Adjuvant nivolumab versus ipilimumab (CheckMate 238 trial): Reassessment of 4-year efficacy outcomes in patients with stage III melanoma per AJCC-8 staging criteria
James Larkin, Jeffrey S. Weber, Michele Del Vecchio, Helen Gogas, Ana Arance, Stéphane Dalle, C. Lance Cowey, Michael Schenker, Jean‐Jacques Grob, Vanna Chiarion‐Sileni, Iván Márquez‐Rodas, Marcus O. Butler, Anna Marie Di Giacomo, Mark R. Middleton, Luis de la Cruz‐Merino, Petr Arenberger, Victoria Atkinson, Andrew Hill, Leslie A. Fecher, Michael Millward, Nikhil I. Khushalani, Paola Queirolo, Georgina V. Long, Maurice Lobo, Margarita Askelson, Paolo A. Ascierto, Mario Mandalà
Abstract
PURPOSE: Nivolumab was approved as adjuvant therapy for melanoma based on data from CheckMate 238, which enrolled patients per American Joint Committee on Cancer version 7 (AJCC-7) criteria. Here, we analyse long-term outcomes per AJCC-8 staging criteria compared with AJCC-7 results to inform clinical decisions for patients diagnosed per AJCC-8. PATIENTS AND METHODS: In a double-blind, phase 3 trial (NCT02388906), patients aged ≥15 years with resected, histologically confirmed AJCC-7 stage IIIB, IIIC, or IV melanoma were randomised to receive nivolumab 3 mg/kg every 2 weeks or ipilimumab 10 mg/kg every 3 weeks for 4 doses and then every 12 weeks, both intravenously ≤1 year. Recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) were assessed in patients with stage III disease, per AJCC-7 and AJCC-8. RESULTS: Per AJCC-7 staging, 42.4% and 57.3% of patients were in substage IIIB and IIIC, respectively; per AJCC-8, 1.1%, 30.4%, 62.8%, and 5.0% were in IIIA, IIIB, IIIC, and IIID. After 4 years' minimum follow-up, the AJCC-7 superior efficacy of nivolumab over ipilimumab in patients with resected stage III melanoma was preserved per AJCC-8 analysis. No statistically significant difference in RFS between stage III substage hazard ratios was observed per AJCC-7 or -8 staging criteria (interaction test: AJCC-7, P = 0.8115; AJCC-8, P = 0.1051; P = 0.8392 ((AJCC-7) and P = 0.8678 (AJCC-8) for DMFS). CONCLUSIONS: CheckMate 238 4-year RFS and DMFS outcomes are consistent per AJCC-7 and AJCC-8 staging criteria. Outcome benefits can therefore be translated for patients diagnosed per AJCC-8.