A 12-Week, Open-Label, Multicenter Pilot Study to Evaluate the Efficacy and Safety of Lemborexant in Patients with...

The efficacy and safety of lemborexant, a dual orexin receptor antagonist, for treating insomnia associated with depressive episodes remain unclear. This pilot study aimed to evaluate the changes in clinical symptoms following the initiation of lemborexant treatment and its safety in patients with insomnia comorbid with depressive episodes.

The inclusion criteria for this multicenter, prospective, interventional, open-label pilot study conducted in Japan were adults (≥ 18 years) diagnosed with insomnia and either major depressive disorder (MDD) or bipolar disorder (BD) according to DSM-5, receiving treatment for a depressive episode for ≥ 4 weeks, and having a baseline Hamilton Depression Rating Scale (HAM-D-17) score of ≥ 8. Patients were classified into four cohorts on the basis of their MDD or BD diagnosis and concomitant insomnia medication use (lemborexant add-on or monotherapy). After a 2-week lead-in period with unchanged prior medications for insomnia MDD or BD, 12-week lemborexant treatment was administered. The primary endpoint was the change from baseline in the Insomnia Severity Index (ISI) total score at week 4, which was analyzed using paired t-tests with a two-sided significance level of 5%. For other endpoints, summary statistics and 95% confidence intervals (CIs) for observed values and changes from baseline were calculated by cohort. Safety outcomes included the evaluation of the safety and tolerability of lemborexant during the treatment period.

A total of 83 patients with comorbid insomnia and depressive episodes were enrolled (MDD add-on cohort, n = 29; MDD monotherapy, n = 23; BD add-on, n = 16; and BD monotherapy, n = 15). The average age was 47.2 years and 64.6% were female. Mean baseline ISI total score (SD) was 14.5 (4.8), 13.2 (5.5), 13.5 (6.0), and 11.8 (4.6), respectively. At week 4, mean change from baseline in the ISI total score [95% CI, p-value] was - 2.3 [- 3.9, - 0.7, p = 0.0065], - 3.2 [- 5.0, - 1.3, p = 0.0018], - 5.2 [- 7.9, - 2.5, p = 0.0012], - 4.5 [- 6.3, - 2.6, p = 0.0001], respectively. Improvements were sustained through week 12. Sleep diary measures such as sleep onset latency and total sleep time improved in some cohorts, but the results were inconsistent. Mean baseline HAM-D-17 scores were 13.6 (5.1), 12.6 (5.1), 13.9 (4.3), and 11.4 (3.4), respectively, with mean changes at week 12 of - 6.4 [- 7.8, - 4.9], - 6.2 [- 7.7, - 4.6], - 5.2 [- 8.4, - 2.1], and - 5.4 [- 7.2, - 3.5], respectively. No serious treatment-emergent adverse events (TEAEs) were reported, with TEAE incidence ranging from 30% to 40%, all mild to moderate in severity. Somnolence was the most common adverse reaction, reported in 10.3-25.0% of cohorts except BD monotherapy. Nightmare followed, occurring in 4.3-12.5% across cohorts.

Lemborexant was associated with improvements in insomnia severity and depressive symptoms related to MDD or BD, with no new safety concerns. It may be a treatment option for residual insomnia following treatment for depression associated with MDD or BD, though somnolence and nightmares warrant attention. Confirmatory studies are needed to establish its therapeutic value.

Japan registry of clinical trials (jRCTs071220037; registered on 4 August 2022).