Tumor targeted 4-1BB agonist antibody-albumin fusions with high affinity to FcRn induce anti-tumor immunity without toxicity.
iScience 2022;
25:104958. [PMID:
36072551 PMCID:
PMC9441337 DOI:
10.1016/j.isci.2022.104958]
[Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 07/21/2022] [Accepted: 08/12/2022] [Indexed: 11/25/2022] Open
Abstract
Costimulation of tumor-infiltrating T lymphocytes by anti-4-1BB monoclonal antibodies (mAbs) has shown anti-tumor activity in human trials, but can be associated with significant off-tumor toxicities involving FcγR interactions. Here, we introduce albumin-fused mouse and human bispecific antibodies with clinically favorable pharmacokinetics designed to confine 4-1BB costimulation to the tumor microenvironment. These Fc-free 4-1BB agonists consist of an EGFR-specific VHH antibody, a 4-1BB-specific scFv, and a human albumin sequence engineered for high FcRn binding connected in tandem (LiTCo-Albu). We demonstrate in vitro cognate target engagement, EGFR-specific costimulatory activity, and FcRn-driven cellular recycling similar to non-fused FcRn high-binding albumin. The mouse LiTCo-Albu exhibited a prolonged circulatory half-life and in vivo tumor inhibition, with no indication of 4-1BB mAb-associated toxicity. Furthermore, we show a greater therapeutic effect when used in combination with PD-1-blocking mAbs. These findings demonstrate the feasibility of tumor-specific LiTCo-Albu antibodies for safe and effective costimulatory strategies in cancer immunotherapy.
Tumor targeted 4-1BB agonist antibody-albumin fusions with high affinity to FcRn
Potent EGFR-specific 4-1BB costimulation and FcRn-driven cellular recycling
Prolonged circulatory half-life and in vivo tumor inhibition, without toxicity
Combination with an anti-PD-1 blocking antibody further enhanced anti-tumor activity
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