Study to Assess the Efficacy, Safety, and Tolerability of Vixarelimab in Reducing Pruritus in Prurigo Nodularis

Study of the efficacy, safety, tolerability, pharmacokinetics (PK), and immunogenicity of Vixarelimab (KPL-716) in subjects with prurigo nodularis.

This is a Phase 2a/b randomized, double-blind, placebo-controlled study to investigate the efficacy, safety, tolerability, PK and immunogenicity of Vixarelimab administered subcutaneously (SC) in subjects with prurigo nodularis experiencing pruritus.

Phase 2a portion (completed):

Forty-nine subjects with moderate to severe PN experiencing moderate to severe pruritus were treated in the Phase 2a portion of the study. At Baseline, subjects were randomized 1:1 to receive double-blind Vixarelimab or placebo: Vixarelimab 720 mg loading dose followed by 360 mg every week; Placebo loading dose followed by placebo every week. The treatment Period was 8 weeks or 16 weeks (treatment duration was reduced from 16 weeks to 8 weeks in a protocol amendment \[Protocol Version 3\]).

Phase 2b portion (enrolling):

The Phase 2b study (Figure 1) will consist of a 4-week Screening Period and a 16-week Double-Blind Period, followed by a 36-week Open-Label-Extension (OLE) Period. Approximately 180 subjects with PN, experiencing severe pruritus, will be randomized (at 1:1:1:1 ratio) into one of 4 arms (3 active arms and one placebo arm). A total of 4 doses of study drug will be administered during the Double-Blind Period to measure the efficacy, safety, and PK of Vixarelimab. After the Double-Blind Period, all subjects will have the option to receive Vixarelimab during the OLE Period to evaluate the long-term safety and PK.

Eligibility Criteria:
Inclusion Criteria (apply to both Phase 2a and Phase 2b unless otherwise specified):

1. Male or female aged 18 to 75 years (Phase 2a), 18 to 80 years (Phase 2b)
2. Have clinical diagnosis of prurigo nodularis for at least 6 months
3. Have at least 10 nodules (Phase 2a), 20 nodules (Phase 2b) at the Screening Visit and Day 1
4. Moderate to severe pruritus (Phase 2a); severe pruritus (Phase 2b)
5. Female subjects of childbearing potential must have a negative pregnancy test, be nonlactating, and having agreed to use a highly effective method of contraception, as specified in the protocol, from the Screening Visit until 16 weeks after final study drug administration
6. Able to comprehend and willing to sign an Informed Consent Form and able to abide by the study restrictions and comply with all study procedures for the duration of the study

Exclusion Criteria (apply to both Phase 2a and Phase 2b unless otherwise specified):

1. Use of prohibited medications within the indicated timeframe from Day 1
2. Is currently using medication known to cause pruritus
3. Presence of any inflammatory, pruritic, and/or fibrotic skin condition other than moderate to severe prurigo nodularis or atopic dermatitis unless approved by the Sponsor
4. Laboratory abnormalities that fall outside the windows specified in the protocol at the Screening Visit
5. Has an active infection, including skin infection
6. Any medical or psychiatric condition which, in the opinion of the Investigator or the Sponsor, may place the subject at increased risk as a result of study participation, interfere with study participation or study assessments, affect compliance with study requirements, or complicate interpretation of study results