A Study of SI-B036 in Patients With Locally Advanced or Metastatic Gastrointestinal Tumors and Other Solid Tumors

A Phase I Clinical Study to Evaluate the Safety, Tolerability, Pharmacokinetic Characteristics and Preliminary Efficacy of SI-B036 Bispecific Antibody Injection in Patients With Locally Advanced or Metastatic Gastrointestinal Tumors and Other Solid Tumors

This study is an open-label, multicenter, non-randomized Phase I clinical study with dose-escalation and expansion cohorts, designed to evaluate the safety, tolerability, pharmacokinetic characteristics, and preliminary efficacy of SI-B036 bispecific antibody injection in patients with locally advanced or metastatic gastrointestinal tumors and other solid tumors.

Study Overview

• Status: Not yet recruiting
• Conditions: Solid Tumor; Gastrointestinal Tumor
• Intervention / Treatment: Drug: SI-B036

Detailed Description

The study consists of two phases: a dose-escalation phase (Phase Ia) and an expansion cohort phase (Phase Ib).

• Study Type: Interventional
• Enrollment (Estimated): 16
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Sa Xiao, PHD; Phone Number: 15013238943; Email: xiaosa@baili-pharm.com

Study Locations

• China
  • Heilongjiang
    • Harbin, Heilongjiang, China
      • Harbin Medical University Cancer Hospital
      • Contact: Tongsen Zheng

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Voluntarily sign the informed consent form and agree to follow the protocol requirements;
2. No gender restriction;
3. Age: ≥18 years and ≤75 years;
4. Expected survival time ≥3 months;
5. Locally advanced or metastatic digestive tract tumors and other solid tumors;
6. Agree to provide archived tumor tissue specimens within 2 years from the primary or metastatic lesion, or fresh tissue samples;
7. Must have at least one measurable lesion as defined by RECIST v1.1;
8. Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1;
9. Toxicity from prior anti-tumor therapy must have recovered to ≤ Grade 1 as defined by NCI-CTCAE v6.0;
10. No severe cardiac dysfunction, with left ventricular ejection fraction (LVEF) ≥50%;
11. Organ function levels must meet the protocol requirements;
12. Coagulation function: International Normalized Ratio (INR) ≤1.5, and activated partial thromboplastin time (APTT) ≤1.5 × upper limit of normal (ULN);
13. Urine protein ≤2+ or ≤1000 mg/24 h;
14. For premenopausal women of childbearing potential, a pregnancy test must be performed within 7 days before starting treatment, with a negative serum pregnancy result, and they must not be breastfeeding; all enrolled patients (regardless of male or female) should use adequate barrier contraceptive measures throughout the entire treatment period and for 6 months after treatment completion;
15. Trial participants are capable of and willing to comply with the visit schedules, treatment plans, laboratory tests, and other study-related procedures as stipulated in the study protocol.

Exclusion Criteria:

