Efficacy and Safety Study of Mepolizumab in Subjects With Severe Hypereosinophilic Syndrome (HES)

Summary

Mepolizumab is a humanized monoclonal antibody. In conditions where eosinophilia is considered to play an important part in the pathology, including eosinophilic asthma, HES, and eosinophilic granulomatosis with polyangiitis, a consistent reduction in blood eosinophil counts is observed in association with mepolizumab administration, with concomitant clinical improvement. This is a 32-week treatment period, randomized, double-blind, placebo-controlled, parallel group, multicentre study of mepolizumab in adolescent and adult subjects with severe HES receiving standard of care (SoC) therapy. This study will demonstrate the efficacy of mepolizumab compared with placebo based on maintenance of control of HES symptoms during the treatment period. The study will comprise of a screening period of up to approximately 4 weeks followed by a 32-Week study treatment period (subjects will be randomized 1:1 to placebo or mepolizumab) and up to 8-week additional follow-up period (12 weeks after the last dose of study treatment).

Conditions

• Hypereosinophilic Syndrome

Interventions

DRUG

Mepolizumab 300 mg

Mepolizumab is available as lyophilized powder for injection reconstituted with Sterile Water for Injection, just prior to use.

DRUG

Placebo matching mepolizumab

Placebo is available as 0.9% sodium chloride solution

DRUG

Active OCS capsules (5 mg prednisolone or prednisone)

All subjects will be provided with 2 bottles of blinded OCS capsules, one containing 5mg OCS capsules (active OCS treatment) and a second one containing matching placebo capsules (placebo OCS treatment). These will be dispensed to each subject at each scheduled clinic visit and as needed. Subjects with an increase in blood eosinophils above the pre-specified threshold will be instructed to start blinded OCS treatment from one of the bottles provided (active treatment) unless the subject's HES therapy has already been increased due to a symptom flare within the past 2 weeks.

DRUG

Placebo matching OCS capsules

All subjects will be provided with 2 bottles of blinded OCS capsules, one containing 5mg OCS capsules (active OCS treatment) and a second one containing matching placebo capsules (placebo OCS treatment). These will be dispensed to each subject at each scheduled clinic visit and as needed.A subject who does not reach the pre-specified blood eosinophil threshold with a similar blood draw date will be selected to initiate a placebo OCS treatment in a blinded manner, unless the subject's HES therapy has already been increased due to a symptom flare within the past 2 weeks.

Sponsors & Collaborators

• GlaxoSmithKline

  lead INDUSTRY

Principal Investigators

• GSK Clinical Trials · GlaxoSmithKline

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

12 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2017-03-07

Primary Completion

2019-08-08

Completion

2019-08-08

FDA Drug

Yes

Countries

• United States
• Argentina
• Belgium
• Brazil
• France
• Germany
• Italy
• Mexico
• Poland
• Romania
• Russia
• Spain
• United Kingdom

Study Locations