Trial Outcomes & Findings for Study of DAXDILIMAB for the Treatment of Moderate-to-Severe Alopecia Areata (NCT NCT05368103)

NCT ID: NCT05368103

Last Updated: 2025-01-07

Results Overview

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms. A decrease in SALT score from baseline indicated a reduction in AA symptoms. Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

• Recruitment status: COMPLETED
• Study phase: PHASE2
• Target enrollment: 30 participants
• Primary outcome timeframe: Baseline to Week 24
• Results posted on: 2025-01-07

Participant Flow

A total of 30 participants were enrolled at 5 trial centers located in the United States and 7 trial centers in Canada between 27 April 2022 and 26 January 2024.

Of the 55 participants who were screened for enrolment in the trial, 25 were screen failures. A total of 30 participants were enrolled and received daxdilimab.

Participant milestones

Measure	Daxdilimab 300 mg Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Overall Study STARTED	30
Overall Study Received Daxdilimab	30
Overall Study COMPLETED	22
Overall Study NOT COMPLETED	8

Reasons for withdrawal

Measure	Daxdilimab 300 mg Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Overall Study Withdrawal by Subject	4
Overall Study Lost to Follow-up	1
Overall Study Lack of Efficacy	3

Baseline Characteristics

Study of DAXDILIMAB for the Treatment of Moderate-to-Severe Alopecia Areata

Baseline characteristics by cohort

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Age, Continuous	42.7 years STANDARD_DEVIATION 13.83 • n=5 Participants
Sex: Female, Male Female	20 Participants n=5 Participants
Sex: Female, Male Male	10 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	2 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	28 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants
Race/Ethnicity, Customized Asian	6 Participants n=5 Participants
Race/Ethnicity, Customized Black or African American	2 Participants n=5 Participants
Race/Ethnicity, Customized White	20 Participants n=5 Participants
Race/Ethnicity, Customized Other	2 Participants n=5 Participants
Severity of Alopecia Tool (SALT) Score	74.4 score on a scale STANDARD_DEVIATION 15.72 • n=5 Participants

PRIMARY outcome

Timeframe: Baseline to Week 24

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms. A decrease in SALT score from baseline indicated a reduction in AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percent Change From Baseline in SALT Score at Week 24	-12.6 percent change in score on a scale Standard Deviation 35.15

SECONDARY outcome

Timeframe: Baseline to Weeks 12, 16, 20, 28, 32, and 36

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms. A decrease in SALT score from baseline indicated a reduction in AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percent Change From Baseline in SALT Score at Weeks 12, 16, 20, 28, 32, and 36 Week 12	-5.4 percent change in score on a scale Standard Deviation 21.57
Percent Change From Baseline in SALT Score at Weeks 12, 16, 20, 28, 32, and 36 Week 16	-8.1 percent change in score on a scale Standard Deviation 26.58
Percent Change From Baseline in SALT Score at Weeks 12, 16, 20, 28, 32, and 36 Week 20	-10.0 percent change in score on a scale Standard Deviation 30.10
Percent Change From Baseline in SALT Score at Weeks 12, 16, 20, 28, 32, and 36 Week 28	-16.2 percent change in score on a scale Standard Deviation 34.35
Percent Change From Baseline in SALT Score at Weeks 12, 16, 20, 28, 32, and 36 Week 32	-17.2 percent change in score on a scale Standard Deviation 37.16
Percent Change From Baseline in SALT Score at Weeks 12, 16, 20, 28, 32, and 36 Week 36	-18.2 percent change in score on a scale Standard Deviation 37.22

SECONDARY outcome

Timeframe: Baseline to Weeks 12, 16, 20, 24, 28, 32, and 36

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms. A decrease in SALT score from baseline indicated a reduction in AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 12	3.3 percent of participants Interval 0.1 to 17.2
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 16	10.0 percent of participants Interval 2.1 to 26.5
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 20	13.3 percent of participants Interval 3.8 to 30.7
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 24	20.0 percent of participants Interval 7.7 to 38.6
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 28	20.0 percent of participants Interval 7.7 to 38.6
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 36	20.0 percent of participants Interval 7.7 to 38.6
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 32	20.0 percent of participants Interval 7.7 to 38.6

