Regeneron has a new multiple myeloma hope

The tough time Regeneron has had in developing CD3-based T-cell engagers hasn’t stopped the company from pursuing this approach. A recent listing on the clinicaltrials.gov registry reveals the group working on a T-cell engager against the multiple myeloma target GPRC5D, and it’s about to go into phase 1.

Regeneron’s multiple myeloma work has until now mostly focused on the anti-BCMA drug Lynozyfic, which finally made it over the regulatory finish line last July; the latest revelation appears to be the first sign of the company also working on GRPC5D. In this highly competitive space Regeneron’s key rival is Johnson & Johnson, which boasts approved T-cell engagers against both targets.

Those two J&J drugs are Tecvayli (anti-BCMA T-cell engager) and Talvey (GPRC5D); both are approved in late-line multiple myeloma, but J&J’s assault on earlier settings is already well under way, with Tecvayli scoring its first approval in the second line this month. An early-line pivotal study, Monumental-6, combines Tecvayli with Talvey and standard of care, and ends this year.

REGN17372

Disclosure of Regeneron’s Talvey me-too, a molecule coded REGN17372, comes against this competitive backdrop. REGN17372’s phase 1/2 trial is to begin later this month, and even though this is a first-in-human test it will already evaluate a combo with Lynozyfic, and have an active comparator cohort giving patients Lynozyfic alone.

It concerns a late-line setting, patients who are at least fourth line and have “exhausted all therapeutic options”. If Lynozyfic performs in line with its uncontrolled Linker-MM1 trial in fourth-line multiple myeloma then the bar to clear will be a 70% ORR and a 45% complete response rate.

It was Linker-MM1 that backed Lynozyfic’s accelerated US approval last year, making this the third approved anti-BCMA T-cell engager, arguably with better data than either Tecvayli or Pfizer’s Elrexfio. But the nod came after a complete response letter, and CRLs have cast a cloud over Regeneron’s work in T-cell engagers, with the anti-CD20 drug Ordspono still not approved in the US.

Recently disclosed first-in-human studies*

Note: *these projects were first listed on the clinicaltrials.gov database between 6 and 12 Mar 2026.

Other first-in-human studies recently listed on clinicaltrials.gov include another degrader of the androgen receptor, this time from the Chinese company Gan & Lee, which is advancing its GLR203701 project.

It’s possible that Bristol Myers Squibb’s success with the AR degrader gridegalutamide, as revealed at ESMO in 2024, has spurred others to enter this mechanism. Gridegalutamide is already in phase 3, and could soon be joined by Novartis’s Arvinas-originated luxdegalutamide; meanwhile, AstraZeneca’s AZD9750 and GSK’s GSK5471713 started first-in-human studies this year.

And China’s Qilu is advancing into the clinic a molecule coded QLS5308, which from the trial’s exclusion criteria seems likely to be an ADC against LIV-1. If this is the case then QLS5308 will become the second anti-LIV-1 ADC in active clinical development, joining BioRay’s laventatug tivedotin; what was once the furthest-advanced industry asset here, ladiratuzumab vedotin, was discontinued by its developers, Seagen and Merck & Co, in 2023.