Biotech among biggest Nasdaq gainers

NEW YORK (Reuters) - Biotech stocks were among the biggest percentage gainers on the Nasdaq on Friday, though the benchmark index only posted mild gains on the day.

Agios Pharmaceuticals surged 20 percent to $64.02 on its heaviest one-day volume since its initial public offering last year. Earlier, the company said it would present clinical data from an ongoing phase I study.

Among other big gainers, Repros Therapeutics climbed 18 percent to $10.59 after reporting the trial results for its secondary hypogonadism treatment. Esperion Therapeutics was up 16 percent at $20.95. Both stocks moved on volume that was much heavier than average.

Despite the gains, the Nasdaq Biotech index was up a more moderate 0.3 percent. The index was pressured as AcelRx plummeted 19 percent to $5.44 after saying it was looking to resubmit the new drug application for its Zalviso product in the first quarter of 2015.

(Editing by Nick Zieminski)