(Sharecast News) - AstraZeneca announced on Tuesday that the phase three 'CAPItello-290' trial for 'Truqap', or capivasertib, in combination with paclitaxel did not achieve its primary endpoints.

The FTSE 100 pharmaceuticals giant said the study aimed to assess the efficacy of Truqap with paclitaxel against paclitaxel with placebo, in patients with advanced or metastatic triple-negative breast cancer (TNBC).

It said the dual primary endpoints focussed on overall survival (OS) in both the general trial population and a subgroup with specific biomarker alterations.

Unfortunately, the trial did not demonstrate a significant improvement in OS for either group.

TNBC, a particularly aggressive and difficult-to-treat form of breast cancer, lacks oestrogen receptors, progesterone receptors, and HER2 expression, making it unresponsive to some common treatments.

Around 59,000 patients with TNBC receive treatment in the first-line setting annually.

Mutations in the biomarkers targeted by the trial - PIK3CA, AKT1, and PTEN - are present in about 35% of TNBC patients.

Despite the trial's outcome, AstraZeneca said it would continue its efforts to find effective treatments for the challenging cancer type.

Breast cancer remained the second most common cancer globally and a leading cause of cancer-related deaths, underscoring the ongoing need for innovative therapeutic strategies.

"We are committed to advancing science for patients in some of the most challenging cancers, including this heterogeneous subtype of breast cancer," said Susan Galbraith, executive vice-president of oncology research and development.

"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 programme and across our pipeline."

AstraZeneca said the safety profile of Truqap, in combination with paclitaxel in CAPItello-290 was broadly consistent with the known safety profile of each medicine with no new safety concerns identified.

Data would be shared in due course.

Truqap was currently being evaluated in phase three trials for the treatment of breast cancer in CAPItello-292, and prostate cancer in CAPItello-280 and CAPItello-281, in combination with established treatments.

At 0844 BST, shares in AstraZeneca were up 0.03% at 12,430p.

Reporting by Josh White for Sharecast.com.