Novel Combination Immunotherapy and Clinical Activity in Patients With HPV-Associated Cancers

IMPORTANCE Patients who experience progression of advanced human papillomavirus (HPV)–associated cancers and who have previously received first-line systemic treatment have a poor prognosis and limited therapeutic options. OBJECTIVE To assess the clinical activity of the combination of the HPV type 16 therapeutic vaccine PDS0101, the tumor-targeting interleukin 12 antibody-drug conjugate PDS01ADC, and the bifunctional anti–programmed cell death ligand 1 (PD-L1)/transforming growth factor β (TGF-β) bintrafusp alfa in advanced HPV-associated cancers. DESIGN, Setting, and Participants This nonrandomized clinical trial was phase 1/2 and investigator initiated, and was conducted at a single US cancer research center between June 2020 and July 2022. Patients with advanced or metastatic HPV-associated cancers were eligible, including patients who were both immune checkpoint blockade (ICB) naive and ICB resistant. The cutoff date for data analysis was May 13, 2024. INTERVENTION Patients received 1 mL of PDS0101 subcutaneously every 4 weeks for 6 doses then every 12 weeks for 2 additional doses, PDS01ADC, 16.8 µg/kg, subcutaneously every 4 weeks or PDS01ADC, 8 µg/kg, subcutaneously every 2 weeks, and bintrafusp alfa, 1200 mg, intravenously every 2 weeks. MAIN OUTCOMES AND MEASURES Objective response rate (ORR) by Response Evaluation Criteria in Solid Tumors version 1.1 in ICB-naive patients. RESULTS Of the 50 eligible patients, 26 (52%) were men and the median age was 56 years (range, 28-80 years). The median (IQR) follow-up was 37.7 (30.6-42.0) months. Fourteen patients (28%) were ICB naive, with an ORR of 35.7% (95% CI, 12.8%-64.9%), and median overall survival (OS) 42.4 months (95% CI, 8.3 months-not estimable); in ICB-resistant patients, the ORR was 16.7% (6 of 36 patients; 95% CI, 6.4%-32.8%) and median OS was 15.8 months (95% CI, 9.0-21.3 months). Among patients with HPV-16–positive tumors (37 patients [74%]), in the ICB-naive group (8 patients [21.6%]) the ORR was 62.5% (95% CI, 24.5%-91.5%) and a median OS measure was not reached. Grade 3 and 4 treatment-related adverse events occurred in 26 of 50 patients (52%). There were no treatment-related deaths. CONCLUSIONS AND RELEVANCE In this trial, the combination of PDS0101, PDS01ADC, and bintrafusp alfa showed an acceptable safety profile and promising antitumor activity and improved OS in patients with HPV-16–positive cancers, in both ICB-naive and ICB-resistant patients, warranting further evaluation of the combination of PDS0101 and PDS01ADC with simultaneous PD-L1/TGF-β inhibition in these populations. Trial Registration ClinicalTrials.gov Identifier: NCT04287868