1. Use of chemotherapy, biotherapy, immunotherapy, etc. within 4 weeks or 5 half-lives prior to the first dose;
2. Receipt of immunosuppressive medications within 2 weeks prior to the first dose;
3. History of severe cardiac or cerebrovascular disease;
4. Prolonged QTc interval, complete left bundle branch block, third-degree atrioventricular block, or frequent and uncontrolled arrhythmias;
5. Active autoimmune diseases and inflammatory diseases;
6. Prior history of ≥ Grade 3 toxicity related to anti-angiogenic therapy during previous anti-angiogenic treatment;
7. Diagnosis of another solid tumor within 5 years prior to the first dose;
8. Unstable thrombotic events requiring therapeutic intervention within 6 months prior to the first dose;
9. Uncontrolled hypertension;
10. Diabetic patients with poorly controlled blood glucose;
11. History of interstitial lung disease (ILD) requiring steroid therapy, or current ILD, or ≥ Grade 2 radiation pneumonitis;
12. Concurrent pulmonary disease resulting in severe impairment of respiratory function;
13. Patients with active central nervous system (CNS) metastases;
14. History of allergy to recombinant humanized antibodies or human-mouse chimeric antibodies, or allergy to any excipient component of SI-B036;
15. Prior history of organ transplantation or allogeneic hematopoietic stem cell transplantation;
16. Positive for human immunodeficiency virus (HIV) antibodies, active tuberculosis, active hepatitis B virus infection, or active hepatitis C virus infection;
17. Active infection requiring systemic therapy within 4 weeks prior to the first study drug administration;
18. Presence of pleural, abdominal, or pelvic effusion or pericardial effusion requiring drainage and/or accompanied by symptoms within 4 weeks prior to the first study drug administration;
19. Imaging findings indicating that the tumor has invaded or encased the major thoracic blood vessels;
20. Subjects with clinically significant bleeding or obvious bleeding tendency within 4 weeks prior to screening;
21. History of fistula, gastrointestinal perforation, or abdominal abscess within 6 months prior to the first dose;
22. Use of another investigational drug within 4 weeks or 5 half-lives prior to the first dose;
23. Pregnant or lactating women;
24. Other conditions deemed by the investigator to make the subject unsuitable for participation in this clinical trial.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: SI-B036; Participants receive SI-B036 for the first cycle (3 weeks). Participants with clinical benefit could receive additional treatment for more cycles. The administration will be terminated because of disease progression or intolerable toxicity occurring or other reasons.	Drug: SI-B036; Administration by intravenous infusion for a cycle of 3 weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phase Ia: Dose limiting toxicity (DLT)	DLTs are assessed according to NCI-CTCAE v5.0 during the first cycle and defined as occurrence of any of the toxicities in DLT definition if judged by the investigator to be possibly, probably or definitely related to study drug administration.	Up to 21 days after the first dose
Phase Ia: Maximum tolerated dose (MTD)	MTD is defined as the highest dose level at which no more than 1 in 6 participants experienced a DLT during the first cycle.	Up to 21 days after the first dose
Phase Ib: Recommended Phase II Dose (RP2D)	The RP2D is defined as the dose level chosen by the sponsor (in consultation with the investigators) for phase II study, based on safety, tolerability, efficacy, PK, and PD data collected during the dose escalation study of SI-B036.	Up to approximately 24 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate (ORR)	ORR is defined as the percentage of participants, who has a CR (disappearance of all target lesions) or PR (at least a 30% decrease in the sum of diameters of target lesions). The percentage of participants who experiences a confirmed CR or PR is according to RECIST 1.1.	Up to approximately 24 months
AUC0-t	AUC0-t is defined as area under the serum concentration-time curve from time 0 to the time of the last measurable concentration.	Up to approximately 24 months
Phase Ib: Disease Control Rate (DCR)	The DCR is defined as the percentage of participants who has a CR, PR, or Stable Disease (SD: neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease [PD: at least a 20% increase in the sum of diameters of target lesions and an absolute increase of at least 5 mm. The appearance of one or more new lesions is also considered PD]).	Up to approximately 24 months
Phase Ib: Duration of Response (DOR)	The DOR for a responder is defined as the time from the participant's initial objective response to the first date of either disease progression or death, whichever occurs first.	Up to approximately 24 months
Treatment-Emergent Adverse Event (TEAE)	TEAE is defined as any unfavorable and unintended change in the structure, function, or chemistry of the body temporally emerging, or any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a pre-existing condition during the treatment of SI-B036. The type, frequency and severity of TEAE will be evaluated during the treatment of SI-B036.	Up to approximately 24 months
Cmax	Maximum serum concentration (Cmax) of SI-B036 will be investigated.	Up to approximately 24 months
Tmax	Time to maximum serum concentration (Tmax) of SI-B036 will be investigated.	Up to approximately 24 months
T1/2	Half-life (T1/2) of SI-B036 will be investigated.	Up to approximately 24 months
CL (Clearance)	CL in the serum of SI-B036 per unit of time will be investigated.	Up to approximately 24 months
Ctrough	Ctrough is defined as the lowest serum concentration of SI-B036 prior to the next dose will be administered.	Up to approximately 24 months
ADA (anti-drug antibody)	Frequency of anti-SI-B036 antibody (ADA) will be investigated.	Up to approximately 24 months
Phase Ia: Progression-free survival (PFS)	Progression-free survival (PFS) as assessed by BICR is defined as the time between the date subjects were randomized and the first observation of disease progression (based on BICR's image-based assessment) or death.	Up to approximately 24 months

Collaborators and Investigators

• Sponsor: Sichuan Baili Pharmaceutical Co., Ltd.
• Collaborators: Baili-Bio (Chengdu) Pharmaceutical Co., Ltd.

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: June 25, 2026
• First Submitted That Met QC Criteria: June 25, 2026
• First Posted (Actual): July 1, 2026

Study Record Updates

• Last Update Posted (Actual): July 1, 2026
• Last Update Submitted That Met QC Criteria: June 25, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Digestive System Diseases; Digestive System Neoplasms
• Other Study ID Numbers: SI-B036-102

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No