FDA Grants Fast Track Designation to CTX-009 in Biliary Tract Cancer

CTX-009, a bispecific antibody, plus chemotherapy has received a Fast Track designation by the FDA for patients with pretreated biliary tract cancer.

The Food and Drug Administration (FDA) has granted Fast Track Designation to the bispecific antibody CTX-009 in combination with the chemotherapy paclitaxel. The treatment combination treats patients with metastatic or locally advanced biliary tract cancers that have been previously treated, according to an announcement from CTX-009 manufacturer Compass Therapeutics, Inc.

Fast Tracking, according to the FDA’s website, “is a process designed to facilitate the development, and expedite the review of drugs to treat serious conditions and fill an unmet medical need. The purpose is to get important new drugs to the patient earlier. Fast Track addresses a broad range of serious conditions.”

“We are delighted that CTX-009 has received FDA Fast Track Designation highlighting the large unmet need in patients with advanced BTC where current therapies have low, single-digit response rates, and limited effect on patient survival,” stated Dr. Thomas Schuetz, co-founder, president of research and development, and vice chairman of the Compass board, in the company’s news release. “Our current study is evaluating the combination of CTX-009 with paclitaxel following the observation of nine partial responses in 24 patients treated in our Phase 2 study, leading to an overall response rate [patients whose disease responded partially or completely to treatment] of 37.5%, a median progression-free survival [the time a patient lives without their disease spreading or worsening] of 9.4 months and a median overall survival [the time a patient lives following treatment, regardless of disease status] of 12.5 months. Compass remains on track to complete enrollment by mid-year and reporting top-line data by year-end.”

With approximately 150 participants, the phase 2/3 trial is expected to be completed by December 2025, according to its listing on ClinicalTrials.gov.

A bispecific DLL4/VEGF-A antibody, CTX-009 is intended to block the formation of blood vessels in a patient’s tumor. According to Compass Therapeutics, early data suggests that treatment with CTX-009 resulted in anti-tumor activity in solid tumors. These cancer types include colorectal, gastric, cholangiocarcinoma, pancreatic and non-small cell lung cancers.

Phase 2 study results published in 2023 in the Journal of Clinical Oncology showed that treatment-related side effects of any grade were reported in 100% of patients with advanced biliary tract cancer, with grade 3 or higher treatment-related side effects being reported in 75% of patients, including one death from pneumonia.

The most frequent grade 3 or higher side effects were neutropenia (a low count of neutrophils, a type of white blood cell; 50%), hypertension (16.7%), anemia (low red blood cell count; 12.5%) and thrombocytopenia (low platelet count; 8.3%), while six patients (25% of patients) discontinued the study treatment due to treatment-emergent side effects (confusional state, pulmonary embolism, increased blood creatinine, pneumonia, biliary fistula and large intestine perforation), researchers reported.

The FDA previously approved Keytruda (pembrolizumab) plus the chemotherapy drugs gemcitabine and cisplatin for the treatment of patients with locally advanced unresectable or metastatic biliary tract cancer in 2023 and the agency approved Imfinzi (durvalumab) plus gemcitabine and cisplatin for the treatment of patients with locally advanced or metastatic biliary tract cancer in 2022.

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