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Drug

Tasimelteon

Established medicine
ClassMelatonin receptor agonistResearchActive indication expansion

Also known as Hetlioz, Tasimelteonum.

RxNorm1490468ChEMBLCHEMBL2103822ATCN05CH03UNIISHS4PU80D9
2
Active clinical trials
2
Protein targets
7
Regulatory events
Latest activity
beta

Recent clinical, regulatory, research and industry developments relating to this drug.

A Multicenter, Double-blind, Randomized Study to Evaluate the Effects of Tasimelteon vs. Placebo in Participants With Delayed Sleep-Wake Phase Disorder (DSWPD)

Clinical trial2026-07-27Status changed to Active, not recruiting · ClinicalTrials.gov

Supplemental approval: TASIMELTEON (NDA205677)

Regulatory2026-07-27FDA

A Double-Blind, Randomized, Two-Period Crossover Study to Evaluate the Effects of Tasimelteon Vs. Placebo in Subjects with Delayed Sleep-Wake Phase Disorder (DSWPD) and the CRY1Δ11 Variant

Clinical trial2025-06-30Primary completion · ClinicalTrials.gov

Open-Label Safety Study of a 1-Year 20 mg Dose Regimen of Tasimelteon for Treatment of Non-24-Hour-Sleep-Wake Disorder (N24HSWD) in Blind Individuals With No Light Perception

Clinical trial2024-12-05Primary completion · ClinicalTrials.gov

A Single Center, Open Label Prospective Observational Pilot Study to Evaluate the Effects of Tasimelteon in Participants With REM Behavior Disorder (RBD)

Clinical trial2023-12-01Terminated · ClinicalTrials.gov

Evaluating the Effects of Tasimelteon vs. Placebo on Jet Lag Type Insomnia

Clinical trial2023-09-15Results posted · ClinicalTrials.gov

An Open-Label, Two-Period, Randomized, Single Oral Dose, Crossover Study to Evaluate the Bioequivalence of Tasimelteon Capsule Formulation Relative to Tasimelteon Liquid Suspension Formulation in Healthy Volunteers

Clinical trial2022-06-15Completed · ClinicalTrials.gov

A Double-blind, Randomized, Two-period Crossover Study Evaluating the Effects of Tasimelteon vs. Placebo on Sleep Disturbances of Individuals With Smith-Magenis Syndrome (SMS)

Clinical trial2022-01-01Completed · ClinicalTrials.gov

A Proof of Concept Study to Evaluate the Effects of Tasimelteon and Placebo in Travelers With Jet Lag Disorder

Clinical trial2021-11-03Results posted · ClinicalTrials.gov

Indication expansion: TASIMELTEON (NDA205677)

Regulatory2020-12-01FDA

Label change: TASIMELTEON (NDA205677)

Regulatory2019-10-07FDA

Supplemental approval: TASIMELTEON (NDA205677)

Regulatory2016-04-11FDA

Profile

Identifiers & mechanism

Canonical identifiers, marketed brand names and mechanism, resolved across RxNorm, ChEMBL and ATC.

Canonical name
Tasimelteon
Aliases & brands
HetliozTasimelteonum
RxNorm CUI
1490468
ChEMBL ID
CHEMBL2103822
ATC codes
N05CH03
UNII
SHS4PU80D9
Primary mechanism
Melatonin receptor agonist
Regulatory jurisdictions
emafda

Pharmacology & targets

2 targets

Known molecular targets and mechanisms supported by curated pharmacology databases.

Melatonin receptor type 1A
MTNR1A · P48039
AGONISTMelatonin receptor agonist
Melatonin receptor type 1B
MTNR1B · P49286
AGONISTMelatonin receptor agonist

Regulatory timeline

7 events

The complete regulatory record, grouped by authority — approvals, safety advisories and label changes. Each authority shows its most recent events; expand one to read its full history.

Approval / market entry confirmed across FDA and EMA (2014-01-31 → 2015-07-03)
Earliest approval
2014-01-31
Latest approval
2026-07-27
Authorities
FDA · EMA
Total events
7
fdaU.S. Food and Drug Administration· 6 events
2026-07-27Supplemental approval
Supplemental approval: TASIMELTEON (NDA205677)
Evidence ↗
2020-12-01Indication expansion
Indication expansion: TASIMELTEON (NDA205677)
Evidence ↗
2019-10-07Label change
Label change: TASIMELTEON (NDA205677)
Evidence ↗
emaEuropean Medicines Agency· 1 event
2015-07-03ApprovalMulti-authority
Approval: Hetlioz (EMA)

Indication: Hetlioz is indicated for the treatment of Non-24-Hour Sleep-Wake Disorder (Non-24) in totally blind adults.

