Participants rated pruritus daily on the Worst Itch [pruritis] Numeric Rating Scale (WI-NRS: 0=no pruritus; 10=worst imaginable pruritus). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

Modified Intent to Treat (mITT) Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Part 2a: Last Observation Carried Forward (LOCF); Part 2b: Multiple imputation (WI)

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; LOCF.

At every visit, participants rated the intensity of their average pruritus over previous 3 days on VAS 0-10 line scale (0=no pruritis, 10=worst imaginable pruritis)

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; LOCF.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 16: LOCF; Weeks 17-24: participants with an assessment at given time point.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 16: LOCF; Weeks 17-24: participants with an assessment at given time point.

Participants rated intensity of their average pruritus over previous 3 days on VAS 0-10 line scale (0=no pruritis, 10=worst imaginable pruritis)

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 9-24: participants with an assessment at given time point.

Participants rated intensity of their average pruritus over previous 3 days on VAS 0-10 line scale (0=no pruritis, 10=worst imaginable pruritis). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 9-24: participants with an assessment at given time point.

Administered every 2 visits, the 5-D Pruritus Scale evaluates pruritus in 5 domains: duration, degree, direction, disability and distribution. The scores from each domain are added together to obtain a total 5-D score ranging from 5 (no pruritus) to 25 (most severe pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 10-24: participants with an assessment at given time point.

Administered every 2 visits, the 5-D Pruritus Scale evaluates pruritus in five domains: duration, degree, direction, disability and distribution. The scores from each domain are added together to obtain a total 5-D score ranging from 5 (no pruritus) to 25 (most severe pruritus). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 10-24: participants with an assessment at given time point.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; Baseline through Week 16: LOCF; Weeks 17-24: participants with an assessment at given time point.

Participants rated intensity of their average sleeplessness over previous 3 days on 0-10 line scale (0=no sleeplessness, 10=worst imaginable sleeplessness).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 9-24: participants with an assessment at given time point.

Participants rated intensity of their average sleeplessness over previous 3 days on 0-10 line scale (0=no sleeplessness, 10=worst imaginable sleeplessness). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 9-24: participants with an assessment at given time point.

Participants rate difficulty falling asleep daily on Numerical Rating Scale (0=no difficulty, 10=extremely difficult).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 16: LOCF; Weeks 17-24: participants with an assessment at given time point.

Participants rate difficulty falling asleep daily on Numerical Rating Scale (0=no difficulty, 10=extremely difficult). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 16: LOCF; Weeks 17-24: participants with an assessment at given time point.

Participants rated daily sleep quality on Numerical Rating Scale (0=best possible sleep, 10=worst possible sleep).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 16: LOCF; Weeks 17-24: participants with an assessment at given time point.

Participants rated daily sleep quality on Numerical Rating Scale (0=best possible sleep, 10=worst possible sleep). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 16: LOCF; Weeks 17-24: participants with an assessment at given time point.

QoL was assessed at designated visits and includes the DLQI whereby 0=no effect on quality of life; 30= extremely large effect on QoL.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 12-24: participants with an assessment at given time point.

QoL was assessed at designated visits and includes the DLQI whereby 0=no effect on quality of life; 30= extremely large effect on QoL.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 12-24: participants with an assessment at given time point.

ItchyQoL focuses on impact of pruritus on daily activities and on the level of psychological stress. It contains 22 items. The frequency items are scored using a 5-point Likert scale ranging from "never" to "all the time". The bother items are scored from 1 (not bothered) to 5 (severely bothered). The recall period in ItchyQoL is the past week. The ItchyQoL total score is defined as the sum of all 22-items scores. Total scores can be classified as little (0-30), mild (31-50), moderate (51-80), and severe (81-110).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 12-24: participants with an assessment at given time point.

ItchyQoL focuses on impact of pruritus on daily activities and on the level of psychological stress. It contains 22 items. The frequency items are scored using a 5-point Likert scale ranging from "never" to "all the time". The bother items are scored from 1 (not bothered) to 5 (severely bothered). The recall period in ItchyQoL is the past week. The ItchyQoL total score is defined as the sum of all 22-items scores. Total scores can be classified as little (0-30), mild (31-50), moderate (51-80), and severe (81-110). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 12-24: participants with an assessment at given time point.

PN-NAT, assessed at designated visits, is a novel exploratory tool for the evaluation of disease severity based on estimate of the number of nodules over the whole body, estimate of hardness of nodules over the whole body, estimate of extent of excoriation over the whole body, distribution of nodules, exact number of nodules in the representative area. The first three components (number of nodules over the whole body, estimate of hardness of nodules over the whole body, estimate of extent of excoriations over the whole body) were analyzed as secondary endpoints. For the Number of Nodules over the Whole Body score: 0=0 nodules; 1=1 to 9 nodules; 2=10 to 50 nodules; and 3=more than 50 nodules. A higher score indicates worse disease.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 10-24: participants with an assessment at given time point.

PN-NAT, assessed at designated visits, is a novel exploratory tool for the evaluation of disease severity based on estimate of the number of nodules over the whole body, estimate of hardness of nodules over the whole body, estimate of extent of excoriation over the whole body, distribution of nodules, exact number of nodules in the representative area. The first three components (number of nodules over the whole body, estimate of hardness of nodules over the whole body, estimate of extent of excoriations over the whole body) were analyzed as secondary endpoints. For the Estimate of Hardness of Nodules Over the Whole Body score: 0=No nodules are hard; 1=Up to one-third of nodules are hard; 2=One-third to two-thirds of nodules are hard; and 3=More than two-thirds of nodules are hard. A higher score indicates worse disease.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 10-24: participants with an assessment at given time point.

