SEROLOGIC RESPONSE TO THE SECOND AND THIRD DOSE OF THE SARS-COV-2 VACCINE IN PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA: RESULTS OF A PROSPECTIVE, CENTRALIZED, MULTICENTER STUDY

Background: Patients with chronic lymphocytic leukemia (CLL) show high infection-related morbidity and mortality due to variable degree of humoral and cellular immune deficiency. High Covid-related mortality and reduced response to the SARS-Cov-2 vaccine have been reported in this patient population. Aims: We carried out a prospective multicenter study to define the rate of CLL patients with an appropriate immune response after the mRNA SARS-CoV2 vaccine (Pfizer-BioNTech;Moderna). Methods: Two-hundred patients with CLL received the first dose of the SARS-CoV-2 vaccine between February and August 2021. Centralized assessment of the anti-SARS-Cov-2 IgG levels (Sero Index, Kantaro Quantitative SARS-CoV-2 IgG Antibody, RUO-R&D System) was performed at the Istituto Superiore di Sanità of Rome, Italy. The median followup of this study is 10.7 months (range 1-12.9). Results: The median age of patients was 70 years, the median IgG level was 635 mg/dl, 61% of patients were IGHV unmutated, and 34% showed TP53 disruption. The majority of patients, 83.5%, were previously treated. Prior treatment included chemoimmunotherapy in 20 (10%) patients, ibrutinib-based therapy in 72 (36%;front-line, 21%;advanced line, 15%), venetoclax-based therapy in 75 (37.5%;front-line, 13.5%;advanced line, 24%). Overall, 135 (77.5%) patients had been previously treated with rituximab, 33 (16.5%) of them within 12 months before vaccination. We assessed the serologic response after the second dose of the SARS-CoV2 vaccine in 195 patients while five were excluded from the analysis (positive test before vaccination, 3 patients;lost to the follow-up, 1;Richter syndrome, 1). Adequate levels of anti-SARS-Cov-2 IgG were detected in 76/195 (39%) patients. Age (<70 vs.≥ 70 years;p <0.0001), CIRS value (<6 vs. ≥6;p=0.005), beta-2 microglobulin (<3.5 vs. ≥ 3.5mg/dl;p=0.04), IgG levels (<550 vs. ≤ 550 mg/dl;p <0.0001), prior treatment (p=0.0001), number of prior treatments (0+1 vs. ≥ 2;p=0.002) and the time between prior rituximab and vaccination (>12 vs. ≤12 month;p=0.001) showed a significant impact on the humoral response. In multivariate analysis only age (OR: 0.92 [95% CI: 0.92-0.97] p=0.0001), IgG levels (OR: 0.28 [95% CI: 0.13-0.58] p<0.001), and the time between prior rituximab and vaccination (OR: 0.10 [95% CI: 0.03-0.37] p=0.001), revealed a significant and independent impact on response. When the analysis was restricted to patients who received targeted therapy, in addition to the younger age (OR: 0.96 [95% CI: 0.92-0.99] p=0.04), higher IgG levels at baseline (OR: 0.31 [95% CI: 0.12-0.79] p=0.014), longer time between the start of ibrutinib or venetoclax-based therapy and vaccination (<18 vs.≥18 months;OR: 0.17 [95% CI: 0.06-0.44], p <0.0001) showed a favorable and independent impact on response. Ninety-three% (182/195) of patients received a third dose of the vaccine. A significant increase in the rate of serologic responses, 51.5% (85/165 evaluated patients, p=0.019), was observed after the booster dose. Moreover, a response was detected in 25% (26/103 evaluated patients) of previously seronegative patients. Summary/Conclusion: In this prospective, multicenter, centralized study, we recorded an effective immune response to the SARS-CoV-2 vaccine in about a third of patients with CLL. Younger age, higher IgG levels, no prior treatment, or stable disease after targeted therapy that suggest preserved immunocompetence were associated with a greater likelihood of achieving an effective immune response. A booster dose of the SARS-CoV-2 vaccine proved beneficial also in previously seronegative patients.

