Context Therapeutics (CNTX) investor relations material

Study background and design

• CTIM-76 is a Claudin 6/CD3 bispecific T cell engager in phase I for advanced solid tumors, focusing on platinum-resistant ovarian, endometrial, and testicular cancers.

• The phase I study began in January 2025, enrolling CLDN6-positive patients with high tumor burden and prior therapies.

• Dose escalation started at 22.5 µg weekly, progressing through six dose levels, with active dose cohorts at 140–280 µg.

• Step dosing and steroid prophylaxis were used to mitigate cytokine release syndrome (CRS).

• Q3-week dosing arm has recently opened, with 280 µg as the starting dose and further evaluation planned.

Patient population and baseline characteristics

• 69% of enrolled patients had ovarian cancer, 23% testicular, and 8% endometrial; median age 61 and median prior therapies was seven.

• Most patients had high tumor burden, frequent liver metastases, and high Claudin 6 expression (median H-score 145).

• In the PROC cohort, all had prior VEGF inhibitor, most had prior ADC exposure, and extensive prior treatments.

Efficacy and anti-tumor activity

• In platinum-resistant ovarian cancer, CTIM-76 achieved a confirmed overall response rate (ORR) of 29% and a disease control rate (DCR) of 57%.

• Tumor reductions and durable responses were observed, including an 85% decrease in target lesion diameter and 95% CA-125 reduction in a notable case.

• Responses were seen in heavily pretreated, ADC-experienced patients, with some maintaining benefit for up to 10 months.

• Anti-tumor activity was also observed in testicular cancer patients.