SECONDARY outcome

Timeframe: Weeks 12, 16, 20, 24, 28, 32, and 36

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 16	0.0 percent of participants Interval 0.0 to 11.6
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 20	0.0 percent of participants Interval 0.0 to 11.6
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 24	3.3 percent of participants Interval 0.1 to 17.2
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 28	6.7 percent of participants Interval 0.8 to 22.1
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 32	10.0 percent of participants Interval 2.1 to 26.5
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 36	13.3 percent of participants Interval 3.8 to 30.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 12	0.0 percent of participants Interval 0.0 to 11.6

SECONDARY outcome

Timeframe: Weeks 12, 16, 20, 24, 28, 32, and 36

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 12	0.0 percent of participants Interval 0.0 to 11.6
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 20	6.7 percent of participants Interval 0.8 to 22.1
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 24	13.3 percent of participants Interval 3.8 to 30.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 28	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 32	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 36	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 16	0.0 percent of participants Interval 0.0 to 11.6

SECONDARY outcome

Timeframe: Weeks 12, 16, 20, 24, 28, 32, and 36

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 16	10.0 percent of participants Interval 2.1 to 26.5
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 20	10.0 percent of participants Interval 2.1 to 26.5
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 24	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 28	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 32	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 36	20.0 percent of participants Interval 7.7 to 38.6
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 12	6.7 percent of participants Interval 0.8 to 22.1

SECONDARY outcome

Timeframe: Weeks 12, 16, 20, 24, 28, 32, and 36

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 12	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 16	23.3 percent of participants Interval 9.9 to 42.3
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 20	26.7 percent of participants Interval 12.3 to 45.9
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 24	26.7 percent of participants Interval 12.3 to 45.9
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 28	30.0 percent of participants Interval 14.7 to 49.4
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 32	30.0 percent of participants Interval 14.7 to 49.4
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 12, 16, 20, 24, 28, 32, and 36 Week 36	30.0 percent of participants Interval 14.7 to 49.4

SECONDARY outcome

Timeframe: Baseline to Weeks 40, 44, and 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms. A decrease in SALT score from baseline indicated a reduction in AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percent Change From Baseline in SALT Score at Weeks 40, 44, and 48 Week 40	-19.4 percent change in score on a scale Standard Deviation 37.72
Percent Change From Baseline in SALT Score at Weeks 40, 44, and 48 Week 44	-20.6 percent change in score on a scale Standard Deviation 40.67
Percent Change From Baseline in SALT Score at Weeks 40, 44, and 48 Week 48	-22.1 percent change in score on a scale Standard Deviation 41.43

SECONDARY outcome

Timeframe: Baseline to Weeks 40, 44, and 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms. A decrease in SALT score from baseline indicated a reduction in AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 40, 44, and 48 Week 40	20.0 percent of participants Interval 7.7 to 38.6
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 40, 44, and 48 Week 44	26.7 percent of participants Interval 12.3 to 45.9
Percentage of Participants Who Achieved a ≥ 50% Reduction in SALT Score From Baseline at Weeks 40, 44, and 48 Week 48	23.3 percent of participants Interval 9.9 to 42.3

SECONDARY outcome

Timeframe: Weeks 40, 44 and 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 40, 44 and 48 Week 40	10.0 percent of participants Interval 2.1 to 26.5
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 40, 44 and 48 Week 44	10.0 percent of participants Interval 2.1 to 26.5
Percentage of Participants Who Had an Absolute SALT Score ≤ 10 at Weeks 40, 44 and 48 Week 48	13.3 percent of participants Interval 3.8 to 30.7

SECONDARY outcome

Timeframe: Weeks 40, 44 and 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 40, 44 and 48 Week 40	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 40, 44 and 48 Week 44	16.7 percent of participants Interval 5.6 to 34.7
Percentage of Participants Who Had an Absolute SALT Score ≤ 20 at Weeks 40, 44 and 48 Week 48	16.7 percent of participants Interval 5.6 to 34.7

