DUSA Pharmaceuticals Inc. (Nasdaq: DUSA) shares rallied 22.5% to $5.55, after the developer of dermatology products reported first-quarter results. Volume for the stock topped 2.2 million shares shortly before Thursday’s close, compared to a daily average of 350,000.

The company, based out of Wilmington, Massachusetts, reported total product revenues were $11.1 million for the quarter, representing a $2.4 million or 27% year-over-year improvement, and experienced a net loss on a GAAP basis of $600,000 or $0.02 per common share for the first quarter of 2011, compared to a net loss of $400,000 or $0.02 per common share in the first quarter of 2010.

According to DUSA Chief Executive Officer Robert Doman, “We are off to a great start in 2011. Continued growth of our core domestic PDT revenues, as well as record gross margins, drove significant year-over-year improvement in our non-GAAP profitability and cash flow.” Doman concluded, “The results of the quarter are even more impressive given the fact that they followed our record performance of the fourth quarter of 2010.”

DUSA Pharmaceuticals, Inc. is an integrated dermatology pharmaceutical company focused primarily on the development and marketing of its Levulan® PDT technology platform, and other dermatology products. Levulan® Kerastick® for topical solution plus DUSA’s BLU-U® Blue Light Photodynamic Therapy Illuminator is currently approved for the treatment of minimally to moderately thick actinic keratoses (AKs) of the face or scalp.