Leap Therapeutics has initiated Part B of the DeFianCe Phase II study to assess DKN-01 along with bevacizumab and chemotherapy as a second-line treatment for patients with advanced colorectal cancer (CRC).

The randomised controlled Part B of the study intends to enrol 130 patients with advanced CRC.

Progression-free survival is the primary objective of the study while overall survival, duration of response, and overall response rate are secondary objectives.

Leap plans to start enrolling patients for Part B in the upcoming 12 months and announce initial data late next year.

Leap Therapeutics chief medical officer Cynthia Sirard said: “The study enrolled quickly and has already exceeded the 20% overall response rate threshold.

“After the planned safety review meeting with our investigators, we decided to initiate the randomised controlled study.

“We continue to follow these Part A patients to assess the durability of response, progression-free survival, and to determine whether additional patients with stable disease may become responders over time.”

The initiation of Part B is based on the early efficacy results from Part A, which included 33 patients who were previously exposed to standard-of-care bevacizumab and had early progression on first-line therapy.

Patients who had tumours harbouring Ras mutations or liver metastases were also included in Part A of the study.

DKN-01, a humanised monoclonal antibody targeting the Dickkopf-1 (DKK1) protein, is in development for treating patients with esophagogastric and gynecologic cancers along with CRC.

Leap’s portfolio also includes a humanised monoclonal antibody targeting Claudin18.2, FL-301, designed for treating gastric and pancreatic cancer.