Traditional drug safety assessment often fails to predict complications in humans, especially when the drug targets the immune system. Here, we show the unprecedented capability of two human Organs-on-Chips to evaluate the safety profile of T-cell bispecific antibodies (TCBs) targeting tumor antigens. Although promising for cancer immunotherapy, TCBs are associated with an on-target, off-tumor risk due to low levels of expression of tumor antigens in healthy tissues. We leveraged in vivo target expression and toxicity data of TCBs targeting folate receptor 1 (FOLR1) or carcinoembryonic antigen (CEA) to design and validate human immunocompetent Organs-on-Chips safety platforms. We discovered that the Lung-Chip and Intestine-Chip could reproduce and predict target-dependent TCB safety liabilities, based on sensitivity to key determinants thereof, such as target expression and antibody affinity. These novel tools broaden the research options available for mechanistic understandings of engineered therapeutic antibodies and assessing safety in tissues susceptible to adverse events.

CTLA-4 and CD28 exemplify a co-inhibitory and co-stimulatory signaling axis that dynamically sculpts the interaction of antigen-specific T cells with antigen-presenting cells. Anti-CTLA-4 antibodies enhance tumor-specific immunity through a variety of mechanisms including: blockade of CD80 or CD86 binding to CTLA-4, repressing regulatory T cell function and selective elimination of intratumoral regulatory T cells via an Fcγ receptor-dependent mechanism. AGEN1884 is a novel IgG1 antibody targeting CTLA-4. It potently enhanced antigen-specific T cell responsiveness that could be potentiated in combination with other immunomodulatory antibodies. AGEN1884 was well-tolerated in non-human primates and enhanced vaccine-mediated antigen-specific immunity. AGEN1884 combined effectively with PD-1 blockade to elicit a T cell proliferative response in the periphery. Interestingly, an IgG2 variant of AGEN1884 revealed distinct functional differences that may have implications for optimal dosing regimens in patients. Taken together, the pharmacological properties of AGEN1884 support its clinical investigation as a single therapeutic and combination agent.

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Unprecedented rates of durable clinical responses have been observed for antibody-based therapeutics targeting immune checkpoint proteins such as cytotoxic T lymphocyte antigen-4 (CTLA-4) or programmed death receptor-1 (PD-1). Nonetheless, a significant number of patients experience de novo resistance or relapse due to adaptive resistance mechanisms. T-cell immunoglobulin and mucin domain containing-3 (TIM-3) is an inhibitory receptor involved in immune tolerance often co-opted by tumors to prevent successful antitumor responses. Accordingly, TIM-3 is frequently expressed on myeloid and so-called exhausted T and NK cells within the tumor microenvironment. Targeting the TIM-3 pathway in preclinical models has provided additional rationale for pharmacologic modulation of this axis in cancer patients. INCAGN02390 is a novel and fully human Fc-engineered IgG1κ antibody developed to antagonize the TIM-3 pathway for the treatment of human malignancies. INCAGN02390 forms a high-affinity interaction with TIM-3, occluding access to the CC'-FG binding cleft and blocking phosphatidylserine binding. In addition, INCAGN02390 elicits rapid receptor internalization, potentially obviating interactions with other described or undescribed ligands. INCAGN02390 also enhances IFN-γ production from T cells undergoing tonic TCR stimulation when combined with PD-1 blockade. Finally, to demonstrate combinatorial potential, we show potent antitumor activity of an anti-mouse TIM-3 antibody in concert with other checkpoint antibodies in vivo. In summary, these data support assessment of INCAGN02390 in patients with advanced or metastatic solid tumors. Citation Format: Jeremy Waight, Priyadarshini Iyer, Ekaterina Breous-Nystrom, Christina Riordan, Mark Findeis, Dennis Underwood, Joseph Connolly, Michele Sanicola-Nadel, Horacio Nastri, Peggy Scherle, Gregory Hollis, Reid Huber, Robert Stein, Mark van Dijk, Nicholas S. Wilson. INCAGN02390, a novel antagonist antibody that targets the co-inhibitory receptor TIM-3 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3825.

Traditional drug safety assessment often fails to predict complications in humans, especially when the drug targets the immune system. Here, we show the unprecedented capability of two Organs-on-Chips to evaluate the safety profile of T-cell bispecific antibodies (TCBs) targeting tumor antigens. Although promising for cancer immunotherapy, TCBs are associated with an on-target, off-tumor risk due to low levels of expression of tumor antigens in healthy tissues. We leveraged in vivo target expression and toxicity data of TCBs targeting folate receptor 1 (FOLR1) or carcinoembryonic antigen (CEA) to design and validate human immunocompetent Organs-on-Chips safety platforms. We discovered that the Lung-Chip and Intestine-Chip could reproduce and predict target-dependent TCB safety liabilities, based on sensitivity to key determinants thereof, such as target expression and antibody affinity. These novel tools broaden the research options available for mechanistic understandings of engineered therapeutic antibodies and assessing safety in tissues susceptible to adverse events.