Pfizer reports ELREXFIO met the primary PFS endpoint in Phase 3 MagnetisMM-32 in relapsed or refractory multiple myeloma; overall survival remains immature.
Written By: Aasritha Thippavajjala, PharmD
Reviewed By: Pharmacally Editorial Team
Pfizer reported on October 27, 2026, that ELREXFIO (elranatamab) met the primary endpoint in the Phase 3 MagnetisMM-32 trial in adults with relapsed or refractory multiple myeloma (RRMM). At a prespecified interim efficacy analysis, the study demonstrated a statistically significant and clinically meaningful reduction in the risk of disease progression or death compared with investigator’s choice of standard treatment regimens. Progression-free survival (PFS) was assessed by blinded independent central review (BICR).
MagnetisMM-32 Trial Design
MagnetisMM-32 (NCT06152575) was an open-label, multicentre, randomised Phase 3 study that enrolled 523 adults across 26 countries. Participants had received at least one prior line of treatment that included an anti-CD38 antibody, either daratumumab or isatuximab, and lenalidomide.
The trial compared elranatamab monotherapy with investigator’s choice of one of three regimens: elotuzumab, pomalidomide and dexamethasone (EloPd); pomalidomide, bortezomib and dexamethasone (PVd); or carfilzomib and dexamethasone (Kd).
Elranatamab was administered subcutaneously, beginning with two step-up priming doses, followed by weekly dosing and subsequent transitions to every-two-week and monthly dosing. PFS assessed by BICR was the primary endpoint, while overall survival (OS) was a key secondary endpoint.
Elranatamab Meets the Primary PFS Endpoint
At the prespecified interim analysis, elranatamab met the primary PFS endpoint. Pfizer reported that the treatment reduced the risk of disease progression or death compared with investigator’s choice, describing the result as statistically significant and clinically meaningful.
Median PFS in the elranatamab arm had not been reached at the reported analysis. Pfizer also reported an estimated PFS rate of 68% at 18 months and stated that more than 75% of patients receiving elranatamab had not experienced a PFS event at the time of analysis.
However, the topline announcement does not provide the hazard ratio, confidence interval, exact p-value or corresponding PFS estimates for the investigator’s-choice arm. These omissions limit independent assessment of the magnitude and precision of the comparative treatment effect. The reported 18-month PFS estimate indicates sustained disease control in the elranatamab arm but does not, by itself, quantify the treatment’s advantage over standard regimens.
OS data remain immature. Follow-up will continue until the next prespecified OS analysis, meaning that the reported findings establish neither an overall survival benefit nor the long-term survival impact of treatment.
Infections and Safety Profile
Pfizer reported that the safety profile of elranatamab was consistent with its known profile, with no new safety signals identified.
Grade 3 or higher infections occurred in 27.5% of patients receiving elranatamab, compared with 18.1% receiving investigator’s choice. Grade 5 infections, which are fatal infections, were reported in 0.8% and 1.6% of patients, respectively. Pfizer also stated that infection-prophylaxis measures introduced from the beginning of the study helped mitigate infection risk, including Grade 3 or higher infections.
These findings highlight an important consideration in interpreting the efficacy results. Although elranatamab met the primary PFS endpoint, the higher reported rate of severe infections warrants attention. The lower reported rate of fatal infections does not establish an overall safety advantage. Detailed adverse-event data, event counts and additional safety analyses will be needed to assess the comparative benefit-risk profile.
Regulatory and Development Plans
Pfizer plans to submit the MagnetisMM-32 findings to global health authorities and present detailed results at a future medical meeting, with publication also planned.
ELREXFIO already has authorisations for more heavily pretreated RRMM populations in several regions. Pfizer reports that its US authorisation covers adults who have received at least four prior lines of therapy, while its European Union authorisation covers adults who have received at least three prior therapies and whose disease progressed on their last therapy.
The MagnetisMM-32 findings could support consideration of elranatamab in an earlier treatment setting, but any expansion of its authorised use will depend on regulatory review. The topline announcement does not constitute a new approval for the population studied.
Clinical Interpretation
MagnetisMM-32 met its primary PFS endpoint, providing evidence that elranatamab monotherapy can improve disease-control outcomes relative to investigator-selected standard regimens in the studied population. The result is relevant because it evaluates treatment in patients previously exposed to anti-CD38 therapy and lenalidomide, while ELREXFIO’s existing authorisations cover more heavily pretreated populations.
The strength of the comparative benefit remains difficult to quantify without the hazard ratio, confidence interval and control-arm PFS results. Immature OS data also leave the survival impact unresolved. In addition, the higher incidence of Grade 3 or higher infections underscores the importance of evaluating efficacy alongside treatment-related risks.
The forthcoming detailed trial results will be important for determining the magnitude of the PFS benefit, the durability of disease control and the overall benefit-risk profile. Until those data become available, the findings should be interpreted as promising topline evidence rather than a complete assessment of elranatamab’s clinical benefit.
References
Pfizer’s ELREXFIO Outperforms Standard Regimens and Meets Primary Endpoint in Phase 3 Study in Relapsed or Refractory Multiple Myeloma. Pfizer Inc October 27, 2026.
MagnetisMM-32: A Study to Learn About the Study Medicine Called Elranatamab in People with Multiple Myeloma (MM) That Has Come Back After Taking Other Treatments (Including Prior Treatment with an Anti-CD38 Antibody and Lenalidomide), ClinicalTrials.gov ID NCT06152575
About the Writer
Aasritha Thippavajjala (Linkedin) is a pharm D student and aspiring medical writer with medical writing, clinical training experience and a strong interest in clinical research and patient safety She has hands-on exposure to clinical pharmacy activities including medication profile assessment, clinical case review, identification of potential drug-related problems, ADR awareness, patient counselling, and clinical documentation. She has also gained experience in medical literature review, evidence synthesis, and scientific communication through her published review article on digital twin-based patient simulation and her poster presentation at the 74th Indian Pharmaceutical Congress. Certified in ICH Good Clinical Practice (E6(R3)) and Scientific Writing in Health Research, she is passionate about applying her clinical knowledge and research skills to medical writing ,clinical research and contributing to accurate, evidence-based healthcare.