Pfizer claims second place in the myeloma order

In the three-way battle of BCMA-targeting T-cell engagers Pfizer’s Elrexfio just staked a claim to second place, on Wednesday toplining a win in the phase 3 Magnetismm-5 study in multiple myeloma patients after as little as one prior line of therapy. This trial is broadly analogous to the Majestec-3 study of Johnson & Johnson’s rival Tecvayli, which impressed on PFS and OS, and which resulted in US approval for a Tecvayli/Darzalex combo last month. One quirk is that Magnetismm-5 tested Elrexfio monotherapy as well as a Darzalex doublet, but Pfizer’s win relates specifically to monotherapy. Magnetismm-5 was extensively delayed, having at one point been expected in the first half of 2025, and investors will have to await a scientific meeting – the EHA conference is one possibility – to scrutinise the details; Pfizer says the study produced a win on PFS, with OS said still to be immature. Elrexfio also lags Tecvayli in the post-Darzalex setting, where J&J’s Majestec-9 study has read out positively for PFS and OS, but where Pfizer’s Magnetismm-32 trial is still ongoing. Tecvayli, Elrexfio and Regeneron’s Lynozyfic all have monotherapy approvals in late-line myeloma, and in the earlier Majestec-3/Magnetismm-5 setting the Regeneron drug trails both rivals.

Phase 3 trials of anti-BCMA T-cell engagers in ≥2nd-line multiple myeloma

Notes: *MRD negativity expected to be registrational endpoint; PI=proteasome inhibitor; IMID=Revlimid or Pomalyst; D=Darzalex; P=Pomalyst; d=dexamethasone; V=Velcade; E=Empliciti; K=Kyprolis. Source: OncologyPipeline.