Japanese-based company Astellas Pharma, along with US-based biopharmaceutical company Medivation, is planning to start a Phase III clinical trial to study enzalutamide in combination with paclitaxel chemotherapy or as monotherapy versus placebo with paclitaxel, to treat patients with locally advanced or metastatic triple-negative breast cancer (TNBC).
The proposed Phase III trial, ENDEAR, is a randomised, international trial will enrol around 780 TNBC patients whose tumours test positive for a new gene expression profile, which is referred to as diagnostic-positive TNBC.
The trial's primary efficacy endpoint is progression-free survival (PFS), defined as the time from randomisation to the first evidence of disease progression or death, whichever occurs first.
The trial will assess enzalutamide at a dose of 160mg per day taken orally, either with paclitaxel given intravenously once weekly for 16 weeks or longer at investigator discretion, or as monotherapy compared to placebo with paclitaxel.
To be led by Medivation, ENDEAR trial will start enrolling patients in the fourth quarter of this year.
Astellas Pharma senior vice-president and oncology therapeutic area head Claire Thom said: "Our initiation of this trial represents our commitment to explore the potential of enzalutamide in patients with advanced TNBC.
"The initiation of the ENDEAR trial reflects our ongoing commitment to investigate the full clinical utility of enzalutamide."
Astellas noted that anzalutamide, known by the brand name XTANDI, is not approved for use in patients with TNBC.
However, XTANDI (enzalutamide) capsules, which are an androgen receptor inhibitor that blocks multiple steps in the androgen receptor signalling pathway within the tumour cell, has been approved by the US Food and Drug Administration to treat patients with metastatic castration-resistant prostate cancer (mCRPC).
In the US, breast cancer is one of the most commonly diagnosed cancers and according to the American Cancer Society, around 246,000 new cases of breast cancer will be diagnosed in women and 40,000 women will die of breast cancer this year.
There are currently no therapies specifically approved to treat TNBC.