A Study Comparing Different Dosing Regimens of Ixekizumab (LY2439821) in Participants With Moderate to Severe Plaque Psoriasis

The purpose of this study is to evaluate both the safety and efficacy of ixekizumab dosing
regimens. There are 3 study periods: Screening Period, Blinded Treatment Dosing Period, and
Post-Treatment Follow-Up.

Inclusion Criteria:

- Present with chronic plaque psoriasis for at least 6 months prior to enrollment

- At least 10% BSA of psoriasis at screening and at enrollment

- sPGA score of at least 3 and PASI score of at least 12 at screening and at enrollment

- Candidates for phototherapy and/or systemic therapy

- Participant must agree to use reliable method of birth control during the study; women
must continue using birth control for at least 12 weeks after stopping treatment

Exclusion Criteria:

- Predominant pattern of pustular, erythrodermic, or guttate forms of psoriasis

- History of drug-induced psoriasis

- Cannot avoid excessive sun exposure or use of tanning booths for at least 4 weeks
prior to enrollment and during the study

- Received systemic non-biologic psoriasis therapy or phototherapy within the previous 4
weeks; or had topical psoriasis treatment within the previous 2 weeks prior to
enrollment

- Concurrent or recent use of any biologic agent

- Have participated in any study with ixekizumab

- Received a live vaccination within 12 weeks prior to enrollment

- Serious disorder or illness other than psoriasis

- Ongoing or serious infection within the last 12 weeks or evidence of tuberculosis

- Major surgery within 8 weeks of baseline, or will require surgery during the study

- Breastfeeding or nursing (lactating) women