PN-NAT, assessed at designated visits, is a novel exploratory tool for the evaluation of disease severity based on estimate of the number of nodules over the whole body, estimate of hardness of nodules over the whole body, estimate of extent of excoriation over the whole body, distribution of nodules, exact number of nodules in the representative area. The first three components (number of nodules over the whole body, estimate of hardness of nodules over the whole body, estimate of extent of excoriations over the whole body) were analyzed as secondary endpoints. For the Extent of Excoriations over the Whole Body score: 0=No nodules are excoriated; 1=Up to one-third of nodules are excoriated; 2=One-third to two-thirds of nodules are excoriated; and 3=More than two-thirds of nodules are excoriated. A higher score indicates worse disease.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Baseline through Week 8: LOCF; Weeks 10-24: participants with an assessment at given time point.

PN-IGA, assessed at designated visits, is a novel exploratory tool for the overall investigator assessment of PN disease severity based on the presence/absence of nodules and the size of the nodules as defined by their elevation. The IGA utilizes a 5-point scale that ranges from 0 (clear) to 4 (severe disease).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; Baseline through Week 8: LOCF; Weeks 10-24: participants with an assessment at given time point.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (0=no pruritus; 10=worst imaginable pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responder imputation.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (0=no pruritus; 10=worst imaginable pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responder imputation.

PN-IGA, assessed at designated visits, is a novel exploratory tool for the overall investigator assessment of PN disease severity based on the presence/absence of nodules and the size of the nodules as defined by their elevation. The IGA utilizes a 5-point scale that ranges from 0 (clear) to 4 (severe disease); 0 (clear) indicates no nodules and 1 (almost clear) indicates nodules are present, few of the nodules are moderately raised.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Participants with an assessment at given time point.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Participants with an assessment at given time point.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responders imputation.

Participants rated pruritus daily on the Worst Itch [pruritis]-Numeric Rating Scale (WI-NRS; 0=no pruritus; 10=worst imaginable pruritus).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responders imputation.

PN-IGA is a novel exploratory tool for the overall investigator assessment of PN disease severity based on the presence/absence of nodules and the size of the nodules as defined by their elevation. The IGA utilizes a 5-point scale that ranges from 0 (clear) to 4 (severe disease); 0 (clear) indicates no nodules and 1 (almost clear) indicates nodules are present, few of the nodules are moderately raised.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responders imputation.

PN-IGA is a novel exploratory tool for the overall investigator assessment of PN disease severity based on the size of the nodules as defined by their elevation. The IGA utilizes a 5-point scale that ranges from 0 (clear) to 4 (severe disease).

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responders imputation.

IGA-CNPG-S is a novel tool for the investigator assessment of PN disease severity based on the number of palpable nodules and utilizes a 5-point scale that ranges from 0 (clear) to 4 (severe); 0 (clear) indicates no nodules and 1 (almost clear) indicates rare palpable pruriginous nodules (approximately 1-5 nodules). A score is assigned based on the appearance of the disease at the time of the evaluation without referring to the baseline state.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responders imputation.

IGA-CNPG-S, administered at designated visits, is a novel tool for the investigator assessment of PN disease severity based on the number of palpable nodules and utilizes a 5-point scale that ranges from 0 (clear) to 4 (severe). A score is assigned based on the appearance of the disease at the time of the evaluation without referring to the baseline state.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period. Non-responders imputation.

Participants rated intensity of their average sleeplessness over previous 3 days on 0-10 line scale (0=no sleeplessness, 10=worst imaginable sleeplessness). A score was set to missing after a participant received prohibited/rescue medication that potentially impact efficacy analyses prior to Week 16, and the participant's worst post baseline observation before the time of the medication usage was carried forward (WOCF) to impute missing endpoint value (for participants whose postbaseline values were all missing, the baseline was used to impute). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; WOCF: Baseline through Week 52.

Participants rated intensity of their average sleeplessness over previous 3 days on 0-10 line scale (0=no sleeplessness, 10=worst imaginable sleeplessness). A score was set to missing after a participant received prohibited/rescue medication that potentially impact efficacy analyses prior to Week 16, and the participant's worst post baseline observation before the time of the medication usage was carried forward (WOCF) to impute missing endpoint value (for participants whose postbaseline values were all missing, the baseline was used to impute). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; WOCF: Baseline through Week 52.

ItchyQoL focuses on impact of pruritus on daily activities and on the level of psychological stress. It contains 22 items. The frequency items are scored using a 5-point Likert scale ranging from "never" to "all the time". The bother items are scored from 1 (not bothered) to 5 (severely bothered). The recall period in ItchyQoL is the past week. The ItchyQoL total score is defined as the sum of all 22-items scores. Total scores can be classified as little (0-30), mild (31-50), moderate (51-80), and severe (81-110). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; WOCF: Baseline through Week 52.

ItchyQoL focuses on impact of pruritus on daily activities and on the level of psychological stress. It contains 22 items. The frequency items are scored using a 5-point Likert scale ranging from "never" to "all the time". The bother items are scored from 1 (not bothered) to 5 (severely bothered). The recall period in ItchyQoL is the past week. The ItchyQoL total score is defined as the sum of all 22-items scores. Total scores can be classified as little (0-30), mild (31-50), moderate (51-80), and severe (81-110). The least squares mean (LSM) and LSM difference were rounded up or down to the nearest single decimal place.

mITT Analysis Set: All randomized participants who receive at least 1 dose of vixarelimab or placebo and have at least 1 post-baseline efficacy assessment in the double-blind treatment period; WOCF: Baseline through Week 52.