Promising Biologic for Eosinophilic Esophagitis

A recent study (I Hirano et al. Gastroenterol 2019; 156: 592-603) showed that RPC4046, a monoclonal antibody against IL13 is a promising agent for eosinophilic esophagitis. This multicenter double-blind study with 99 adults compared RPC4046 at doses of either 180 mg or 360 mg to placebo for 16 weeks.  Endoscopy was performed at baseline and at 16 weeks.  The study population included a high number who were considered steroid-refractory and excluded patients who were responsive to proton pump inhibitors. The study drug was administered initially as an IV load followed by weekly subcutaneous injections.

Key findings:

  • Mean changes in esophageal eosinophil count dropped by 94.8 in patients receiving 180 mg dosing and 99.9 in patients receiving 360 mg dosing.  In contrast, placebo-treated patients had a meager reduction of 4.4.
  • In this phase II study, there were no serious safety issues identified
  • There were no significant changes relative to placebo in dysphagia symptoms using the DSD (dysphagia symptom diary) composite score. Though there was improvement in global PRO measures compared to placebo.

There is an associated editorial (pg 545) explains the need for better therapies.  While both dietary therapies and topical steroids are likely effective in >70%, dietary therapy is plagued by problems with long-term adherence and there may become less effective with longer-term administration.

My take: Particularly for patients with refractory EoE, newer therapies are needed.  Given the chronic nature of EoE, cost of new treatments could be another hurdle.

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