Daratumumab, Bortezomib, Melphalan, and Prednisone (D-VMP) Versus Bortezomib, Melphalan, and Prednisone (VMP) Alone in Transplant-Ineligible Asian Patients with Newly Diagnosed Multiple Myeloma: Final Analysis of the Phase 3 Octans Study

Introduction: Daratumumab is a human IgGκ monoclonal antibody targeting CD38 with a direct on-tumor and immunomodulatory mechanism of action and has shown clinical efficacy for the treatment of multiple myeloma (MM). In an updated analysis of the global phase 3 ALCYONE study, D-VMP demonstrated a significant progression-free survival (PFS) benefit compared to VMP in transplant-ineligible patients with newly diagnosed MM (NDMM). A prior analysis of the phase 3 OCTANS study (median follow-up, 12.3 months) also showed a favorable clinical benefit/risk profile for D-VMP versus VMP in transplant-ineligible Asian patients with NDMM. Here, we report results from the final analysis of OCTANS, with a median follow-up of >3 years.

Methods: The randomized, phase 3 OCTANS study (NCT03217812) enrolled Asian patients with NDMM who were ineligible for autologous stem-cell transplant due to age or presence of comorbidities. Patients were randomized 1:2 (VMP:D-VMP) to receive up to nine 42-day cycles of VMP (bortezomib 1.3 mg/m ² SC twice weekly in Cycle 1 and weekly in Cycles 2-9, and melphalan 9 mg/m ² and prednisone 60 mg/m ² orally on Days 1-4 of each cycle) or D-VMP (VMP + daratumumab 16 mg/kg IV weekly in Cycle 1, every 3 weeks in Cycles 2-9, and every 4 weeks thereafter until disease progression). Per a protocol amendment, patients receiving daratumumab IV were permitted to switch to daratumumab SC 1,800 mg (same schedule as IV) on Day 1 of any cycle. The primary endpoint was achievement of a very good partial response (VGPR) or better.

Results: A total of 220 patients were randomized to D-VMP (n = 146) or VMP (n = 74). At the time of the final analysis, with a median follow-up of 41.2 months, the rate of VGPR or better was significantly higher with D-VMP versus VMP (80.1% vs 47.3%; P <0.0001; Table). The rate of measurable residual disease negativity (10 ^-5) was also higher with D-VMP versus VMP (40.4% vs 10.8%; P <0.0001). D-VMP continued to show a significant improvement in PFS versus VMP (median, 38.7 vs 19.2 months; HR, 0.35; 95% CI, 0.23-0.52; P <0.0001; Table, Figure), as well as a longer time to subsequent antimyeloma therapy (median, 46.8 vs 20.6 months; HR, 0.31; 95% CI, 0.20-0.47; P <0.0001). However, median overall survival was not yet reached for either group. The overall safety profile of D-VMP was consistent with that observed for the primary analysis. Grade 3/4 treatment-emergent adverse events (TEAEs) were reported for 133 (92.4%) patients who received D-VMP and 60 (84.5%) patients who received VMP and were primarily hematologic events; nonhematologic grade 3/4 TEAEs in ≥10% of patients included pneumonia (D-VMP, 31.3% vs VMP, 18.3%), hypokalemia (15.3% vs 4.2%), and hypertension (13.2% vs 8.5%). Grade 3/4 infection TEAEs were reported for 67 (46.5%) and 22 (31.0%) patients who received D-VMP or VMP, respectively. Serious TEAEs were reported for 75 (52.1%) and 28 (39.4%) patients in the D-VMP and VMP groups, respectively, and TEAEs led to treatment discontinuation in 6 (4.2%) and 4 (5.6%) patients, respectively. The incidence of infusion-related reaction TEAEs in the D-VMP group was 33.3%, which is consistent with that previously reported for daratumumab; most events were of grade 1 or 2 severity. The risk of immunogenicity to daratumumab was low, with 1 of 130 evaluable patients testing positive for daratumumab antibodies. Within the D-VMP group, 76 patients switched from daratumumab IV to SC administration. Among these patients, 64 (84.2%) patients preferred SC administration, 7 (9.2%) preferred IV administration, and 15 (19.7%) had no preference on ≥1 of 2 surveys. Of the 64 patients who preferred SC administration, primary reasons included treatment administration time (84.4%), more comfortable administration process (57.8%), less caregiver burden (31.2%), and fewer administration-related reactions (26.6%).

Conclusions: With a median follow-up of >3 years, this final analysis of OCTANS demonstrated a continued clinical benefit with D-VMP versus VMP in Asian patients, with PFS improvement comparable to that observed in the global ALCYONE study (HR, 0.35 vs 0.42, respectively). No new safety concerns were identified for D-VMP with extended follow-up. In addition, daratumumab SC administration was preferred by the majority of patients who switched from daratumumab IV. These results further support the use of daratumumab IV or SC in combination with VMP in transplant-ineligible Asian patients with NDMM.