A randomized phase II study of daratumumab, lenalidomide, ixazomib, and dexamethasone in transplant-ineligible or deferred patients with newly diagnosed multiple myeloma: Alliance Foundation Trial 41 (AFT-41)

Abstract Introduction The treatment of newly diagnosed multiple myeloma (NDMM) has rapidly evolved. Quadruplet induction combining an anti-CD38 monoclonal antibody, lenalidomide, a proteasome inhibitor, and dexamethasone has become a standard of care. In this prospective randomized phase 2 trial, we evaluated the efficacy and safety of induction with a four-drug combination of daratumumab (Dara), lenalidomide (R), ixazomib (I), and dexamethasone (d) (Dara-RId) in older, transplant ineligible or deferred patients, followed by maintenance with Dara RI versus R for up to 2 years. We hypothesized that this quadruplet would offer improved tolerability with less peripheral neuropathy in this older population as well as the convenience of largely oral therapy. Herein, we present the initial results of the induction phase of the study. Methods Transplant-ineligible or deferred patients with NDMM were eligible to participate. This was a multicenter trial sponsored by the Alliance Foundation Trials, LLC, AFT-41 (NCT04009109). Each cycle of treatment was 28 days. All patients received 12 cycles of induction therapy with daratumumab 1800 mg subcutaneously on the conventional schedule, lenalidomide 15 mg orally (po) on days 1-21, ixazomib 4 mg po on days 1, 8, 15, and dexamethasone weekly. After 12 cycles, patients received maintenance based on prior randomization (1:1) to Dara-RI or R for up to 2 years. In maintenance, R was reduced to 10 mg and I was reduced to 3 mg. Randomization assignment occurred prior to starting induction. Stratification was based on presence of high-risk features defined as ISS stage III or high-risk FISH cytogenetics (del 17, t (14;16), t (14;20), t (4;14), del (1p), or gain (1q)). The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate (ORR) and adverse events. Results We enrolled 79 patients across 7 sites from October 2020 until December 2023. Accrual was affected by the COVID19 pandemic, leading to early closure to accrual in December 2023. Median age was 74 years (range 63-86); ≥75 years of age (45.6%); female (59.5%); white (83.5%), African American (7.6%), Asian (1.3%), and Hispanic ethnicity (6.3%). Additional baseline characteristics included ISS staging I (41.8%), II (35.4%), and III (22.8%) with high-risk features in 37% by ISS stage III and/or high-risk FISH. The 12-month PFS was 92% (95% confidence interval [CI] 86.1-98.4%). The ORR (≥ partial response [PR]) during induction was 92.4% (PR 22.8%; very good partial response [VGPR] 46.8%; complete response 15.2%; stringent complete response 7.6%). Notable grade ≥3 adverse events included neutropenia (16.5%), infections (11.4%), anemia (10.1%), thrombocytopenia (8.9%), and syncope (7.6%). There was no grade ≥3 peripheral neuropathy (grade 1, 15%; grade 2, 14%). No treatment-related mortality was reported. Sixty-one patients went on to maintenance therapy and seven patients discontinued treatment for adverse events during induction (8.9%). Conclusions Dara-RId therapy in NDMM appears to be efficacious with an ORR of 92.4%; VGPR or better of 69.6% and 12-month PFS of 92%. The combination was generally tolerated well with manageable toxicity, despite 45.6% of patients being ≥75, offering the convenience of an oral proteasome inhibitor, ixazomib, that minimizes the risk of peripheral neuropathy for older, transplant-ineligible or deferred patients. Follow-up is ongoing to determine the benefit of maintenance with Dara-RI v. R alone in this population. Support: AFT, Celgene, Janssen, Takeda.