INHIBITION OF PROTEIN KINASE CK2 AND BCL-2: A NOVEL THERAPEUTIC STRATEGY TO ANTAGONIZE MANTLE CELL LYMPHOMA CELL GROWTH

Background: Mantle cell lymphoma (MCL) is a B-cell tumor which often relapses. BCR inhibitors (Ibrutinib, Acalabrutinib) and antiapoptotic BCL2-family members blockers BH3-mimetics (Venetoclax, ABT-199) are effective drugs to fight MCL. However, the disease remains incurable, due to therapy resistance, even to the promising Venetoclax and Ibrutinib combination. Therefore, there is a profound need to explore novel useful therapeutic targets. CK2 is a S/T kinase overexpressed in several solid and blood tumors. We demonstrated that CK2, operating through a 'non-oncogene addiction' mechanism promotes tumor cell survival, and counteracts apoptosis, by activating pro-survival signaling cascades, such as NF-κ B, STAT3 and AKT. CK2 could regulate also BCL2 family members. The CK2 chemical inhibitor CX-4945 (Silmitasertib, Sil) is already under scrutiny in clinical trials in relapsed multiple myeloma, solid tumors and COVID-19. Aims: In this work, we tested the effect of CK2 chemical inhibition or knock down on Venetoclax (Ven)-induced cytotoxicity in MCL pre-clinical models to effectively reduce MCL cell growth and clonal expansion. Methods: CK2 expression and BCR/BCL2 related signaling components were analyzed in MCL cells and control cells by Western blotting. CK2 and BCL2 inhibition was obtained with Sil and Ven, respectively and with CK2 gene silencing through the generation of anti-CK2 shRNA IPTG-inducible MCL cell clones. Survival, apoptosis, mitochondrial membrane depolarization and proliferation were investigated by FACS analysis of AnnexinV/PI and JC-10 staining. The synergic action of Ven and Sil was analyzed by the Chou-Talalay combination index (CI) method. CK2 knock down in vivo was obtained in xenograft NOD-SCID mouse models Results: CK2 inactivation (with Sil or CK2 silencing) determined a reduction in the activating phosphorylation of S529 p65/RelA and S473 and S129 AKT, important survival cascades for MCL. Sil or CK2 silencing caused BCL2 and related MCL1 protein reduction, causing cell death. Importantly, we confirmed these results also in an in vivo xenograft mouse model of CK2 knockdown in MCL. Sil +Ven combination increased MCL cell apoptosis, as judged by the augmented frequency of Annexin V positive cells and expression of cleaved PARP protein, and JC-10 mitochondrial membrane depolarization, with respect to the single treatments. Captivatingly, Sil or CK2 gene silencing led to a substantial reduction of the Ven-induced increase of MCL-1, potentially counteracting a deleterious Ven-induced drawback. Analysis of cell cycle distribution confirmed an increased frequency of apoptotic cells in the sub G1 phase in CK2-silenced cells and a modulation of the other phases of the cell cycle. Remarkably, the calculated CI less than 1 suggested a strong synergic cell-killing effect between Sil and Ven, on all the cell lines tested, including those less sensitive or resistant to Ven Summary/Conclusion: We demonstrated that the simultaneous inhibition/knock down of CK2 and BCL2 synergistically cooperates in inducing apoptosis and cell cycle arrest of MCL malignant B-lymphocytes and has the potential of reducing MCL clonal growth, also counterbalancing mechanism of resistance that may arise with Ven. Therefore, CK2 is a rational therapeutic target for the treatment of MCL to be tested in combination with Ibrutinib or Ven.

