Preferences for Attributes of Sodium Oxybate Treatment: A Discrete Choice Experiment in Patients with Narcolepsy

Current US FDA-approved treatments for narcolepsy include sodium oxybate (SXB) and calcium, magnesium, potassium, and sodium oxybates (mixed-salt oxybates), which require 2 nightly doses, 1 at bedtime and another 2.5 to 4 hours later. Once-nightly SXB (ON-SXB; FT218) is under FDA review to treat adults with narcolepsy. This study quantitatively characterized attributes of SXB treatment preferred by individuals with narcolepsy via a discrete choice experiment (DCE) and evaluated preferences for the product profiles of once-nightly vs twice-nightly SXB treatment.

Adults with self-reported physician-diagnosed narcolepsy for ≥1 year and current or prior twice-nightly SXB treatment were eligible for this 30-minute, web-based study capturing patient experiences and a DCE. Participants responded to a survey instrument using 9-point scales; higher scores indicated greater severity/preference/satisfaction. In the DCE, hundreds of profiles were generated, each combining attributes of twice-nightly SXB and ON-SXB based on clinical trial data. The DCE was analyzed using a hierarchical Bayesian model.

Seventy-five participants were surveyed (50 current and 25 past twice-nightly SXB users). Dosing frequency was the most important attribute of SXB treatment; once nightly was significantly preferred vs twice nightly. The most common reasons for overall product preference were lack of need to wake up in the middle of the night for a second dose (48%), fewer side effects (46%), and ease of administration (32%). Number of nightly doses was the most important driver of taking the medication exactly as directed and reduced anxiety/stress. Participants were significantly more likely to prefer the blinded product profile of once-nightly SXB over twice-nightly SXB (mean rating, 7.5 vs 4.3; P<0.05).

Among the choices presented, dosing frequency was the most important attribute for overall product choice, likelihood to take medication exactly as directed, and reducing anxiety/stress. The ON-SXB blinded profile was significantly preferred over twice-nightly SXB.