KemPharm Announces Initiation of Phase 2 Clinical Trial Investigating KP1077 for the Treatment of Idiopathic Hypersomnia

KemPharm, Inc. recently announced the initiation of a Phase 2 clinical trial evaluating KP1077 as a treatment for idiopathic hypersomnia (IH), a rare neurological sleep disorder. KP1077 is comprised solely of serdexmethylphenidate (SDX), KemPharm’s proprietary prodrug of d-methylphenidate. SDX was recently granted Orphan Drug Designation by the US FDA for the treatment of IH.

The Phase 2 clinical trial is a double-blind, placebo-controlled, randomized-withdrawal, dose-optimizing, multi-center study evaluating the efficacy and safety of KP1077 for the treatment of IH. KemPharm expects to enroll approximately 48 adult patients with IH in more than 30 centers in the United States. Part 1 of the trial will consist of a five-week open-label titration phase during which patients will be optimized to one of four doses of SDX (80, 160, 240, or 320 mg/day). Part 2 of the trial will entail a two-week randomized, double-blind, withdrawal phase, during which two-thirds of the trial participants will continue to receive their optimized dose while the remaining one-third will receive placebo. Participants will be further assigned into two evenly divided cohorts. The first cohort will receive a single daily dose just before bedtime, and the second cohort will receive half the daily dose shortly after awakening and half the daily dose prior to bedtime.

The primary endpoint is the safety and tolerability of SDX. The major secondary efficacy endpoint is the change in Epworth Sleepiness Scale (ESS) total score. Additional exploratory endpoints include the Patient Global Impression of Severity (PGI-S), the Clinical Global Impression of Severity (CGI-S), change in total score on the Idiopathic Hypersomnia Severity Scale (IHSS), and a new scale to assess the symptoms and severity of “Brain Fog.”

“Initiation of the Phase 2 clinical trial investigating KP1077 for the treatment of IH is a significant milestone for KemPharm and a key inflection point as we continue to pursue our strategic transformation to develop or acquire novel therapeutics designed to address a range of underserved rare diseases,” said Travis C. Mickle, PhD, President and CEO of KemPharm. “We believe the design of the Phase 2 study will allow us to evaluate KP1077’s effect on several symptoms associated with IH, including excessive daytime sleepiness, extreme difficulty waking, and severe brain fog. Additionally, this study provides an opportunity to explore both the optimal SDX dose range and dosing regimen(s) – nighttime dosing or twice daily – which will inform the design of future Phase 3 studies for the IH and narcolepsy indications. We expect to report interim data from the trial as early as Q3 2023.”

It is estimated that 37,000 patients are currently diagnosed with IH and seeking treatment, although the total population may be much larger due to patients not seeking treatment, undiagnosed and misdiagnosed. KP1077 may have the potential to capture a large share of the IH market based on anticipated clinical differentiation and the possibility to be used in combination with sodium oxybate-based products.

Serdexmethylphenidate (SDX) is KemPharm’s proprietary prodrug of d-methylphenidate (d-MPH) and the sole active pharmaceutical ingredient (API) in KP1077, KemPharm’s lead clinical candidate being developed as a treatment for idiopathic hypersomnia (IH) and narcolepsy.  KemPharm is currently advancing a multicenter, dose-optimizing, double-blind, placebo-controlled, randomized-withdrawal Phase 2 clinical trial to evaluate safety and efficacy of KP1077 as a treatment for IH.

SDX is also the primary API in AZSTARYS, a once-daily product for the treatment of attention deficit hyperactivity disorder (ADHD) in patients ages 6 and older being commercialized in the US by Corium, Inc., and is the sole API in KP879, which KemPharm is developing as a treatment for Stimulant Use Disorder (SUD).

SDX has been granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) for the treatment of IH, and the US Drug Enforcement Agency (DEA) has classified SDX as a Schedule IV controlled substance based on evidence suggesting SDX has a lower potential for abuse when compared to d-MPH, a Schedule II controlled substance.

KemPharm is a rare disease therapeutics company focused on the discovery, development, and commercialization of novel treatments for rare CNS and neurodegenerative diseases, lysosomal storage disorders and related treatment areas. KemPharm has a diverse product portfolio, combining a clinical-stage development pipeline with NDA-stage and commercial assets. The pipeline includes arimoclomol, an orally-delivered, first-in-class investigational product candidate for Niemann-Pick disease type C (NPC), and KP1077, which the Company is developing as a treatment for idiopathic hypersomnia (IH), a rare neurological sleep disorder, and narcolepsy. In addition, the US FDA has approved AZSTARYS, a once-daily treatment for ADHD in patients age six years and older containing KemPharm’s prodrug, serdexmethylphenidate (SDX), which is being commercialized by Corium, Inc. in the US. The FDA has also approved APADAZ, an immediate-release combination product containing benzhydrocodone, KemPharm’s prodrug of hydrocodone, and acetaminophen, which is being commercialized by KVK-Tech, Inc. in the US. For more information, visit www.kempharm.com.