Medivation and Astellas Pharma US, a subsidiary of Tokyo-based Astellas Pharma, have announced the commencement of a Phase IV clinical trial 'PLATO'.
PLATO is a double-blind, placebo-controlled trial designed to measure the safety and efficacy of continued treatment with enzalutamide plus abiraterone acetate and prednisone when compared to treatment with abiraterone acetate and prednisone alone in patients with chemotherapy-naive metastatic prostate cancer whose disease has progressed following enzalutamide therapy.
The Phase IV study will enrol approximately 500 chemotherapy-naive patients with metastatic castration-resistant prostate cancer.
All enrolled patients in the study will initially receive treatment with enzalutamide, an androgen receptor inhibitor that acts on different steps in the androgen receptor signalling pathway.
Enzalutamide competitively inhibits androgen binding to androgen receptors, and inhibits androgen receptor nuclear translocation and interaction with DNA.
Eligible patients with disease progression on enzalutamide will be randomised to treatment with enzalutamide plus abiraterone acetate and prednisone or to abiraterone acetate and prednisone.
Progression-free survival is the primary endpoint of the clinical trial.
The Phase IV clinical trial will assess enzalutamide at a dose of 160mg taken orally once daily in combination with abiraterone acetate at a dose of 1,000mg taken orally once daily and prednisone at a dose of 5mg taken orally twice daily, versus placebo plus the same doses of abiraterone acetate and prednisone.
Xtandi (enzalutamide) capsules have been approved to treat metastatic castration-resistant prostate cancer patients who have previously received docetaxel.
Medivation president and CEO Dr David Hung said this Phase IV study offers an important opportunity to help determine the potential clinical benefit of extending time on enzalutamide treatment by adding an additional therapy in patients with progressive chemotherapy-naïve metastatic prostate cancer.
"This trial underscores our continued commitment to discovering how enzalutamide can be used most effectively to benefit prostate cancer patients across the disease continuum," Dr Hung said.
Image: Prostatic adenocarcinoma with perineural invasion. Photo: courtesy of Nephron.