ALX Oncology’s investigational CD47 blocker has been shown to improve tumour response in pre-treated gastric cancer (GC), according to mid-stage results shared by the company.
The phase 2 ASPEN-06 trial has been evaluating the candidate, evorpacept, as part of a combination treatment for human epidermal growth factor receptor 2 (HER2)-positive advanced GC or gastro oesophageal junction (GEJ) cancer in patients who have previously received an anti-HER2 agent.
Patients were randomised to receive ALX’s drug alongside rastuzumab, ramucirumab and paclitaxel (TRP) or TRP alone.
The evorpacept combination demonstrated an overall response rate (ORR) of 40.3% compared to 26.6% for TRP in the full intent-to-treat population.
For those with fresh HER2-positive biopsies, the ORR difference widened to 54.8% for evorpacept plus TRP versus 23.1% for the TRP control.
Evorpacept on top of TRP was also associated with clinically meaningful improvements in duration of response (DoR), demonstrating a median DoR of 15.7 months compared to 7.6 months for TRP alone in the full trial population, and was generally well tolerated.
ALX’s chief executive officer, Jason Lettmann, said: “The top-line results from the ASPEN-06 clinical trial confirm the robust response that evorpacept can deliver, generating a clinically meaningful impact on key measures of anti-cancer activity for patients with GCs and continuing to surpass benchmarks in the field.”
Lettmann added that the data from the study “provides support for developing evorpacept in combination with anti-cancer antibodies in additional tumour types and drives ALX’s development strategy”.
More than 6,500 new diagnoses of GC are made in the UK every year and adenocarcinomas, which develop from cells in the innermost lining of the stomach, account for the majority of cases.
The disease usually develops slowly over many years without early symptoms, meaning the majority of cases go undetected until an advanced stage.
Sophia Randolph, the company’s chief medical officer, said the results from ASPEN-06 “represent a significant advancement for immuno-oncology” and outlined that evorpacept is now the first CD47 blocker to demonstrate clinical benefit and a well-tolerated safety profile in a randomised trial.
The candidate has already been granted fast track designation from the US Food and Drug Administration as a second-line treatment for HER2-positive gastric or GEJ carcinoma, as well as orphan drug designation from the US regulator and the European Commission for this indication.