Bintrafusp alfa, a first-in-class bifunctional fusion protein composed of the extracellular domain of the TGF-βRII receptor fused to a human IgG1 monoclonal antibody blocking PD-L1, showed a long-term efficacy and a manageable safety profile in patients with pretreated, immune checkpoint inhibitor-naive malignancies associated with human papillomavirus (HPV). The findings are reported by Prof. James Gulley of the Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health in Bethesda, MD, US during the proffered papers session on investigational immunotherapy at ESMO Congress 2021 (16-21 September).
Prof. Gulley told the audience that anti–PD(L)1 agents are active in HPV-associated malignancies, with median overall survival (mOS) of ≤12 months. HPV infection has been linked to upregulation of tumour TGF-β signalling.
The study team previously reported a post hoc pooled analysis of patients with HPV-associated malignancies who were treated with bintrafusp alfa. At ESMO Congress 2021, they report longer follow-up of additional patients with HPV-associated malignancies pooled from the phase I (INTR@PID 001; NCT02517398) and phase II (study 012; NCT03427411) studies.
A total of 75 patients with pretreated HPV-associated malignancies received bintrafusp alfa in the phase I study until 15 May 2020 and until 22 December 2020 in the phase II study. Among included patients 39 had cervical cancer, 19 patients had squamous cell carcinoma of head and neck, 9 patients had anal cancer, and 8 patients had other cancer types. Median duration of treatment was 3.2 months (range, 0.5-29.9). Median follow-up was 33 months and 3 patients remained on treatment.
The objective response rate was 28.0% with 4 complete responses and 17 partial responses (PR); 3 additional patients had a delayed PR leading to a clinical response rate of 32.0% according RECIST. Responses occurred in various HPV-associated malignancies.
Median duration of response was 17.3 months (95% confidence interval [CI] 7.8-NE).
The mOS was 21.3 months (95% CI, 10.8-NE) with 12-months OS rate of 59.7% and 18-months OS rate of 51.5%, respectively.
The most common treatment-related adverse events (TRAEs) were pruritus occurring in 25.3% cases and all being of grade 1, dermatitis acneiform occurring in 24.0% and all grade 1, and anaemia occurring in 18.7% patients with grade 3 occuring in 6.7% patients. There were no deaths due to TRAEs.
The authors concluded that in this population with a high unmet medical need, bintrafusp alfa showed long-term efficacy and manageable safety. Clinical studies with bintrafusp alfa are ongoing in patients with HPV-associated malignancies.
This study was funded by Merck KGaA, Darmstadt, Germany, and GlaxoSmithKline.
957O – Strauss J, Gatti-Mays M, Cho BC, et al. Long-term follow-up of patients (pts) with human papillomavirus (HPV)–associated malignancies treated with bintrafusp alfa, a bifunctional fusion protein targeting TGF-β and PD-L1. ESMO Congress 2021 (16-21 September).