Combining a WT1 Vaccine (Galinpepimut-S) With Checkpoint Inhibition (Nivolumab) in Patients With WT1–Expressing Diffuse Pleural Mesothelioma: A Phase 1 Study

Introduction: WT1 often presents on the surface of diffuse pleural mesotheliomas (DPMs) and is an ideal therapeutic target. Galinpepimut-S (GPS), a tetravalent, non–human leukocyte antigen–restricted, heteroclitic WT1–specific peptide vaccine was safe and effective in early phase clinical trials and...

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Main Authors: Prashasti Agrawal, MD, Michael Offin, MD, Victoria Lai, MD, Michelle S. Ginsberg, MD, Prasad S. Adusumilli, MD, FACS, Valerie W. Rusch, MD, Jennifer L. Sauter, MD, Teresa Ho, BS, Phillip Wong, PhD, Marjorie G. Zauderer, MD
Format: Article
Language:English
Published: Elsevier 2025-01-01
Series:JTO Clinical and Research Reports
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666364324001267
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Summary:Introduction: WT1 often presents on the surface of diffuse pleural mesotheliomas (DPMs) and is an ideal therapeutic target. Galinpepimut-S (GPS), a tetravalent, non–human leukocyte antigen–restricted, heteroclitic WT1–specific peptide vaccine was safe and effective in early phase clinical trials and upregulates T-cell suppressive programmed death-ligand 1 in the tumor microenvironment of other malignancies. A randomized phase 2 study of adjuvant GPS in patients with DPM trended toward improved median overall survival. Methods: To further enhance immunogenicity, we combined GPS with nivolumab, an anti-PD1 monoclonal antibody, in an open-label, single-center phase 1 study, examining tolerability and immunogenicity in patients with previously treated DPM. We enrolled patients with progressive or recurrent DPM treated with at least one course of pemetrexed-based chemotherapy. Patients received two doses of GPS followed by six doses of GPS with intravenous nivolumab every 2 weeks, and up to six additional cycles until disease progression or unacceptable toxicity. Results: Ten patients were treated; 70% experienced mostly mild treatment-related adverse events; two experienced a grade 3 or higher adverse event. Three of the 10 patients (30%) reported vaccine-specific T-cell responses. There were no partial responses; three patients had prolonged stable disease with up to 17% decrease in tumor volume. Median progression-free survival was 3.9 months and the median overall survival was 7.4 months. Conclusions: Coadministration of GPS and nivolumab reported a tolerable toxicity profile and induced immune responses in a subset of patients, but initial response and survival benefit were limited possibly owing to the small sample size.
ISSN:2666-3643