Durable clinical outcomes in patients (pts) with advanced melanoma and progression-free survival (PFS) >= 3y on nivolumab (NIVO) +/- ipilimumab (IPI) or IPI in checkmate 067

9542 Background: NIVO + IPI has demonstrated durable clinical benefit at 7.5 y in pts with advanced melanoma in the phase 3 CheckMate 067 study. PFS curves plateaued at ~3 y in this study, suggesting that being alive and progression-free for ≥ 3 y (PFS ≥ 3y) may be a good surrogate for long-term clinical benefit. We conducted analyses to quantify this association. Methods: Pts with treatment (tx)-naive, unresectable stage III/IV melanoma (stratified by PD-L1 expression, BRAF mutation status, and metastasis stage) received NIVO 1 mg/kg + IPI 3 mg/kg for 4 doses Q3W, followed by NIVO 3 mg/kg Q2W (n = 314); NIVO 3 mg/kg Q2W + placebo (n = 316); or IPI 3 mg/kg Q3W for 4 doses + placebo (n = 315) until progression or unacceptable toxicity. Exploratory post hoc analysis was performed in pts with PFS ≥ 3y. Results: In the NIVO + IPI, NIVO, and IPI arms, respectively, 99 (32%), 78 (25%), and 21 (7%) pts had PFS ≥ 3y. Objective response rates (ORRs) in these pts were ≥ 95% (table). The majority of responses were complete responses (CRs; table); in almost all pts with partial responses (PRs) on NIVO + IPI or NIVO, target-lesion size decreased by ≥ 50%. At 7.5 y of follow-up among pts alive and progression-free at 3 y, PFS rates were ≥ 68%, overall survival (OS) rates were ≥ 85%, and melanoma-specific survival (MSS) rates were ≥ 95% in the 3 tx groups (table). Among pts in this group who died after 3 y on study, the majority of deaths were unrelated to disease (table). The majority of pts with PFS ≥ 3y who were alive and in follow-up were tx-free at the 7.5-y data cutoff (77/84, 57/64, and 13/16). Pts who received NIVO + IPI were off tx (median) for 75.5 mo (NIVO, 55.7 mo; IPI, 59.2 mo). Among pts with PFS ≥ 3y in the 3 tx groups, 4%, 5%, and 19% received subsequent systemic tx (table). No new safety signals were observed in pts with PFS ≥ 3y. Conclusions: This exploratory post hoc analysis suggested that PFS ≥ 3y may be a good surrogate for long-term MSS with NIVO + IPI or NIVO, with very few occurrences of progression or death due to melanoma in this population through 7.5 y. Most pts were tx-free without having received subsequent systemic tx after demonstrating PFS ≥ 3y. Further study of pts with PFS ≥ 3y may allow the burden of imaging and follow-up visits to be reduced in this group. Clinical trial information: NCT01844505 . [Table: see text]