Roche today announced that the phase III IPATential150 study met its co-primary endpoint of radiographic progression-free survival (rPFS) in patients with metastatic castration-resistant prostate cancer (mCRPC) and whose tumours had PTEN loss. In this patient group, ipatasertib in combination with abiraterone and prednisone/prednisolone provided a statistically significant reduction in the risk of disease worsening or death, compared to current standard of care (abiraterone and prednisone/prednisolone) plus placebo. The other co-primary endpoint of rPFS in the overall study population (ITT) was not met. The safety profile for the combination of ipatasertib and abiraterone was consistent with previous analyses and known risks. The results of the IPATential150 study will be presented at an upcoming medical meeting.

While initial data are encouraging, overall survival benefit and additional secondary endpoints are not yet mature. The trial will continue until the next planned analysis and data will be shared with health authorities.

“Prostate cancer remains a leading cause of death in men worldwide and patients with metastatic castration-resistant prostate cancer can be difficult to treat,” said Levi Garraway, M.D., Ph.D., Roche’s Chief Medical Officer and Head of Global Product Development. “The early results of the IPATential150 study are encouraging in our ongoing mission to develop new treatment options for people with advanced prostate cancer.”

Ipatasertib is an oral, highly specific, investigational medicine designed to target and bind to all three isoforms of AKT (protein kinase B), which blocks the PI3K/AKT signalling pathway – a key driver of cancer cell growth and proliferation in prostate cancer.^1,2 The PI3K/AKT pathway has also been implicated in resistance to anti-androgen therapy as androgen receptor (AR) inhibition is associated with an increase in AKT pathway activation.^2,3 Functional loss of the tumour suppressor protein PTEN within the tumour, seen in approximately 40-60% of mCRPC patients, results in hyperactivation of the PI3K/AKT pathway and is associated with adverse outcomes such as increased tumour grade and stage, earlier biochemical recurrence after radical prostatectomy, metastasis, prostate-cancer-specific death, and androgen-independent progression.^4,5

Roche’s clinical development programme for ipatasertib focuses on tumours that are frequently found to have activation of the PI3K/AKT pathway. In addition to prostate cancer, ipatasertib is being studied in certain types of breast cancer including triple-negative breast cancer (TNBC) and hormone-receptor positive (HR+), HER2- negative breast cancer. Results are anticipated later in 2020.