Incyte's povorcitinib asthma readout slips again as Phase 2 nears finish
The JAK1 inhibitor's proof-of-concept trial has pushed its primary completion date five times, and Incyte still points to an H2-2026 data window for a lung-function endpoint no placebo-controlled JAK1 asthma trial has yet delivered.
Executive Summary
- Incyte's placebo-controlled Phase 2 trial of the oral JAK1 inhibitor povorcitinib in moderate-to-severe asthma has finished enrolling and is approaching its primary completion date, positioning the company for a proof-of-concept readout later this year.
- The trial asks whether blocking JAK1 can move lung function in asthma, a question no other placebo-controlled trial at this target and phase has yet answered.
- The completion date behind this readout has moved five separate times since the study opened, a pattern that matters more here because the sponsor has repeatedly guided investors to specific data windows that then shifted.
- Asthma is served almost entirely by biologics and bronchodilators; a positive signal for an oral JAK1 inhibitor would open a mechanism class that has no approved precedent in this indication.
The trial
NCT05851443 is a Phase 2, placebo-controlled study testing povorcitinib, an oral JAK1 inhibitor, in adults with inadequately controlled moderate-to-severe asthma. The primary endpoint is absolute change in pre-bronchodilator FEV1, a direct measure of airway obstruction, against placebo. The trial enrolls patients with pre-BD FEV1 below 80% of predicted, documented bronchodilator reversibility, at least two exacerbations in the prior year, and an ACQ-6 score of 1.5 or higher, a population selected for room to show a treatment effect. The study moved to Active, not recruiting status on July 7, 2026, with enrollment finalized at 247 participants against an original target of 240. NCT05851443A Study to Evaluate the Efficacy and Safety Study of Povorcitinib in Participants With Inadequately Controlled Moderate to Severe AsthmaNCT05851443
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
The timing history
The trial's primary completion date has changed five times since the study was first posted: from July 2025 to December 2024, then to December 2024, then to October 2025, then to June 2026, and now to November 20, 2026. That amounts to 714 cumulative days of delay from the earliest guided date. Incyte has separately guided investors to a data window for this readout three times in company disclosures: second-half 2025, then 2026 broadly, then H2-2026 in its February 10, 2026 earnings release, the most recent guidance on record. The registry's current primary completion date of November 20, 2026 sits inside that H2-2026 window. NCT05851443+1A Study to Evaluate the Efficacy and Safety Study of Povorcitinib in Participants With Inadequately Controlled Moderate to Severe AsthmaNCT05851443Incyte Reports Fourth Quarter and Full Year 2025 Financial ResultsFeb 10, 2026
What would count as a signal
Asthma treatment beyond inhaled corticosteroids and biologics has not established a validated oral, targeted mechanism; the closest comparators to povorcitinib share only the drug class (small molecule) or indication, not the JAK1 target. Two active industry trials study JAK1 in asthma, and no completed Phase 2 trial at this target-indication pairing has been recorded as terminated. Against that backdrop, a placebo-adjusted improvement in pre-BD FEV1 that also moves exacerbation rates and post-bronchodilator FEV1, the trial's own secondary endpoints, would be the result that distinguishes an oral JAK1 approach from the biologic-dominated standard of care. NCT05851443A Study to Evaluate the Efficacy and Safety Study of Povorcitinib in Participants With Inadequately Controlled Moderate to Severe AsthmaNCT05851443
Readthrough
Povorcitinib itself carries no other active asthma trials in Incyte's portfolio; this is the company's sole Phase 2 test of the drug in the indication. The broader JAK1 class has extensive precedent in atopic dermatitis, ulcerative colitis and myelofibrosis through drugs including upadacitinib, abrocitinib and ruxolitinib, but none of those programs targets asthma, so this trial functions as the class's first placebo-controlled test in the airway-obstruction setting rather than a replication of an established result. NCT05851443A Study to Evaluate the Efficacy and Safety Study of Povorcitinib in Participants With Inadequately Controlled Moderate to Severe AsthmaNCT05851443
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.