The complete safety and efficacy of a new extended-release (ER) minocycline hydrochloride formulation were assessed in an analysis of a phase 2 dose-finding study and 2 phase 3 safety and efficacy studies. The studies were similar in design, subject populations, and shared common dose groups of subjects given ER minocycline 1 mg/kg daily or placebo over 12 weeks. The similar designs were prospective, multicenter, randomized, double-blinded, and placebo-controlled. A total of 1038 subjects with moderate to severe acne were available for the pooled analysis. Independently, each study showed that treatment with ER-minocycline significantly reduced (P < .001) the number of inflammatory lesions and significantly improved (P < .001) their Evaluator's Global Severity Assessment (EGSA) scores (phase 3 studies). Analysis of the pooled population confirmed the results of the individual studies. The percentage of subjects reporting acute vestibular adverse events (AVAEs) was comparable between those receiving the ER-minocycline 1-mg/kg dose and placebo (approximately 10% of subjects in each group) for both the individual studies and the pooled population. It was concluded that a novel ER-minocycline formulation that delivers consistent levels of drug at a 1-mg/kg dose reduces dose-dependent AVAEs while reducing inflammatory lesions and improving the overall appearance of patients with acne vulgaris.