Open-Label Extension Study of GSK1605786A

This is a multi-centre, open-label extension study to assess the long-term safety,
tolerability and effectiveness of GSK1605786A in subjects with Crohn's disease. Subjects
will enter the study via one of three routes:

1. completion of the placebo-controlled induction study, CCX114151, without achieving
clinical response (CDAI decrease of at least 100 points) or clinical remission (CDAI
score less than 150) at Week 12 or completion of any other GSK-sponsored induction
study as designated by the sponsor

2. completion of maintenance study CCX114157 at Week 52

3. withdrawal from maintenance study CCX114157 due to worsening of Crohn's disease and
requiring a treatment change.

The primary objective is to evaluate the safety of GSK1605786A, as assessed by recording of
adverse events, clinical laboratory parameters, vital signs and electrocardiogram.
Secondary objectives will include assessments of effectiveness of long-term treatment with
GSK1605786A. Health outcomes assessments will include changes in Inflammatory Bowel Disease
Questionnaire (IBDQ), SF-36v2, EQ-5D, Work and Productivity Activity Impairment-Crohn's
Disease (WPAI-CD) and disability.

It is estimated that approximately 800 subjects will be enrolled in total. All subjects will
enter the study at baseline (Week 0) and commence oral treatment with GSK1605786A 500 mg
twice daily.

The study will be conducted for 108 weeks. Once the results of the induction study
CCX114151 are known, the risk-to-benefit ratio will be re-assessed and the study duration
may be amended.

Study assessments for Crohn's disease will be performed every 12 weeks through Week 108. At
week 12, the investigator will make a determination of whether the subject is receiving
clinical benefit, and subjects who are not receiving clinical benefit must be withdrawn.
More frequent blood draws are required for liver function testing only; every 2 weeks for
the first 12 weeks, then every 4 weeks up to Week 52, and every 12 weeks after Week 60 for
the duration of the study.

Inclusion Criteria:

- Previous participation in a GSK-sponsored study with GSK1605786A

- Written informed consent prior to any study-specific procedures

- Female subjects: To be eligible, females of child-bearing potential must be sexually
inactive or commit to consistent and correct use of a contraceptive method of birth
control with less than 1% failure rate

Exclusion Criteria:

- If female, is pregnant, has a positive pregnancy test or is breast-feeding, or is
planning to become pregnant

- Subjects with known or suspected coeliac disease or a positive screening test for
anti-tissue transglutaminase antibodies should have been excluded from enrolment into
any induction study. Subjects in whom a diagnosis of coeliac disease is subsequently
suspected should be tested for anti-tissue transglutaminase antibodies and excluded
or withdrawn from the study upon positive test result

- Fixed symptomatic stenoses or strictures of small bowel or colon

- Enterocutaneous, abdominal or pelvic fistulae likely to require surgery during the
study period

- Current sepsis or infections requiring intravenous antibiotic therapy greater than 2
weeks

- Evidence of hepatic dysfunction or viral hepatitis

- Subjects who have demonstrated safety or tolerability issues during participation in
a previous study with GSK1605786A which, in the opinion of the investigator, was
possibly related to study treatment and poses an unacceptable risk to the subject.