In a prior phase 1/2 trial (NCT03374085), at a median follow-up of 7.5 months (range, 0.5-21.9), the combination of mezigdomide and dexamethasone given at the recommended phase 2 dose generated an overall response rate (ORR) of 41% (95% CI, 31%-51%), a mediation duration of response of 7.6 months (95% CI, 5.4-9.5), and a median PFS of 4.4 months (95% CI, 3.0-5.5) in patients with triple-class refractory multiple myeloma (n = 101).3
Take-Home Points: Phase 3 Outcomes for Mezigdomide-Based Therapy in R/R Myeloma
- Mezigdomide plus Kd improved PFS compared with Kd alone in patients with relapsed/refractory multiple myeloma.
- The safety profile of the combination was consistent with the known profile of the CELMoD and the other combination components.
- Data are being submitted for presentation at a future medical meeting and to global health authorities.
Regarding safety, at a median of 4 treatment cycles (range, 1-20), common any-grade adverse effects comprised neutropenia (77%), infection (65%), anemia (52%), thrombocytopenia (43%), and febrile neutropenia (15%).
SUCCESSOR-2 was a phase 3, 2-stage, randomized, multicenter, open-label trial that enrolled patients at least 18 years of age with multiple myeloma with measurable disease.4 At least 1 prior line of therapy for multiple myeloma was required for enrollment, including prior treatment with lenalidomide and at least 2 cycles of an anti-CD38 monoclonal antibody, and patients needed to have documented disease progression during or after their most recent line of therapy. Notably, a minimal response or better to at least 1 prior line of therapy was required.
Patients were excluded if they received prior treatment with mezigdomide or carfilzomib; or underwent allogeneic stem cell transplant at any time or autologous stem cell transplant within 12 weeks of beginning study treatment.
Enrolled patients were randomly assigned to receive mezigdomide plus Kd or Kd alone.
Along with the primary end point of PFS, secondary end points included overall survival, ORR, very good partial response or better rate, complete response or better rate, time to response, DOR, time to progression, time to next treatment, time to second progression, minimal residual disease–negativity rate, safety, and quality of life.
“It is important for patients to have treatment options that offer enduring disease control,” Meletios-A. (Thanos) Dimopoulos, MD, professor and chairman of the Department of Clinical Therapeutics at Alexandra Hospital, School of Medicine, National and Kapodistrian University of Athens, added in a news release.1 “These positive interim data show that adding mezigdomide, a CELMoD specifically optimized for enhanced myeloma cell killing and immune activation compared with immunomodulatory agents, to carfilzomib and dexamethasone may provide clinical benefit in earlier relapse.”
References
- Bristol Myers Squibb announces positive phase 3 results from the SUCCESSOR-2 study of oral mezigdomide in relapsed or refractory multiple myeloma. News release. Bristol Myers Squibb. March 9, 2026. Accessed March 9, 2026. https://news.bms.com/news/corporate-financial/2026/Bristol-Myers-Squibb-Announces-Positive-Phase-3-Results-from-the-SUCCESSOR-2-Study-of-Oral-Mezigdomide-in-Relapsed-or-Refractory-Multiple-Myeloma/default.aspx
- Hartley-Brown MA, Mo CC, Nadeem O, Midha S, Laubach JP, Richardson PG. Mezigdomide-A Novel Cereblon E3 Ligase Modulator under Investigation in Relapsed/Refractory Multiple Myeloma. Cancers (Basel). 2024;16(6):1166. Published 2024 Mar 15. doi:10.3390/cancers16061166
- Richardson PG, Trudel S, Popat R, et al. Mezigdomide plus dexamethasone in relapsed and refractory multiple myeloma. N Engl J Med. 2023;389(11):1009-1022. doi:10.1056/NEJMoa2303194
- A study to evaluate mezigdomide in combination with carfilzomib and dexamethasone (MeziKD) versus carfilzomib and dexamethasone (Kd) in participants with relapsed or refractory multiple myeloma (SUCCESSOR-2). https://clinicaltrials.gov/study/NCT05552976