Clinical relevance of adjunctive minocycline microspheres in patients with chronic periodontitis: secondary analysis of a phase 3 trial

BACKGROUND: A recent Phase 3 trial demonstrated that adjunctive treatment with minocycline microspheres resulted in significant reductions in patient mean probing depths as compared to scaling and root planing (SRP) alone. The objective of the present study was to evaluate clinical relevance of these changes within the trial using proposed site-based criteria. METHODS: A total of 499 patients with moderate to advanced chronic periodontitis were enrolled in a multi-center trial and randomized to either: 1) SRP alone or 2) SRP plus minocycline microspheres. Subjects received complete probing examinations including the measurement of probing depths at baseline, and 1 and 3 months. Probing depth reductions were tabulated by treatment, examination time, and baseline depths, and inter-group differences were evaluated with logistic regression models for correlated data. RESULTS: Significantly more sites treated with adjunctive minocycline microspheres exhibited probing depths < 5 mm at 1 (P = 0.0009) and 3 (P = 0.01) months as compared to sites treated with SRP alone, both in the overall population and in smokers. In addition, significantly more sites decreased by 1, 2, or 3 mm in the adjunctive minocycline group than in the SRP alone group at 1 and 3 months, both overall as well as in smokers (P < 0.05). CONCLUSION: This secondary analysis indicates that treatment with SRP plus minocycline microspheres is consistently more effective than SRP alone in providing clinically relevant site-based responses in patients with chronic periodontitis.