DREAMM-7: A Phase III Study of the Efficacy and Safety of Belantamab Mafodotin (Belamaf) with Bortezomib, and Dexamethasone (B-Vd) in Patients with Relapsed/Refractory Multiple Myeloma (RRMM)

Introduction: Belantamab mafodotin (belamaf; GSK2857916) is a B-cell maturation antigen (BCMA)–targeting antibody-drug conjugate. In the pivotal Phase II DREAMM-2 study, single-agent belamaf demonstrated deep and durable responses and a manageable safety profile in patients refractory and/or intolerant to ≥3 lines of therapy, including an anti-CD38 monoclonal antibody such as daratumumab (Lonial et al. Lancet Oncol 2020). Responses were sustained at 13 months of follow-up with belamaf (2.5 mg/kg intravenously [IV] every 3 weeks [Q3W]); overall response rate (ORR) was 32% and median duration of response (DoR) was 11.0 months (Lonial et al. ASCO 2020 Poster 436).

Triple combination regimens, such as daratumumab plus bortezomib and dexamethasone (D-Vd), are considered a standard of care for patients with RRMM and have demonstrated superior antimyeloma activity to monotherapy and dual combination regimens, such as bortezomib and dexamethasone.

Preclinical data suggest synergistic antimyeloma activity of belamaf and bortezomib (a proteasome inhibitor), and initial results from the ongoing Phase I/II DREAMM-6 study of B-Vd indicate an acceptable safety profile for the combination (Nooka et al. ASCO 2020 Oral 8502). The DREAMM-7 study (NCT04246047) will evaluate the efficacy and safety of B-Vd compared with D-Vd in patients with RRMM.

Methods: DREAMM-7 is an ongoing, randomized, open-label, global, multicenter, Phase III, two-arm study in patients with measurable RRMM who had received ≥1 prior therapy with documented disease progression during or after their most recent therapy. Patients aged ≥18 years with Eastern Cooperative Oncology Group Performance Status 0–2, adequate organ system function, and who provide informed consent will be eligible. Patients intolerant/refractory to daratumumab or bortezomib, or with prior exposure to anti-BCMA therapy, will be excluded. Patients will be stratified by the Revised International Staging System, prior exposure to bortezomib, and number of prior lines of therapy.

Approximately 478 patients will be randomized (1:1) to Arm A (B-Vd) or Arm B (D-Vd).

In Arm A, patients will receive belamaf 2.5 mg/kg (IV) Q3W on Day 1 of each cycle; bortezomib 1.3 mg/m² (subcutaneously) on Days 1, 4, 8, and 11 of Cycles 1–8 (21-day cycles); and dexamethasone 20 mg (IV or orally) on the day of, and the day after, bortezomib treatment. In Arm B, patients will receive daratumumab 16 mg/kg (IV) in 21-day cycles: Cycles 1–3 Q1W, Cycles 4–8 Q3W, and from Cycle 9 onwards Q4W; dexamethasone and bortezomib schedules will be the same as in Arm A. Treatment will continue in both arms until disease progression, death, unacceptable toxicity, withdrawal of consent, or study end.

The primary endpoint is progression-free survival (PFS; time from randomization to the earliest date of documented disease progression or death [any cause]). The key secondary endpoint is minimal residual disease negativity rate, as assessed by next-generation sequencing. Additional secondary endpoints include complete response rate, ORR, DoR, PFS2 (PFS after initiation of new anticancer therapy), overall survival, and endpoints related to pharmacokinetics, antidrug antibodies, safety, and health-related quality of life. As of August 2020, the study is enrolling.

Funding: GSK (Study 207503); drug linker technology licensed from Seattle Genetics; mAb produced using POTELLIGENT Technology licensed from BioWa.