Replimune disclosed on 22 July that US regulator the Food and Drug Administration (FDA) issued a complete response letter (CRL) for its oncolytic virus RP1 (vusolimogene oderparepvec) combined with nivolumab in advanced melanoma. The institution cited insufficient evidence from the single-arm Phase II IGNYTE trial (n=140), which showed a 32.9% objective response rate (ORR) and 33.7-month median duration of response (mDOR) in PD-1-refractory patients. The agency noted heterogeneous patient populations and unresolved questions about study design components.

Replimune plans to request a Type A meeting within 30 days to address these concerns. RP1, a herpes simplex virus engineered with GALV-GP R- fusogenic protein and GM-CSF, aims to enhance tumour lysis and systemic immunity. The setback delays a potential new option for melanoma patients progressing on immune checkpoint inhibitors. No safety issues were raised in the CRL.

According to PharmCube's TrialCube™ database, RP1 has so far entered 9 trials across 11 diseases. Click here to request a free trial for TrialCube™.