Chronic Lymphocytic Leukemia (CLL) Patients Quality of Life (QoL): A Cross-Sectional Analysis of the Italian Experience in the Choice Study during the First Wave of the COVID-19 Pandemic

Introduction Although plenty of data exists on efficacy and safety of CLL drugs, their impact on patients' Health-Related Quality of Life (HRQoL) is largely unknown (1-2). Documentation of drug safety via traditional use of adverse events (AE) in hematology is limited if not complemented with Patient-Reported Outcomes (PRO) measures (3-4). Incorporation of HRQoL PROs is now essential to better evaluate risk-benefit of new therapeutic approaches and it is also highly valued by regulatory stakeholders (5). Most PRO data currently available for CLL patients (pts) came from randomized controlled trial settings (6-7), hence limiting generalizability of findings to CLL real-life patients. CHOICE study was designed to investigate CLL patients' QoL and preference towards different treatment profiles through a Discrete Choice Experiment (DCE) methodology in Italy. Due to the timelines of the study, which started in February 2020, the related data offer an insight into patients' perception and worries during the first wave of the COVID-19 pandemic. Methods This cross sectional, multi-center, observational study included CLL patients, treatment naïve during the watch & wait period (W&W) or already TREATED (around 50% each, controlled at site level), who signed the informed consent for study participation. Exclusion criteria were inability to take oral drugs, cognitive disorders that could impair the comprehension of the questionnaires and concomitant treatment for other malignancies. Patients were asked to fill in the following HRQoL questionnaires: EQ-5D-5L, EORTC QLQ-C30 and QLQ CLL-16, as well as a DCE questionnaire, (described elsewhere). Each questionnaire was completed by the patient on a tablet - using an App specifically developed for the study. Results 401 pts were enrolled in Italy in 16 hematology centers (Feb - July 2020);199 W&W and 196 TREATED pts completed the questionnaires and were included in the evaluable population. Main patients' characteristics are shown in Table 1. 73.7% of TREATED pts were ON-treatment (30.8% were in 1st-line, 69,2% in further lines) and 26.3% were OFF-treatment;the majority of pts (55,6%) were currently treated with a target therapy (Table1). The EQ-5D-5L questionnaire showed no significant differences between groups. In both groups more than 80% of pts reported low values (1 or 2, indicating no or small impact) on all items. Median VAS was 75 for the TREATED group and 80 for the W&W group (0-100;higher scores indicate higher QoL). QLQ C-30 / CLL-16 scores had very similar results between TREATED and W&W pts suggesting a limited impact of CLL on pts QoL. The median (IQR) QoL Scale was 83.3 (67- 83) for TREATED and 83.3 (67- 92) for W&W pts (0-100;all functional scales had high scores, that represent a better level of functioning;all symptoms' scales had low values, representing a less important symptomatology or problem, Figure 1). The main symptoms reported were fatigue, insomnia, pain, and dyspnea, while the main worry was for “future health” (Figure 1). Distribution of data was statistically different between the 2 groups only for the Role functioning Scale (p=0.024) and the Social Functioning Scale (p=0.003) of QLQ-C30 and for the Infection Scale (p<0.001) of QLQ CLL-16, always with slightly but significantly better results for the W&W group. Conclusions CHOICE study helps to understand the CLL patients' mindset and feeling in the light of the COVID-19 pandemic impact on health care for this category of pts, highlighting their preferences and worries in a large cohort of pts in Italy, allowing a comparison between TREATED and W&W pts. The main limitation of the study was its cross-sectional design, which does not allow us to evaluate any change in QoL neither with respect to the impact of the pandemic, nor to the effects of the treatment, if any. CLL pts showed a good QoL, as confirmed by both EQ-5D-5L and EORTC QLQ C-30 / CLL-16 scores, with very similar results between TREATED and W&W pts (although slightly better results in the W&W vs TREATED group). The results of th present study are consistent with previous reports, and fatigue was the most reported symptom, while worry for future health was the most relevant score in CLL-16 questionnaire. Hospital accesses reduction that was detected during the pandemic might have influenced patients' response, as well as the extreme attention towards the danger of infections, and might have impacted patients' perception on future health. [Formula presented] Disclosures: Tedeschi: Beigene: Honoraria, Speakers Bureau;AstraZeneca: Honoraria, Speakers Bureau;AbbVie: Honoraria, Speakers Bureau;Janssen: Honoraria, Speakers Bureau. Gozzetti: Janssen: Honoraria;AbbVie: Honoraria. Reda: Beigene: Consultancy;Astra Zeneca: Consultancy;Abbvie: Consultancy;Janssen: Consultancy. Gualberti: AbbVie: Current Employment. Malgieri: AbbVie: Current Employment. Finsinger: AbbVie: Current Employment.

