A Phase 1/2 study of BDC-4182, a claudin18.2-targeting next generation immune-stimulating antibody conjugate (ISAC), in patients with advanced gastric and gastroesophageal cancer
Presenter: Sophia Frentzas, MD Session: Phase I Clinical Trials in Progress Time: 4/20/2026 9:00:00 AM → 4/20/2026 12:00:00 PM
Authors
Sophia Frentzas 1 , Michelle Morris 2 , Megan Barnet 3 , Niall Tebbutt 4 , Mark Wong 5 , Michael Michael 6 , Hyung-Don Kim 7 , Keun-Wook Lee 8 , Sun Young Rha 9 , Sang Cheul Oh 10 , I-Chen Wu 11 , Li-Yuan Bai 12 , Wen-Chi Chou 13 , Ming-Huang Chen 14 , Yen-Yang Chen 15 , Chia-Chi Lin 16 , Anthony Rodrigues 3 , Jason Ptacek 17 , Michael N. Alonso 17 , Tariq Arshad 17 , Jakob Dupont 17 , Kristi Balacy 17 , Sung Hee Lim 18 1 Monash Medical Centre, Clayton, Australia, 2 Sunshine Coast University Hospital, Birtinya, Australia, 3 St Vincent Hospital Sydney (The Kinghorn Cancer Centre), Darlinghurst, Australia, 4 Austin Health, Heidelberg, Australia, 5 Westmead Hospital, Westmead, Australia, 6 Peter MacCallum Cancer Centre, Melbourne, Australia, 7 Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of, 8 Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea, Republic of, 9 Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea, Republic of, 10 Korea University Guro Hospital, Seoul, Korea, Republic of, 11 Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan, 12 China Medical University Hospital, China Medical University, Taichung City, Taiwan, 13 Linkou Chang Gung Memorial Hospital, Taoyuan City, Taiwan, 14 Taipei Veterans General Hospital, Taipei City, Taiwan, 15 Kaohsiung Chang Gung Memorial Hospital, Kaohsiung City, Taiwan, 16 National Taiwan University Hospital, Taipei, Taiwan, 17 Bolt Biotherapeutics, Redwood City, CA, 18 Samsung Medical Center, Seoul, Korea, Republic of
Abstract
Background: Claudin 18.2 (CLDN18.2) is a transmembrane tight junction protein with expression restricted to the gastric mucosal epithelia where CLDN18.2 protects against paracellular acid leakage and associated gastritis. 1 CLDN18.2 overexpression has been observed in several tumor types, including gastric, esophageal, and pancreatic cancer. 2,3 Loss of cell polarity in these tumors results in CLDN18.2 localization to surfaces that are more readily accessible to biologics and effector cells. This expression pattern makes CLDN18.2 a compelling target for immune-stimulating antibody conjugates (ISACs) that combine the specificity of tumor-targeting antibodies with the potency and durability of immune activation. BDC-4182 is a next-generation ISAC consisting of a CLDN18.2-targeting antibody covalently attached to a novel toll-like receptor (TLR)7/8 agonist via a non-cleavable linker. In preclinical models, systemic delivery of ISACs has been shown to broadly activate the innate and adaptive immune system, leading to complete tumor regression. A BDC-4182 surrogate induced immunologic memory and epitope spreading as evidenced by rejection of tumor cells that no longer express the target antigen (CLDN18.2) following re-challenge. 4,5 Methods: This is a first-in-human Phase 1 dose escalation and Phase 2 expansion study of BDC-4182. Up to 122 patients with advanced gastric and gastroesophageal cancer will be enrolled. To optimize tolerability, BDC-4182 is administered via an intra-patient step-up dosing regimen wherein subjects receive lower initial priming doses prior to the target dose. Primary objectives are to define safety and tolerability and to determine the recommended phase 2 dose (RP2D) of BDC-4182 as a single agent. Secondary objectives will evaluate the preliminary anti-tumor activity of BDC-4182, analyze PK characteristics of BDC-4182, and evaluate the immunogenicity of BDC-4182 as a single agent. Exploratory analyses will also be conducted to explore potential biomarkers in blood and tumor tissue associated with exposure, efficacy, or safety of BDC-4182, and to define CLDN18 expression in tumor tissue. This study is being conducted in Australia, South Korea, and Taiwan. References: 1. Suzuki K, Sentani K, Tanaka H, et al. Cell Mol Gastroenterol Hepatol. 2019;8:119-142. 2. Hong JY, An JY, Lee J, et al. Transl Cancer Res. 2020;9:3367-3374. 3. Chen J, Xu Z, Hu C, et al. Front Oncol. 2023;13:1132319.4. Fu C, Luo A, Liu J, et al. J Immunother Cancer. 2024;12(Suppl 2):Abstract 1052. 5. Kim HK, Monnier J, Fu C, et al. J Immunother Cancer. 2023;11(Suppl 1):Abstract 1147-D.
Disclosure
S. Frentzas, None.. M. Morris, None.. M. Barnet, None.. N. Tebbutt, None.. M. Wong, None.. M. Michael, None.. H. Kim, None. K. Lee, Bolt Biotherapeutics ). ALX Oncology ). Amgen ). Arcus ). Astellas Independent Contractor, ), Other, Honoraria / speaker fees. AstraZeneca ). BeOne ). Daiichi Sankyo Independent Contractor, ), Other, Honoraria / speaker fees. Exelixis ). AbbVie Independent Contractor. GSK ). Sanofi/Aventis ), Other, Honoraria / speaker fees. Immuneoncia Independent Contractor, ). Jazz ). Leap ). Medicenna ). MedPacto ). Merck KGaA Honoraria / speaker fees. Pfizer ). Roche ). S. Rha, None.. S. Oh, None.. I. Wu, None.. L. Bai, None.. W. Chou, None.. M. Chen, None.. Y. Chen, None.. C. Lin, None.. A. Rodrigues, None. J. Ptacek, Bolt Biotherapeutics Employment, Stock Option. M. N. Alonso, Bolt Biotherapeutics Employment, Stock Option. T. Arshad, Bolt Biotherapeutics Employment, Stock Option. J. Dupont, Bolt Biotherapeutics g., Board of Directors, non-salaried role). K. Balacy, Bolt Biotherapeutics Employment, Stock Option. S. Lim, None.
Cited in
Control: 10028 · Presentation Id: 12191 · Meeting 21436