A Study to Evaluate the Efficacy and Safety of Imsidolimab (ANB019) in Adults With Generalized Pustular Psoriasis

Clinical response was defined as "Very much improved," "Much Improved," or "Minimally Improved" on the CGI scale according to the Modified Japanese Dermatological Association Severity Index (JDA-SI) total score.

The JDA-SI includes assessment of skin lesions (area of erythema with pustules, area of erythema total, and area of edema) and fever, white blood cell count, C-reactive protein and serum albumin levels. The total score ranges from 0 to 17 (severe).

CGI was assessed based on the JDA-SI according to the following:

• Very Much Improved: Reduction in JDA-SI total score by 3 or > points;
• Much improved: Reduction in JDA-SI total score by 1 or 2 points;
• Minimally improved: No change in JDA-SI total score and area of erythema with pustules reduced by <20% or clinically meaningful improvement in at least 1 other component of the modified JDA-SI.

Excluding palms and soles from 0% to 100%. The palmar surface of one hand (using the subject's hand and including the fingers) represents 1% of his or her total BSA.

The area of erythema with pustules, area of total erythema and area of edema were assessed by the Investigator and scored from 0 to 3 on the following scale:

• 0: 0% body surface area (BSA) affected;
• 1: > 0%, < 10% BSA affected;
• 2: ≥ 10%, < 50% BSA affected;
• 3: ≥ 50% BSA affected.

The JDA-SI Total Skin Lesions Score is the sum of the area of erythema with pustules score, area of total erythema score and area of edema score and ranges between 0 and 9 (worst). A negative change from Baseline indicates improvement.

The GPPPGA scale was used to assess the impact and severity of GPP on the following scale:

• 0: Clear (normal skin or post-inflammatory hyperpigmentation, no visible pustules, no scaling or crusting).
• 1: Almost clear (faint, diffuse pink or slight red erythema, low density occasional small discrete pustules (noncoalescent), superficial focal scaling or crusting restricted to periphery of lesions).
• 2: Mild (light red erythema, moderate density grouped discrete small pustules (noncoalescent), predominantly fine scaling or crusting).
• 3: Moderate (bright red erythema, high density pustules with some coalescence, moderate scaling or crusting covering most or all lesions).
• 4: Severe (deep fiery red erythema, very high density pustules with pustular lakes, severe scaling or crusting covering most or all lesions).

The DLQI is a 10-item questionnaire that asks participants to evaluate the degree that their skin problem has affected their quality of life in the last week in the following 6 aspects: symptoms and feelings, daily activities, leisure, work or school activities, personal relationships and treatment related feelings. Participants answer the 10 questions on a scale from 0 (not at all) to 3 (very much). The DLQI is calculated by summing the scores of the 10 questions, resulting in a maximum of 30 and a minimum of 0 with higher scores indicating more impaired quality of life. A negative change from Baseline indicates improvement.