April 01, 2025, Compass Therapeutics, Inc. (Nasdaq: CMPX), a clinical-stage, oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics, announced statistically significant top-line data on the primary efficacy endpoint for COMPANION-002, the Company’s ongoing Phase 2/3 randomized trial of tovecimig (formerly CTX-009) in combination with paclitaxel in patients with advanced BTC. Learn more about our DLL4 catalog.
"We are thrilled to share these positive primary endpoint data from the COMPANION-002 study of tovecimig in patients with advanced biliary tract cancer," said Thomas Schuetz, MD, PhD, CEO of Compass and Vice Chairman of the Board of Directors. “We would like to thank all of the patients and their caregivers who have participated and continue to participate in this study. We believe these findings highlight the potential of tovecimig to provide a much-needed treatment option for the majority of patients with BTC who have limited alternatives after first-line therapy. We look forward to discussing these data with regulatory authorities."
“As a treating clinician for over 20 years, I have seen firsthand how challenging a disease biliary tract cancer is. Patients currently have very limited treatment options, with the vast majority in the second-line setting having no approved therapeutic alternative whatsoever. For every statistic there is a person – a mother, father, relative, or friend – fighting for more time. Each investigative trial helps in this fight to advance new treatment options, and I look forward to following tovecimig’s continued progress,” said Juan Valle, MD, Chief Medical Officer of the Cholangiocarcinoma Foundation.
Biliary tract cancer is estimated to affect approximately 23,000 patients annually in the United States. For the approximately 85% of patients with BTC whose tumors do not harbor an actionable mutation with an approved targeted therapy, there is currently no FDA-approved treatment in the second line setting. The combinations of therapeutics used in this setting, which are not labeled for this indication, generally have an ORR of ~5% or less and patients face a median overall survival of approximately six months.
COMPANION-002 (tovecimig + paclitaxel versus paclitaxel alone): Top-Line Results
The trial is a Phase 2/3 randomized, controlled study of tovecimig in patients with unresectable advanced, metastatic or recurrent biliary tract cancers who have received one prior systemic chemotherapy regimen. The study enrolled 168 adult patients, randomized in a 2:1 ratio to receive tovecimig plus paclitaxel (n=111) or paclitaxel alone (n=57). All patients were dosed with 80 mg/m2 of paclitaxel on days 1, 8 and 15 of every 28-day cycle. Patients in the tovecimig arm were also dosed with 10 mg/kg of tovecimig on days 1 and 15 of each 28-day cycle. The primary endpoint of the trial is ORR as confirmed by independent central radiology review and secondary endpoints include PFS, OS and DoR, among others. Patients in the paclitaxel-only arm who progressed could cross over to the tovecimig plus paclitaxel arm after centrally confirmed progression if they also still met the enrollment criteria for the study.
Top-line results of the study are summarized below, and the Company expects to announce additional data, including key secondary endpoints, in Q4 2025:
Primary Endpoint (ORR as confirmed by independent central radiology review). 17.1% ORR for tovecimig in combination with paclitaxel (19 of 111 patients) including one complete response, compared to 5.3% for paclitaxel alone (3 of 57 patients), in patients with BTC in the second line setting. This 11.8% relative improvement in ORR for those receiving the combination was statistically significant (p=0.031).
| Tovecimig + Paclitaxel | Paclitaxel | ||
| Intent-to-Treat Population | n=111 | n=57 | |
| Overall Response Rate (CR+PR) | 19 (17.1%) (p=0.031) | 3 (5.3%) | |
| Best Overall Response n (%) | Complete Response (CR) | 1 (0.9%) | 0 (0.0%) |
| Partial Response (PR) | 18 (16.2%) | 3 (5.3%) | |
| Stable Disease (SD) | 49 (44.1%) | 19 (33.3%) | |
| Non-CR / Non-PD* | 9 (8.1%) | 2 (3.5%) | |
| Progressive Disease (PD) | 18 (16.2%) | 24 (42.1%) | |
| Not Evaluable (NE)** | 16 (14.4%) | 9 (15.8%) | |
*Non-CR / Non-PD: patients enrolled based on local radiology scan results, but displayed no clearly definable target lesions as determined by independent central radiology.
** Not Evaluable: patients who did not receive a Week-8 scan.
Secondary Endpoints. The COMPANION-002 study is ongoing and the data are not yet mature for the analyses of the secondary outcome measures (including PFS, OS and DoR). The trial requires a threshold of events in 80% of patients to trigger the secondary endpoint analyses. Based on current projections, the Company anticipates this pre-specified number of events to be reached in Q3 2025, and expects to report data from the secondary endpoints in Q4 2025.
Safety & Tolerability. The safety profile of tovecimig in this study to date is consistent with prior studies of tovecimig. An independent Data Monitoring Committee (DMC) has reviewed safety data at four separate (pre-specified) DMC meetings and, after each meeting, recommended continuation of the study without modification. The Company expects to report detailed safety data with the analyses of secondary endpoints in Q4 2025.
