1129PWindow of opportunity for durvalumab (MEDI4736) plus metformin trial in squamous cell carcinoma of the head and neck (SCCHN): Interim safety analysis

Abstract Background Despite the application of PD-1 inhibitors in clinical practice in SCCHN, only a fraction of patients shows durable responses to monotherapy. Numerous combinatorial strategies have been utilized to attempt to augment immunotherapy efficacy. While dysregulated tumour metabolism (TM) is a critical feature of the tumour microenvironment (TME) and impacts immune function within the TME, much remains to be done to bridge these areas and explore therapeutic opportunities. Recent murine xenograft and clinical translational data suggests that metformin alters TM, and preclinical data suggests possible potentiation of PD-1 axis inhibition by metformin. Methods This is a single-center, randomized trial for patients with all stages of resectable SCCHN, with planned enrollment of 38 patients. Part 1, which has been completed, was a safety run-in with 6 patients treated with metformin (met) + durvalumab (durva) for safety evaluation. Part 2 will enroll 32 additional patients with a 3:1 randomization to treatment arm A (met 1000 mg BID Day 1-31 + durva 1500 mg IV x 1 on Day 3) and treatment arm B (durva 1500 mg IV x 1). Tumor and blood will be collected pre and post treatment with analysis of immune cell composition. The primary endpoint is the combined effect of metformin and durvalumab on the immune TME, specifically with respect to alterations in T cell and macrophage polarization. Secondary endpoints include safety and tolerability, alterations in immunohistochemical markers of the TME, transcriptome and circulating DNA analysis, and objective response rate. Results Six patients were enrolled in Part 1. All were males with a mean age of 65.7 ± 6.8 years. All patients had grade 1 adverse events (AE) consisting mainly of gastrointestinal (diarrhea, nausea, or abdominal cramps) and constitutional (anorexia, fatigue, or sleep disturbance) symptoms. No patient experienced AE > = grade 2. All patients were able to proceed to surgery without unanticipated delays. Conclusions The combination of met and durva was safe in the first cohort of patients. Enrollment for Part 2 is ongoing. Clinical trial identification NCT03618654. Legal entity responsible for the study Sidney Kimmel Cancer Center at Thomas Jefferson University Sidney Kimmel Cancer Center at Thomas Jefferson University Sidney Kimmel Cancer Center at Thomas Jefferson University Sidney Kimmel Cancer Center at Thomas Jefferson University. Funding Sidney Kimmel Cancer Center at Thomas Jefferson Uni