NEW YORK – Aston Sci. said on Thursday that it will begin evaluating the investigational cancer vaccine AST-301 in hormone receptor-negative, HER2-low breast cancer patients in a Phase II clinical trial in the US.
The US Food and Drug Administration has cleared the Seoul-based firm's investigational new drug application for AST-301, allowing for the start of a Phase II trial. Aston is already studying the drug in breast cancer patients in Australia and Taiwan.
The trial, dubbed CornerStone-001, will enroll patients whose breast cancers express low levels of HER2, defined as 1+ or 2+ by immunohistochemistry and without gene amplification by in situ hybridization. Patients can partake in the trial if they have stage I, II, or III disease prior to surgery and fail to achieve pathologic complete response, or still have residual invasive cancer, after neoadjuvant therapy.
In the randomized trial, 146 patients will receive either a combination of AST-301, recombinant human granulocyte-macrophage colony-stimulating factor (rHuGM-CSF), and standard adjuvant treatment comprising chemotherapy and Merck's Keytruda (pembrolizumab), or the same regimen with a placebo instead of AST-301. The study's primary endpoint is two-year invasive-free survival.
Because Aston Sci. expects a Phase III trial will include the same population and have the same design, the firm will discuss with the FDA the possibility of making the current Phase II trial registrational, data from which could support a biologics license submission for AST-301.
According to Aston Sci., AST-301 has demonstrated safety and encouraging preliminary efficacy in Phase I trials. The drug appeared in early studies to cause few adverse events and, relative to existing cancer treatments, maintained long-term immunological memory, the company said.