A Study to Determine the Optimal Dose of Tildrakizumab (SCH 900222/MK-3222) for the Treatment of Moderate-to-severe Chronic Plaque Psoriasis (P05495) (MK-3222-003)

The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease). PASI 75 response was defined as >=75% improvement in PASI score when compared to the baseline score.

An adverse event is any unfavorable and unintended change in the structure, function, or chemistry of the body whether or not considered related to the study treatment.

An adverse event is any unfavorable and unintended change in the structure, function, or chemistry of the body whether or not considered related to the study treatment. Participants may be discontinued from study drug due to adverse events, but remain on the study.

The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease). PASI 75 response was defined as >=75% improvement in PASI score when compared to the baseline score.

The PGA is used to determine the overall severity of a subject's psoriasis lesions at a given time point. Overall lesions will be graded for induration, erythema, and scaling on a scale from 0 to 5. The sum of the 3 scales will be divided by 3 to obtain the PGA score. PGA is assessed as: 0= Cleared, except for residual discoloration. 1= Minimal, majority of lesions have individual scores that average . 2 =Mild, majority of lesions have individual scores that average 2. 3= Modreate, majority of lesions have individual scores that average 3. 4= Marked, majority of lesions have individual scores that average 4. 5= Severe, majority of lesions have individual scores that average 5.

The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease). PASI 90 response was defined as >=90 % improvement in PASI score when compared to the baseline score.

The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease). PASI 100 response was defined as 100 % improvement in PASI score when compared to the baseline score.

The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease).PASI 75 response was defined as >=75% improvement in PASI score when compared to the baseline score at Week 2, 4, 6, 8, 12, or 16.

The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease).

The PASI score measures the severity and extent of psoriasis. Using a scale of 0=none to 4= very severe, each body region (head, trunk, arms, and legs) is rated for redness, thickness, and scaling of the largest psoriatic area in that region producing a Lesion Score. The percentage of the area affected by disease is then estimated, ranging from 0 = no lesions to 6 = 90-100% of the region is covered providing an Area Score. Then, the Lesion Score and Area Score for each region are multiplied, producing 4 subtotals. The 4 region subtotals are multiplied by a standardized percentage of body surface area for that region (head = 0.1, trunk = 0.3, arms=0.2, and legs = 0.4); these four region calculations are added to provide the final PASI score, ranging from 0 = no disease to 72 = maximal disease). PASI 50 response was defined as >=50 % improvement in PASI score when compared to the baseline score.

The DLQI is a 10-item questionnaire that measures how much participant skin problems have affected their life. Responses range from 0=Not at all to 3=Very much. The DLQI is broken down into 6 subscales: Symptoms and feelings (range 0-6), Daily activities (range 0-6), Leisure (range 0-6), Work and school (range 0-3), Personal relationships (range 0-6), and Treatment (range 0-3). DLQI subscales were summed to yield the DLQI total score, which could range from 0 to 30. For both DLQI subscales and DLQI total score, a higher score indicated a greater negative impact on life.

The DLQI is a 10-item questionnaire that measures how much participant skin problems have affected their life. Responses range from 0=Not at all to 3=Very much. The DLQI is broken down into 6 subscales: Symptoms and feelings (range 0-6), Daily activities (range 0-6), Leisure (range 0-6), Work and school (range 0-3), Personal relationships (range 0-6), and Treatment (range 0-3). DLQI subscales were summed to yield the DLQI total score, which could range from 0 to 30. For both DLQI subscales and DLQI total score, a higher score indicated a greater negative impact on life.

The DLQI is a 10-item questionnaire that measures how much participant skin problems have affected their life. Responses range from 0=Not at all to 3=Very much. The DLQI is broken down into 6 subscales: Symptoms and feelings (range 0-6), Daily activities (range 0-6), Leisure (range 0-6), Work and school (range 0-3), Personal relationships (range 0-6), and Treatment (range 0-3). DLQI subscales were summed to yield the DLQI total score, which could range from 0 to 30. For both DLQI subscales and DLQI total score, a higher score indicated a greater negative impact on life.