Trial Outcomes & Findings for Study Evaluating the Efficacy and Safety of Povorcitinib in Adults With Chronic Spontaneous Urticaria (NCT NCT05936567)

Last Updated: 2026-03-12

Results Overview

The UAS7 is defined as the 7-day sum of the individual, daily recorded scores for the hive severity score (HSS) and the itch severity score (ISS). The ISS7 is defined as the 7-day sum of the daily ISS scores (ranging from 0 to 3), and the HSS7 is defined as the 7-day sum of the daily HSS scores (ranging from 0 to 3). The UAS7 score is calculated as the sum of the available UAS scores, divided by the number of days that have a UAS score, multiplied by 7. The UAS7 (ranging from 0 to 42) is equal to the ISS7 (ranging from 0 to 21) plus the HSS7 (ranging from 0 to 21). Higher scores represent more intense/severe hives and itching. Change from baseline was calculated as the post-baseline value minus the baseline value.

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

136 participants

Primary outcome timeframe

Baseline; Week 12

Results posted on

2026-03-12

Participant Flow

This study was conducted in 35 sites in Germany, Poland, and the United States.

Participant milestones

Participant milestones
Measure	Placebo Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD to 15 mg QD Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the extension (EXT) period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 15 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Povorcitinib 45 mg QD to 45 mg QD Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Povorcitinib 75 mg QD to 75 mg QD Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 15 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 15 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 45 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
12-Week Placebo-Controlled (PC) Period STARTED	34	33	34	35	0	0	0
12-Week Placebo-Controlled (PC) Period COMPLETED	26	29	30	32	0	0	0
12-Week Placebo-Controlled (PC) Period NOT COMPLETED	8	4	4	3	0	0	0
24-Week Extension Period STARTED	0	29	30	32	9	7	10
24-Week Extension Period COMPLETED	0	26	24	26	7	7	8
24-Week Extension Period NOT COMPLETED	0	3	6	6	2	0	2

Reasons for withdrawal

Reasons for withdrawal
Measure	Placebo Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD to 15 mg QD Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the extension (EXT) period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 15 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Povorcitinib 45 mg QD to 45 mg QD Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Povorcitinib 75 mg QD to 75 mg QD Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 15 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 15 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
12-Week Placebo-Controlled (PC) Period Adverse Event	0	0	2	0	0	0
12-Week Placebo-Controlled (PC) Period Lost to Follow-up	1	0	0	1	0	0
12-Week Placebo-Controlled (PC) Period Protocol Violation	0	1	0	1	0	0
12-Week Placebo-Controlled (PC) Period Physician Decision	1	0	1	0	0	0
12-Week Placebo-Controlled (PC) Period Withdrawal by Subject	5	2	1	1	0	0
12-Week Placebo-Controlled (PC) Period Noncompliance with Study Treatment	0	1	0	0	0	0
12-Week Placebo-Controlled (PC) Period Sponsor Decision to Terminate Patient	1	0	0	0	0	0
24-Week Extension Period Adverse Event	0	0	2	1	0	1
24-Week Extension Period Death	0	0	0	1	0	0
24-Week Extension Period Lack of Efficacy	0	0	0	0	1	0
24-Week Extension Period Lost to Follow-up	0	1	1	0	0	0
24-Week Extension Period Pregnancy	0	0	0	0	0	1
24-Week Extension Period Withdrawal by Subject	0	2	3	4	1	0

Baseline Characteristics

Study Evaluating the Efficacy and Safety of Povorcitinib in Adults With Chronic Spontaneous Urticaria

