9502 Background: Patients (pts) with stage II melanoma account for ~50% of those who develop metastatic disease. Checkpoint inhibitor neoadjuvant therapy (NAT) is standard for resectable stage III melanoma (NADINA CT prior RES; dermoscopy and reflectance confocal microscopy (RCM) baseline, wk 3 and prior to RES. The primary endpoint was the path complete response (pCR) rate. Secondary endpoints included feasibility of NAT in stage II, RECIST response, RFS, OS, safety/tolerability, surgical outcomes, QOL. Exploratory; biomarker, dermoscopy and RCM analyses. Results: From 6 Oct 2023 to 21 Oct 2025, 20 pts were recruited and received NAT, demonstrating partial biopsy leaving residual macroscopic stage IIA-C primary melanoma was feasible. Median age 67 yrs (46-81yrs), 9 females, 8 IIA, 8 IIB and 4 IIC. 18 (90%) pts received both NAT doses. 12 (60%) pts had pCR in the primary melanoma, 1 near-pCR (MPR 65%), 1 pPR and 6 (30%) pNR. Drug treatment related adverse events (TRAE) gd ≤ 2 occurred in all 20 pts (100%); 11 (55%) with fatigue, 8 rash (40%) and 5 arthralgia (25%). 3 (15%) pts had gd 3 (secondary adrenal insufficiency, nephritis, pneumonitis). There were no gd 4 or 5 TRAEs. 1 (5%) pt had a gd 3 AE related to surgery (cellulitis). 19 (95%) pts had no change in SLN mapping from pre to RES. 2 pts with pNR in primary melanoma had postitive SLN and 1 pt with pCR had focal fibrosis within a negative SLN, suggestive of possible treatment effect. Dermoscopy showed regression in all 12 MPR (100%) pts; 11 also showed changes in RCM (collagen reorganization and imflammatory infiltrates) concordant with pathology. At datacut off (11 Dec 25) 2 pts recurred, 5 and 11 mo respectively (both pNR);1 died due to melanoma (15 mo after 1 st recurrence; 20 mo after enrolement. Positive SLNBx at pNR). Conclusions: NAT with nivo + rela in resectable stage II melanoma was feasible and induced a high rate of pCR and MPR in the primary melanoma. Clinical trial information: NCT05418972 .
Long et al. (Thu,) studied this question.