Takeda's narcolepsy drug advances to Phase III after positive results

Takeda has unveiled the results of a Phase IIb clinical trial assessing its new oral medication, TAK-861, aimed at treating narcolepsy type 1 (NT1). In an announcement made in February, the company highlighted that its orexin receptor 2 agonist demonstrated statistically significant and clinically meaningful improvements compared to placebo across both primary and secondary endpoints in a study involving 112 patients.

The randomized trial explored the effects of different doses of TAK-861, administered either once or twice daily, over an eight-week treatment period. The primary outcome revealed that TAK-861 substantially increased mean sleep latency, measured by the Maintenance of Wakefulness Test (MWT), at the eighth week compared to placebo across all dose groups. Specifically, mean sleep latency improved from 16.5 minutes for the lowest dose of 0.5mg/0.5mg, up to 30.7 minutes for the highest dose of 2mg/5mg. In contrast, the placebo group showed a mean sleep latency of only 7 minutes.

Significant benefits were also observed in key secondary outcomes. By the end of the eight-week period, between 66.7% and 95.2% of patients in the TAK-861 dose groups achieved an Epworth Sleepiness Scale (ESS) score of 10 or less, which falls within the normative range. In comparison, only 19% of patients in the placebo group achieved this score. Additionally, TAK-861 notably decreased weekly cataplexy rates. The twice-daily doses of 2mg/2mg and 2mg/5mg reduced the median cataplexy events to just 0.7 per week, whereas the placebo group experienced a median of 4.1 events per week.

Takeda emphasized that most NT1 patients in the trial reached normative ranges for both MWT and ESS by the end of the treatment period, attributing these outcomes to the consistent improvements seen with TAK-861. The medication was generally well-tolerated among participants, with no serious treatment-related adverse events reported, and no discontinuations due to adverse events.

Based on the promising results from this mid-stage trial, Takeda plans to proceed with global Phase III trials for TAK-861 in NT1 patients, aiming to commence in the first half of fiscal year 2024.