Because biliary tract cancers produce few symptoms in the early stages, most cases of this rare and aggressive cancer are advanced or metastatic and unresectable at the time of diagnosis. The prognosis is very poor: Five-year relative survival is only 9-10% at any stage, and only 2% for patients with metastatic disease, for whom few effective treatment options are available.
Those patients are the focus of a phase 2/3 clinical trial underway at Roswell Park Comprehensive Cancer Center and 31 other centers nationwide to evaluate a therapy that showed promising results in a previous phase 2 trial — a combination of the bispecific antibody CTX-009 and the chemotherapy drug paclitaxel. CTX-009 inhibits the signaling molecules DLL4 and VEGF A, which promote angiogenesis in the tumor microenvironment, while paclitaxel disrupts cancer cells’ ability to divide. The study is open only to patients for whom it will be second-line therapy.
Sponsored by Compass Therapeutics, this open-label, two-arm, randomized study will compare the efficacy of the combination therapy versus paclitaxel alone in previously treated patients. Patients randomized to receive paclitaxel alone may have the option of crossing over to the CTX-009 + paclitaxel arm if they experience disease progression.
Renuka Iyer, MD, Co-Leader of the Liver and Pancreas Tumor Program and Section Chief for Gastrointestinal Oncology, Department of Medicine, serves as site principal investigator at Roswell Park for A Study of CTX-009 in Combination with Paclitaxel in Adult Patients with Unresectable Advanced, Metastatic or Recurrent Biliary Tract Cancers (COMPANION-002) (NCT05506943).
The combination was evaluated previously in a phase 2 single-arm clinical trial conducted in South Korea in patients with unresectable advanced, metastatic or recurrent biliary tract cancer (BTC) in a second- or third-line setting. All patients in that trial (n=24; two not evaluable) received the combination therapy. Results of the trial, reported at the 2023 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium, documented an objective response rate of 37.5% and a 12-month overall survival rate of 53%. Median overall survival was not reached.
The principal focus of the current clinical trial will be the percentage of patients whose best overall response is assessed as a complete or partial response, gauged from the time of randomization to treatment discontinuation for any reason. Secondarily, investigators will concentrate on progression-free survival, duration of response, overall response, disease control rate, safety profile of the combination therapy, patient-reported quality of life and exposure response by pharmacokinetic sampling.
“We are excited to offer this option to all BTC patients with and without targetable mutations,” says Dr. Iyer. “This is a well-designed study in which all patients receive the active agent that targets both VEGF-A and notch signaling, either initially with a taxane or at progression on taxane. It is well positioned to find much-needed new therapeutic options for these patients.”
BROADCASTMED