Phase 2 Study of CTX-009 Doses First Patient With Metastatic Colorectal Cancer

After preclinical and early clinical studies show promising data with CTX-009 therapy, a phase 2 study of the agent has dosed its first patient with metastatic colorectal cancer.

The first patient has been dosed in the phase 2 study (NCT05513742) of CTX-009 given in the third- or fourth-line setting to patients with metastatic colorectal cancer, according to Compass Therapeutics, Inc.1

CTX-009 is a bispecific antibody which works by simultaneously blocking Delta-like ligand 4/Notch and vascular endothelial growth factor A (VEGF-A) signaling pathways. Both of these are critical to angiogenesis and tumor vascularization.

In preclinical and early clinical studies of CTX-009, data has shown that blockade of both pathways provides robust anti-tumor activity across several solid tumors, including colorectal, gastric, cholangiocarcinoma, pancreatic and non-small cell lung cancer.In heavily pre-treated patients with cancer resistant to currently approved anti-VEGF therapies, partial responses to CTX-009 monotherapy have been observed.

“We are very pleased to begin dosing patients with colorectal cancer in the United States. We have previously seen 2 confirmed responses among 6 patients dosed at the projected efficacious doses in a phase 1 monotherapy study” said Thomas Schuetz, MD, PhD, chief executive officer and scientific founder of Compass Therapeutics, Inc, in the press release. “Colorectal cancer patients in whom 2 or more lines of therapy have failed face very limited treatment options, and we look forward to assessing the potential of CTX-009 in those patients.” Preliminary results from this study may become available in mid-2023.

The phase 2, open-label study will evaluate the efficacy of CTX-009 in patients with metastatic colorectal cancer.2 An estimated 84 patients who have received at least 2 previous systemic therapies will be enrolled.

Approximately 37 patients will be enrolled into Stage 1, and if criteria are met to move to Stage 2, another 47 patients will be enrolled. Patients will be treated with CTX-009 monotherapy at a dose of 10 mg/kg administered every 2 weeks.

The primary end point of the trial is overall response rate with secondary end points including disease control rate, duration of response, progression-free survival, overall survival, safety profile of CTX-009, quality-of-life changes, and exposure response by pharmacokinetics.

Patients aged 18 years of age or older are eligible for enrollment if they have histologically or cytologically confirmed metastatic or recurrent colorectal cancers, a primary tumor which had been resected > 3 months prior to starting CTX-009 treatment, at least 1 measurable lesion as defined by RECIST v1.1, an ECOG performance status of 0-1, and a life expectancy of at least 12 weeks. Those enrolled must also have experienced progressive disease or relapse after receiving 2 or 3 prior lines of systemic therapy in the metastatic setting.

The study is currently ongoing in Texas with an estimated study completion date of June 2024.

Compass Therapeutics announces first patient dosed in the phase 2 U.S. study of CTX-009 in patients with metastatic colorectal cancer. News release. Compass Therapeutics Inc. January 6, 2023. Accessed January 10, 2023.
Study of CTX-009 in adult patients with metastatic colorectal cancer. Updated December 12, 2022. Accessed January 10, 2023.