A Study to Evaluate the Efficacy and Safety of Two Dose Levels of Certolizumab Pegol (CZP) in Subjects With Plaque Psoriasis (PSO)

This study consists of the following Periods:

- Initial Treatment Period from Week 0 to Week 16

- Maintenance Treatment Period from Week 16 to Week 48

- Open-label Treatment Period from Week 48 to Week 144

- Safety Follow-Up Period from Week 144 to Week 152

Inclusion Criteria:

- Provided informed consent

- Adult men or women >= 18 years

- Chronic plaque psoriasis for at least 6 months

- Baseline psoriasis activity and severity index >= 12 and body surface area >= 10 % and
Physician's Global Assessments score >= 3

- Candidate for systemic psoriasis therapy and/or phototherapy and/or chemophototherapy

- Other protocol-defined inclusion criteria may apply

Exclusion Criteria:

- Erythrodermic, guttate, generalized pustular form of psoriasis

- History of current, chronic, or recurrent infections of viral, bacterial, or fungal
origin as described in the protocol

- Congestive heart failure

- History of a lymphoproliferative disorder including lymphoma or current signs and
symptoms suggestive of lymphoproliferative disease

- Concurrent malignancy or a history of malignancy as described in the protocol

- History of, or suspected, demyelinating disease of the central nervous system (e.g.,
multiple sclerosis or optic neuritis)

- Female subjects who are breastfeeding, pregnant, or plan to become pregnant during the
study or within 3 months following last dose of study drug. Male subjects who are
planning a partner pregnancy during the study or within 10 weeks following the last
dose

- Any other condition which, in the Investigator's judgment, would make the subject
unsuitable for participation in the study

- Other protocol-defined exclusion criteria may apply