OBJECTIVES: To assess the cost-effectiveness of adding omalizumab to standard therapy (ST) alone in patients with uncontrolled severe allergic asthma from Brazilian public healthcare system perspective. METHODS:  A Markov model comparing lifetime ST with omalizumab add-on therapy was developed based on efficacy data from INNOVATE (Phase III trial, N=419, 28 weeks). Outcomes are expressed as clinically significant exacerbation (CSE) and clinically significant severe exacerbation (CSSE) avoided. A CSE is defined in INNOVATE as worsening of asthma requiring treatment with rescue systemic corticosteroids and a CSSE is defined as PEF/FEV1 <60% of personal best, in addition to requiring rescue treatment with corticosteroids or requiring emergency room treatment or hospitalization. Resources use data (physician consultations, laboratory tests, emergency rooms visits, hospitalizations, drug treatments) was obtained from INNOVATE and valued from the perspective of healthcare payer. In the model, subjects move back and forth between daily symptoms (optimized asthma control) and the CSE or CSSE states, as they have exacerbations and then recover.  Patients can have several CSE sequentially, or can remain with no exacerbation for a long period, determined by the transition probabilities. The death states are separated into deaths from all causes and asthma-related deaths due to severe exacerbations. One-way-sensitivity-analysis (OWSA) was performed. Annual discount rate of 5% was applied both to costs and outcomes. RESULTS: Base case analysis showed that more CSE and CSSE were avoided with omalizumab add-on therapy than ST alone (incremental of 17.57 and 9.27 respectively) with additional cost of BRL 122,392. Hence, omalizumab ICERs are BRL 6,967/CSE avoided and BRL 13,198/CSSE avoided (1BRL=0.487USD). OWSA confirms the favorable results of base case for omalizumab. CONCLUSIONS: The pharmacoeconomic evaluation confirms that omalizumab add-on therapy is very cost-effective versus ST in the treatment of patients with uncontrolled severe allergic asthma (i.e. <1GDP per capita or BRL 19,000; WHO threshold).