PRGN-2009 and bintrafusp alfa for patients with advanced or metastatic human papillomavirus-associated cancer
Charalampos S. Floudas, Meghali Goswami, Renee N. Donahue, Julius Strauss, Danielle M. Pastor, Jason M. Redman, Isaac Brownell, Evrim Türkbey, Seth M. Steinberg, Lisa M. Cordes, Jennifer L. Marté, Maheen Khan, Sheri McMahon, Elizabeth Lamping, Michell Manu, Manuk Manukyan, Douglas E. Brough, Amy Lankford, Caroline Jochéms, Jeffrey Schlom, James L. Gulley
Abstract
BACKGROUND: This first-in-human phase 1 study (NCT04432597) evaluated the safety and recommended phase 2 dose (RP2D) of PRGN-2009, a gorilla adenoviral-vector targeting oncoproteins E6, E7 (human papillomavirus (HPV)16/18) and E5 (HPV16), as monotherapy (Arm 1A) and combined with the bifunctional TGF-β "trap"/anti-PD-L1 fusion protein bintrafusp alfa (BA; Arm 1B), in patients with recurrent/metastatic HPV-associated cancer. METHODS: particle units, subcutaneously) every 2 weeks for 3 doses, then every 4 weeks (Arm 1A), or PRGN-2009 (RP2D, schedule per Arm 1A) and BA (1200 mg, intravenously) every 2 weeks (Arm 1B). Primary endpoints were safety and RP2D of PRGN-2009; secondary objectives included overall response rate (ORR) and overall survival (OS). RESULTS: PU was selected as RP2D, no responses were observed, and median OS (mOS) was 7.4 months (95% CI 2.9-26.8). In Arm 1B (n = 11), grade 3/4 TRAEs occurred in 27% of patients, ORR was 20% for all patients (22% in checkpoint-resistant patients), and mOS was 24.6 months (95% CI 9.6-not reached). Multifunctional HPV-specific T cells were increased or induced de novo in 80% of patients and not impacted by anti-vector antibodies. Higher serum IL-8 at baseline associated with shorter OS. CONCLUSIONS: PRGN-2009 was well tolerated, and immune responses were observed to PRGN-2009. Encouraging anti-tumor activity and OS were noted in the combination with BA arm, consisting mainly of checkpoint-resistant patients. Trial Registration ClinicalTrials.gov Identifier: NCT04432597.