SALVO: Single-Arm Trial of Ipilimumab and Nivolumab as Adjuvant Therapy for Resected Mucosal Melanoma

Purpose: Mucosal melanoma is a rare, aggressive form of mel-anoma with extremely high recurrence rates despite definitive surgical resection with curative intent. Currently there is no con -sensus on adjuvant therapy. Data on checkpoint inhibitors for adjuvant therapy are lacking. Patients and Methods: We performed a single-arm, multicenter clinical trial using "flip dose" ipilimumab (1 mg/kg q3w x 4 cycles), and nivolumab (3 mg/kg q3w x 4 cycles), then nivolumab 480 mg q4w x 11 cycles to complete a year of adjuvant therapy. Participants must have had R0/R1 resection & LE;90 days before registration, no prior systemic therapy (adjuvant radiotherapy allowed), ECOG 0/1, and no uncontrolled autoimmune disease or other invasive cancer. Patients were recruited through the Midwest Melanoma Partner-ship/Hoosier Oncology Network. Results: From September 2017 to August 2021, 35 patients were enrolled. Of these, 29 (83%) had R0 resections, and 7 (20%) received adjuvant radiotherapy. Median age was 67 years, 21 (60.0%) female. Recurrence-free survival (RFS) rates at 1 and 2 years were 50% [95% confidence interval (CI), 31%-66%] and 37% (95% CI, 19%-55%), respectively. Overall survival rates at 1 and 2 years were 87% (95% CI, 68%-95%) and 68% (95% CI, 46%-83%), respectively. Median RFS was 10.3 months (95% CI, 5.7-25.8). Most common grade 3 toxicities were diarrhea (14%), hypertension (14%), and hypona-tremia (11%), with no grade 4/5 toxicities. Conclusions: Flip-dose ipilimumab and nivolumab after resec-tion of mucosal melanoma is associated with outcomes improved over that of surgical resection alone. Long-term follow-up, sub group analyses and correlative studies are ongoing.