Elranatamab in relapsed or refractory multiple myeloma: phase 2 MagnetisMM-3 trial results
- Study type
- Clinical trial
- Study name
- MagnetisMM-3
- Phase
- Phase 2
- Design
- Single-arm, open-label, multicentre study; report of cohort A (no prior anti-BCMA therapy)
- Sample size
- 123 patients (cohort A)
- Source
- Nat Med · 2023
- Trial registration
- NCT04649359
In plain words
Like teclistamab, elranatamab is a two-armed (bispecific) antibody against BCMA that links immune cells to myeloma cells, and it is injected under the skin at a fixed dose (not based on weight). In patients for whom several earlier treatments had failed, about 6 out of 10 responded. After 6 months, in patients who respond, the injections are spaced out to every two weeks, which reduces side effects. As with other drugs in this group, preventing infection and treating it quickly are very important.
Key results
Treatment arms and regimens
Elranatamab subcutaneously in 28-day cycles: step-up doses of 12 mg on day 1 and 32 mg on day 4 of cycle 1, then 76 mg weekly; after six cycles, sustained responders (partial response or better for at least 2 months) switched to dosing every 2 weeks.
Source of the regimen details: Full text of the paper in PMC (PMC10504075), Methods section; FDA label for ELREXFIO (2026 version)
Doses are given for the information of specialists, as in this study’s protocol, and are not a prescription. Every drug must be prescribed by the treating physician for the individual patient.
Study population
Patients with relapsed or refractory multiple myeloma (refractory to at least one immunomodulatory drug, one proteasome inhibitor and one anti-CD38 antibody) who had not received prior anti-BCMA therapy.
Endpoints
Primary endpoint: confirmed objective response rate by blinded independent central review.
Secondary endpoints: duration of response, progression-free survival, overall survival and safety.
Safety and side effects
Common adverse events (any grade; grade 3 or 4): infections (69.9%; 39.8%), cytokine release syndrome (57.7%; 0%), anaemia (48.8%; 37.4%) and neutropenia (48.8%; 48.8%). ICANS in 4 of 119 patients (3.4%), all grade 1 or 2 (full text of the paper). With dosing every 2 weeks, grade 3 or 4 adverse events fell from 58.6% to 46.6%.
Clinical significance and place in guidelines
Based on this study, in August 2023 the FDA granted accelerated approval to elranatamab (Elrexfio) for relapsed or refractory myeloma after at least four prior lines of therapy (including a proteasome inhibitor, an immunomodulatory drug and an anti-CD38 antibody), and the EMA also granted conditional approval. The FDA label allows the dosing interval to be extended to every 2 weeks and then every 4 weeks in sustained responders.
Limitations
The study is single-arm with no comparison group, and follow-up in this report was about 15 months. Infections were common and sometimes severe. Patients with prior anti-BCMA therapy (cohort B) were not included in this report.
This summary was prepared by the editorial team from the published paper; the original paper is the final reference. Read the original abstract on PubMed.