Impact of Low-Dose Oral Minocycline (DFD-29) on Skin, Gastrointestinal, and Vaginal Microflora in Healthy Adults.

BACKGROUND

DFD-29 (minocycline hydrochloride extended-release capsules, 40 mg) has shown significant therapeutic benefit vs placebo and doxycycline in treating moderate-to-severe rosacea. However, the impact of its use on skin, vaginal, and gastrointestinal microbiota is unknown.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled trial, 60 healthy adults were randomized in a 2:1 ratio to receive either DFD-29 (40 mg) orally or a matching placebo once daily for 16 weeks. Microbiological samples were collected from the skin (forehead), vagina, and stool at baseline and weeks 4, 8, and 16 to evaluate changes in normal microbiota species (via culture and 16S rRNA sequencing), in the MIC90 of selected colonized microbial species, and in opportunistic microbiota with DFD-29 vs placebo. Safety was evaluated via analysis of adverse events, vital signs, and laboratory tests.

RESULTS

Thirty-eight adults assigned to DFD-29 and 19 adults assigned to placebo were included in the microbiota evaluable population. There were no significant differences detected in the abundance of microbial species in the skin, stool, or vagina from baseline to week 16 between the DFD-29 and placebo groups. No significant differences were detected in resistance to minocycline between DFD-29 and placebo. There were also no significant differences in the presence of opportunistic microbiota at any time point. No significant safety issues were reported.

CONCLUSION

Administration of DFD-29 for 16 weeks had no detectable effects on skin, GI tract, or vaginal microflora and was well tolerated in healthy adults, reinforcing its potential as a therapeutic option in moderate-to-severe rosacea. &nbsp.