Efficacy and Safety of Front-Line Venetoclax and Rituximab (VenR) for the Treatment of Young Patients with Chronic Lymphocytic Leukemia and an Unfavorable Biologic Profile. Preliminary Results of the Gimema Study ‘Veritas‘

Fixed-duration treatment with venetoclax (Ven), a highly selective Bcl-2 inhibitor combined with an anti-CD20 monoclonal antibody, showed high efficacy inducing high rates of deep responses with undetectable minimal residual disease (uMRD) in patients with previously treated and untreated chronic lymphocytic leukemia (CLL). The efficacy and safety of the Ven and rituximab (VenR) combination have been investigated in a multicenter, prospective study of the GIMEMA group that included young patients with previously untreated CLL (LLC 1518, VERITAS, NCT03455517). The primary endpoint of this study was the CR rate assessed according to the iwCLL criteria. Inclusion criteria were: treatment requirement per iwCLL criteria, age ≤65 years, cumulative Illness rating scale score ≤6, creatinine clearance ≥30 mL/min, and an unfavorable biologic profile with IGHV unmutated and or TP53 disruption. Treatment consisted of the Ven dose ramp-up (from 20 to 400 mg daily, during 5-weeks) followed by Ven 400 mg daily, combined with R for six 28-day courses (375 mg/m2, course 1;500 mg/m2, courses 2-6). Patients continued with Ven single agent, 400 mg daily, until month 13. Tumor lysis syndrome (TLS) prophylaxis measures included hydration, allopurinol, or rasburicase. All patients received Pneumocystis Jirovecii prophylaxis. G-CSF was given in patients with recurrent and severe granulocytopenia. Adverse events (AEs) were graded according to the CTCAE criteria v.5, TLS events were classified according to Howard's criteria. Response was assessed at months 7 and 15 and included clinical examination, PB evaluation, BM aspirate, BM biopsy, and CT scan. MRD was checked centrally in the PB and BM by a 6/4-color flow-cytometry assay with a sensitivity of at least 10-4 according to the internationally standardized European Research Initiative on CLL. Quantitative MRD results assessed by flow-cytometry were categorized as uMRD (uMRD4;<10-4), intermediate MRD, or high MRD (≥10-2). MRD was further evaluated by allele-specific oligonucleotide PCR with a sensitivity up to 10-5 in the PB and BM of patients who showed uMRD4 by flow-cytometry. During the follow-up, MRD was monitored every 6 months. Between October 2018 and May 2020, 77 patients with CLL were included in this study. Two patients were off study before the start of treatment (withdrawal of consent, 1;Covid-19 infection, 1) and were not included in the analysis. The median age was 53.5 years (range 38-65). Binet stage B/C was present in 84% of patients, increased beta-2 microglobulin in 41%. Seventy-one (96%) of patients were IGHV unmutated, while 3 (4%) were IGHV mutated and showed TP53 mutation (Table 1). At the data cutoff of June 30, 2020, 65 (87%) patients completed the ramp-up phase. The planned 400 mg dose of Ven was reached within 5 weeks in 78.5% of patients. Response was assessed in 34 patients at the end of the VenR combination therapy. A response was achieved by 32 (94%) patients. Responses included 20 (59%) CRs, 1 CRi (3%) and 11 (32%) PRs due to residual enlarged nodes (median maximum size, 1.9 cm). Treatment failure due to toxicity was recorded in 2 (6%) patients. Overall, a response with uMRD4 by flow-cytometry in the PB was observed in 26 (76.5%) cases, and in the PB and BM, in 17 (50.0%). The rates of patients with CR and uMRD4 by flow-cytometry in the PB, and both in the PB and BM, were 44%, and 35%, respectively (Table 2). No detectable disease by PCR, both in the PB and BM, was observed in 4 (12%) patients. With a median follow-up of 4.5 months from the start of therapy, no patient has progressed or died. Fifty-three percent of patients were hospitalized during the first seven days of the Ven ramp-up phase. A transient laboratory TLS was observed in 3 patients. Treatment was discontinued after the first dose of Ven in 1 patient with evidence of laboratory TLS associated with severe neurologic toxicity due to the concomitant administration of fentanyl. Selected grade ≥3 AEs included neutropenia in 10 patients (ramp-up phase, 5) and neutropenic fever in 4. Gra e ≥3 infection was recorded in 3 patients and was the reason for treatment discontinuation in 1 who developed COVID-19 pneumonia. In conclusion, the preliminary results of this study demonstrate the high