Sichuan Baili trims early Phase 1 trial of SI-B036 to 10 patients before dosing starts
The bispecific antibody's first-in-human dose-escalation study cut its target enrollment from 16 to 10 before recruitment opened, a routine sizing move in a Phase 1 safety study.
Executive Summary
- Sichuan Baili Pharmaceutical Co., Ltd. reduced the anticipated enrollment for a Phase 1 study of its bispecific antibody SI-B036 before the trial began recruiting patients.
- The smaller cohort still needs to establish a tolerable dose and a recommended Phase 2 dose, the questions this early-stage safety study is designed to answer.
- The study has not opened for recruitment, so the adjustment reflects trial planning rather than any patient-level outcome or safety signal.
- SI-B036's target and mechanism are not established in the registry, so no direct competitor can be identified, and the closest comparator in this dataset shares only the gastrointestinal-tumor indication, not the drug's biology.
The change
Sichuan Baili Pharmaceutical Co., Ltd. cut the anticipated enrollment target for NCT07678970, a Phase 1 study of its bispecific antibody SI-B036, from 16 to 10 patients on July 16, 2026. The trial, first posted July 1, 2026, has a status of Not yet recruiting, meaning the adjustment took effect before a single patient enrolled. The study is designed to test SI-B036 in patients with locally advanced or metastatic gastrointestinal tumors and other tumors who have received at least one prior line of therapy. NCT07678970A Study of SI-B036 in Patients With Locally Advanced or Metastatic Gastrointestinal Tumors and Other Solid TumorsNCT07678970
What the trial tests
The study is an open-label, single-arm dose-escalation and dose-expansion design with no masking and one treatment arm. Its primary endpoints are dose-limiting toxicity and maximum tolerated dose in the Phase Ia escalation portion, assessed over the first 21 days of dosing, followed by a recommended Phase II dose determination in Phase Ib over roughly 24 months. Secondary endpoints cover pharmacokinetics, immunogenicity, objective response rate, disease control rate, duration of response, and treatment-emergent adverse events. This is the standard information a first-in-human dose-finding study is built to produce: a tolerable dose and a signal on whether to advance into expansion cohorts, not a decision-grade efficacy readout. NCT07678970A Study of SI-B036 in Patients With Locally Advanced or Metastatic Gastrointestinal Tumors and Other Solid TumorsNCT07678970
Reading the enrollment cut
A registry-derived risk read flags the enrollment reduction as a 37.5% decrease against the original target, but the trial's own operational-stability tracking still classifies the study as Stable, with one enrollment change recorded since the trial posted and no other protocol edits. Because the study has not opened enrollment, the change reflects a planning adjustment to cohort size rather than a mid-trial retreat from a recruiting shortfall. The primary completion date remains set for December 1, 2028, unchanged by this update. NCT07678970A Study of SI-B036 in Patients With Locally Advanced or Metastatic Gastrointestinal Tumors and Other Solid TumorsNCT07678970
Where it sits competitively
SI-B036's molecular target is not established in available registry data, so no target-sharing competitor can be identified, and the study cannot be assessed against a first-in-class or isolation claim. Within the gastrointestinal-tumor indication, the nearest entry in this landscape is Novartis's ERW316, a Phase 1/2 program that shares the indication family but differs in modality; the rest of the surrounding field consists of programs in other tumor indications spanning small molecules, antibody-drug conjugates, and monoclonal antibodies rather than direct comparators. SI-B036 is one of 119 active or planned trials across Sichuan Baili's broader pipeline, which includes 71 recruiting, 30 active-not-recruiting, and 14 not-yet-recruiting studies, alongside a single terminated and a single withdrawn trial.
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