Complete Response to BET Inhibitor in Primary Pulmonary NUT Carcinoma With Single-Cell Sequencing-Based Analysis: A Case Report

NUT carcinoma is a rare and highly aggressive malignancy characterized by rapid progression, resistance to conventional therapies, and an extremely poor prognosis. This report presents a 36-year-old patient with stage IIIB primary pulmonary NUT carcinoma who achieved remarkable clinical outcomes with NHWD-870 monotherapy, a novel BET inhibitor. After just 1 month of treatment, imaging revealed a partial response, and a complete response was achieved within 5 months. Postoperative pathologic examination confirmed no residual cancer cells, and the patient has remained disease-free without recurrence or metastasis to date. To explore the underlying mechanisms of this therapeutic response, single-cell RNA sequencing was performed on the tumor tissue, revealing enhanced activity of immune cells, particularly effector CD8+ T-cells, within the tumor microenvironment. This suggests that NHWD-870 exerts its effects through both direct tumor suppression and modulation of the immune microenvironment. This case highlights the exceptional efficacy of BET inhibitors in the treatment of NUT carcinoma, as evidenced by the first report of complete response achieved with BET inhibitor monotherapy, and supports their potential as a personalized therapeutic strategy.