Dr In on the Safety and Efficacy of RP1 in Patients With Melanoma Post–PD-1 Inhibitor Progression

Gino Kim In, MD, a medical oncologist, Medical Oncology, Melanoma Surgery, Sarcoma and Melanoma Surgery and associate professor of clinical medicine at Keck School of Medicine of the University of Southern California, discussed the safety and efficacy of superficial and deep or visceral vusolimogene oderparepvec (RP1) injection in a registrational cohort of patients from the phase 3 IGNYTE trial (NCT03767348) with melanoma who progressed on anti–PD-1 inhibitors.

In a post hoc analysis of this study, a cohort of 46 patients with melanoma who achieved a response to RP1 was evaluated to determine whether injected and uninjected lesions demonstrated similar response patterns, In detailed. Up to 10 measurable lesions per patient were analyzed by independent, blinded radiologists to assess response depth, duration, and kinetics, regardless of injection status, In said.

Findings from the analysis were presented at the 2025 ASCO Annual Meeting, and demonstrated that responses were comparable in both injected and uninjected lesions, with similar depth, duration, and kinetics observed across all sites evaluated, he shared. This finding was corroborated visually using waterfall plots and spider plots, suggesting the potential for a systemic effect induced by RP1 treatment, In reported.

Meaningful systemic responses were observed irrespective of the injection status of individual lesions or their anatomical location, he continued. These results indicate that the overall response was driven by the effect on both injected and non-injected lesions. Furthermore, the safety profile of deep or visceral RP1 injections was consistent with that of superficial injections, and efficacy remained similar across these groups, In noted.

Overall, these findings support the potential systemic activity of RP1 in patients with melanoma who have progressed on prior anti–PD-1 therapy. This analysis further underscores the consistency of responses and the comparable safety profile across different lesion injection sites, In concluded.