Evidence ↗

Data from the U.S. Food and Drug Administration (U.S. Food and Drug Administration), public domain (CC0).

Contains information from the European Medicines Agency (European Medicines Agency), © EMA, reused under CC BY 4.0.

Clinical trials

22 trials

The current development programme across all trial phases — status mix, phase distribution and the late-stage studies shaping the evidence base.

Development programme
CLINICALTRIALS.GOV · LIVE REGISTRY
22
registered trials across all phases
LATEST COMPLETION 2022
2
Active studies
1
Recruiting
10
Late-stage (III+)
18
Completed
2
Discontinued
PHASE DISTRIBUTIONn = 22
Early Phase 11Phase 110Phase 21Phase 2 / 32Phase 37Phase 41

Late-stage studies

Phase III+ trials still open or recently active — where late-stage evidence is being generated.

A Single Dose, Open-Label, Randomized Two-Period Crossover Study in Healthy Young Subjects to Assess the Absolute Bioavailability of Tasimelteon (HETLIOZ™)

CompletedPH IVVanda Pharmaceuticalsn=142014

A Multicenter, Double-blind, Randomized Study to Evaluate the Effects of Tasimelteon vs. Placebo in Participants With Delayed Sleep-Wake Phase Disorder (DSWPD)

Active, not recruitingPH IIIVanda Pharmaceuticalsn=702026

A Double-Blind, Randomized, Two-Period Crossover Study to Evaluate the Effects of Tasimelteon Vs. Placebo in Subjects with Delayed Sleep-Wake Phase Disorder (DSWPD) and the CRY1Δ11 Variant

RecruitingPH IIIVanda Pharmaceuticalsn=602025

Open-Label Safety Study of a 1-Year 20 mg Dose Regimen of Tasimelteon for Treatment of Non-24-Hour-Sleep-Wake Disorder (N24HSWD) in Blind Individuals With No Light Perception

Unknown statusPH IIIVanda Pharmaceuticalsn=1402024

A Double-blind, Randomized, Two-period Crossover Study Evaluating the Effects of Tasimelteon vs. Placebo on Sleep Disturbances of Individuals With Smith-Magenis Syndrome (SMS)

CompletedPH II/IIIVanda Pharmaceuticalsn=492022

Recent completions

Trials that read out recently, adding to the completed evidence base.

An Open-Label, Two-Period, Randomized, Single Oral Dose, Crossover Study to Evaluate the Bioequivalence of Tasimelteon Capsule Formulation Relative to Tasimelteon Liquid Suspension Formulation in Healthy Volunteers

CompletedPH IVanda Pharmaceuticalsn=362022

A Double-blind, Randomized, Two-period Crossover Study Evaluating the Effects of Tasimelteon vs. Placebo on Sleep Disturbances of Individuals With Smith-Magenis Syndrome (SMS)

CompletedPH II/IIIVanda Pharmaceuticalsn=492022

A Randomized, Double-blind, Double-dummy, Placebo-controlled, Three-way Crossover Study in Healthy Subjects to Evaluate the Next-day Residual Effects of 20 mg Tasimelteon

CompletedPH IVanda Pharmaceuticalsn=482018

Evaluating the Effects of Tasimelteon vs. Placebo on Jet Lag Type Insomnia

CompletedPH IIIVanda Pharmaceuticalsn=3202018

Open-label Study to Investigate the Pharmacokinetics and Safety of Tasimelteon in Children and Adolescents

CompletedPH IVanda Pharmaceuticalsn=242017

A Proof of Concept Study to Evaluate the Effects of Tasimelteon and Placebo in Travelers With Jet Lag Disorder

CompletedPH IIVanda Pharmaceuticalsn=252017
References & data sources
  • RxNorm (U.S. National Library of Medicine) — drug identity
  • ChEMBL (EMBL-EBI) & UniProt — pharmacology and targets
  • ClinicalTrials.gov — clinical trials
  • Regulatory event sources are credited in the Regulatory Timeline above.