Molloy ME, Austin RJ, Lemon BD, Aaron WH, Ganti V, Jones A, Jones SD, Strobel KL, Patnaik P, Sexton K, Tatalick L, Yu TZ, Baeuerle PA, Law CL, Wesche H. Preclinical Characterization of HPN536, a Trispecific, T-Cell-Activating Protein Construct for the Treatment of Mesothelin-Expressing Solid Tumors.
Clin Cancer Res 2020;
27:1452-1462. [PMID:
33262134 DOI:
10.1158/1078-0432.ccr-20-3392]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 10/12/2020] [Accepted: 11/25/2020] [Indexed: 11/16/2022]
Abstract
PURPOSE
Mesothelin (MSLN) is a glycophosphatidylinositol-linked tumor antigen overexpressed in a variety of malignancies, including ovarian, pancreatic, lung, and triple-negative breast cancer. Early signs of clinical efficacy with MSLN-targeting agents have validated MSLN as a promising target for therapeutic intervention, but therapies with improved efficacy are still needed to address the significant unmet medical need posed by MSLN-expressing cancers.
EXPERIMENTAL DESIGN
We designed HPN536, a 53-kDa, trispecific, T-cell-activating protein-based construct, which binds to MSLN-expressing tumor cells, CD3ε on T cells, and to serum albumin. Experiments were conducted to assess the potency, activity, and half-life of HPN536 in in vitro assays, rodent models, and in nonhuman primates (NHP).
RESULTS
HPN536 binds to MSLN-expressing tumor cells and to CD3ε on T cells, leading to T-cell activation and potent redirected target cell lysis. A third domain of HPN536 binds to serum albumin for extension of plasma half-life. In cynomolgus monkeys, HPN536 at doses ranging from 0.1 to 10 mg/kg demonstrated MSLN-dependent pharmacologic activity, was well tolerated, and showed pharmacokinetics in support of weekly dosing in humans.
CONCLUSIONS
HPN536 is potent, is well tolerated, and exhibits extended half-life in NHPs. It is currently in phase I clinical testing in patients with MSLN-expressing malignancies (NCT03872206).
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