efficacy of the front-line VenR combination, which resulted in a high proportion of CRs and responses with uMRD4 in young patients with CLL and an unfavorable biologic profile. [Formula presented] Disclosures: Mauro: Astrazeneca: Membership on an entity's Board of Directors or advisory committees;Takeda: Membership on an entity's Board of Directors or advisory committees;Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Jannsen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Octopharma: Consultancy. Reda: Gilead: Membership on an entity's Board of Directors or advisory committees;Janssen: Membership on an entity's Board of Directors or advisory committees;Abbvie: Membership on an entity's Board of Directors or advisory committees. Trentin: Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau;Shire: Honoraria;Takeda: Membership on an entity's Board of Directors or advisory committees;Octapharma: Membership on an entity's Board of Directors or advisory committees. Coscia: Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees;Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees;Karyopharm Therapeutics: Research Funding;Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Sportoletti: Janssen: 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. Laurenti: Roche: Membership on an entity's Board of Directors or advisory committees;AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Gaidano: Astrazeneca: Membership on an entity's Board of Directors or advisory committees;Janssen: 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;Sunesys: Membership on an entity's Board of Directors or advisory committees. Marasca: Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Shire: Honoraria;Roche: Membership on an entity's Board of Directors or advisory committees. Murru: Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Janssen: 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. Rigolin: Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau;Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Scarfo: Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;AstraZeneca: Honoraria;Gilead: Membership on an entity's Board of Directors or advisory committees. Marchetti: Pfizer: Membership on an entity's Board of Directors or advisor committees;Takeda: Membership on an entity's Board of Directors or advisory committees;Amgen: Membership on an entity's Board of Directors or advisory committees;Novartis: Membership on an entity's Board of Directors or advisory committees;Abbvie: Membership on an entity's Board of Directors or advisory committees;Gilead: Membership on an entity's Board of Directors or advisory committees. Levato: Gilead: 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;Janssen: 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. Galieni: Celgene: Honoraria;Takeda: Honoraria;AbbVie: Honoraria;Janssen: Honoraria. Liberati: Verastem: Research Funding;Onconova: Research Funding;Janssen: Honoraria, Research Funding;Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding;Abbvie: Honoraria, Research Funding;Pfizer: Research Funding;Karyopharm: Research Funding;Morphosys: Research Funding;Novartis: Research Funding;GSK: Research Funding;Incyte: Honoraria;Oncopeptides: Research Funding;Takeda: Research Funding. Molica: Roche: Membership on an entity's Board of Directors or advisory committees;Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Gilead: Membership on an entity's Board of Directors or advisory committees;Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Visentin: Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Gilead: Membership on an entity's Board of Directors or advisory committees, SpeakersBureau;Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Vitale: Janssen: Honoraria. Del Giudice: Janssen: Other: grant for meeting participation;Tolero: Membership on an entity's Board of Directors or advisory committees;Roche: Other: grant for meeting partecipation;AstraZeneca: Membership on an entity's Board of Directors or advisory committees. Cuneo: Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Astra Zeneca: Honoraria;Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Foà: Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Incyte: Speakers Bureau;Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau;Roche: Membership on an entity's Board of Directors or advisory committees;Novartis: Speakers Bureau;Roche: Membership on an entity's Board of Directors or advisory committees.