Nemolizumab and the Future of Chronic Itch Therapy: A New Clinical Trial Takes Center Stage

Nemolizumab's initiation in a Phase II trial marks the first targeted test of an IL‑31 antagonist in Chronic Pruritus of Unknown Origin (CPUO), a condition that currently has no approved therapies.

Galderma announced first-patient enrollment in the U.S. study. This trial represents the first randomized, targeted Phase II evaluation of an IL‑31 antagonist in CPUO. The randomized, double-blind, placebo-controlled study will assess nemolizumab’s efficacy and safety, with primary endpoints focused on itch reduction and key secondary endpoints tracking responder thresholds and safety signals.

The protocol includes cohorts for pharmacokinetics/pharmacodynamics and uses a subcutaneous dosing schedule aligned with prior nemolizumab programs; measurable clinician-facing outcomes include validated itch-intensity scales and predefined responder rates. A successful outcome would show a clinically meaningful reduction in itch intensity with an acceptable safety profile to support progression to later-stage development.

The trial enrolls adults with CPUO defined by pruritus persisting for more than six weeks without an identifiable cause and who have failed standard symptomatic therapies. Typical exclusions mirror prior CPUO research—identifiable dermatologic or systemic causes, active uncontrolled comorbidities, or recent biologic therapy—which will necessitate targeted screening and referral workflows in dermatology clinics.

Patients most affected will be those with refractory, unexplained chronic itch who have exhausted topical and systemic symptomatic options; these patients are the primary candidates for referral and screening.

IL‑31 acts on neural and cutaneous pathways to drive pruritus. Nemolizumab binds the IL‑31 receptor α, inhibiting downstream signaling to reduce neuroimmune activation and peripheral itch transmission—mechanisms that can translate into decreased itch intensity. Blocking IL‑31 receptor signaling can attenuate sensory neuron sensitization and cutaneous inflammation, offering a dual pathway to symptom relief in CPUO.