Investigational Drug
Ubamatamab
TrialFetch AI Analysis
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Overview
Ubamatamab (REGN4018) is an investigational bispecific antibody being studied primarily in recurrent ovarian cancer. Human results are available from a phase 1 study and a randomized phase 2 study, but the reported response rates are preliminary and do not establish a survival benefit. (annalsofoncology.org)
Mechanism of action
Ubamatamab binds MUC16 on tumor cells and CD3 on T cells, bringing the cells together to promote T-cell-mediated tumor killing. (annalsofoncology.org)
Efficacy
In phase 1, the objective response rate was 14.3% (6 of 42 patients) who received at least one full dose in the analyzed dose range; median duration of response was 12.2 months. These patients had received a median of 4.5 prior therapies. (annalsofoncology.org)
In the randomized phase 2 study of 150 patients with platinum-resistant ovarian cancer, objective response rates were 14% with ubamatamab 250 mg, 18% with 800 mg, and 12% with 250 mg plus cemiplimab (50 patients per group). The study abstract reported no efficacy improvement from adding cemiplimab. Among patients without liver metastases, the response rate with 800 mg was 23% (9 of 39). These are subgroup and early-follow-up results, not proof of a comparative benefit. (annalsofoncology.org)
Safety
In phase 2, the most common treatment-emergent events were cytokine release syndrome (85%) and pain (73%), generally grade 1–2 and concentrated during initial step-up dosing. Grade 3 or higher treatment-related events occurred in 40% of patients in each group; neutropenia (14%) and anemia (8%) were the most frequently reported at that severity. 5% discontinued treatment because of a treatment-emergent event. (annalsofoncology.org)
Further reading
- Randomized phase 2 results, Annals of Oncology (2025)
- Phase 1 monotherapy results, Annals of Oncology (2022)
- Mechanism and translational study, Clinical and Translational Science (2024)
Last updated: Sep 2026
Active trials using Ubamatamab
Found 5 active trials using this drug:
TrialFetch AI summary: For patients with previously treated unresectable stage IIIB/IIIC or metastatic NSCLC and ECOG 0–1, this study evaluates ubamatamab, a MUC16 × CD3 T-cell–engaging bispecific antibody, with or without REGN7075, an EGFR × CD28 T-cell–costimulating bispecific antibody. Sarilumab is included to manage immune-related adverse effects.
ClinicalTrials.gov ID: NCT07154290
TrialFetch AI summary: For patients with measurable, progressive platinum-resistant serous or endometrioid ovarian, primary peritoneal, or fallopian tube cancer and ECOG performance status 0–1, this study evaluates ubamatamab, an investigational MUC16×CD3 T-cell–engaging bispecific antibody, with sarilumab. Other arms add bevacizumab, pegylated liposomal doxorubicin, or cemiplimab plus investigational fianlimab, an anti–LAG-3 antibody.
ClinicalTrials.gov ID: NCT06787612
TrialFetch AI summary: Eligible adults have previously treated, locally advanced or metastatic SMARCB1-deficient renal medullary carcinoma or epithelioid sarcoma with MUC16 expression; unclassified renal carcinoma with a medullary phenotype is also eligible. Treatment is ubamatamab, an investigational MUC16×CD3 bispecific antibody that recruits T cells to tumors, alone or with the PD-1 inhibitor cemiplimab.
ClinicalTrials.gov ID: NCT06444880
TrialFetch AI summary: Eligible patients have previously platinum-treated advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer, or recurrent/progressive endometrial cancer after platinum chemotherapy and anti–PD-1 therapy; ECOG performance status must be 0–1. Treatment is REGN5668, an investigational MUC16×CD28 bispecific antibody that provides tumor-directed T-cell costimulation, alone or with cemiplimab (anti–PD-1), cemiplimab plus fianlimab (anti–LAG-3), or ubamatamab (MUC16×CD3), with or without sarilumab.
ClinicalTrials.gov ID: NCT04590326
TrialFetch AI summary: Eligible patients have recurrent or progressive advanced ovarian, fallopian tube, or primary peritoneal cancer after platinum therapy, or recurrent endometrial cancer after platinum chemotherapy and anti–PD-1 therapy with MUC16 expression in at least 25% of tumor cells. Treatment is ubamatamab, an investigational MUC16×CD3 bispecific antibody that recruits T cells to kill tumor cells, alone or with the PD-1 inhibitor cemiplimab.
ClinicalTrials.gov ID: NCT03564340
