Churchill Pharma NDA for Yonsa Accepted by FDA

FDA has accepted for review a Churchill Pharmaceuticals NDA for Yonsa (abiraterone acetate) ultramicrosize tablets for treating metastatic castration-resistant prostate cancer. The agency has set a 3/19/2018 user fee review action target date.

The submission was based on data from the STAAR study, a randomized, open label patient trial in the U.S. comparing Yonsa 500 mg once daily plus methylprednisolone 4 mg twice daily, to another formulation of abiraterone acetate (Zytiga) 1,000 mg once daily plus prednisone 5 mg twice daily. The primary endpoint was comparative lowering of serum testosterone at pharmacodynamic steady-state.

Yonsa is a CYP17 inhibitor that sees its active ingredient converted in vivo to abiraterone, an androgen biosynthesis inhibitor, that inhibits 17 a-hydroxylase/C17,20-lyase, according to the company. This enzyme is expressed in testicular, adrenal and prostatic tumor tissues and is required for androgen biosynthesis, it says.