Abstract 2263: Complete remission of a patient with Merkel cell carcinoma treated with durvalumab

Abstract

Abstract Merkel cell carcinoma (MCC) is a rare, cutaneous, neuroendocrine tumor that is highly aggressive. It is the second leading cause of death from skin cancer, after melanoma, despite accounting for less than 1% of malignant skin tumors. Due to the characteristic histopathological neuroendocrine features of the neoplasm, cases of MCC are often misdiagnosed as undifferentiated skin cancers or other tumors with small blue cell types. Clinical examination fails to establish the diagnosis in 99% of cases and pathological assessment by biopsy with immunohistochemistry is essential to confirm MCC diagnosis. Historically, cytotoxic chemotherapy combinations with platinum-based agents (Carboplatin or Cisplatin) plus Etoposide or Cyclophosphamide, Epirubicin, and Vincristine (CAV) agents were the primary systemic treatment for advanced cases. Despite available evidence sensitivity of MCC to chemotherapy, responses are not durable, and the literature is not supportive of combination chemotherapy (NCCN guidelines). The introduction of immunotherapy such as checkpoint inhibitors (ICI) particularly PD-1/PD-L1 blockers increased overall survival and achieved durable tumor regression in clinical trials leading to FDA approval in locally advanced and metastatic disease. Permbrluzimab and Avelumab are the only two FDA-approved ICIs as first-line standard-of-care treatments for MCC patients. What we are missing is data or trials examining the efficacy of other ICI such as Durvalumab, (anti-PD-L1) in MCC. We hereby report an unprecedented case of an 84-year-old female MCC patient with extensive axillary nodal involvement achieving complete remission after treatment with Durvalumab combined with Carboplatin and Etoposide. Citation Format: Saad Sabbagh, Barbara Dominguez, Houssein Abdul Sater. Complete remission of a patient with Merkel cell carcinoma treated with durvalumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2263.