SECONDARY outcome

Timeframe: Weeks 40, 44 and 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 40, 44 and 48 Week 40	20.0 percent of participants Interval 7.7 to 38.6
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 40, 44 and 48 Week 44	20.0 percent of participants Interval 7.7 to 38.6
Percentage of Participants Who Had an Absolute SALT Score ≤ 30 at Weeks 40, 44 and 48 Week 48	16.7 percent of participants Interval 5.6 to 34.7

SECONDARY outcome

Timeframe: Weeks 40, 44 and 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The SALT score determined the degree of hair loss based on the percentage of scalp surface area involved on the top, back, and each side of the scalp for AA. The Investigator determined the percent scalp hair loss in a given quadrant, multiplied this by the total scalp area delineated by that quadrant, and summed the resultant numbers for each quadrant to give the total percent scalp hair loss with a range of 0-100. Higher scores indicated more severe AA symptoms.

Baseline indicates last non-missing valid observation prior to the first dose of daxdilimab.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 40, 44 and 48 Week 40	26.7 percent of participants Interval 12.3 to 45.9
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 40, 44 and 48 Week 44	30.0 percent of participants Interval 14.7 to 49.4
Percentage of Participants Who Had an Absolute SALT Score ≤ 50 at Weeks 40, 44 and 48 Week 48	23.3 percent of participants Interval 9.9 to 42.3

SECONDARY outcome

Timeframe: Baseline: 2 hours post-dose; Weeks 4-32: Pre-dose; Weeks 36-48: Any time during the visit.

Population: Pharmacokinetic (PK) Analysis Set: Included all participants who received any dose of daxdilimab and had at least one measurable PK concentration post-dose. Only participants with evaluable data at each timepoint were included.

Blood samples were collected at the visits and time points specified.

All post-baseline concentrations below the limit of quantification (BLQ) were imputed as half of the lower limit of quantification value.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Serum Concentration of Daxdilimab Baseline	0.640 ng/mL Standard Deviation 1.354
Serum Concentration of Daxdilimab Week 4	6.698 ng/mL Standard Deviation 3.514
Serum Concentration of Daxdilimab Week 8	8.823 ng/mL Standard Deviation 4.439
Serum Concentration of Daxdilimab Week 12	9.978 ng/mL Standard Deviation 5.569
Serum Concentration of Daxdilimab Week 16	9.582 ng/mL Standard Deviation 5.410
Serum Concentration of Daxdilimab Week 20	9.473 ng/mL Standard Deviation 5.616
Serum Concentration of Daxdilimab Week 24	10.322 ng/mL Standard Deviation 6.154
Serum Concentration of Daxdilimab Week 28	10.595 ng/mL Standard Deviation 6.663
Serum Concentration of Daxdilimab Week 32	10.638 ng/mL Standard Deviation 6.549
Serum Concentration of Daxdilimab Week 36	10.480 ng/mL Standard Deviation 6.074
Serum Concentration of Daxdilimab Week 40	3.543 ng/mL Standard Deviation 2.878
Serum Concentration of Daxdilimab Week 44	1.309 ng/mL Standard Deviation 1.218
Serum Concentration of Daxdilimab Week 48	0.430 ng/mL Standard Deviation 0.465

SECONDARY outcome

Timeframe: Baseline to Weeks 4, 12, 24, 32, 36 and 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab. Only participants with evaluable data at each time point were included.

Blood samples were collected at the visits and timepoints specified and analyzed using flow cytometry.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Percent Change From Baseline in Plasmacytoid Dendritic Cell (pDC) Levels Week 4	-88.89 percent change in pDC levels Interval -100.0 to -16.7
Percent Change From Baseline in Plasmacytoid Dendritic Cell (pDC) Levels Week 12	-87.50 percent change in pDC levels Interval -100.0 to 33.3
Percent Change From Baseline in Plasmacytoid Dendritic Cell (pDC) Levels Week 24	-85.71 percent change in pDC levels Interval -100.0 to -50.0
Percent Change From Baseline in Plasmacytoid Dendritic Cell (pDC) Levels Week 32	-85.71 percent change in pDC levels Interval -100.0 to 33.3
Percent Change From Baseline in Plasmacytoid Dendritic Cell (pDC) Levels Week 36	-82.86 percent change in pDC levels Interval -96.6 to 66.7
Percent Change From Baseline in Plasmacytoid Dendritic Cell (pDC) Levels Week 48	-40.00 percent change in pDC levels Interval -90.5 to 200.0

