D3.28 - Comparative Efficacy and Safety of Omalizumab Intended copy Biosimilar vs. Biologic in Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is a challenging condition that severely impacts patients' quality of life. Omalizumab, a monoclonal anti-IgE antibody, has revolutionised its management, but high costs limit accessibility, particularly in resource-limited settings like India. Biosimilars offer a cost-effective alternative, though their efficacy and safety in CU remain underexplored. We aimed to compare the efficacy of omalizumab intended copy biosimilars (Available in India) to the reference biologic in patients with chronic urticaria (CU) based on Urticaria Activity Score (UAS) and Urticaria Control Test (UCT) outcomes.

It was a prospective, open-level, observational, real-world unicentric cohort study. The patients in this study were previously on omalizumab biologics for varying durations and had achieved good disease control. Due to the unavailability of the biologics, they were transitioned to omalizumab-intended copy biosimilars, with the transition period marked as 0 months. 

At baseline (0 months), patients transitioned to omalizumab biosimilars had well-controlled chronic urticaria, with a mean UAS of 2.55±2.12 and a mean UCT of 15.33±0.71 while on the reference biologic (mean dose: 266.67 mg/month). However, after switching to biosimilars, disease control worsened progressively, peaking at month 5 with a mean UAS of 12.11±6.62 and a mean UCT of 11.77±3.19, despite dose escalation. The dose was increased to 450 mg/month for four patients at month 5 to address the worsening disease control. Despite this, two patients showed minimal improvement, leading to further escalation to 600 mg/month. Following these adjustments, some improvement was noted by month 6, with the mean UAS decreasing to 9.88±3.1 and the mean UCT improving to 13±1.73. 

Our study highlights significant differences in the efficacy of omalizumab intended copy biosimilars compared to biologics in managing CSU. However, the discrepancies observed in our study may be due to the subtle differences between biosimilar and intended copy biosimilar which are available in India. It may also vary in patient populations, disease severity, or dosing protocols.