Phase III SUNRISE 1 and SUNRISE 2 trials of E 2006 show safety and efficacy in insomnia

Eisai Inc. announced new long-term safety and pooled analyses from the Phase III clinical development program for E 2006 (lemborexant), an investigational agent for sleep-wake regulation, currently being studied for the treatment of insomnia, a sleep-wake disorder, and irregular sleep-wake rhythm disorder (ISWRD). These analyses of lemborexant assessed its efficacy on key insomnia measures, improvement in patient daytime function and long-term safety. Additionally, sleep architecture data were presented from the Phase III SUNRISE 1 study.

In this post hoc pooled analysis of the Phase III SUNRISE 1 (Study 304) and SUNRISE 2 (Study 303) studies, which included a total of 1,693 patients (lemborexant 5 mg, n=582; lemborexant 10 mg, n=584; placebo, n=527), Insomnia Severity Index (ISI) total scores decreased compared to baseline after one month of nightly use as measured by least squares mean (LSM) (-7.2 for lemborexant 5 mg, -7.5 for lemborexant 10 mg, – 5.5 for placebo). Approximately one-third of those taking lemborexant experienced declines in the ISI total score below 10, the clinical threshold for insomnia, at the end of one month (33.0% for lemborexant 5 mg, 33.4% for lemborexant 10 mg, 20.3% for placebo). The proportion of patients with a decrease in ISI total score of at least 7 at the end of one month of treatment was greater with both doses of lemborexant compared with placebo (47.3% for lemborexant 5 mg, 47.8% for lemborexant 10 mg, 33.6% for placebo). In addition, median reductions from baseline in subjective sleep onset latency (sSOL) were larger for lemborexant 5 mg and 10 mg compared to placebo during the first seven days of treatment (-12.9 for lemborexant 5 mg, -13.6 for lemborexant 10 mg, -2.9 for placebo) and at the end of month one of treatment (-16.1 for lemborexant 5 mg, -17.9 for lemborexant 10 mg, -5.2 for placebo).

From SUNRISE 2, the majority of treatment-emergent adverse events (TEAEs) reported were mild or moderate. Serious TEAEs were observed in a small proportion of patients (2.2% with lemborexant 5 mg, 2.9% with lemborexant 10 mg, 1.6% with placebo). Treatment-related TEAEs were reported in a higher proportion of lemborexant 5 mg and 10 mg subjects compared to placebo (24.8%, 29.0%, 13.8%), with the most common treatment-related TEAE being somnolence. Overall, the incidence of TEAEs leading to discontinuation of the study drug was higher in the lemborexant 10 mg (8.3%) group vs. the lemborexant 5 mg (4.1%) and placebo (3.8%). The findings were presented at the 33rd annual meeting of the Associated Professional Sleep Societies (SLEEP 2019).