Would you have any hesitation in prescribing Xolair to a patient who is planning to go to a country for a few weeks where parasites are common problem, such as India. I read some articles that stated there is no clinical/real-word evidence that Xolair makes one more susceptible to parasites, and this issue has been looked at in a few small studies. This suggests that circulating eosinophils are more important at fighting parasites than free-floating IgE in the bloodstream, in my opinion.

I would like to know your opinion on the matter. Would you prescribe Xolair to a patient who needs it for chronic idiopathic urticaria and who goes to a country where parasites are endemic? (Most asthmatics who have a real-need for Xolair probably should not be going to countries that don't have great, prompt medical care)


Thank you for your inquiry.

Unfortunately I cannot give you a definitive statement regarding the risk of parasitic infections in patients taking omalizumab. The reason for this is there simply is not enough data to come to a conclusion in this regard. Thus far it has not been my practice to discontinue omalizumab in patients traveling to areas endemic for parasitic infections, but I would in no way be critical of the decision to do so.

To understand why one cannot give a definitive opinion, it is important to look at the available literature dealing with this issue, and as you can see from the abstracts copied below, there is a dearth of studies. In fact, I am only aware of one study that has looked at the issue, and a review that discusses the issue in a speculative way in more detail. As you can see from simply reading the abstract from the single study that has looked at this issue (from Brazil), the authors seem to “hedge their bets” to some extent as evidenced by their conclusions. In addition, this contrasting approach is seen when one looks at information online for patients (statement and a link to the statement is copied below) contrasted with the Package Insert for Xolair (also copied below)..

Thus, as noted, one cannot reach a definitive conclusion. But, also as noted, I have in the past not discontinued omalizumab in patients traveling to countries where parasitic infection is endemic.

Thank you again for your inquiry and we hope this response is helpful to you.

Allergy. 2008 Apr;63(4):409-17. doi: 10.1111/j.1398-9995.2007.01601.x.
Geohelminth infections: a review of the role of IgE and assessment of potential risks of anti-IgE treatment.
Cooper PJ, Ayre G, Martin C, Rizzo JA, Ponte EV, Cruz AA.
Laboratorio de Investigaciones extensión Quinindé, Hospital Pedro Vicente Maldonado, Pichincha Province, Ecuador.
Geohelminth infections are major parasitic infections with a worldwide distribution. Immunoglobulin E (IgE) is considered to play a central role in protective immunity against these parasites although the evidence from experimental animal models infected with helminth parasites and treated with anti-IgE antibodies and from observational studies in human populations of the immunologic correlates of protective immunity against helminths do not support a critical role for IgE in mediating protection against helminths. Anti-IgE treatment of human allergic disorders using a humanized monoclonal IgE antibody (omalizumab, Xolair) has been approved for clinical use in the USA and Europe and there is concern that this treatment may be associated with increased morbidity in populations exposed to helminth infections. A recently published randomized controlled trial investigating the risk of geohelminth infections in allergic patients receiving omalizumab in Brazil has provided some evidence that omalizumab may not be associated with increased morbidity attributable to these parasites. This review examines the evidence for a role of IgE in protective immunity against helminth parasites, discusses the findings of the randomized controlled trial, assesses the potential risks and provides recommendations for anti-IgE treatment in groups of allergic patients with different exposure risks for helminth infections.

Clin Exp Allergy. 2007 Feb;37(2):197-207.
Safety of anti-immunoglobulin E therapy with omalizumab in allergic patients at risk of geohelminth infection.
Cruz AA, Lima F, Sarinho E, Ayre G, Martin C, Fox H, Cooper PJ.
ProAR, Faculdade de Medicina da Bahia-UFBA, Instituto de Investigação em Imunologia (iii), CNPq, Salvador, BA, Brazil.
Background: Although the role of immunoglobulin E (IgE) in immunity against helminth parasites is unclear, there is concern that therapeutic antibodies that neutralize IgE (anti-IgE) may be unsafe in subjects at risk of helminth infection.
Objective: We conducted an exploratory study to investigate the safety of omalizumab (anti-IgE) in subjects with allergic asthma and/or perennial allergic rhinitis at high risk of intestinal helminth infection. The primary safety outcome was risk of infections with intestinal helminths during anti-IgE therapy.
Methods: A randomized, double-blind, placebo-controlled trial was conducted in 137 subjects (12-30 years) at high risk of geohelminth infection. All subjects received pre-study anthelmintic treatment, followed by 52 weeks' treatment with omalizumab or placebo.
Results: Of the omalizumab subjects 50% (34/68) experienced at least one intestinal geohelminth infection compared with 41% (28/69) of placebo subjects [odds ratio (OR) 1.47, 95% confidence interval (CI) 0.74-2.95, one-sided P=0.14; OR (adjusted for study visit, baseline infection status, gender and age) 2.2 (0.94-5.15); one-sided P=0.035], providing some evidence for a potential increased incidence of geohelminth infection in subjects receiving omalizumab. Omalizumab therapy was well tolerated, and did not appear to be associated with increased morbidity attributable to intestinal helminths as assessed by clinical and laboratory adverse events, maximal helminth infection intensities and additional anthelmintic requirements. Time to first infection (OR 1.30, 95% CI 0.79-2.15, one-sided P=0.15) was similar between treatment groups. Infection severity and response to anthelmintics appeared to be unaffected by omalizumab therapy.
Conclusions: In this exploratory study of allergic subjects at high risk of helminth infections, omalizumab therapy appeared to be safe and well tolerated, but may be associated with a modest increase in the incidence of geohelminth infection.

Other IgE-associated disorders:
Xolair has not been studied in patients with anaphylaxis, hyperimmunoglobulin E syndrome, allergic bronchopulmonary aspergillosis, food allergy or atopic dermatitis. Parasitic infestation may also result in elevation of serum IgE concentrations. In a study of asthmatic patients who had been treated for gut parasites, the level of reinfection did not differ significantly between omalizumab and placebo groups and there were no serious or severe infections. There is no current evidence to suggest that parasitic infections are predisposed to by omalizumab. Source: PI XOLAIR

One study in Brazil suggested that people taking Xolair have a higher risk of parasitic infections. Talk with your healthcare provider if you live in (or will be traveling to) areas that have a higher risk of parasites.

Xolair Warnings and Precautions

Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology