First AKT Inhibitor Approved for Advanced Breast Cancer

The FDA approved the first-in-class AKT inhibitor capivasertib (Truqap), in combination with fulvestrant, for locally advanced/metastatic hormone receptor (HR)-positive/HER2-negative breast cancer and at least one specific genetic alteration.

The approval stipulates use in patients whose disease has progressed on at least one endocrine-based regimen in the metastatic setting or recurred during or within 12 months of completing adjuvant therapy. At the same time, the FDA approved the FoundationOne CDx assay as a companion diagnostic to identify patients with mutant gene protein targeted by the treatment (PIK3CA, AKT1, or PTEN).

“Patients with advanced HR-positive breast cancer typically experience tumor progression or resistance with widely used first-line endocrine therapies and there is an urgent need to extend the effectiveness of these approaches,” said Komal Jhaveri, MD, of Memorial Sloan Kettering Cancer Center in New York City, in a statement from AstraZeneca.

“The combination of capivasertib and fulvestrant, a first-of-its-kind combination, provides a much-needed new treatment option for up to half of patients in this setting with these specific biomarkers, offering the potential to delay disease progression and provide more time with their disease under control.”

Support for the approval came primarily from the CAPItello-291 trial, a randomized, placebo-controlled trial involving 708 patients with locally advanced/metastatic HR-positive/HER2-negative breast cancer. The protocol allowed up to two prior lines of endocrine therapy and one line of chemotherapy. Eligible patients had disease progression on an aromatase inhibitor-based regimen. All patients received fulvestrant and were randomized to capivasertib or placebo.

The primary endpoint was investigator-assessed progression-free survival (PFS) in the overall population and in the subgroup of patients whose tumors had one or more of the specified mutations (n=289). The results showed that the addition of capivasertib approximately doubled the median PFS in the overall population (7.2 vs 3.6 months) and in the AKT-altered subgroup (7.3 vs 3.1 months).

Adverse events occurring in ≥20% of patients were diarrhea, cutaneous adverse reactions, increased random and fasting glucose, decreased lymphocytes, decreased hemoglobin, nausea, fatigue, decreased leukocytes, increased triglycerides, decreased neutrophils, increased creatinine, vomiting, and stomatitis.