FDA Grants Fast Track Designation to CTIM-76 for Platinum-Resistant Ovarian Cancer

The FDA has granted Fast Track Designation to CTIM-76, a claudin-6 (CLDN6) x CD3 T cell engaging bispecific antibody, for the treatment of platinum-resistant ovarian cancer (PROC) in patients who have received all standard of care therapies, according to Context Therapeutics, the company developing the novel treatment.¹

The designation underscores the significant unmet need in a disease setting where treatment options remain limited and outcomes are poor for patients who progress following platinum-based regimens.

“We are pleased to receive Fast Track Designation for CTIM-76, which underscores its potential to improve the lives of patients with platinum-resistant ovarian cancer,” Karen Chagin, MD, chief medical officer of Context, stated in a news release. “This designation is an important step forward in our goal to quickly and efficiently advance CTIM-76 through clinical development and we look forward to sharing interim data for this program in June 2026.”

Rationale for Targeting CLDN6 With CTIM-76

CLDN6 is a validated therapeutic target for multiple solid tumor types, including ovarian, endometrial, testicular, and gastric cancers. It is differentially expressed on cancer cells with no reported expression in normal, healthy tissue, making it an attractive target for tumor-directed immunotherapy.

CTIM-76 is a CLDN6 x CD3 T cell engaging bispecific antibody engineered to bind with high selectivity to CLDN6, redirecting T cells to recognize and kill CLDN6-expressing cancer cells. In preclinical ovarian cancer xenograft models, CTIM-76 effectively inhibited tumor growth and induced complete responses. The molecule's high target specificity relative to closely related claudin family members, particularly CLDN9, has been a key focus of its preclinical development.¹

Phase 1 Trial Design

A phase 1a/b, open-label study (NCT06515613) is underway to examine the safety and efficacy profile of CTIM-76 in patients with PROC and other advanced solid tumors expressing CLDN6.² The study is structured in two sequential components—an initial dose-escalation stage followed by a dose-expansion stage—with interim findings anticipated for release in June 2026.

During the dose-escalation stage, up to 9 cohorts of patients diagnosed with PROC, testicular cancer, or endometrial cancer will be enrolled to identify the optimal dose to carry forward. Patients receive CTIM-76 as an intravenous infusion once per week within 28-day treatment cycles, continuing until progression, intolerable side effects, or a decision by the patient or treating physician to discontinue.

Once escalation is complete, the expansion stage will assess CTIM-76 in at least one tumor type across up to two doses or dosing schedules, with each cohort comprising 20 response-evaluable patients. The tumor types under investigation remain consistent with those in the escalation stage—PROC, testicular cancer, and endometrial cancer. Dose selection for the expansion stage will draw from safety, pharmacokinetic, pharmacodynamic, biomarker, and early efficacy data generated during escalation, ultimately guiding the identification of a recommended phase 2 dose.

To be eligible, patients must be at least 18 years of age with a confirmed CLDN6-positive diagnosis of PROC, advanced testicular cancer, or advanced endometrial cancer. Additional requirements include measurable disease by RECIST v1.1, an ECOG performance status of 0 to 2, a minimum life expectancy of 12 weeks, and adequate baseline organ function. Individuals with CNS metastases, leptomeningeal involvement, spinal cord compression, active uncontrolled infections, or other conditions that would interfere with safe participation are excluded. Total enrollment across both stages is projected at approximately 80 patients.²

The trial's primary end point has 2 components: the rate of dose-limiting toxicities occurring within the first 28 days following the initial dose during the escalation stage, and overall response rate.

References

1. Context Therapeutics Inc. Context Therapeutics announces FDA Fast Track Designation for CTIM-76 for platinum-resistant ovarian cancer [press release]. GlobeNewswire. April 2, 2026. Accessed April 3, 2026. https://tinyurl.com/582fpk72

2. O'Cearbhaill RE, et al. A phase 1, first-in-human study of CTIM-76, a claudin-6 (CLDN6)-directed bispecific antibody, in patients with recurrent ovarian cancer and other advanced solid tumors. J Clin Oncol. 2025;43(16 suppl):TPS2685. doi:10.1200/JCO.2025.43.16_suppl.TPS2685