YONSA

[Blair77]

Churchill Pharmaceuticals also announces positive results from the pivotal STAAR Study evaluating serum testosterone levels in patients with mCRPC in a head-to-head comparison trial of YONSA to Zytiga®

What have people heard about this new drug?

[pjoshea13]

Micronized Zytiga at half the dose + Methylprednisolone.

What advantage over Zytiga + Prednisone? How much more expensive?

STAAR: "Over 90% of patients treated with YONSA achieved absolute testosterone levels of <1 ng/dL at each time point, while non-detectable testosterone levels (≤0.1 ng/dL) were achieved in a higher percentage of patients treated with YONSA versus patients treated with the comparator." [1]

Who knows how this translates to improved survival?

Abiraterone acetate is a CYP17A1 inhibitor, so halts the conversion of pregnenolone and progesterone to downstream androgens.

If we are to compare the two forms of Zytiga based on the effects on testrosterone [T], it follows that neither drug will be effective while T is undetectable, and that T should perhaps be monitored while on either drug. No need to switch to YONSA while Zytiga is working.

-Patrick

[1] prnewswire.com/news-release...

[Neal-Snyder in reply to pjoshea13]

Hi Patrick,

This study seems small & short to be a Phase 3. Or are the rules different because Zytiga was previously approved?

Could YONSA become an additional option for men who had a good period of success on Zytiga before it failed, at least under some circumstances? In my case, after Zytiga failed recently, I've just completed Provenge, & Xtandi will be next.

Thank you.

Neal

[pjoshea13 in reply to Neal-Snyder]

Neal,

The few lines I quoted tells me very little. The Yonsa design tweak seems to have created a better mousetrap, but only a long-term full-scale study would quantify the benefit.

-Patrick

[Neal-Snyder in reply to pjoshea13]

As always, thank you very much, Patrick.

Neal

[pjoshea13]

FDA Accepts Marketing Application for Churchill’s Yonsa Microsize Tablets for Advanced Prostate Cancer

prostatecancernewstoday.com...