# MagnetisMM-3: elranatamab, a second BCMA bispecific, with a switch to fortnightly dosing after response

Source: https://onco.cc/key-papers/paper-magnetismm-3-elranatamab-natmed-2023/  
OnCo record `paper-magnetismm-3-elranatamab-natmed-2023` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Elranatamab produced responses in 61% of heavily pretreated myeloma patients and showed that dosing can be thinned to every two weeks once patients respond.

## Summary

MagnetisMM-3 was a phase 2 single-arm study of elranatamab, a subcutaneous BCMA x CD3 bispecific, in 123 patients with triple-class-exposed relapsed or refractory multiple myeloma who had not received prior BCMA-directed therapy (cohort A). After two step-up doses and weekly dosing, patients who had responded for at least six months moved to every-two-week dosing. The overall response rate was 61% with complete response or better in 35%; most responses were ongoing at a year. CRS occurred in about 58% of patients, all grade 1-2 with the priming regimen, and neurotoxicity in a small minority. Infections were the main serious toxicity. The FDA granted accelerated approval in 2023.

## Fields

- Kind: Key paper
- Last checked: 2026-09-08
- Journal: Nature Medicine
- Year: 2023
- DOI: 10.1038/s41591-023-02528-9
- Authors: Lesokhin AM, Tomasson MH, Arnulf B, et al.
- Findings: 123 BCMA-naive, triple-class-exposed patients (cohort A); median 5 prior lines.; Overall response 61%; complete response or better 35%.; Responses were durable, with most responders still in response at 12 months.; CRS in about 58%, all grade 1-2 after two step-up doses; ICANS uncommon.; Responders switched to every-two-week dosing after 6 months without loss of response in most cases.
- What it means: Elranatamab confirmed that BCMA bispecifics are a class, not a one-off, and its protocol-built dose reduction after response set a precedent for lowering the immunosuppressive burden of T-cell engagers. Patients now have two approved BCMA bispecifics and one against GPRC5D (talquetamab). Choosing between them, and sequencing them with CAR-T, remains guided by availability and toxicity profile rather than head-to-head data.
- Caveats: Single-arm; no comparator or randomised evidence at approval.; Excluded patients with prior BCMA therapy in the registrational cohort; cohort B (BCMA-exposed) had lower responses.; Infection risk and hypogammaglobulinaemia similar to teclistamab.; Durability beyond two years still being reported.

## Sources

- PubMed search: https://pubmed.ncbi.nlm.nih.gov/?term=MagnetisMM-3%20elranatamab%20Lesokhin%20Nature%20Medicine%202023
- ClinicalTrials.gov NCT04649359: https://clinicaltrials.gov/study/NCT04649359

## Connected records

- key papers: [MajesTEC-1: teclistamab, an off-the-shelf BCMA bispecific antibody, in heavily pretreated myeloma](https://onco.cc/key-papers/paper-majestec-1-teclistamab-nejm-2022/)
- pairings: [Caution: T-cell redirectors and infections](https://onco.cc/pairings/bispecific-infection-prophylaxis/)
- cancers: [Multiple myeloma](https://onco.cc/cancers/multiple-myeloma/)
- technologies: [Bispecific antibodies](https://onco.cc/technologies/bispecific-antibody/), [T-cell engagers (bispecific)](https://onco.cc/technologies/t-cell-engager/)
- targets: [BCMA](https://onco.cc/targets/bcma/), [CD3](https://onco.cc/targets/cd3/), [GPRC5D](https://onco.cc/targets/gprc5d/)
- drugs: [Elranatamab](https://onco.cc/drugs/elranatamab/), [Talquetamab](https://onco.cc/drugs/talquetamab/), [Teclistamab](https://onco.cc/drugs/teclistamab/)
- companies: [Pfizer (incl. Seagen)](https://onco.cc/companies/pfizer/)
- terms: [Cytokine release syndrome (CRS)](https://onco.cc/terms/crs/), [Objective response rate (ORR)](https://onco.cc/terms/orr/)
- trials: [LINKER-MM1](https://onco.cc/trials/linker-mm1/), [MagnetisMM-3](https://onco.cc/trials/magnetismm-3/)
- bottlenecks: [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/), [Wrong doses](https://onco.cc/bottlenecks/b-dose-optimisation/)
- journals: [Nature Medicine](https://onco.cc/journals/nature-medicine/)

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