Acne vulgaris is a chronic inflammatory skin condition commonly resulting in negative aesthetic and social impacts on those affected. Minocycline, currently available as an oral antibiotic for moderate to severe acne, has a known minimum inhibitory concentration (MIC) for the acne-causing bacterium Propionibacterium acnes (P. acnes) in vitro, with its anti-inflammatory properties also eliciting inhibitory effects on pro-inflammatory molecules. A novel topical gel composition containing solubilized minocycline (BPX-01) has been developed to directly deliver the drug to the skin. Because minocycline is a known fluorophore, fluorescence microscopy and concurrent quantitative measurements were performed on excised human facial skin dosed with different concentrations, in order to determine the spatial distribution of the drug and quantification of its local concentration in the epidermis and the pilosebaceous unit where P. acnes generally reside. Local minocycline delivery confirmed achievement of an adequate therapeutic dose to support clinical studies. Subsequently, a 4-week double-blind, randomized, vehicle controlled clinical study was performed to assess the safety and efficacy of 1% minocycline BPX-01 applied daily. No instances of cutaneous toxicity were reported, and a greater than 1 log reduction of P. acnes count was observed at week 4 with statistical significance from baseline and vehicle control. In addition, no detectable amounts of minocycline in the plasma were reported, suggesting the potential of this new formulation to diminish the known systemic adverse effects associated with oral minocycline. Follow-on clinical plans are underway to further establish the safety of BPX-01 and to evaluate its efficacy against inflammatory acne lesions in a 225 patient multi-center dose-finding study.
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