Depth of response and minimal residual disease status in ultra high-risk multiple myeloma and plasma cell leukemia treated with daratumumab, bortezomib, lenalidomide, cyclophosphamide and dexamethasone (Dara-CVRd): Results of the UK optimum/MUKnine trial.
Authors: Martin F. Kaiser, Andrew Hall, Katrina Walker, Ruth De Tute, Sadie Roberts, Emma Ingleson, Kristian Bowles, Mamta Garg, Anand Lokare, Christina Messiou, Graham H. Jackson, Guy Pratt, Gordon Cook, Mark Drayson, Roger G. Owen, Sarah R Brown, Matthew Jenner
Journal: Journal of Clinical Oncology (2021)

8001 Background: Patients with ultra high-risk (UHiR) newly diagnosed multiple myeloma (NDMM) and patients with plasma cell leukemia (PCL) continue to have dismal outcomes and are underrepresented in clinical trials. Recently, improved responses with anti-CD38 monoclonal antibody combination therapy have been reported for NDMM patients. We report here outcomes for NDMM UHiR and PCL patients treated in the OPTIMUM/MUKnine (NCT03188172) trial with daratumumab, cyclophosphamide, bortezomib, lenalidomide, dexamethasone (Dara-CVRd) induction, augmented high-dose melphalan (HDMEL) and ASCT. With final analysis follow-up surpassed in Feb 2021, we report here early protocol defined endpoints from induction to day 100 post ASCT. Methods: Between Sep 2017 and Jul 2019, 107 patients with UHiR NDMM by central trial genetic (≥2 high risk lesions: t(4;14), t(14;16), t(14;20), gain(1q), del(1p), del(17p)) or gene expression SKY92 (SkylineDx) profiling, or with PCL (circulating plasmablasts &gt; 20%) were included in OPTIMUM across 39 UK hospitals. Patients received up to 6 cycles of Dara-CVRd induction, HDMEL and ASCT augmented with bortezomib, followed by Dara-VR(d) consolidation for 18 cycles and Dara-R maintenance. Primary trial endpoints are minimal residual disease (MRD) status post ASCT and progression-free survival. Secondary endpoints include response, safety and quality of life. Data is complete but subject to further data cleaning prior to conference. Results: Median follow-up for the 107 patients in the safety population was 22.2 months (95% CI: 20.6 – 23.9). Two patients died during induction due to infection. Bone marrow aspirates suitable for MRD assessment by flow cytometry (10 -5 sensitivity) were available for 81% of patients at end of induction and 78% at D100 post ASCT. Responses in the intention to treat population at end of induction were 94% ORR with 22% CR, 58% VGPR, 15% PR, 1% PD, 5% timepoint not reached (TNR; withdrew, became ineligible or died) and at D100 post ASCT 83% ORR with 47% CR, 32% VGPR, 5% PR, 7% PD, 10% TNR. MRD status was 41% MRDneg, 40% MRDpos and 19% not evaluable post induction and 64% MRDneg, 14% MRDpos and 22% not evaluable at D100 post ASCT. Responses at D100 post ASCT were lower in PCL with 22% CR, 22% VGPR, 22% PR, 22% PD, 12% TNR. Most frequent grade 3/4 AEs during induction were neutropenia (21%), thrombocytopenia (12%) and infection (12%). Grade 3 neuropathy rate was 3.7%. Conclusions: This is to our knowledge the first report on a trial for UHiR NDMM and PCL investigating Dara-CVRd induction and augmented ASCT. Response rates were high in this difficult-to-treat patient population, with toxicity comparable to other induction regimens. However, some early progressions highlight the need for innovative approaches to UHiR NDMM. Clinical trial information: NCT03188172.