After-hours trading was mixed and thin Friday, and among the winners was Ariad Pharmaceuticals ( ARIA), which leapt 9.2% to $4.85 after filing a patent-infringement claim against biotech giants Amgen ( AMGN) and Wyeth ( WYE).

The action is a response to Amgen's own lawsuit against Ariad, which seeks to invalidate one of the latter's patents. At issue are "activities related to" two of Amgen's products, one of which is co-owned by Wyeth. Amgen recently added 25 cents to $59.28, and Wyeth was unchanged after finishing the regular session up 2.6% at $56.28.

USEC ( USU) was climbing 4.5% to $20.65 after regulators granted it a 30-year license to build and operate a uranium-enrichment facility in Piketon, Ohio. The Maryland-based company plans to start related commercial operations in late 2009.

On the flip side, Florida-based Parlux Fragrances ( PARL) sank after posting a continuing-operations loss on revenue of $43.4 million -- $6.3 million below estimates, per Thomson Financial. Shares of the fragrance- and beauty-products maker declined 7.3% to $5.35.

Also hit hard was small-cap optical-components maker LightPath Technologies ( LPTH), which preliminarily reported about an 8% sales slide year over year to $2.9 million in the third fiscal quarter. Shares lately sank 49 cents, or 8.2%, at $5.50.

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