Success in the clinic is all about context. In the case of Dusa Pharmaceuticals Inc., use of Levulan with laser light to remove leg hairs resulted in 20-24 percent fewer hairs six months after the procedure. The result may seem unimpressive, but the company argues that it will compete favorably with other so-called "permanent" hair removal procedures that use heat to destroy hair follicles, often missing the deeper hair root and allowing regrowth or damaging skin around the follicle.

In the Phase I/II trial, the topical