Preliminary results from a phase II study of nivolumab for patients with metastatic adrenocortical carcinoma (ACC)

96 Background: ACC is an exceedingly rare malignancy with an estimated incidence of 0.7 cases per million per year. Patients presenting with metastatic disease have an estimated 5-year survival rate of < 15%, without effective standard treatment options. Immunotherapy approaches such as checkpoint inhibitors have emerged as effective therapies for multiple malignancies. Nivolumab, a monoclonal IgG4 antibody against the programmed death-1 (PD-1) receptor on T-cells, acts by inhibiting the interaction with PD-L1 and PD-L2 and thus eliciting an increased anti-tumor immune response. This phase II study will assess the efficacy of nivolumab monotherapy according to objective response rate (ORR) in patients with advanced ACC – the study is currently in the patient enrollment phase. Methods: Patients with metastatic or locally advanced ACC with disease progression after treatment with ≥ 1 line of therapy (including mitotane and/or chemotherapy), or not eligible for first-line chemotherapy are currently being enrolled on this phase II study. Nivolumab is given at a fixed dose of 240mg IV q2 weeks until confirmed disease progression, unacceptable toxicity, or withdrawal. Planned accrual of up to 33 patients will follow a Simon two stage design with interim analysis for efficacy after 10 evaluable patients are enrolled. Results: This is an initial report of the first 7 evaluable patients enrolled on study. Median age 57 years; female (4/7); endocrine hyperfunction (2/7); prior chemotherapy with EDP +/- mitotane (5/7). Patients were treated with a median of 4 doses of nivolumab. Median time to progression of 8 weeks. Best overall response rate thus far has been progression of disease in 5 pts, with 2 pts pending evaluation. Grade 3 or 4 adverse events (AEs) at least possibly related to nivolumab: tremor, hypokalemia (1 pt each). Reported grade 1 and 2 AEs: LFT elevation (3 pts), lower extremity edema (2 pts), lymphopenia, urinary frequency and fatigue (1 pt each). Conclusions: Nivolumab has been well tolerated in this population of patients with metastatic ACC. Clinical trial information: NCT02720484.