This study is designed to evaluate the proportion of patients achieving reversal of chronic plaque psoriasis at week 4 and 12 following multiple doses of secukinumab administered subcutaneously (sc) compared to placebo. Starting from week 13, all patients will receive multiple doses of secukinumab up to week 52 to study long term effects of secukinumab. Clinical endpoints including biomarker assessments, PASI, IGA and DLQI will be compared to better understand, why secukinumab may be effective in psoriasis patients.

Inclusion criteria:

• Chronic plaque-type psoriasis diagnosed for at least 6 months
• Moderate to severe psoriasis as defined by: PASI score of ≥12, IGA score of ≥3, BSA (body surface area) affected by plaque-type psoriasis of ≥10%
• Chronic plaque-type psoriasis considered inadequately controlled by: topical treatment and/or; phototherapy and/or previous systemic therapy

Exclusion criteria:

• Forms of psoriasis other than chronic plaque-type
• Evidence of skin conditions at the time of the screening visit (e.g., eczema) that would interfere with evaluations of the effect of the investigational product on psoriasis
• History or evidence of active tuberculosis or evidence of latent tuberculosis (or other infections like Hepatitis-C/B), malignancy; active or known use of other immunosuppressive drugs (for eg: AIDs, RA, organ rejection etc.) at the screening visit
• Pregnant or nursing (lactating) women