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Verified 4 Aug 2026

Pipeline › Discontinued

Discontinued

Compounds that left the pipeline, and why. A class is judged by its failures as much as its approvals, and two of these three shaped how the surviving programs were designed.

No longer in development

TAK-994

Takeda · verified 4 Aug 2026

Stopped in Phase 2 after liver safety signals emerged. Oveporexton is the successor compound.

Source
Registry IDStudyPhaseStatusPrimary completion
NCT04833049 Study to Evaluate Absorption, Metabolism, and Excretion, of TAK-994 in 6 Healthy Male Adults6 participants Phase 1 Completed 20 Jun 2021
NCT04745767 A Study of Different Forms of TAK-994 in Healthy Adults54 participants Phase 1 Completed 25 Mar 2021
NCT04551079 A Study to Evaluate the Safety, Tolerability, Pharmacodynamics, and Pharmacokinetics (PK) of Oral TAK-994 in an Acute Sleep Phase Delay Paradigm in Healthy Male Participants19 participants Phase 1 Completed 31 Dec 2020
NCT03933488 A Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of TAK-994 in Healthy Participants121 participants Phase 1 Completed 29 Mar 2020
NCT04820842 A Study of TAK-994 in Adults With Narcolepsy26 participants Phase 2 Terminated 3 Nov 2021
NCT04096560 A Study of TAK-994 in Adults With Type 1 and Type 2 Narcolepsy97 participants Phase 2 Terminated 5 Nov 2021

danavorexton

Takeda · verified 4 Aug 2026

TAK-925, an intravenous OX2R agonist used to establish the mechanism in humans. Superseded by oral compounds.

Source
Registry IDStudyPhaseStatusPrimary completion
NCT05180890 A Study of Danavorexton (TAK-925) in Adults With Obstructive Sleep Apnea13 participants Phase 1 Completed 23 Nov 2022
NCT05025397 A Study of Danavorexton in Anesthetized Adults28 participants Phase 1 Completed 8 Mar 2022
NCT04091438 A Study of a Single Intravenous Infusion Dose of TAK-925 in Participants With Idiopathic Hypersomnia28 participants Phase 1 Completed 19 Nov 2020
NCT04091425 Study of TAK-925 in Participants With Obstructive Sleep Apnea (OSA) Who Are Experiencing Excessive Daytime Sleepiness (EDS) Despite Adequate Use of Continuous Positive Airway Pressure (CPAP)25 participants Phase 1 Completed 2 Apr 2020
NCT03748979 A Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of TAK-925 in Healthy Volunteers and Participants With Narcolepsy57 participants Phase 1 Completed 24 Oct 2019
NCT03522506 A Study to Evaluate the Safety, Tolerability, Pharmacokinetics (PK) and Pharmacodynamics (PD) of TAK-925 Study in Sleep-Deprived Healthy Adults20 participants Phase 1 Completed 7 Nov 2018
NCT03332784 Phase 1 TAK-925 Study in Healthy Adult and Elderly Volunteers and Participants With Narcolepsy58 participants Phase 1 Completed 4 Sept 2018
NCT05814016 A Study of Danavorexton in People With Obstructive Sleep Apnea After General Anesthesia for Abdominal Surgery41 participants Phase 2 Terminated 25 Sept 2024

JZP441

Jazz Pharmaceuticals · verified 4 Aug 2026

Oral OX2R agonist licensed from Sumitomo Pharma (as DSP-0187). The Phase 1b efficacy study in narcolepsy type 1 (NCT06961266) was terminated in early 2026 for business reasons, not a safety signal. The compound no longer appears on Jazz's pipeline page.

Source
Registry IDStudyPhaseStatusPrimary completion
NCT05720494 A Multiple Ascending Dose Study to Investigate the Safety, Tolerability, and Pharmacokinetics of JZP441 in Healthy Participants24 participants Phase 1 Completed 29 Sept 2023
NCT05651152 A Study to Investigate The Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of JZP441 in Sleep-deprived Healthy Participants105 participants Phase 1 Completed 15 Nov 2023
NCT06961266 A Study to Investigate Efficacy, Safety, Tolerability, and Pharmacokinetics of JZP441 Compared With Placebo in Participants With Narcolepsy Type 16 participants Phase 1 Terminated 29 Jan 2026

Why it matters

TAK-994 is the reason long-term liver safety is the first question anyone asks about this class. It reached Phase 2 and was stopped when liver signals emerged, and every programme that followed has been designed and read with that history in view.

Danavorexton never failed. It was an intravenous compound built to answer whether stimulating the orexin receptor restores wakefulness in humans at all. It did, and the field moved on to making that work in a pill.

JZP441 is the reminder that programmes also stop for reasons that have nothing to do with the science. Jazz terminated its Phase 1b study in early 2026 for business reasons, not a safety signal.