Roche has announced results from a Phase Ib trial assessing its AKT-inhibitor ipatasertib, Tecentriq (atezolizumab) and chemotherapy in triple-negative breast cancer (TNBC), showing a 73% overall response rate irrespective of PD-L1 status.

Out of the first 26 subjects in the study, 19 had confirmed responses.

The trial consisted of two arms; ipatasertib in combination with Tecentriq and Taxol (paclitaxel), and the drug in combination with Tecentriq and Abraxane (nab-paclitaxel).

The drug itself is an oral, highly specific, investigational medicine designed to target and bind to all three isoforms of AKT, which blocks the PI3K/AKT signaling pathway and may prevent cancer cell growth and survival.

The positive early phase trial result of 73% ORR irrespective of tumour biomarker status shows that by inhibiting the PI3K/AKT pathway, the combination may contribute to the reversal of T-cell-mediated immunotherapy resistance.

“We are enthusiastic about the potential of this combination in triple-negative breast cancer, an aggressive type of breast cancer,” said Sandra Horning, Roche’s chief medical officer and head of Global Product Development.

“These early results support the contribution of ipatasertib to our combination treatment approach in TNBC and reinforce our vision to develop medicines that may benefit patients with this challenging disease.”

Trial enrolment for the Phase Ib study is still ongoing, with plans to initiate a Phase III study later this year investigating the combination as first-line therapy for locally advanced and metastatic triple-negative breast cancer.

The drug was initially discovered by Roche subsidiary Genentech in alliance with Array BioPharma.