Giving investors a welcome surprise, QLT (Nasdaq: QLTI) announced yesterday that the FDA had removed some safety testing requirements from its acne-treatment drug Aczone. QLT is best known for its macular degeneration treatment Visudyne, partnered with Novartis (NYSE: NVS), and hormone therapy drug Eligard, marketed by Sanofi-Aventis (NYSE: SNY) in some parts of the world. In Aczone's case, QLT has retained full rights.

Even though Aczone won FDA approval in mid-2005, it previously bore a restrictive and onerous label that required blood testing before its use. QLT didn't even bother to market the drug after former partner Astellas gave up on the compound two days before its approval. Now that the Aczone label has been loosened, the drug may gain appeal among dermatologists who would have understandably balked at the testing it formerly required.

Since last year, QLT has been searching for a potential buyer of its stake in Eligard and Aczone. Obviously, the less restrictive label makes Aczone a much more valuable asset. When the drug won approval three years ago, QLT estimated the total topical prescription-drug acne market at $800 million.  

What would another drugmaker pay for a compound like Aczone? Other acne drugs like Roche's Accutane are now genericized products, but a compound like Aczone would fit well into the product portfolio of a health-care company like Allergan (NYSE: AGN), which already markets compounds like Botox to dermatologists.

In my very unempirical estimate, Aczone might fetch anywhere from $50 million to $100 million for North American marketing rights, plus single-digit royalties to QLT. That may not sound like a lot of cash, but QLT is only trading at a market capitalization around $240 million. No wonder shares of QLT jumped more than 40% on news of the FDA's unexpected benevolence.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has an A+ disclosure policy.