The purpose of this study is to evaluate the safety of an additional 28 weeks of treatment with pegsunercept for subjects who have completed treatment in a previous double-blind study (20000201 or 20000198). In addition, this study will evaluate the efficacy and the feasibility of subject self-administration on an outpatient basis.

Inclusion Criteria: - Subjects who have completed 24 weeks of double-blind treatment in a previous protocol (20000201 or 20000198) - Females of childbearing potential and males must practice adequate contraception, in the judgement of the investigator, during the course of the study - The subject or legally acceptable representative must give informed consent for participation in the study before any study specific procedures are performed Exclusion Criteria: - Greater than a 7-day duration from the week 24 visit in the previous study to the first dose in this study - Any medical disability or condition (e.g., evidence of clinically significant liver dysfunction, active infection requiring treatment with systemic anti-infective agents) that would interfere with the assessment of safety of the study material or would compromise the ability of the subject to provide adequate informed consent - Concurrent treatment with an investigational agent