The U.S. Food and Drug Administration (FDA) has accepted a New Drug Application (NDA) for Yonsa (abiraterone acetate) ultramicrosize tablets for the treatment of castration resistant prostate cancer that has spread outside the prostate, according to the drug’s developer, Churchill Pharmaceuticals.
The FDA has until March 19, 2018, to review the NDA under the Prescription Drug User Fee Act.
“We are pleased that the NDA for Yonsa has been accepted,” Scott Megaffin, president of Churchill, said in a press release.
“The notification from the FDA indicated that the application is sufficiently complete to permit a substantive review and that no potential review issues have been identified. Our team looks forward to working closely with the FDA throughout the review process,” he added.
Yonsa is a new formulation of abiraterone acetate, which is an already approved medication for men with advanced, castration resistant prostate cancer. It sold as Zytiga.
Studies have shown that the ultramicrosize tablets used in Yonsa, double the bioavailability of the drug — that is, how much of the drug ends up in the blood after swallowing a pill — compared to Zytiga.
Churchill based its application mainly on data from the Phase 2 STAAR clinical trial (NCT02737332), which enrolled 53 men with metastatic castration-resistant prostate cancer (mCRPC).
The U.S.-based study randomly assigned patients to receive either 500 mg of Yonsa once daily plus 4 mg of methylprednisolone twice daily, or 1,000 mg of Zytiga once daily plus 5 mg of prednisone twice daily. The study was not blinded, meaning that both patients and study staff knew which treatment a patient was assigned.
Both drugs lower testosterone levels, and a comparison showed that more patients treated with Yonsa had undetectable testosterone levels after the treatment, compared to those treated with Zytiga.
Abiraterone acetate acts on an enzyme called CYP17, found in testicular, adrenal, and prostatic tumor tissues. The enzyme is needed for the synthesis of male sex hormones.
“Yonsa represents a new potential treatment option for the nearly 30,000 men diagnosed annually in the U.S. with mCRPC,” said Ben Steinmetz, senior vice president, Commercial, at Churchill.
“Yonsa sets the stage in our initial commercial approach with an exciting and innovative opportunity to deliver on the Churchill commitment to responsibly enhance product access to critical therapies,” Steinmetz added.