Successful Treatment of HIV-Associated Kaposi Sarcoma with Immune Checkpoint Blockade

Kaposi sarcoma (KS) is an incurable, human immunodeficiency virus (HIV)-associated malignancy. We reviewed 320 immunotherapy-treated patient records. Seventeen had HIV-associated malignancies, including nine men with KS. Median viral load was 20 copies/mL (range, undetectable to 549,704) and median CD4 count was 256 cells/μL (range, 10-603). Eight patients received nivolumab and one received pembrolizumab. Six patients (67%) achieved partial (N = 5) or complete remission (N = 1). No drug-related grade >2 toxicities occurred. In seven patients, CD4 counts increased (P = 0.09). Tissue and/or blood-derived circulating tumor DNA (ctDNA) was evaluated by next-generation sequencing. Four evaluable patients each showed anomalies in distinct genes: TP53, KRAS, TLL2, PTPN6 (tissue and/or ctDNA), and NF1 (ctDNA). Tumor mutational burden was low, and PD-L1 immunohistochemistry was negative (three and four assessable patients, respectively). Responders included patients with low CD4 counts, high HIV load, and/or visceral disease. In summary, checkpoint blockade demonstrated significant antitumor activity and low toxicity in patients with HIV-associated KS. Cancer Immunol Res; 6(10); 1129-35. ©2018 AACR.