A Phase 3 Study of Fenfluramine Hydrochloride in Rett Syndrome

Purpose

The purpose of this study is to investigate the efficacy of fenfluramine hydrochloride (HCl) versus placebo in study participants with Rett syndrome (RTT).

Condition

  • Rett Syndrome

Eligibility

Eligible Ages
Between 5 Years and 35 Years
Eligible Sex
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • Participant has typical or classic Rett Syndrome (RTT) according to the RettSearch Consortium 2010 revised criteria - Participant has a documented disease-causing mutation or deletion in the methyl-CpG-binding protein 2 (MECP2) gene - Participant meets criteria for postregression for at least 6 months prior to Screening, defined as: - No loss or degradation of ambulation (including gait, coordination, or independence of walking/standing); - No loss or degradation of hand function; no loss or degradation of speech (including babbling, words, or previously developed communicative vocalizations); - No loss or degradation of nonverbal communicative or social skills (including eye gaze, using body to indicate communicative intent, or social attentiveness) - Participant has an Rett Syndrome Clinical Severity Scale (RTT-CSS) rating of 10 to 36 (inclusive) - Participant has a Clinical Global Impression-Severity (CGIS) score of ≥4 - Participant has a legal representative capable of providing signed informed consent on behalf of the participant as described in the protocol, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol. - Participant is aged 5 to 35 years of age (inclusive) at the time of first administration of investigational intervention. - Male or female. - Participant has a consistent caregiver who is ≥18 years of age at the Screening Visit. The caregiver needs to be able to complete the caregiver assessments defined for the entire study. Every attempt should be made to have the same evaluator complete the assessments for the duration of the study.

Exclusion Criteria

  • Participant has a history of lymphoma, leukemia, or any malignancy within the past 5 years except for basal cell or squamous epithelial carcinomas of the skin that have been resected with no evidence of metastatic disease for 3 years. - Participant has clinically significant abnormality in vital signs according to the Investigator - Participant has an exclusionary cardiovascular or cardiopulmonary abnormality based on echocardiogram (ECHO), electrocardiogram (ECG), or physical examination, and is not approved for entry by the central cardiac reader. Exclusionary abnormalities include, but are not limited to: 1. Greater than trace aortic valve regurgitation. 2. Greater than mild mitral valve regurgitation. 3. Possible signs of pulmonary arterial hypertension (PAH) with abnormal pulmonary artery systolic pressure (PASP) or PASP ≥35 mmHg. 4. Evidence of left ventricular dysfunction (systolic or diastolic). 5. Clinically significant structural cardiac abnormality, including but not limited to mitral valve prolapse, atrial or ventricular septal defects, or patent ductus arteriosus with reversal of shunt (right to left shunt). Note: Patent foramen ovale without a reversal of shunt or a bicuspid aortic valve is not considered exclusionary - Participant has a clinically significant medical condition, including chronic obstructive pulmonary disease, interstitial lung disease, portal hypertension, or need for invasive mechanical ventilation (eg, via tracheostomy), or has had clinically relevant symptoms or a clinically significant illness currently or in the 4 weeks prior to the Screening Visit that would negatively impact study participation, collection of study data, or pose a risk to the participant - Participant is taking >4 concomitant antiseizure medications (ASMs). Rescue medications are not included in the count

Study Design

Phase
Phase 3
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Treatment
Masking
Triple (Participant, Care Provider, Investigator)
Masking Description
The study consists of a Double-Blind and an Open-Label (OL) Intervention Period. During OL Intervention Period, the sponsor, participants, caregivers, and Investigators will be unblinded to treatment assignment.

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
fenfluramine hydrochloride
Participants will receive fenfluramine hydrochloride for 14 weeks in a double-blind period (including titration and maintenance), followed by a 2-week double-blind transition period. This is followed by a 52-week open-label treatment period. Participants may continue treatment until alternative access is available. Those who discontinue without continued access will undergo an 8-day taper and a 26-week follow-up.
  • Drug: fenfluramine hydrochloride
    Oral solution
    Other names:
    • Fintepla, ZX008
Placebo Comparator
Placebo
Participants will receive a matching placebo for 14 weeks in a double-blind period (including titration and maintenance). After this period, they transition into a 2-week double-blind period with fenfluramine hydrochloride, followed by a 52-week open-label treatment period. Participants may continue treatment until alternative access is available. Those who discontinue without continued access will undergo an 8-day taper and a 26-week follow-up.
  • Other: Placebo
    Oral solution

Recruiting Locations

Ep0247 21010
Little Rock, Arkansas 72202

Ep0247 21011
Orlando, Florida 32806

Ep0247 21007
Atlanta, Georgia 30322

Ep0247 21005
Houston, Texas 77030

Ep0247 21013
Irving, Texas 75062

More Details

Status
Recruiting
Sponsor
UCB BIOSCIENCES, Inc.

Study Contact

UCB Cares
+18445992273
ucbcares@ucb.com