NEW YORK – AstraZeneca on Tuesday said a Phase III clinical trial of its AKT inhibitor Truqap (capivasertib) with paclitaxel failed to demonstrate improvement in overall survival in patients with advanced or metastatic triple-negative breast cancer, either in the overall population or in those with tumors harboring PIK3CA, AKT1, or PTEN alterations.
A combination of Truqap with the estrogen receptor antagonist fulvestrant is approved in the US, Japan, and other countries as a treatment for patients with estrogen receptor-positive, HER2-negative advanced or metastatic breast cancer with one or more alterations in PIK3CA, AKT1, or PTEN and who have progressed on an endocrine-based therapy regimen. The European Medicines Agency's Committee for Medicinal Products for Human Use has also recommended the drug combo for approval in this setting. In the Phase IIII CAPItello-291 trial, patients on Truqap-fulvestrant had a 50 percent reduced risk of death or disease progression compared to patients on fulvestrant alone.
However, the success of Truqap in combination with fulvestrant in ER-positive, HER2-negative patients did not translate to the Truqap-paclitaxel combination in patients with triple-negative breast cancer. In the CAPItello-290 trial, AstraZeneca is evaluating the safety and efficacy of Truqap and paclitaxel as a first-line treatment for over 900 patients with advanced triple-negative breast cancer compared to placebo and paclitaxel. In addition to overall survival as the primary outcome measure of the trial, researchers are also tracking endpoints including progression-free survival, overall response rate, duration of response, and clinical benefit rate. The trial includes a subgroup of patients with qualifying alterations in the PI3K/AKT pathway, including PIK3CA, AKT1, and PTEN.
"While we are disappointed in the CAPItello-290 outcome, these results will further our understanding of the role of the PI3K/AKT pathway in breast cancer as we continue our clinical research across the Truqap clinical development program and across our pipeline," AstraZeneca Executive VP of Oncology R&D Susan Galbraith said in a statement.