Jazz Pharmaceuticals Presents Phase 3 Study Results of Xywav (calcium, magnesium, potassium, and sodium oxybates) Oral Solution in Adult Patients with Idiopathic Hypersomnia at 2021 American Academy of Neurology Annual Meeting - Seite 2

All study participants were treated with Xywav during an open-label titration and optimization period of up to 14 weeks (OLT), followed by a two-week, open-label, stable-dose period (SDP). Participants entered the study with a mean (standard deviation; SD) Epworth Sleepiness Scale (ESS) score of 16.1 (3.59), indicating substantial excessive sleepiness. Improvement in ESS score with open-label Xywav therapy was observed from a mean of 15.7 (3.77) at study entry to a mean of 6.1 (3.99) at end of SDP.

For Idiopathic Hypersomnia Severity Scale (IHSS), participants entered the study with a mean (SD) IHSS score of 32.1 (7.97), representative of patients with untreated IH. Like ESS, improvement in IHSS score with open-label Xywav therapy was observed from a mean of 31.6 (8.34) at study entry to a mean of 15.3 (8.46) at end of SDP.

Participants were then randomized to placebo or to continue Xywav during a two-week, double-blind, randomized withdrawal period. The primary endpoint of change in ESS score and the key secondary endpoints of change in IHSS score and proportion of participants who reported worsening on the Patient Global Impression of Change (PGIc) scale were measured during the randomized withdrawal portion of the trial, which included 115 participants.

At the end of the double-blind randomized withdrawal period, participants who were randomized to placebo (n=59) experienced significant worsening compared to those who continued Xywav treatment (n=56) in ESS scores LS mean difference [95% CI] in change from SDP to end of DBRWP: −6.51 [−7.99,−5.03]; P<0.0001), PGIc ratings (88.1% vs 21.4% rated minimally/much/very much worse; P<0.0001), and IHSS scores; (estimated median difference [95% CI] in change from end of SDP to end of DBRWP: −12.00 [−15.0,−8.0]; P<0.0001).⁵

The most common treatment-emergent adverse events observed in the study included nausea (21.4%), headache (16.2%), dizziness (11.7%), anxiety (10.4%) and vomiting (10.4%). Four participants reported serious treatment-emergent adverse events, all of which were deemed by the study investigator to not be study drug-related (non-cardiac chest pain, rhabdomyolysis, syncope and nephrolithiasis/pyelonephritis).

Webcast/conference call details
The company will host an audio webcast today at 12:30 p.m. ET to review the Phase 3 idiopathic hypersomnia data being presented at the 2021 AAN Annual Meeting. The live webcast may be accessed from the Investors section of the company's website at www.jazzpharmaceuticals.com. Investors may participate in the conference call by dialing [phone] in the U.S. or [phone] outside the U.S., and entering passcode 8075156.