SESSION TITLE: Obstructive Lung Disease Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: October 18-21, 2020 PURPOSE: Severe asthma is asthma that is uncontrolled despite adherence to maximal optimized controller therapy e.g medium or high dose inhaled steroids with a second controller or maintenance Oral Corticosteroids. Over the past few years, multiple biological therapies have been used to treat severe eosinophilic asthma. One of the first ones approved was Mepolizumab which is an anti-IL-5 antibody that has been utilized to treat severe asthma. Our study aims to evaluate the efficacy and safety of Mepolizumab for the treatment of severe asthma in a real-world severe asthma clinic in a tertiary hospital in Riyadh, Saudi Arabia. METHODS: We did a chart review on severe asthma patients who were started on Mepolizumab in the past two years. Multiple outcomes were observed which include the rate of annual asthma exacerbation, reduction in Oral Corticosteroids (OCS) dose, and improvement in Asthma Control. RESULTS: 53 severe asthma patients ( 75% females ) were on mepolizumab for the past two years. Mepolizumab was switched to Dupilumab in 4 patients. 3 of them were due to lack of effectiveness and one was due to significant headache post-injection. The average age was 45 +/- 13. 69% of patients were early-onset asthmatics (defined as asthma diagnosed < 13 years of age). 63.42% of patients were on Mepolizumab for one year or more. At baseline, patients had an average 18.46 Emergency Room (ER) visits due to asthma exacerbations and 12.8 short courses of Prednisone for asthma attacks. Their average Asthma Control Test (ACT) was 12 +/- 4.7 at baseline. 83% of patients were uncontrolled at baseline. 42% of patients were on daily OCS at baseline. After 12 months, the average ER visits dropped to 1.35 visits (reduction by 92.6%), and the need for short courses of prednisone was reduced to 2.4 courses ( reduction of 81%). At 12 months, 8 patients were off daily steroids (53% of total patients who were of daily steroids at baseline). There was a 36% improvement in ACT score after one year of Mepolizumab (ACT score 17.57) compared to baseline. 42% of patients became controlled after one year of Mepolizumab compared to baseline. CONCLUSIONS: In this retrospective real-life study, we have shown that Mepolizumab had a significant effect in reducing annual asthma exacerbations that require ER visits or short courses of Steroids. It also helped in reducing daily OCS dose. Overall, Mepolizumab was a safe medication as we only had one patient who had one significant side effect that led to its discontinuation. CLINICAL IMPLICATIONS: To the best of our knowledge, this is the first and largest real-life retrospective study in the country that examined the efficacy and safety of Mepolizumab on severe asthma patients. This will help in having better access to this medication and other biological therapies. DISCLOSURES: No relevant relationships by Riyad Al-Lehebi, source=Web Response No relevant relationships by Ali Alqahtani, source=Web Response No relevant relationships by Yahya Asiri, source=Web Response