Replimune marks another oncolytic virus failure

So much for a revival of enthusiasm in oncolytic viruses. The latest failure is Replimune’s vusolimogene oderparepvec, which today flunked its registrational phase 2 Cerpass study in cutaneous squamous cell carcinoma, sending the group’s shares down 50%. The trial added vuso-vec, an HSV-1 virus coding for GM-CSF, on top of Regeneron’s Libtayo, and its only positive sign is that a complete response rate of 38% nominally beat Libtayo alone (25%). However, the study split alpha allocation between CR rate and ORR, and the resulting p=0.025 boundary failed to be cleared. Not only that, but ORR was similar in both cohorts, and disease control rate was worse with the combo, likely scuppering hopes of a survival benefit. Replimune is highlighting the Ignyte study, where vuso-vec plus Opdivo has shown 37% ORR in PD-(L)1-failed melanoma, and which it hopes will back a 2024 US filing. Melanoma is the setting for Imlygic, the only oncolytic virus to gain US approval, whose sales are so insignificant Amgen no longer splits them out. Despite this, the failure of Sillajen/Transgene’s Pexa-Vec, and the inability of Oncolytics Biotech, for instance, to make meaningful progress, OncologyPipeline lists 242 oncolytic virus projects, including 88 in clinical trials.

Summary of the Cerpass data

Notes: *co-primary endpoint; **comprises CR, PR & SD. Source: Replimune.