The FDA released draft guidance on clinical trial designs for treatments of eosinophilic esophagitis (EoE), a chronic inflammatory disease, including recommendations for selecting trial participants.

The randomized, double-blind, placebo-controlled trials should include a prespecified screening period before patients are randomized to confirm their eligibility, the agency said.

Trials conducted to support a drug’s marketing approval should evaluate the drug’s effect on both symptoms and the underlying inflammation of the disease by assessing the coprimary endpoints in Phase 3 trials.