mAb. Pts with central nervous system involvement were not eligible. Pts who had received prior anti-BCMA therapy were excluded, but included in a supportive cohort for safety and preliminary efficacy assessment. IBER (1.6 mg) was given orally on days (D) 1-21, in combination with DEX (40 mg;20 mg if > 75 years of age) on D1, 8, 15, and 22 of each 28-day cycle. Thrombo-embolism prophylaxis was mandatory for all pts. Primary objective was to determine efficacy expressed as overall response rate (ORR). Secondary endpoints included additional efficacy and safety assessments. Exploratory endpoints included evaluation of health-related quality of life (HRQoL). Results: As of June 2, 2021, 107 pts had received IBER + DEX. Median age was 64 (44-83) years;median time since initial diagnosis was 6.9 (1.6-24.5) years. Extramedullary plasmacytomas were present in 25.2% of pts;29.9% of pts had high-risk cytogenetics. Median number of prior regimens was 6 (3-23). All pts were triple-class exposed;prior therapies included autologous stem cell transplantation (78.5%), PIs (100%), IMiD agents (LEN [100%] and POM [100%]), and anti-CD38 mAbs (100%);99.1% of pts were refractory to last myeloma regimen and 97.2% of pts were triple-class refractory. Median follow-up was 7.69 (0.5-17.5) months, with a median number of 4 (1-17) cycles received and 13 (12.1%) pts continuing treatment. Main reason for discontinuation was progressive disease (69.2%). ORR was 26.2%, with 1 (0.9%) stringent complete response, 8 (7.5%) very good partial responses, and 19 (17.8%) partial responses (Table);the clinical benefit rate (≥ minimal response) was 36.4% and disease control rate (≥ stable disease) was 79.4%. Median duration of response was 7.0 (4.5-11.3) months (Table), median progression-free survival was 3.0 (2.8-3.7) months, and median overall survival was 11.2 (9.0-not reached) months. Similar response rates were observed among a cohort of pts also exposed to BCMA therapies (N = 24, Table). Grade (Gr) 3-4 treatment-emergent adverse events (TEAEs) were reported in 88 (82.2%) pts. Most frequent (≥ 20% pts) hematologic Gr 3-4 TEAEs were neutropenia (44.9%;and 4.7% febrile neutropenia), anemia (28.0%), thrombocytopenia (21.5%), and leukopenia (20.6%). Gr 3-4 infections were reported in 27.1% of pts;Gr 3-4 pneumonia and COVID-19 occurred in 10.3% and 4.7% of pts, respectively. Occurrence of other Gr 3-4 non-hematologic TEAEs was generally low, including gastrointestinal disorders (5.6%), fatigue (2.8%), rash (1.9%). Fifty-six (52.3%) pts and 20 (18.7%) had IBER dose interruptions and reductions due to TEAEs, respectively. Five (4.7%) pts discontinued due to TEAEs. No pt discontinued IBER due to neutropenia. Overall, HRQoL was maintained in these pts. Conclusions: IBER + DEX demonst ated promising efficacy in pts with heavily pretreated, triple-class exposed and refractory RRMM, as well as in pts who had previously received anti-BCMA therapy;this combination was generally well tolerated and TEAEs were manageable with dose reductions and interruptions. These results support the further development of IBER in MM, including phase 3 trials in combination regimens. [Formula presented] Disclosures: Lonial: Abbvie: Consultancy, Honoraria;AMGEN: Consultancy, Honoraria;Takeda: Consultancy, Honoraria, Research Funding;GlaxoSmithKline: Consultancy, Honoraria, Research Funding;TG Therapeutics: Membership on an entity's Board of Directors or advisory committees;Merck: Honoraria;BMS/Celgene: Consultancy, Honoraria, Research Funding;Janssen: Consultancy, Honoraria, Research Funding. Popat: GlaxoSmithKline: Consultancy, Honoraria, Research Funding;Abbvie, Takeda, Janssen, and Celgene: Consultancy;Takeda: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES;AbbVie, BMS, Janssen, Oncopeptides, and Amgen: Honoraria;Janssen and BMS: Other: travel expenses. Hulin: Sanofi: Honoraria;Celgene/BMS: Honoraria;Janssen: Honoraria;Takeda: Honoraria;abbvie: Honoraria. Jagannath: Legend Biotech: Consultancy;Bristol Myers Squibb: Consultancy;Karyopharm Therapeutics: Consultancy;Janssen Pharmaceuticals: Consultancy;Sanofi: Consultancy;Takeda: Consultancy. Oriol: Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees;Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees;BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Richardson: Karyopharm: Consultancy, Research Funding;Regeneron: Consultancy;AbbVie: Consultancy;Celgene/BMS: Consultancy, Research Funding;Oncopeptides: Consultancy, Research Funding;GlaxoSmithKline: Consultancy;Protocol Intelligence: Consultancy;Janssen: Consultancy;Secura Bio: Consultancy;Takeda: Consultancy, Research Funding;Sanofi: Consultancy;AstraZeneca: Consultancy;Jazz Pharmaceuticals: Consultancy, Research Funding. Weisel: Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Roche: Honoraria;Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees;Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Abbvie: Consultancy;Novartis: Honoraria;Pfizer: Honoraria. Minnema: Cilag: Consultancy;Janssen: Consultancy;Alnylam: Consultancy;Celgene: Other: Travel expenses;Kite/Gilead: Consultancy;BMS: Consultancy. Badros: J&J: Research Funding;Janssen: Research Funding;BMS: Research Funding;GlaxoSmithKline: Research Funding. Knop: BMS/Celgene: Consultancy, Honoraria, Research Funding;Amgen: Research Funding;Janssen: Consultancy;Oncopeptides: Consultancy;Pfizer: Consultancy;Sanofi: Consultanc . Stadtmauer: Janssen: Consultancy, Honoraria;Takeda: Consultancy, Honoraria;Abbvie: Consultancy, Honoraria;Amgen: Consultancy, Honoraria;Bristol Myers Squibb: Consultancy, Honoraria, Research Funding. Chen: Bristol Myers Squibb: Current Employment. Nguyen: Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Amin: Bristol Myers Squibb: Current Employment. Kueenburg: Celgene a BMS company: Current Employment. Peluso: Celgene, a Bristol-Myers Squibb Company: Current Employment. van de Donk: BMS/Celgene: Consultancy, Honoraria;Janssen: Consultancy, Research Funding;Amgen: Consultancy, Research Funding;Cellectis: Research Funding;Takeda: Consultancy;Roche: Consultancy;Novartis /bayer/servier: Consultancy.

