Background: Treatment options for cervical, vaginal, and vulvar (GYN) cancers are limited after first-line therapy. Human papillomavirus (HPV) infection is associated with squamous cell carcinomas of the cervix (≥90%) and vulva/vagina (40–70%), and may elicit an immune reaction. Programmed death (PD)-1 and its major ligand PD-L1 are expressed in GYN cancers and inhibit immune responses. Nivolumab disrupts PD-1–mediated signaling, restoring antitumor immunity. Methods: In CheckMate 358 (NCT02488759), an ongoing multicohort study of 5 virus-associated cancers, PD-L1–unselected adults with R/M GYN cancers, ECOG PS 0–1, and ≤2 prior systemic therapies for R/M disease were eligible to receive nivolumab 240 mg every 2 weeks until progression or unacceptable toxicity. Primary endpoints were objective response rate (ORR) and safety; secondary endpoints were duration of response (DoR), progression-free survival (PFS), and overall survival (OS). Results: Of 24 treated patients (pts), 19 had cervical and 5 had vaginal or vulvar cancer; median age was 51 y. At a median follow-up of 31 wks (range: 6–38), ORR was 20.8% (Table), and disease control rate (ORR + SD) was 70.8%. All responses were in pts with cervical cancer (ORR, 26.3%) and were observed regardless of PD-L1 or HPV status or number of prior R/M therapies. Median PFS was 5.5 mo (95% CI: 3.5, NR); median OS was NR. Conclusions: Nivolumab demonstrated encouraging clinical activity in pts with cervical cancer and a manageable safety profile in virus-associated GYN cancers, supporting further evaluation in these pts. Updated clinical and biomarker data to be presented. Clinical trial information: NCT02488759

NR = not reached.