Bristol Myers Squibb (NYSE:BMY) today announced positive late-breaking results from the Phase 3 SUCCESSOR-2 trial (NCT05552976) of CELMoD (cereblon E3 ligase modulation) mezigdomide in combination with carfilzomib and dexamethasone (MeziKd) versus carfilzomib and dexamethasone alone (Kd) in patients with relapsed or refractory multiple myeloma (RRMM). Results showed MeziKd demonstrated a clinically meaningful and statistically significant improvement in progression-free survival (PFS) (95% CI: 18 months vs. 8.3 months [HR:0.48; p<0.0001]), representing a 52% reduction in the risk of disease progression or death compared with Kd.

These data, representing the first Phase 3 results for mezigdomide, are being presented in a late-breaking oral presentation (#LBA7506) at the 2026 American Society of Clinical Oncology (ASCO®) Annual Meeting.

"The combination of MeziKd demonstrated a promising median progression-free survival rate of 18 months in multiple settings of relapsed, refractory multiple myeloma, along with a consistent safety profile and the convenience of oral administration and ability to implement across diverse care settings," said Paul Richardson, MD, Director of Clinical Research and Clinical Program Leader at the Jerome Lipper Multiple Myeloma Center, the Dana-Farber Cancer Institute and RJ Corman Professor of Medicine, Harvard Medical School. "Maintaining durable disease control becomes an increasing challenge with each line of therapy for patients with relapsed or refractory disease and increasing resistance to therapy, so achieving extended progression-free survival of a year and a half is especially meaningful. These promising results at ASCO underscore MeziKd's potential, particularly for those patients who need additional options after both early and later relapse."

Results also showed significantly improved PFS rates with MeziKd across patients in second- and third-line as well as those with higher-risk disease. Higher overall response rate (80.2% vs 53.4%) and complete response or better (26.7% vs 8.9%) were also seen with MeziKd. Median overall survival was not yet reached. The safety profile of MeziKd was consistent with the known profile of mezigdomide and the combination regimen. Grade 3-4 treatment-emergent adverse events were seen in 83.7% vs 56.5% of patients, with neutropenia in 61.1% vs 9.1%, and infections in 34.0% vs 15.6% of patients treated with MeziKd and Kd, respectively.

"Multiple myeloma is a persistent disease and there remains an urgent unmet need for patients as early as first relapse," said Cristian Massacesi, MD, executive vice president, chief medical officer and head of development, Bristol Myers Squibb. "Importantly, these compelling data further validate our targeted protein degradation platform, and cereblon as a critical therapeutic target in multiple myeloma. Mezigdomide is a very potent, oral CELMoD and we're committed to bringing it forward as a potential new standard of care for relapsed/refractory multiple myeloma across multiple settings."

Results from SUCCESSOR-2 will be shared with health authorities. Bristol Myers Squibb thanks the patients and investigators involved in this clinical trial.