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Placebo n=34 Participants Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD n=33 Participants Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 45 mg QD n=34 Participants Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 75 mg QD n=35 Participants Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Total n=136 Participants Total of all reporting groups
Age, Continuous	40.6 years STANDARD_DEVIATION 12.59 • n=9 Participants	37.2 years STANDARD_DEVIATION 11.51 • n=9 Participants	40.8 years STANDARD_DEVIATION 12.01 • n=18 Participants	41.4 years STANDARD_DEVIATION 11.00 • n=15 Participants	40.0 years STANDARD_DEVIATION 11.77 • n=60 Participants
Sex: Female, Male Female	26 Participants n=9 Participants	28 Participants n=9 Participants	28 Participants n=18 Participants	27 Participants n=15 Participants	109 Participants n=60 Participants
Sex: Female, Male Male	8 Participants n=9 Participants	5 Participants n=9 Participants	6 Participants n=18 Participants	8 Participants n=15 Participants	27 Participants n=60 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	4 Participants n=9 Participants	0 Participants n=9 Participants	2 Participants n=18 Participants	4 Participants n=15 Participants	10 Participants n=60 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	30 Participants n=9 Participants	31 Participants n=9 Participants	32 Participants n=18 Participants	31 Participants n=15 Participants	124 Participants n=60 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=9 Participants	2 Participants n=9 Participants	0 Participants n=18 Participants	0 Participants n=15 Participants	2 Participants n=60 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=9 Participants	1 Participants n=9 Participants	0 Participants n=18 Participants	0 Participants n=15 Participants	1 Participants n=60 Participants
Race (NIH/OMB) Asian	1 Participants n=9 Participants	3 Participants n=9 Participants	2 Participants n=18 Participants	2 Participants n=15 Participants	8 Participants n=60 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=9 Participants	0 Participants n=9 Participants	0 Participants n=18 Participants	0 Participants n=15 Participants	0 Participants n=60 Participants
Race (NIH/OMB) Black or African American	2 Participants n=9 Participants	2 Participants n=9 Participants	1 Participants n=18 Participants	2 Participants n=15 Participants	7 Participants n=60 Participants
Race (NIH/OMB) White	31 Participants n=9 Participants	27 Participants n=9 Participants	31 Participants n=18 Participants	31 Participants n=15 Participants	120 Participants n=60 Participants
Race (NIH/OMB) More than one race	0 Participants n=9 Participants	0 Participants n=9 Participants	0 Participants n=18 Participants	0 Participants n=15 Participants	0 Participants n=60 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=9 Participants	0 Participants n=9 Participants	0 Participants n=18 Participants	0 Participants n=15 Participants	0 Participants n=60 Participants

PRIMARY outcome

Timeframe: Baseline; Week 12

Population: Full Analysis Set: all randomized participants who received at least 1 dose of study drug. Treatment groups were determined according to the treatment participants were assigned at the time of randomization. Only participants with available data were analyzed. Mixed model for repeated measures (MMRM): (change from baseline up to Week 12 = treatment + stratification factor \[previous anti-immunoglobulin E use - Yes/No\] + visit + treatment\*visit + baseline measurement + baseline measurement\*visit).

Outcome measures

Outcome measures
Measure	Placebo n=23 Participants Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD n=27 Participants Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 45 mg QD n=27 Participants Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 75 mg QD n=30 Participants Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Placebo to Povorcitinib 45 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
Change From Baseline in the Urticaria Activity Score Over 7 Days (UAS7) at Week 12	-17.90 scores on a scale Standard Error 2.21	-17.25 scores on a scale Standard Error 2.09	-19.83 scores on a scale Standard Error 2.08	-23.91 scores on a scale Standard Error 2.01	—	—

SECONDARY outcome

Timeframe: Week 12

Population: Full Analysis Set. Missing postbaseline visits were imputed as non-responders during the PC period. The 95% confidence interval was based on the Clopper-Pearson exact method.

The UAS7 is defined as the 7-day sum of the individual, daily recorded scores for the HSS and the ISS. The ISS7 is defined as the 7-day sum of the daily ISS scores (ranging from 0 to 3), and the HSS7 is defined as the 7-day sum of the daily HSS scores (ranging from 0 to 3). The UAS7 score is calculated as the sum of the available UAS scores, divided by the number of days that have a UAS score, multiplied by 7. The UAS7 (ranging from 0 to 42) is equal to the ISS7 (ranging from 0 to 21) plus the HSS7 (ranging from 0 to 21). Higher scores represent more intense/severe hives and itching.

Outcome measures

Outcome measures
Measure	Placebo n=34 Participants Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD n=33 Participants Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 45 mg QD n=34 Participants Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 75 mg QD n=35 Participants Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Placebo to Povorcitinib 45 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
Percentage of Participants Who Achieved UAS7 ≤ 6 (Controlled Disease) at Week 12	29.4 percentage of participants Interval 15.1 to 47.5	30.3 percentage of participants Interval 15.6 to 48.7	44.1 percentage of participants Interval 27.2 to 62.1	62.9 percentage of participants Interval 44.9 to 78.5	—	—

SECONDARY outcome

Timeframe: up to Week 12

Population: Full Analysis Set. Evaluable participants were defined as participants with a baseline UAS7 score and at least one post-baseline UAS7 score. The median time to first achievement of UAS7 ≤ 6 from baseline was estimated using the Kaplan-Meier method. The confidence interval for the median time to first achievement of UAS7 ≤ 6 from baseline was calculated using the method of Brookmeyer and Crowley.

