Bolt delays BDC-4182 gastric cancer data to Q3 2026 for step-up dosing fix
A protocol change to add step-up dosing after early immune activity pushed Bolt Biotherapeutics' first BDC-4182 data behind a workforce cut and a cash runway extended into 2027.
Executive Summary
- Bolt Biotherapeutics is preparing to report the first human data for its claudin 18.2 immune-stimulating antibody conjugate, a dose-escalation safety readout rather than an efficacy trial.
- The sponsor pushed its data timeline out and rewrote the dosing regimen after seeing an immune response at the initial dose levels, trading speed for a design change meant to manage tolerability.
- The trial has no peer that shares both its target and its antibody-conjugate modality in gastric cancer, leaving it to test a mechanism against a target class other companies are pursuing with different platforms.
- Enrollment, trial status, and the amendment record show no operational strain behind the timing change: guidance has repeated the same quarter across four disclosures since October 2025.
The catalyst
Bolt Biotherapeutics disclosed on October 1, 2025 that it now expects to report initial clinical data from the Phase 1 dose-escalation study of BDC-4182 in the third quarter of 2026, in gastric and gastroesophageal cancer. The company said a strong immune response was observed at the initial dose levels and it was modifying the trial protocol to allow step-up dosing, an approach it said has been used commercially for T-cell engagers. That guidance window, July 1 through September 30, 2026, has repeated unchanged across four disclosures dated October 2025, November 2025, March 2026, and May 2026, the last just over two months before the current date. BoltBolt Biotherapeutics Provides Update on BDC-4182 and Extends Cash Runway into 2027Oct 1, 2025
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
The trial
The study, registered as NCT06921837, is a first-in-human Phase 1/2 trial testing BDC-4182 as a single agent in patients with claudin 18.2-expressing gastric or gastroesophageal cancer who have received one to two prior lines of therapy. It is recruiting, targets 122 patients, and lists a primary completion date of May 1, 2027. The registered primary endpoints are the incidence of dose-limiting toxicities and the incidence and severity of adverse events graded by CTCAE v5.0, a tolerability readout, not a tumor-response endpoint. Enrollment has held flat at its 122-patient target with no growth recorded, and the trial has logged only two registry events since its April 2025 registration: its initial posting and a May 2025 status change from not-yet-recruiting to recruiting. NCT06921837A First-in-Human Study Using BDC-4182 as a Single Agent in Advanced Gastric and Gastroesophageal CancerNCT06921837
The endpoint bar
Because the primary measure is safety, the Q3 2026 disclosure will test whether the step-up dosing regimen keeps dose-limiting toxicities and serious adverse events within a tolerable range while the immune activity observed at the starting doses persists into later cohorts. Objective response rate, disease control rate, and progression-free survival are registered as secondary endpoints, so any activity signal reported alongside the safety data would be exploratory rather than the trial's formal test. NCT06921837A First-in-Human Study Using BDC-4182 as a Single Agent in Advanced Gastric and Gastroesophageal CancerNCT06921837
The competitive frame
Claudin 18.2 is an actively pursued gastric cancer target: zolbetuximab, an antibody now in Phase 3 testing with pembrolizumab and chemotherapy, and osemitamab, an antibody-drug candidate also in Phase 3, both target the same antigen through conventional antibody or antibody-drug conjugate mechanisms rather than an immune-stimulating antibody conjugate. No competitor in the supplied claudin 18.2 field combines that target with Bolt's antibody-conjugate modality, leaving BDC-4182 without a direct modality comparator even as the target itself carries clinical validation from later-stage rivals. The nearest context is a broader claudin 18.2 field of eight trials in the supplied set, spanning antibody, bispecific, CAR-T, and antibody-drug conjugate approaches, phase-weighted toward early development.
Sponsor context
Bolt Biotherapeutics' broader pipeline includes three terminated trials and one active recruiting trial, the BDC-4182 study itself. The company has separately been seeking a partner for BDC-3042, a Dectin-2 agonist that completed a first-in-human Phase 1 dose-escalation trial. BoltBolt Biotherapeutics Provides Update on BDC-4182 and Extends Cash Runway into 2027Oct 1, 2025
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.