A Randomized, Double-Blind, Placebo-Controlled Study of Omalizumab for Idiopathic Anaphylaxis
Status:
Completed
Trial end date:
2019-05-31
Target enrollment:
Participant gender:
Summary
Background:
- Omalizumab is an approved drug for the treatment of asthma by the Food and Drug
Administration.
- Researchers are now studying this drug in a double-blind placebo-controlled manner to
assess efficacy in patients with idiopathic anaphylaxis (recurrent hypersensitive
allergic episodes for which a cause is not identified).
- The study will improve understanding of the mechanisms involved in anaphylactic
reactions as a response to the downregulation (a decrease in the number of receptors on
the surface of cells) in mast cell (a resident cell with several types of tissues)
activation, and lead to the development of strategies to better prevent or treat
anaphylaxis.
Objectives:
- To determine whether treatment with omalizumab will reduce or prevent episodes of
unprovoked anaphylaxis (an acute allergic reaction) in subjects with a history of
idiopathic anaphylaxis.
- To assess pharmacodynamics (physiological effects of a drug) and identify patients with
undiagnosed mastocytosis (rare disorders caused by too many mast cells).
- To investigate cellular and molecular mechanisms of signaling and the effect of
omalizumab on mast cells or basophils (a cell in the leukocyte family that releases
histamine, which affects allergic response) and explore other regulatory pathways that
may be involved with modulation of mast cell degranulation.
Eligibility:
- Patients between 18 and 70 years of age who have been diagnosed with idiopathic
anaphylaxis, a diagnosis that is made only after other causes of anaphylaxis have been
considered.
- Patients with documented anaphylaxis episodes (mild to severe) at least six times within
the past 1 year period, at least once within the last 4 months, and with at least one of
the following:
- Elevated serum tryptase above baseline within 2 hours of the event.
- Emergency room visit with documented anaphylaxis without a known cause established
by the acute onset of an illness (minutes to several hours) with involvement of the
skin, mucosal tissue, or both (generalized hives, itching or flushing, swollen
lips-tongue-throat) and at least one of the following: (1) respiratory compromise
or gastrointestinal involvement (shortness of breath, wheeze-bronchospasm, throat
tightness, low oxygen levels, nausea, vomiting, or abdominal pain); or (2) reduced
blood pressure or associated symptoms of end-organ dysfunction (collapse, loss of
consciousness, or loss of bladder or bowel control).
- Hospitalization for anaphylaxis.
- Patients must provide a letter of referral, with copies of pertinent medical history and
laboratory tests, from the prospective participant s local physician, and have the
ability to give informed consent.
- Women with childbearing potential must have a negative pregnancy test, and must agree to
practice abstinence or effective birth control from the start of the protocol and for 3
months following the last injection of the study drug.
Design:
- Participants will undergo a clinical evaluation, blood tests, and a bone marrow biopsy
and aspirate.
- Participants will be randomized to either drug or placebo and will receive two doses of
omalizumab or a matched placebo while hospitalized, followed by continued outpatient
therapy, every 2 to 4 weeks, for up to 6 months.
- Participants will remain on the assigned regimen for 6 months or until they have
experienced new onset of severe adverse event on one occasion within 24 hours of study
medication that are related to the study drug, whichever comes first. At that time, the
participant will be discontinued from drug administration.
Phase:
Phase 2
Details
Lead Sponsor:
National Institute of Allergy and Infectious Diseases (NIAID)