1122P - Interim analysis of a single arm phase II study of adjuvant nivolumab after salvage resection in head and neck squamous cell carcinoma patients previously treated with definitive therapy

Abstract

BackgroundSurgical salvage is often the only potentially curative treatment in patients with recurrent head and neck squamous cell carcinoma (HNSCC). However, local control rates after salvage remain at 33-50% with a dismal long term overall survival of 20-40%. Many patients are ineligible for re-irradiation and chemotherapy alone has no survival benefit after salvage surgery necessitating new therapies. Although immune checkpoint inhibitors have demonstrated clinical activity in the metastatic setting, immunotherapy has not been explored after salvage surgery. Therefore, we initiated a multi-center Phase II investigation of adjuvant nivolumab after salvage resection in HNSCC patients (NCT03355560) supported by BMS. MethodsHNSCC patients who failed definitive radiation, subsequently treated with curative intent salvage resection, were enrolled to receive 6 months of nivolumab beginning 4 to 11 weeks after surgery. Safety was evaluated with CTCAE v5.0 and disease free survival (DFS) was evaluated using time to event endpoints and Kaplan-Meier curves. ResultsEighteen of 35 planned patients have been enrolled. Median age is 70 years (range, [45-85]), 4/18 (22%) were female, 17/18 (94%) were white, disease sites included oropharyngeal 3/18 (17%), oral cavity 8/18 (44%) and larynx 7/18 (39%), and 5/18 (28%) had high risk (positive margins or extranodal spread) pathological features. Four patients have recurred with DFS estimated at 55% at 10.2 months. Although estimated DFS is less than the predicted 62.3% DFS at 10.2 months (extrapolated from 2-year DFS of 33%), the chi-square p-value was 0.861 suggesting there is not enough evidence to reject the null hypothesis and the trial should proceed to the 2nd stage. Most common adverse events included fever (22%), fatigue (17%), arthralgias (22%), cough (28%) and infections (28%) most of which were unrelated. Grade 3 related events included arthralgia and cough. ConclusionsAdjuvant nivolumab after salvage surgery in HNSCC patients is safe however, increased enrollment is required to establish efficacy. Clinical trial identificationNCT03355560. Legal entity responsible for the studyTrisha Wise-Draper. FundingBMS. DisclosureT. Wise-Draper: Research grant / Funding (self): BMS; Research grant / Funding (self): AstraZeneca; Research grant / Funding (self): Merck; Research grant / Funding (institution): Tesaro. All other authors have declared no conflicts of interest.