A Randomised Evaluation of Low-Dose Ara-C Plus BCT-100 Versus Low Dose Ara-C in Older Patients with Acute Myeloid Leukaemia: Results from the LI-1 Trial

Background: Among patients with Acute Myeloid Leukaemia (AML) over the age of 60, a considerable number are not considered suitable for intensive remission-induction chemotherapy. Survival in these patients is poor, whether they are treated using hypomethylating agents or low-dose ara-C (LDAC). The possibility of combination therapy with additional agents represents an attractive option. Arginine metabolism plays a key role in AML pathogenesis (Mussai et al. Blood 2013);BCT-100 is a pegylated recombinant human arginase that leads to a rapid depletion in extracellular and intracellular arginine concentrations resulting in G0/G1 arrest, and subsequent death by necrosis. BCT-100 demonstrates significant activity as single-agent against AML cell lines, AML xenografts and primary AML blasts from newly diagnosed or relapsed patients (Mussai et al. Blood 2015). Importantly BCT-100 is synergistic in combination with cytarabine. Aims: To assess the efficacy of LDAC+BCT100 versus LDAC alone in patients aged 60+ unsuitable for intensive therapy, in a “pick a winner” design. This design allows several treatments to be assessed simultaneously in a randomised fashion, with the aim of doubling 2-year survival from 11% to 22% (HR 0.69), with interim assessments after 50 and 100 patients per arm are recruited. Methods: LDAC was given at 20mg BD SC on days 1-10 of each course. Patients randomised to the combination received LDAC as above with BCT-100 1600U/kg on Days 1, 8, 15 and 22 as a 1-hour intravenous infusion. Courses occurred at 4-6 week intervals. Toxicities were recorded using CTCAE version 3. Pharmacokinetic and biomarker samples were assessed in BCT-100 patients. Results here are based upon median follow-up of 3.8 months (range: 0.1 - 20.6 months) Results: Between September 2018 and December 2020, 83 patients were randomised. The trial was prematurely closed due to the COVID pandemic and did not reach the pre-planned first evaluation. Median age was 76.7 years (range 62-88). Overall, 65% were male;70% de novo AML, 23% secondary AML, and 6% high risk MDS;2% favourable, 59% intermediate, 23% adverse and 15% unknown/unreported cytogenetics. Median of 2 courses was delivered in either arm (mean 2 LDAC, 2 LDAC+BCT, range for both: 1-12). BCT-100 leads to a depletion of arginine from baseline in the majority of patients. Overall response (CR/CRi) was achieved in 12/81 patients (15%), (LDAC+BCT-100 15%, LDAC 15%, R 1.03 (0.30, 3.51),P=0.963). Thirty-day mortality was not significantly increased (18% vs 11%, HR 1.71 (0.50, 5.84), P=0.393;and 1-year survival showed no evidence of a difference (31% vs 30%, HR 1.28 (0.72, 2.25). Median overall survival time was 3.8 vs 6.4months;overall survival HR 1.11 (0.64, 1.90), P=0.715. The most common cause of death was resistant/recurrent disease: 12(46%) vs 16(59%). BCT-100 was not associated with any haematological toxicity;although rare grade 3/4 cardiac and hepatic events were reported, these were not significantly increased with BCT-100. Summary: The addition of BCT-100 to LDAC did not improve response rate or survival. BCT-100 was well tolerated with an acceptable toxicity profile. Further clinical evaluation of BCT-100 induced arginase depletion continues in a variety of malignancies. Acknowledgements: We are grateful to Blood Cancer UK for funding the trial and Bio-Cancer Treatment International for providing drug and additional support for this Investigator Initiated Study. Figure 1. OS All patients [Formula presented] Disclosures: Knapper: Jazz: Consultancy, Speakers Bureau;Pfizer: Consultancy, Speakers Bureau;Astellas: Ended employment in the past 24 months, Speakers Bureau;Novartis: Consultancy, Research Funding, Speakers Bureau. McMullin: Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: clinical trial support, Research Funding;Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Abb ie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;AOP Orphan: Research Funding, Speakers Bureau. Copland: Incyte: Honoraria, Research Funding, Speakers Bureau;Novartis: Honoraria, Speakers Bureau;Pfizer: Honoraria, Speakers Bureau;Cyclacel Ltd: Research Funding;Astellas: Honoraria, Speakers Bureau;Jazz: Honoraria, Speakers Bureau. Russell: Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding;Novartis: Speakers Bureau;Astellas: Membership on an entity's Board of Directors or advisory committees;Jazz: Research Funding, Speakers Bureau.