Alkermes plc (ALKS) just gave narcolepsy patients something to feel awake about. The company reported positive interim results from its ongoing long-term extension study of its experimental oral therapy alixorexton, showing that the drug's benefits in wakefulness, daytime sleepiness, cognition, and fatigue stick around for the long haul in adults with both type 1 (NT1) and type 2 (NT2) narcolepsy.
The interim analysis looked at participants who had already completed the Phase 2 Vibrance-1 (NT1) and Vibrance-2 (NT2) studies before signing up for the open-label extension. Safety data was collected through May 12, 2026, and efficacy was assessed at week 24 of the extension.
NT1: Staying Awake, Staying Normal
For NT1 patients, the results were pretty impressive. Across all dose groups, participants achieved what's called "normative wakefulness" on the Maintenance of Wakefulness Test at week 24. That's a fancy way of saying they could stay awake like a healthy person would. The mean observed sleep latency was about 29 minutes — basically, it took them nearly half an hour to fall asleep in a boring situation, which is a good thing.
Epworth Sleepiness Scale scores also stayed within the normal range across all doses, and weekly cataplexy rates — those sudden muscle weakness episodes that narcolepsy is famous for — improved from baseline. Patient-reported measures showed that cognition and fatigue improvements were generally maintained through week 24, with most participants reporting cognitive function and fatigue scores within the normal range.
NT2: More Improvement, Same Safety
NT2 patients didn't just hold steady; they actually got better. Participants across all dose groups showed further improvements in wakefulness at week 24, with a mean observed sleep latency of about 18 minutes. Epworth Sleepiness Scale scores remained within the normal range for the 14 mg and 18 mg dose groups.
Cognition and fatigue improvements were also generally maintained, with most participants reporting cognitive function within the normal or mild impairment range and fatigue scores within the normal range. And here's the kicker: no serious treatment-emergent adverse events were reported. The most common side effects were headache, micturition urgency, pollakiuria (frequent urination), and nasopharyngitis (the common cold).
What's Next?
Alkermes plans to present these findings at an upcoming medical meeting. Meanwhile, alixorexton is already being tested in the Phase 3 Brilliance studies for adults with NT1 and NT2, as well as the Phase 2 Vibrance-3 study for adults with idiopathic hypersomnia — a condition where people are sleepy all the time for no obvious reason.
Stock Check: Uptrend Intact, But Momentum Fading
Alkermes stock was down a bit on Monday — about 1.48% to $51.17 — as the broader market also took a hit. The Nasdaq Composite fell more than 1%, and the S&P 500 declined 0.44%.
But zoom out, and the picture looks better. The stock is still trading above its 20-day, 50-day, 100-day, and 200-day simple moving averages. The 50-day moving average remains above the 200-day moving average, following a golden cross that formed back in January. The stock is still about 51% above its 200-day moving average, suggesting the broader uptrend is intact.
However, momentum has weakened in recent sessions. The MACD is below its signal line, and the histogram is negative — that's technical-speak for "bulls are taking a breather." Price action suggests consolidation rather than a breakdown, with the stock trading between its April swing low and July swing high. Traders will be watching whether shares can hold near the 20-day moving average to keep the short-term uptrend alive.
The next resistance level is the 52-week high of $55.67. Initial support sits near $50.38, close to the 20-day moving average.
