A Study to Evaluate the Efficacy and Safety of Bimekizumab in Study Participants With Palmoplantar Pustulosis

The PPPASI50 response is based on at least 50% improvement from baseline in the PPPASI total score which assesses the severity of PPP skin lesions.

The PPPASI evaluates 4 areas: right palm, left palm, right sole, and left sole which account for 20%, 20%, 30%, and 30%, respectively, of the total surface area of the palms or soles. Each palm and sole is evaluated for 3 characteristics: erythema, pustule, and desquamation. Each characteristic is rated on a 5-point severity scale, from 0 (none) to 4 (very severe). The percentage of area affected by PPP skin lesions is also evaluated for each palm and sole. The PPPASI total score ranges from 0 to 72, with a higher score indicating higher disease severity.

The PPPASI75 response is based on at least 75% improvement from baseline in the PPPASI score.

The PPPASI90 response is based on at least 90% improvement from baseline in the PPPASI score.

The PPPASI50 response is based on at least 50% improvement from baseline in the PPPASI score.

PPP-IGA is an overall assessment by a physician regarding condition of skin lesions on the palms and the soles in PPP.

The DLQI is a skin disease-specific questionnaire aimed at the evaluation of how symptoms and treatment affect participants' health-related quality of life (HRQOL). This questionnaire asks participants 10 questions about symptoms and feelings, daily activities, leisure, work and school, personal relationships, and treatment. For each question, participants are asked to evaluate on a 4-point scale (from 0=Not at all to 3=Very much) to which extend their skin disease has affected their life over the last week. The DLQI total score ranges from 0 to 30 with higher scores indicating lower HRQOL.

The study participant will score the worst level of PPP skin pain over the past 24 hours on a 11-point NRS from "0=no skin pain" to "10=very severe skin pain.

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. Treatment-emergent AEs are defined as those AEs that have a start date on or following the first dose of IMP to the end of the SFU Period.

An SAE is any untoward medical occurrence that at any dose:

• Results in death
• Is life-threatening
• Requires inpatient hospitalization or prolongation of existing hospitalization
• Results in persistent or significant disability/incapacity
• Is a congenital anomaly/birth defect
• Other important medical events which based on medical or scientific judgement may jeopardise the patients, or may require medical or surgical intervention to prevent any of the above. Treatment-emergent AEs are defined as those AEs that have a start date on or following the first dose of IMP to the end of the SFU Period.

An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. Treatment-emergent AEs are defined as those AEs that have a start date on or following the first dose of IMP to the end of the SFU Period.

This measure considers any TEAE leading to permanent discontinuation of IMP regardless of reason.