ABSTRACT
Background: Systemic AL amyloidosis is an incurable relapsing plasma cell disorder. Despite therapeutic advances, there are no approved treatments for relapse disease. Treatment is often challenging due to underlying organ dysfunction. Belantamab mafodotin is an antibody-drug conjugate targeting B-cell maturation antigen with approval for relapsed refractory myeloma. In multiply pre-treated myeloma, the DREAMM-2 phase II trial showed an overall response rate of 32% for those with 2.5 mg/kg dose administered every three weeks with 2/3rd patients reporting keratopathy. A small case series of 6 patients with relapsed AL amyloidosis (Zhang et al , ASH 2021) was recently reported and a phase 2 trial is recruiting for patients with refractory amyloidosis (NCT04617925). Aims: We report our initial results using Belantamab monotherapy for the treatment of patients with AL amyloidosis with relapsed disease. Methods: Data for consecutive patients who were administered Belantamab at a specialist referral centre, National Amyloidosis Centre, University College London, was analysed. Results: Eleven patients were included 8 male, 3 female. Median age at Belantamab initiation was 65 (range 42-74) years. Eight patients had λ AL-type and three κ AL-type. At diagnosis, median involved free light-chain concentration was 534 (range 73-7181) mg/l. A median of two organs involved at baseline (range 1-3): 4 had cardiac involvement (half Mayo stage 2;half Mayo stage 3a) and 8 had renal involvement. The median prior lines of therapy was 3 (range 2-5) with all exposed to prior immunomodulatory drugs, proteasome inhibitors and 73% to anti-CD38 antibody treatments. Thirty-six percent had relapsed after melphalan-conditioned autologous stem cell transplantation. A median of 3 cycles of belantamab were delivered (range 1-8). The most frequent adverse event was ocular toxicity which was experienced in 8 patients (grade 1-3), necessitating dose modification of the three-weekly schedule. One patient developed transient grade 1 dyspnoea and liver dysfunction. No patients developed cytopenias, unlike previous reports (Zhang et al , 2021), nor infections beyond COVID (2 patients mild with no hospital admissions). The majority of the cohort required dose reduction either at initiation (patient 4, due to end stage renal failure;patient 11, post-renal transplant) or during therapy (n=5;three to 1.9mg/kg, two to 1.25mg/kg) due to ocular toxicity. Only one patient remained on the standard dose of 2.5mg/kg for >3 cycles. Ocular toxicity improved after treatment interruption (drug intervals 4-6 weeks) and no patients required complete treatment cessation. One patient is too early to assess response. Haematological responses (PR or better) were seen in 7 patients with 3 complete responses and two very good partial responses (VGPR) which are ongoing. Both renal patients (patients 4 and 11) commenced a dose of 1.25mg/kg and sustained a VGPR with no additional toxicity. Patient 3 had a 42% reduction in sFLC after two doses but then a prolonged gap due to keratopathy and has lost the response. There were no cardiac or renal toxicities observed. Summary/Conclusion: Belantamab mafodotin demonstrates significant activity in patients with heavily pre-treated AL amyloidosis with 70% achieving a ≥PR. Apart from keratopathy requiring dose modification, no other substantial toxicity was observed. Two patients with renal impairment (stage V CKD and ESRD) and one patient post-renal transplant tolerated treatment with no additional toxicity. Belantamab mafodotin shows promise in treatment of relapsed AL and needs further prospective trials.
ABSTRACT
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.
ABSTRACT
Background: The role of upfront ASCT for NDTE MM remains under evaluation with high MRD rates following novel induction and consolidation (cons) strategies. K maintenance represents an alternative strategy to lenalidomide maintenance. The CARDAMON trial investigated K maintenance following KCd induction plus either ASCT or KCd cons. Methods: NDTE pts received 4 x KCd induction (K 20/56 mg/m2 biweekly, C 500 mg D 1,8,15, d 40mg weekly) before 1:1 randomisation to ASCT or 4 x KCd cons followed by 18 cycles K maintenance (56mg/m2 D1,8,15). Flow cytometric MRD (10-5) was assessed post induction, pre-maintenance and at 6 months maintenance. Primary endpoints were ≥VGPR post induction and 2-year PFS from randomisation. Secondary endpoints included improvements in disease response and MRD conversion following ASCT/ cons and maintenance. Results: 281 patients were registered, with 218 randomised to either ASCT or cons. The median PFS for ASCT was not yet reached vs 3.4 years for cons, with cons failing to show non-inferiority (difference in 2-year PFS 6.5%, 70% CI 1.0% to 11.1%). 196 patients received K maintenance (99 ASCT, 97 cons), 17 remain on treatment. A median of 16 cycles (1-18) were given over a median of 15.9 months (0-21.5). COVID-19 led to maintenance treatment interruptions in 41 (8 ASCT, 6 Cons) and treatment discontinuation in 15 (9 ASCT, 6 Cons). The median K dose given was 50.6mg/m2 and was similar across both arms (51.2 vs 49.4mg/m2, p=0.03). K maintenance was discontinued for PD in 14.1% (ASCT) vs 22.7% (cons), and for adverse events (AEs) in 7.1% (ASCT) vs 4.1% (cons). Most common AEs were hypertension and infections and more ≥G3 AEs were noted in ASCT vs cons (p=0.01). Patient/ clinician withdrawals from maintenance were low but occurred more in the ASCT arm (9.1% vs 1%). MRD neg patients post ASCT/ Cons had a longer PFS than MRD pos (p=0.002);with a higher MRD neg rate in the ASCT arm (53.6% vs 35.1% in Cons, p=0.01). MRD neg patients at 6 months post maintenance also had longer PFS (p=0.004 cf MRD pos patients);again with higher MRD neg rates in the ASCT arm (58.1% ASCT vs 40.5% Cons, p=0.02). There was no difference in PFS for MRD neg patients according to treatment arm from PBSCH, post-ASCT/ Cons or 6 months maintenance timepoints. Overall, 27.8% of MRD pos patients converted to MRD neg post ASCT/ Cons with more converting with ASCT (39.1% ASCT vs 16.1%, p=0.004). 23.5% of MRD pos patients converted to neg during maintenance (30.6% ASCT, 17.8%: p=0.2). Maintenance of MRD negativity over the first 6 months was similar between ASCT and Cons arms (p=0.3). There was no evidence that the timing of achievement of MRD negativity impacted PFS. Conclusions: K maintenance at 56mg/m2 weekly was deliverable and tolerable, with continued higher MRD neg rates at 6 months post-ASCT compared to post-Cons. However more ≥G3 AEs and discontinuations for AEs/ patient choice were noted for K maintenance after ASCT.