SECONDARY outcome

Timeframe: Baseline and Weeks 4, 8, 12, 24, and 36: Pre-dose

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

The number of participants who experienced an ADA response was defined as participants with ADA positive post-baseline only or boosted their preexisting ADA during the study.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Number of Participants Who Experienced an Anti-drug Antibody (ADA) Response	1 Participants

SECONDARY outcome

Timeframe: Day 1 to Week 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

A TEAE was any untoward medical occurrence in a participant that was not present prior to treatment but appeared following treatment, was present at treatment initiation but worsened during treatment, or was present at the treatment initiation but resolved and then reappeared while the participant was on treatment and did not necessarily have a causal relationship with the treatment.

A serious TEAE was defined as any medical occurrence that had any of the following consequences:

• Resulted in death.
• Was life-threatening.
• Required in-patient hospitalization or prolongation of existing hospitalization.
• Resulted in persistent or significant disability/incapacity.
• Was a congenital anomaly/birth defect.

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Number of Participants Who Experienced a Treatment-emergent Adverse Event (TEAE) TEAEs	23 Participants
Number of Participants Who Experienced a Treatment-emergent Adverse Event (TEAE) Serious TEAEs	0 Participants

SECONDARY outcome

Timeframe: Day 1 to Week 48

Population: Safety Analysis Set: Included all participants who received any dose of daxdilimab.

An AESI was defined as a serious or non-serious adverse event of scientific and medical interest specific to understanding the treatment and may have required close monitoring and collection of additional information by the investigator.

The following were defined as AESIs:

• Hypersensitivity reaction, including anaphylaxis.
• Severe viral infection/reactivation.
• Opportunistic infection.
• Malignancy (except non-melanoma skin cancer).

Outcome measures

Measure	Daxdilimab 300 mg n=30 Participants Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Number of Participants Who Experienced an Adverse Event of Special Interest (AESI)	2 Participants

Adverse Events

Daxdilimab 300 mg

Serious events: 0 serious events

Other events: 17 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure	Daxdilimab 300 mg n=30 participants at risk Participants received 300 mg daxdilimab as two subcutaneous (SC) injections every 4 weeks (Q4W) for 32 weeks. Participants were followed-up until Week 48.
Gastrointestinal disorders Abdominal pain	6.7% 2/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Gastrointestinal disorders Diarrhoea	6.7% 2/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
General disorders Fatigue	13.3% 4/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
General disorders Injection site reaction	20.0% 6/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Immune system disorders Seasonal allergy	6.7% 2/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Infections and infestations COVID-19	10.0% 3/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Infections and infestations Nasopharyngitis	16.7% 5/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Infections and infestations Upper respiratory tract infection	16.7% 5/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Musculoskeletal and connective tissue disorders Arthralgia	6.7% 2/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Nervous system disorders Dizziness	6.7% 2/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Respiratory, thoracic and mediastinal disorders Cough	6.7% 2/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.
Skin and subcutaneous tissue disorders Pruritus	6.7% 2/30 • Day 1 to Week 48 All-cause mortality is reported for all participants enrolled in the study. Serious adverse events and other adverse events are reported for all participants who received at least one dose of daxdilimab.

Additional Information

Study Director

Amgen Inc.

Phone: 866-572-6436

Email: medinfo@amgen.com

Results disclosure agreements

• Principal investigator is a sponsor employee The Clinical Trial Agreement generally does not restrict an investigator's discussion of trial results after completion. The Agreement permits Amgen a limited period of time to review material discussing trial results (typically up to 45 days and possible extension). Amgen may remove confidential information, but authors have final control and approval of publication content. For multicenter studies, the investigator agrees not to publish any results before the first multi-center publication.
• Publication restrictions are in place

Restriction type: OTHER