Efficacy of Elranatamab (ELRA) in Combination with Carfilzomib (CFZ) and Dexamethasone (DEX) in the Phase 1b MagnetisMM-20 Trial in Relapsed or Refractory Multiple Myeloma (RRMM)
Results: Of the 12 treated pts in part 1, the median age was 66.0 years (range, 45.0-80.0), 8 (66.7%) were male, none had extramedullary disease, 3 (25.0%) had high-risk cytogenic abnormalities, 4 (33.3%) had ISS stage III, and 8 (66.7%) had <30% baseline bone marrow plasma cells. Eight pts (66.7%) had Revised International Staging System disease stage I or II (unknown for 2 pts [16.7%]). Pts had a median of 2 prior lines of therapy (range, 1-3), and 41.7% had triple-class refractory disease. No pts had a stem cell transplant. At the time of data cutoff (February 22, 2024), 91.7% of pts were ongoing ELRA and CFZ tx, with DEX tx ongoing in 66.7% of pts. Median tx duration was 3.15 months (range, 0.56-13.37).
Among the 10 pts evaluable for DLTs, none were reported at DL1 or DL2. In the safety analysis population (n=12), the most common adverse events (any grade [≥50%], grade 3/4 [≥10%]) were fatigue (83.3%, 8.3%), CRS (75.0%, 0%), neutropenia (58.3%, 33.3%), thrombocytopenia (58.3%, 25.0%), injection site reaction (50.0%, 0%), leukopenia (50.0%, 16.7%), anemia (41.7%, 25.0%), lymphopenia (33.3%, 25.0%), peripheral edema (33.3%, 16.7%), increased blood alkaline phosphatase (25.0%, 16.7%), and pulmonary embolism (16.7%, 16.7%). Infections were reported in 75.0% of the pts, all grade 1/2. No ICANS was reported in any pt.
At a median follow-up of 3.24 months (range, 1.51-13.47), the unconfirmed ORR by investigator was 100%. Ten pts (83.3%) had confirmed ORR by investigator with a median TTR of 1.41 months (95% CI, 0.53-3.35). Median DOR was not reached.
Conclusions: ELRA + CFZ + DEX has demonstrated clinical efficacy and predictable safety signals. The study continues enrolling and will explore the combination of ELRA + CFZ + DEX in a larger group of pts.