Efficacy and safety of RP1 combined with nivolumab in patients with anti–PD-1–failed melanoma from the IGNYTE clinical trial.
Michael K. Wong, Joseph J. Sacco, Caroline Robert, Judith Michels, Tawnya L. Bowles, Gino K. In, Katy K. Tsai, Célèste Lebbé, Caroline Gaudy‐Marqueste, Eva Muñoz‐Couselo, Mark R. Middleton, Adel Samson, Dirk Schadendorf, Georgia M. Beasley, Jiaxin Niu, Bartosz Chmielowski, Trisha M. Wise‐Draper, Junhong Zhu, Marcus Vinícius Canário Viana, Mohammed Milhem
Abstract
9517 Background: Patients (pts) with melanoma who progress on anti–PD-1 therapy (anti–PD-1–failed) have limited treatment options. RP1 is an HSV-1–based oncolytic immunotherapy expressing human GM-CSF and a fusogenic protein (GALV-GP-R−). Here, we present data from pts with anti–PD-1–failed melanoma, including the initial cohort and updated data from a registration-directed (R-D) cohort, from the phase 1/2 IGNYTE study (NCT03767348). Methods: Pts had locally advanced or metastatic cutaneous melanoma with ≥1 measurable and injectable tumor (≥1 cm) and confirmed progressive disease (PD) while on therapy and received anti–PD-1 ± anti–CTLA-4 therapy for ≥8 consecutive weeks, with anti–PD-1 being the last treatment received. Pts on prior adjuvant anti–PD-1 therapy had confirmed PD while on adjuvant therapy. RP1 was initially given intratumorally at 1×10 6 plaque-forming units (PFU)/mL and then every 2 weeks (Q2W) at 1×10 7 PFU/mL for up to 8 total cycles (≤10 mL/cycle) combined with nivolumab (nivo; cycles 2–8, 240 mg IV); pts then received nivo alone (240 mg Q2W or 480 mg Q4W IV) for up to 2 years, with the option to receive additional courses of RP1 if specified criteria were met. Results: Overall, 156 pts were enrolled (initial melanoma cohort, n = 16; R-D cohort, n = 140); 46.2% of pts had been treated with prior anti–PD-1 combined with anti–CTLA-4, and 51.3% of patients had stage IVM1b-d disease. The overall objective response rate (ORR) was 31.4%, and 12.2% of pts achieved complete response (CR; Table). Responses were observed irrespective of prior anti–PD-1 therapy setting and disease stage (Table). Responses were seen in uninjected lesions and in bulky and visceral disease. The ORR for pts with primary anti–PD-1 resistance was 34.1%. In pts who failed prior ipilimumab + nivo, the ORR was 26.4% (Table). The median duration of response (time from baseline to end of response for responders) was > 24 months, with 100% of responses lasting > 6 months from baseline; 78% of responses were ongoing. Treatment-related adverse events (TRAEs) associated with RP1 + nivo were predominantly grade 1–2; there was 1 grade 5 TRAE (immune-mediated myocarditis attributed to nivo). Conclusions: The updated data from this expanded cohort show that RP1 + nivo provides durable and clinically meaningful antitumor activity in pts with anti–PD-1–failed melanoma. Responses were observed in both injected and uninjected lesions, including visceral lesions. The combination continues to be well tolerated. Clinical trial information: NCT03767348 . [Table: see text]