FDA Presses Pause on Novel Testosterone Product
http://www.medpagetoday.com/Endocrinology/GeneralEndocrinology/54451
The FDA has cancelled an advisory committee, originally scheduled for Tuesday, that would have discussed a new drug application for a novel testosterone product.
Phase III results for enclomiphene citrate (Androxal), an oral estrogen receptor modulator, were reported last Thursday –
http://www.medpagetoday.com/Endocrinology/GeneralEndocrinology/54380 - just before the FDA announced on its website that "outside, expert advice is no longer needed" for the expected advisory committee. The agency did not elaborate and did not respond to a request for clarification. http://www.fda.gov/AdvisoryCommittees/Calendar/ucm459227.htm
But in a conference call with shareholders, Joseph Podolski, president and CEO of Repros Therapeutics, which is developing the drug, said that the FDA had told the company of concerns that the method used for measuring testosterone levels hadn't been properly validated.
http://www.reprosrx.com/investors_events.php
Podolski said the firm did use a properly certified lab running the Siemens Centaur Immunoassay system, which is "very well validated."
http://www.healthcare.siemens.com/immunoassay/systems/advia-centaur-cp-immunoassay-sys
He added that the concerns over the method verification "might have been a hook for the FDA to try to put off this meeting, because there's a much bigger question here." The bigger questions are two-fold, according to the FDA's briefing document that Podolski said he viewed: Who should be treated with the product, and what should the clinical benefits be?
"I really think this was an opportunity for the FDA, and I don't blame them, to back away from the circus," he said, adding that he wished, however, that the FDA would have brought the issue up sooner.
He noted that the uses for testosterone have changed dramatically; traditionally it was used to treat hypogonadism only, but other drug companies have been aggressive in attempting to get it prescribed for men with low testosterone due to aging. Podolski said that he's convinced, from the research done thus far, that clinical benefits of testosterone products don't include increased libido.
http://www.medpagetoday.com/special-reports/slipperyslope/54156
Rather, the benefits are metabolic. In the phase III trial -- which found that enclomiphene citrate boosted testosterone levels without lowering sperm count -- all of the participants that had secondary hypogonadism were obese. "We could not have enrolled enough men in any of the testosterone trials unless a significant number of them had an acquired disorder associated with them being overweight or obese," said Podolski.
http://www.medpagetoday.com/Endocrinology/GeneralEndocrinology/54380
It's unclear whether the company will be made to perform another phase III trial before moving forward. "We need to talk with the FDA first," said Podolski, adding that it will likely take a year to define who should be treated and that the company will likely not fight the FDA over the validation issue.
"We think the FDA's willingness to talk with us, and for us to work with them in a [collegial] fashion, in the final analysis I think this makes for a better development of medicine that's clearly needed in men with low T," he said.
Method changed from Siemens Centaur XP platform to Abbott Architect i2000 platform on November 17, 2014. http://labmed.ucsf.edu/labmanual/db/data/tests/890.html
The new testosterone immunoassay on the Architect i2000 platform correlates better than the older Siemens Centaur XP immunoassay in comparisons with the UCSF LC tandem mass spectrometry testosterone assay. The new Architect immunoassay also has better low end sensitivity than the previous Siemens Centaur immunoassay and gives results that are approximately 27% higher than the previous Siemens Centaur immunoassay.
Also, please note that the reference ranges have changed.