Minocycline nonsuperior to placebo for depressive symptoms in those with TRD
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Administration of minocycline as an add-on to therapy as usual for those with treatment-resistant depression was nonsuperior to placebo after 6 weeks, according to a study published in JAMA Network Open.
“Major depressive disorder is an important cause of disability worldwide,” Julian Hellmann-Regen, MD, of the department of psychiatry and neurosciences at Charite University Hospital of Medicine Berlin, and colleagues wrote. “Insufficient response rates, persistent residual symptoms, frequent relapse or recurrence of symptoms constitute unsatisfactory outcomes of conventional antidepressant treatments.”
Hellmann-Regen and colleagues sought to determine whether minocycline, which inhibits microglial activation, for those dealing with MDD, as add-on to antidepressant treatment as usual can significantly reduce depressive symptoms in patients with TRD.
Their study was conducted at nine university hospitals throughout Germany as a multicenter, double-blind, randomized clinical trial. The researchers included a total of 173 individuals aged 18 to 75 years, with a diagnosis of MDD, severity of depressive symptoms on the Hamilton Depression Rating Scale (HAMD-17) greater than or equal to 16 points, a BMI of 18 to 40, Clinical Global Impression Scale (CGI-S) greater than or equal to 4 and failure to adequately respond to an initial antidepressant standard medication per Massachusetts General Hospital Antidepressant Treatment History Questionnaire who had been on prescribed stable medication for at least 2 weeks.
Participants were randomized on a 1:1 basis to receive either adjunct minocycline (200 mg/d) or placebo for 6 weeks, with a 6-week follow-up. The primary outcome measure was a change in Montgomery-Åsberg Depression Rating Scale (MADRS) score from baseline to week 6 analyzed by intention-to-treat mixed model repeated measures. Secondary outcome measures were response, remission and various other clinical rating scales.
According to the study, 168 participants formed the intention-to-treat sample (79 women, 89 men, 159 white), with 81 in the minocycline group and 87 in the placebo group.
The mean MADRS score for the sample at baseline was 26.5 (5). Minocycline treatment did not alter the course of depression severity compared with placebo as assessed by a decrease in MADRS scores over 6 weeks of treatment (1.46 [1.04 to 3.96]). Minocycline treatment also exhibited no statistically significant effect on secondary outcomes. There was no difference in rates of completion between the minocycline (83.3%) and the placebo group (83.1%).
“Our results ... are of great clinical importance, robustly demonstrating that minocycline add-on treatment does not outperform placebo,” Hellmann-Regen and colleagues wrote.