Biopharmx Corp., of Menlo Park, Calif., said it is starting a phase IIa study for BPX-01, a hydrophilic formulation of the well-established drug minocycline. The study will assess effectiveness in reducing the number of acne-causing bacteria in patients at four weeks and will evaluate the drug's safety and tolerability. Preclinical studies have found the gel formulation of minocycline in BPX-01 can deliver the antibiotic to the layer of skin where the condition develops, suggesting that the skin penetration needed to reach an efficacious dose in humans while minimizing systemic exposure is possible.