A Study to Assess the Long-term Efficacy and Safety of AXS-12 (Reboxetine) in Subjects With Narcolepsy (ENCORE)

November 11, 2025 updated by: Axsome Therapeutics, Inc.

A Study to Assess the Long-term Efficacy and Safety of AXS-12 in the Treatment of Cataplexy and Excessive Daytime Sleepiness in Subjects With Narcolepsy

This study will evaluate the long-term efficacy and safety of AXS-12 in narcoleptic subjects with cataplexy and excessive daytime sleepiness (EDS).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This study is a multi-center trial consisting of a 24-week open-label period, followed by a 4-week double-blind, placebo-controlled, randomized withdrawal period. At the Week 24 visit, subjects will be randomized in a 1:1 ratio either to continue to receive AXS-12 or to switch to placebo, for the next 4 weeks. Eligible subjects will have previously participated in the AXS-12-301 study.

Study Type

Interventional

Enrollment (Actual)

68

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5S 3A3
        • Clinical Research Site
  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85054
        • Clinical Research Site
    • Colorado
      • Boulder, Colorado, United States, 80301
        • Clinical Research Site
      • Colorado Springs, Colorado, United States, 80918
        • Clinical Research Site
    • Florida
      • Brandon, Florida, United States, 33511
        • Clinical Research Site
      • Clearwater, Florida, United States, 33765
        • Clinical Research Site
      • Doral, Florida, United States, 33122
        • Clinical Research Site
      • Miami Lakes, Florida, United States, 33016
        • Clinical Research Site
      • Winter Park, Florida, United States, 32789
        • Clinical Research Site
    • Georgia
      • Atlanta, Georgia, United States, 30328
        • Clinical Research Site
      • Atlanta, Georgia, United States, 30315
        • Clinical Research Site
      • Stockbridge, Georgia, United States, 30281
        • Clinical Research Site
    • Maryland
      • Chevy Chase, Maryland, United States, 20815
        • Clinical Research Site
    • Michigan
      • Kalamazoo, Michigan, United States, 49008
        • Clinical Research Site
      • Novi, Michigan, United States, 48377
        • Clinical Research Site
    • New Jersey
      • Neptune City, New Jersey, United States, 07753
        • Clinical Research Site
    • North Carolina
      • Denver, North Carolina, United States, 28037
        • Clinical Research Site
      • Gastonia, North Carolina, United States, 28054
        • Clinical Research Site
      • Huntersville, North Carolina, United States, 28078
        • Clinical Research Site
    • Ohio
      • Cincinnati, Ohio, United States, 45245
        • Clinical Research Site
    • Pennsylvania
      • Wyomissing, Pennsylvania, United States, 19610
        • Clinical Research Site
    • South Carolina
      • Charleston, South Carolina, United States, 29425
        • Clinical Research Site
      • Columbia, South Carolina, United States, 29201
        • Clinical Research Site
    • Texas
      • Austin, Texas, United States, 78731
        • Clinical Research Site
      • San Antonio, Texas, United States, 78229
        • Clinical Research Site

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

15 years to 75 years (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Completed the treatment period of Study AXS-12-301
  • Willing and able to comply with the study requirements

Exclusion Criteria:

  • Significant change in medical history or concomitant medications since enrolling in the AXS-12-301 study which, in the opinion of the Investigator, would render the subject unsuitable to receive AXS-12

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: AXS-12 (reboxetine)
  • Up to 24 weeks in open-label period
  • Up to 4 weeks in randomized double-blind period
Drug: AXS-12 (reboxetine)
AXS-12 tablets, taken twice daily
Placebo Comparator: Placebo
Up to 4 weeks in randomized double-blind period
Drug: Placebo
Placebo tablets, taken twice daily

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Long-term safety as measured by the incidence of treatment-emergent adverse events
Time Frame: Up to 28 weeks
Up to 28 weeks
Efficacy as measured by change in frequency of cataplexy attacks from baseline.
Time Frame: Baseline to Week 27
Baseline to Week 27

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Axsome Therapeutics, Inc.

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 20, 2021

Primary Completion (Actual)

November 15, 2024

Study Completion (Actual)

November 15, 2024

Study Registration Dates

First Submitted

October 29, 2021

First Submitted That Met QC Criteria

October 29, 2021

First Posted (Actual)

November 9, 2021

Study Record Updates

Last Update Posted (Estimated)

November 13, 2025

Last Update Submitted That Met QC Criteria

November 11, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AXS-12-302

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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