Outcome measures

Outcome measures
Measure	Placebo n=33 Participants Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD n=32 Participants Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 45 mg QD n=34 Participants Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 75 mg QD n=35 Participants Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Placebo to Povorcitinib 45 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
Time to First Achievement of UAS7 ≤ 6 (Controlled Disease) During the Placebo-controlled (PC) Period	NA days Interval 37.0 to The median and the upper limit of the confidence interval were not estimable because there were too few events of UAS7 ≤ 6 .	54.0 days Interval 28.0 to The upper limit of the confidence interval was not estimable because there were too few events of UAS7 ≤ 6 .	54.0 days Interval 27.0 to The upper limit of the confidence interval was not estimable because there were too few events of UAS7 ≤ 6 .	20.0 days Interval 12.0 to 27.0	—	—

SECONDARY outcome

Timeframe: Week 12

Population: Full Analysis Set. Missing postbaseline visits were imputed as non-responders during the PC period. The 95% confidence interval was based on the Clopper-Pearson exact method.

The UAS7 is defined as the 7-day sum of the individual, daily recorded scores for the HSS and the ISS. The ISS7 is defined as the 7-day sum of the daily ISS scores (ranging from 0 to 3), and the HSS7 is defined as the 7-day sum of the daily HSS scores (ranging from 0 to 3). The UAS7 (ranging from 0 to 42) is equal to the ISS7 (ranging from 0 to 21) plus the HSS7 (ranging from 0 to 21). Higher scores represent more intense/severe hives and itching.

Outcome measures

Outcome measures
Measure	Placebo n=34 Participants Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD n=33 Participants Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 45 mg QD n=34 Participants Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 75 mg QD n=35 Participants Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Placebo to Povorcitinib 45 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
Percentage of Participants With UAS7 = 0 at Week 12	23.5 percentage of participants Interval 10.7 to 41.2	24.2 percentage of participants Interval 11.1 to 42.3	29.4 percentage of participants Interval 15.1 to 47.5	42.9 percentage of participants Interval 26.3 to 60.6	—	—

SECONDARY outcome

Timeframe: up to Week 12

Population: Safety Population: all participants who received at least 1 dose of study drug. Treatment groups were determined according to the actual treatment the participants received regardless of assigned study drug treatment.

An adverse event (AE) is defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not it is considered drug related. An AE can therefore be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study drug. A TEAE was defined as an AE reported for the first time or the worsening of a pre-existing event after the first dose of study drug and until 60 days after the last dose of study drug.

Outcome measures

Outcome measures
Measure	Placebo n=34 Participants Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD n=33 Participants Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 45 mg QD n=34 Participants Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 75 mg QD n=35 Participants Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Placebo to Povorcitinib 45 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
Placebo-controlled Period: Number of Participants With Any Treatment-emergent Adverse Event (TEAE)	16 Participants	24 Participants	18 Participants	23 Participants	—	—

SECONDARY outcome

Timeframe: from Week 12 to Week 44

Population: Extension Evaluable Population: all participants who received at least 1 dose of povorcitinib during the extension period

An AE is defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not it is considered drug related. An AE can therefore be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study drug. A TEAE was defined as an AE reported for the first time or the worsening of a pre-existing event after the first dose of study drug and until 60 days after the last dose of study drug.

Outcome measures

Outcome measures
Measure	Placebo n=29 Participants Participants were randomized to receive placebo plus standard of care (SOC) with second-generation H1 antihistamines once daily (QD) for 12 weeks during the Placebo-controlled (PC) period.	Povorcitinib 15 mg QD n=30 Participants Participants were randomized to receive povorcitinib 15 milligrams (mg) plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 45 mg QD n=32 Participants Participants were randomized to receive povorcitinib 45 mg plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Povorcitinib 75 mg QD n=9 Participants Participants were randomized to receive povorcitinib 75 mg plus stable SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period.	Placebo to Povorcitinib 45 mg n=7 Participants Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 45 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.	Placebo to Povorcitinib 75 mg n=10 Participants Participants were randomized to receive placebo plus SOC with second-generation H1 antihistamines QD for 12 weeks during the PC period. At the start of the EXT period, participants initially randomized to placebo were randomly assigned to receive povorcitinib 75 mg QD for 24 weeks. All participants were required to maintain a stable dose of second-generation H1 antihistamine SOC during the study from the time of informed consent until the completion of the post-treatment follow-up visit. Participants returned for a follow-up visit approximately 60 days after their last dose of study drug.
Extension Period: Number of Participants With Any TEAE	20 Participants	20 Participants	23 Participants	5 Participants	5 Participants	4 Participants

Adverse Events

Placebo

Serious events: 3 serious events

Other events: 8 other events

Deaths: 0 deaths