UPDATE 1-Repros submits more testosterone drug data, shrs soar

* Says morning data indicative of 24-hour data

* Shares up as much as 65 pct

Dec 23 (Reuters) - Repros Therapeutics Inc (RPRX.O) said it submitted additional data with U.S. health regulators that showed morning measurements on an experimental testosterone deficiency drug were comparable with 24-hour data, sending its shares up as much as 65 percent.

In November, the U.S. Food and Drug Administration (FDA) had stated the preferred method to determine testosterone levels in treatments designed to replace the hormone is a 24-hour assessment.

On Thursday, the company said data collected from different studies shows that a single assessment of testosterone levels between 8 am and 10 am is indicative of the maximum and average levels of testosterone achieved during a particular day on taking Androxal, the company said.

When measurements were taken six times a day, the Woodlands, Texas-based company said it observed that Androxal raises testosterone level by an average of 200 ng/dl at 12.5 mg and 260 ng/dl at a 25 mg dose, at each time point.

In November, the FDA had also asked Repros to conduct a four-arm trial involving two doses of the drug Androxal, the standard of care and a dummy drug. [ID:nSGE6A80Q0] Repros shares, that have risen 13 percent since it got guidance from the FDA in November, were up 49 percent at $2.10 Thursday afternoon on Nasdaq. They spiked to touch a high of $2.33 in the session. (Reporting by Vidya L Nathan in Bangalore; Editing by Don Sebastian)