CTX-009 when combined with paclitaxel improved the overall response rate for patients with advanced, metastatic biliary tract cancer according to findings presented at the 2023 ASCO Gastrointestinal Cancer Symposium in San Francisco.
CTX-009 is a novel, bispecific antibody which causes blockade of delta-like ligand 4 Notch-1 signalling, inhibiting tumour growth as well as an blocking vascular endothelial growth factors (VEGF), that are recognised as important factors in tumour biology with a role in angiogenesis. Because the overall response rate to the use of a single VEGF inhibitor is often low, there is a need for additional angiogenesis-based therapies. In a previously reported release from the manufacturer, Compass Therapeutics, data from a Phase II trial showed that when added to paclitaxel, CTX-009 demonstrated a 42% overall response rate based on data from 10 patients with partial responses.
The findings presented at ASCO 2023, relate to an open-label, multi-centre, single arm, Phase II trial, in patients with unresectable, advanced biliary tract cancer. Individuals were given CTX-009 as either a second or third-line treatment at a dose of 10 mg/kg biweekly in combination with paclitaxel. The primary aim of the study was to assess the objective response rate (ORR) based on RECIST v1.1.
CTX-009 and overall response rate
A total of 24 patients (median age = 61.5 years, 58.3% male) were included and of whom, 11 were receiving CTX-009 as a second-line treatment and the remainder as a third-line agent. The median duration of follow-up was 12.1 months.
The ORR was 37.5% (95% CI 18.8 – 59.4%) and this was higher for patients receiving the drug as a second-line treatment (ORR = 63.6%) though lower when used third-line (ORR = 15.4%). In addition, the median progression-free survival was 9.4 months and the median overall survival 12.5 months.
In terms of safety, treatment-emergent adverse events > grade 3 occurred in 95.8% of patients and 6 patients discontinued treatment due to adverse events.
The authors concluded that CTX-009 showed promise in biliary tract cancer patients and called for further studies to examine the efficacy and safety of the regime.
Citation
Oh DY et al. CTX-009(ABL001), a bispecific antibody targeting DLL4 and VEGF A, in combination with paclitaxel in patients with advanced biliary tract cancer (BTC): A Phase 2 study. ACSO GI Cancer Symposium 2023
