Novartis AG's breast cancer drug alpelisib almost doubled patients' survival time without the disease worsening in those who have a specific mutation of the disease in updated results from a late-stage trial.

About 40% of patients with hormone receptor positive, or HR+, breast cancer have a PIK3CA mutation, which is associated with tumor growth because of higher levels of the PI3K enzyme. Alpelisib, being studied under the name BYL719, is a PI3K inhibitor that blocks the enzyme from causing cells to multiply.

In the phase 3 study called SOLAR-1, alpelisib in combination with the cancer drug fulvestrant improved survival without disease progression to 11 months against just 6.8 months with fulvestrant alone. Fulvestrant is sold as Faslodex by AstraZeneca PLC.

Novartis plans to present the full results of SOLAR-1 at the San Antonio Breast Cancer Symposium Dec. 6.

The patients in the trial were men and postmenopausal women with HR+, human epidermal growth factor receptor-2 negative, or HER2-, advanced breast cancer who also showed the PIK3CA mutation.

Important to the study was also the finding that a blood test was as effective at diagnosing the mutation as a tumor tissue test, a more invasive diagnostic.

"With the SOLAR-1 trial results, we can confidently say that identifying and targeting PIK3CA mutations is clinically important as we apply the precision oncology paradigm to breast cancer and continuously look for new treatment solutions to extend the lives of patients with this disease," said Dejan Juric, director of the Massachusetts General Hospital Cancer Center's Termeer Center for Targeted Therapies.