Preliminary results from the international neoadjuvant melanoma consortium (INMC).

9581 Background: For several cancers, response to neoadjuvant therapy (NAT) correlates with survival. Targeted and immune therapies achieve high response rates and durable survival in many patients with metastatic melanoma. Their role as NAT for stage III disease is not clear, and whether pathological response following NAT correlates with relapse-free (RFS) or overall survival (OS) in melanoma is unknown. Methods: Pooled clinical data from four ongoing NAT clinical trials (NCT02437279, NCT02231775, NCT02519322, NCT01972347) at three large melanoma centers participating in the INMC were examined. All trials included only patients with surgically resectable clinical stage III melanoma. NAT regimens included dabrafenib/trametinib (DT) and nivolumab (nivo) [single agent or in combination with ipilimumab (ipi/nivo)]. Patients who had undergone surgery prior to 27 th January 2017 are included in this preliminary analysis. A pathological complete response (pCR) was defined as no viable melanoma cells in the resected specimen by hematoxylin and eosin evaluations by dedicated dermatopathologists. Results: 58 patients with clinical stage III melanoma (AJCCv7: 18 IIIB, 40 IIIC) have completed NAT and undergone surgery. 18 received neoadjuvant immunotherapy (IT): ipi/nivo x2 doses (N = 10), ipi/nivo x3 doses (N = 4) or nivo x4 doses (N = 4). 40 received neoadjuvant DT, either for two (N = 10) or three months (N = 30). Median age is 55 years (range 22-84). A pCR was observed in 50% of patients, 7 (39%) with IT and 22 (55%) with DT. Median follow-up is 10.2 months (95% CI 8.7-12.5). 14 (24%) patients have recurred (5 local, 8 distant, 1 both), 2 (11%) after IT, 12 (30%) after DT. For those with pCR, 14% have recurred, 0/7 (0%) after IT, 4/22 (18%) after DT. In contrast, for those without pCR, 34% have recurred, 2/11 (18%) after IT and 8/18 (44%) after DT. Two deaths have occurred, both after neoadjuvant TT. Early data suggests improved RFS in those with pCR. Conclusions: Neoadjuvant targeted and immunotherapy are active regimens in clinical stage III melanoma patients and are associated with high pCR rate. Preliminary data suggest pCR correlates with improved RFS. Updated data will be presented. Clinical trial information: NCT02437279, NCT02231775, NCT02519322, NCT01972347.