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Treatment with depemokimab for uncontrolled hypereosinophilic syndrome

A Randomized, Double-blind, Placebo-controlled Study to Investigate the Efficacy and Safety of Depemokimab in Adults With Hypereosinophilic Syndrome (HES)

Phase 3 Interventional GlaxoSmithKline · NCT05334368

This study is testing if a new medication called depemokimab can help adults with uncontrolled hypereosinophilic syndrome feel better and manage their symptoms more effectively.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment123 (estimated)
Ages18 Years and up
SexAll
SponsorGlaxoSmithKline Industry-sponsored
Drugs / interventionsdepemokimab
Locations91 sites (San Diego, California and 90 other locations)
Trial IDNCT05334368 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the efficacy and safety of depemokimab, a monoclonal antibody targeting interleukin-5, in adults with uncontrolled hypereosinophilic syndrome (HES). The study is a 52-week, randomized, placebo-controlled, double-blind trial where participants will continue their standard of care therapy while receiving either depemokimab or a placebo. Eligible participants must have a confirmed diagnosis of HES, a history of multiple flares, and elevated eosinophil counts. The trial aims to determine if depemokimab can effectively reduce HES symptoms and improve patient outcomes.

Who should consider this trial

Good fit: Ideal candidates are adults with a confirmed diagnosis of hypereosinophilic syndrome who have experienced two or more flares in the past year and are currently on stable therapy.

Not a fit: Patients with HES manifestations that pose unacceptable risks or those with chronic infections may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the management of hypereosinophilic syndrome and reduce the frequency of disease flares.

How similar studies have performed: Other studies targeting interleukin-5 have shown promise in treating eosinophilic disorders, suggesting a potential for success with this approach.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Participants who are greater than or equal (\>=) 40 kilogram (kg) at Screening Visit 1.
* Participants who have a documented diagnosis of HES prior to Visit 2.
* A history of 2 or more HES flares within the past 12 months prior to Visit 1.
* A female participant is eligible to participate if she is not pregnant or breastfeeding, and one of the following conditions applies: a) woman of non-childbearing potential (WONCBP) Or b) woman of childbearing potential (WOCBP) and using a contraceptive method that is highly effective, with a failure rate of less than (\<) 1 percentage (%).
* Capable of giving signed informed consent.

Exclusion Criteria:

* Participants with HES disease manifestations which in the opinion of the investigator may put the participant at unacceptable risk from study participation or confound interpretation of efficacy or safety data.
* Participants with chronic or ongoing active infections requiring systemic treatment or a pre-existing parasitic infestation within 6 months prior to Visit 1.
* Participants with a known immunodeficiency (e.g., Human Immunodeficiency Virus \[HIV\]), other than that explained by the use of OCS or other therapy taken for HES.
* Participants with a history of or current lymphoma.
* Participants with current malignancy or previous history of cancer in remission for less than 5 years prior to Visit 1. Participants that had localized carcinoma (i.e., basal or squamous cell) of the skin which was resected for cure will not be excluded.
* Participants with a haematologic malignancy with hypereosinophilia in which HES is not the primary diagnosis, e.g., chronic myeloid leukaemia, myelodysplastic syndrome, chronic eosinophilic leukaemia-not otherwise specified.
* Cirrhosis or current unstable liver or biliary disease per investigator assessment.
* Participants who have severe or clinically significant cardiovascular disease uncontrolled with standard treatment.
* Participants with current diagnosis of vasculitis.
* Hypereosinophila with no clinical symptoms and/or proof of organ dysfunction.
* Clinical diagnosis of Eosinophilic granulomatosis with polyangiitis (EGPA).
* Participants with an allergy/ intolerance to a monoclonal antibody or biologic, or any of the excipients of the investigational product.
* Participants who have a previous documented failure with anti-interleukin (IL)-5/5R therapy.
* Participants who have received monoclonal antibodies (mAb) within 30 days or 5 half-lives, whichever is longer, prior to Visit 1.
* Participants who test positive for the FIP1L1-PDGFRα fusion gene.
* QT interval corrected for heart rate according to Fridericia's formula (QTcF) ≥450 milliseconds (msec) or QTcF ≥480 msec for participants with Bundle Branch Block at Screening Visit 1.
* Participants who are not responsive to OCS based on clinical response or blood eosinophil counts in the opinion of the Investigator.
* Participants who are pregnant or breastfeeding.

Where this trial is running

San Diego, California and 90 other locations

+41 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Hypereosinophilic SyndromeDepemokimabDESTINYMonoclonal antibodyAnti-interleukin -5
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.