Key messages

• Omalizumab improves symptoms and quality of life in patients with chronic spontaneous urticaria.
• The findings of this summary are consistent with the systematic reviews identified and the recommendations of the main guidelines.

What is the evidence.
See evidence matrix  in Epistemonikos later

We found four systematic reviews [1],[2],[3],[4] that include five primary studies [5],[6],[7],[8],[9], all of which correspond to randomized controlled trials.

What types of patients were included

Five studies included adults with chronic spontaneous urticaria defined by increased itching or hives lasting for 6-8 weeks despite treatment with antihistamines. Three studies included patients with UAS7 (Urticaria Activity Score) > 16 points [5],[6],[7], one study with UAS > 4 points [8] and one study with UAS7 > 10 points [9].

What types of interventions were included

The intervention was omalizumab versus placebo in all the studies, maintaining the antihistamine baseline treatment. One study used omalizumab 300 mg/day [5], one study used 75-375 mg/day [9], two studies used doses of 75, 150 and 300 mg/day [6],[7], and one study used doses of 75, 300 and 600 mg/day [8].

The treatment period with omalizumab lasted 24 weeks in three studies [5],[6],[9], 12 weeks in one study [7] and 4 weeks in one study [8].

What types of outcomes
were measured

The outcomes measured were the change in the index of disease and quality of life.

Index of disease was measured with UAS7, which evaluates itching and hives for seven days with a scale of 0-6 points per day, with a minimum of 0 points and a maximum of 42 points.

To whom this evidence does and does not apply

• This evidence applies to adult patients with chronic spontaneous urticaria refractory to standard management with anti H1 antihistamines.
• It does not apply to other types of chronic and acute urticaria.

• The outcomes selected for the summary of findings are those considered critical for decision making by the authors of this summary.

• The benefits of omalizumab outweigh the risks, with a high certainty of evidence.
• Omalizumab appears to be a safe drug when used in the short and medium term.
• The likelihood of recurrence of symptoms is an element to consider when trying to reduce dose or to discontinue, requiring reinitiating the drug in some cases [10].

• Omalizumab is expensive (approximated cost for 150 mg/ml and 300 mg/ml = £ 256 and £ 512) [11]. In Chile, the price of a 150 mg vial is around $ 450,000 (Xolair®).
•  This factor would be a critical determinant of the decision to use this intervention, from both an individual or health system perspective.

Differences between this summary and other sources

• The conclusions of this summary agree with those of the systematic reviews identified.
• The conclusions of this summary are consistent with the recommendations of the joint guidelines of the European Academy of Allergy and Clinical Immunology (EAACI), the EU-funded Network of Excellence, the Global Allergy and Asthma European Network (GA2LEN), the European Dermatology Forum (EDF), and the World Allergy Organization (WAO) [12].

• The probability of future evidence changing the conclusions of this summary is very low because of the certainty of the evidence.