CBA-1535 (5T4/CD3) T‑cell engager given alone and with pembrolizumab for advanced solid tumors

A Phase I Study to Assess the Safety, Tolerability and Biomarker Profiles of CBA-1535, Recombinant Protein Tribody in Patients With Previously Treated Advanced Solid Tumors.

This trial tests whether CBA-1535, a T‑cell engager that targets 5T4, is safe and shows early signs of benefit when given alone or with pembrolizumab to people with advanced solid tumors who have no standard treatment options.

Quick facts

• Phase: PHASE1
• Study type: Interventional
• Enrollment: 70 (estimated)
• Ages: 20 Years and up
• Sex: All
• Sponsor: Chiome Bioscience Inc. (industry)
• Drugs / interventions: Pembrlizumab, pembrolizumab
• Locations: 2 sites (Nagaizumicho, Shizuoka and 1 other locations)
• Trial ID: NCT07016997 on ClinicalTrials.gov

What this trial studies

This is a first‑in‑human, multicenter, open‑label Phase I dose‑escalation program with two parts: Part 1 tests escalating doses of CBA‑1535 as a single agent and Part 2 tests escalating doses of CBA‑1535 combined with pembrolizumab. The study will enroll patients with advanced solid tumors who have exhausted or are intolerant of standard therapies. Primary endpoints focus on safety and tolerability, with secondary and exploratory endpoints including pharmacokinetics, biomarker profiles, and preliminary anti‑tumor activity. Dose escalation will define the recommended dose for subsequent studies.

Who should consider this trial

Good fit: Adults with advanced solid tumors who have no available standard therapy or are refractory/intolerant to standard treatment, with ECOG performance status 0–1 and an expected life expectancy of at least three months, are the intended candidates.

Not a fit: Patients with poor performance status (ECOG >1), recent exposure to other investigational or anti‑cancer agents within the required washout windows, known hypersensitivity to similar protein drugs, or tumors that lack the target antigen may not receive benefit.

Why it matters

Potential benefit: If successful, the drug could offer a new immunotherapy option that engages patients' T cells against 5T4‑expressing tumors, potentially shrinking cancers that no longer respond to standard treatments.

How similar studies have performed: Bispecific T‑cell engagers have produced strong results in blood cancers but only limited, early‑stage signals in solid tumors, and combining bispecifics with checkpoint inhibitors is an emerging approach with promising but not yet proven outcomes.

Eligibility criteria

Inclusion Criteria:

* Patients who provide voluntary written informed consent to participate in the study
* ECOG performance status: \<= 1
* Patients with 3 months or longer life expectancy
* Patients with solid tumors for whom no standard therapy is available or who are refractory to or intolerant of standard therapy

Exclusion Criteria:

* Patients who received other investigational drug or antibody drugs, including immune checkpoint inhibitor within 28 days prior to enrollment
* Patients who received anti-cancer drug within 14 days prior to enrollment
* Patients with previous or suspected hypersensitivity to protein preparations such as therapeutic antibodies (Chinese hamster ovary cell-derived drugs) or any component of the study drug

Where this trial is running

Nagaizumicho, Shizuoka and 1 other locations

• Shizuoka Cancer Center — Nagaizumicho, Shizuoka, Japan (RECRUITING)
• National Cancer Center Hospital — Chuo-Ku, Tokyo, Japan (RECRUITING)

Study contacts

• Study coordinator: Chiome Bioscience Inc.

Conditions: Solid Tumors, Refractory Cancer, CBA-1535, 5T4, CD3, T cell Engager, Trophoblast Glycoprotein, Tribody