Compass Therapeutics, Inc. announced that the first patient has been dosed in the Phase 2 U.S. study of CTX-009 in patients with metastatic colorectal cancer who are being treated in the third- and fourth-line setting. Patients enrolled in the study have received at least two previous systemic therapies and will be treated with CTX-009 monotherapy at a dose of 10 mg/kg administered every two weeks. Patients will be evaluated for safety and tolerability as well as clinical response as measured by overall response rate (ORR).

The study design is an Adaptive Simon Two Stage, with Stage 1 of the study enrolling 37 patients; if there are 3 or more responses confirmed in Stage 1, then the Study will advance to Stage 2 and an additional 47 patients will be enrolled. ClinicalTrials.gov Identifier: NCT05513742. CTX-009 is a bispecific antibody that simultaneously blocks Delta-like ligand 4/Notch (DLL4) and vascular endothelial growth factor A (VEGF-A) signaling pathways, which are critical to angiogenesis and tumor vascularization.

Preclinical and early clinical data of CTX-009 suggest 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. Partial responses to CTX-009 as a monotherapy have been observed in heavily pre-treated cancer patients who were resistant to currently approved anti-VEGF therapies.