Preliminary results from two phase II studies carried out with methyl aminolevulinate, a second-generation photodynamic therapy (PDT) treatment for moderate to severe acne, showed that the product achieved similar efficacy results when compared to previous PDT approaches for the treatment of acne but was much better tolerated and confirmed that the overall methyl aminolevulinate procedure could be simplified. The larger of the two studies recruited 150 patients from 14 sites in U.S. The primary aim of the study was to establish an effective dose that was well tolerated. In this study the efficacy of therapy was evaluated over time with the maximum efficacy being seen 6 weeks after the last of ...