In patients with eosinophilic esophagitis (EoE), one year of treatment with RPC4046 (a monoclonal recombinant antibody against interleukin-13, IL-13) demonstrated good tolerability. It yielded sustained improvement and maintenance of histologic, endoscopic, and clinical measures of the disease activity relative to the baseline.

An open-label, long-term extension (LTE) study of phase 2, double-blind, 16-week, randomized, controlled (RPC02-201) study was carried out to examine the long-term safety and efficacy of RPC4046 in patients with EoE.

The researchers analyzed data of the participants fulfilling the 16-week, double-blind, induction phase 2 RPC4046 trial (180 or 360 mg/week) vs placebo and then actively fulfilling a 52-week LTE, receiving open-label RPC4046 360 mg/week.

From 28 centers in three countries, the study recruited 66 EoE patients between September 2014 and January 2017. The collected information was actively stratified by the double-blind dose group. Safety, EoE endoscopic reference score, esophageal eosinophil counts, symptom-based EoE activity index score, and EoE histologic scoring system score were the vital outcomes of the study. 

By the 12th week of LTE, participants who were managed with novel anti-IL13 monoclonal antibody and placebo did not portray any remarkable differences in the total EoE endoscopic reference scores, esophageal eosinophil mean and peak counts, and EoE histologic scoring system grade and stage scores.

The responses were maintained through week 52 by most participants. In both placebo‒RPC4046 cand RPC4046‒RPC4046 (either dose) cohort, the symptom remission (symptom-based EoE activity index score, <20) raised remarkably.

As per the study authors, during the LTE, 10 EoE subjects (36%) were found to attain response out of the 28 subjects who not showing a histologic response to RPC4046 during the double-blind induction phase. Notably, nasopharyngitis and infection of the upper respiratory tract were the most frequently noted noxious reactions, as shown below:

In EoE patients, the novel anti-IL13 monoclonal antibody RPC4046 depicted efficacy as a targeted therapeutic option.