To clarify in study description that subjects who withdraw early from the placebo-controlled maintenance study, CCX114157, due to worsening of Crohn’s disease requiring a treatment change, may also be eligible for the open-label extension study. Addition of a new author, Jatin Patel, To add contact details for David J Chang as Medical Monitor, To delete abbreviations not referenced in the protocol, to clarify that subjects can enter Study CCX114644 if they complete Study CCX114151 and do not achieve clinical response (CDAI >=100 point decrease) or remission (CDAI < 150) or they complete any other GSK-sponsored induction study of GSK1605786A as designated by the sponsor. To specify that study will be conducted for 108 weeks with amendment of study duration to be considered following results of Study CCX114151, to amend wording for CDAI assessments every 3 months to every 12 weeks for consistency within the protocol To amend other endpoints for assessment of effectiveness to include the key outcome measures of proportion of subjects in remission(CDAI < 150), proportion of subjects in remission for subjects in remission at baseline, proportion of subjects in remission for subjects not in remission at baseline, and to remove endpoints of remission and response by previous study and include as subgroup analyses; to clarify that response will be measured relative to baseline of previous study, to correct typographical errors to specify 108 weeks rather than 104 weeks or Week 108 rather than Week 104, to amend wording of exclusion criterion #2 to clarify testing requirement for anti-tTG antibodies. To amend wording of exclusion criterion #3 to clarify fixed symptomatic stenoses or strictures of small bowel or colon, to include new exclusion criterion #7 to exclude subjects who have demonstrated safety or tolerability issues which were possibly related to study treatment(in the investigator’s opinion) during participation in a previous clinical study with GSK1605786A.

To clarify that subjects may be enrolled in the study prior to receiving baseline results for LFTs and anti-tTG antibodies (if applicable). Subjects who fulfill these exclusion criteria should be withdrawn due to inability to meet continuation criteria and recorded as screen failures, To include a withdrawal criterion at Week 12 based on investigator assessment that subject is not receiving clinical benefit , to remove reference to randomised subjects, randomisation code or treatment groups made as typographical errors, to clarify text on procedures for an Early Withdrawal visit, to include wording to direct investigators to the Study Procedures Manual for details on Investigational Product, to include immunisation with live vaccines as prohibited therapy To clarify requirements for permitted medications, including allowance for steroid taper and additional use of corticosteroids, 5-ASAs, opioid analgesics and paracetamol/acetaminophen (including correction of daily allowed dose to 2 g/day) and inclusion of treatment for fistulae under permitted medications section, to make the following corrections or amendments to the Time and Events schedule: Correction of visit numbers, as Visit 12 had been replicated in error,Expansion of footnote to clarify only LFTs are assessed at certain visits,Addition of 12 lead ECG at Week 72 and deletion at Weeks 12, 60 and 84, Addition of haematology assessment at Week 96, Deletion of pregnancy testing at Weeks 16, 24, 32, 40 and 48, consistent with initial testing every 4 weeks, and then every 8 weeks after Week 20 and every 12 weeks after Week 60; Amendment of footnote to specify home pregnancy testing every 4 weeks after Week 60

Addition of CRP assessment at Weeks 8, 72 and 96 and at Early Withdrawal and Follow-up visits to align with CDAI assessments Deletion of assessment of fistula closure at Weeks 12, 60 and 84 and addition of assessment of fistula closure at Week 0 (this is not a repeated assessment but carry over from Study CCX114151 Week 12 assessment or end of study visit from any other preceding study of GSK1605786A), Weeks 72 and 108, Addition of * to pregnancy test at Week 0, indicating that the test is not repeated but the result is carried over from the preceding study of GSK1605786A, Inclusion of test for coeliac disease at baseline if indicated and corresponding footnote to specify that testing should be performed upon suspicion of coeliac disease Inclusion of Week 12 investigator assessment of clinical benefit, Amendment of timepoints for assessment of IBDQ, SF-36, EQ5D, WPAI-CD, disability and resource utilisation from Weeks 60 and 84 to Weeks 48 and 72 in Time and Events schedule; Inclusion in footnote that Week 0 disability assessment will not be available for subjects entering from a prior induction study and is not required, To amend timepoints for efficacy, safety and health outcomes assessments in protocol text to correspond with timepoints and changes in timepoints in the Time and Events schedule detailed above, To clarify that the treatment allocation from the previous study will not be available prior to enrolment, To remove the requirement for locally determined haematocrit values for CDAI calculation, To clarify timings for adverse event reporting and wording regarding serious adverse events as reported, To clarify wording for frequency of assessment of LFTs, To include assessment of concomitant medications and CRP in Follow Up visit, To include response and remission status at end of previous induction study as a subgroup analysis with clarification that response will be measured relative to baseline of previous study

To incorporate revisions into description of efficacy analyses to correspond with changes to endpoints To amend CDAI in Appendix 4 to reflect that investigator assessments should be performed based on findings on day of examination To include correct version of IBDQ in Appendix 5 To correct other minor typographical errors in the protocol

To update information on sponsor departmental information To update abbreviations to include revised information To clarify that subjects who completed Study CCX114643 are not eligible to participate in this study To include additional secondary objectives of assessment of activity impairment, unemployment and disability rates and biomarkers of inflammation to clarify that these evaluations are secondary objectives of this study To include exploratory objective of assessment of fistula closure to clarify that this will be an exploratory objective of this study. To clarify for secondary endpoints that changes in body weight and temperature will be performed only in relation to CDAI scoring and not as separate assessments To clarify that changes in CRP concentrations as a biomarker of inflammation will be assessed as an endpoint To amend Inclusion Criteria to include updated criteria for acceptable contraceptive methods of birth control according to sponsor standards To amend Exclusion Criteria • To clarify criteria for fixed symptomatic stenoses and stricture • To include use of prohibited medications at baseline and throughout the study to ensure subject safety. To update withdrawal and stopping criteria and testing procedures for liver chemistry abnormalities and ECG findings to be consistent with revisions to GSK standard withdrawal criteria To clarify that the Investigator should conduct a Follow-up visit in addition to an Early Withdrawal visit for safety follow up To clarify that prohibited medications should not be taken throughout the study and that use of stable doses of Crohn’s disease medications ongoing from a previous study are permissible To include use of digoxin or related cardiac glycosides (e.g digitoxin, deslanoside, lanatoside C, metildigoxin) as a prohibited medication To correct typographical errors in Time and Events table and to amend assessments to be consistent with protocol content.

To extend visit windows with longer intervals between visits to allow flexibility in scheduling To clarify that subjects should initiate study drug administration the evening of the day of the baseline (Week 0) visit To provide additional clarification regarding reporting of worsening of Crohn’s disease as an AE To include information on reporting and analyses of Disease-related events common in Crohn’s disease for consistency with new FDA safety reporting guidance. Protocol-specified events related to worsening of Crohn’s disease will not be reported as SAEs To delete concomitant medications as a safety outcome To provide additional clarification on data handling To include additional information on analyses of components of SF-36v2 and disability benefit data To provide additional clarification on IDMC purpose and safety review To amend CDAI to clarify that Investigator should assess symptoms/findings for subject based on current conditions and fever should be documented if present over the past week

To amend the study duration to 216 weeks, to revise the list of authors, to revise sponsor address and medical monitor contact information, to correct typographical errors, to consistently define draining fistulae as “open.” To indicate that in 2012, GSK1605786A received approval for the generic name vercirnon, to remove information concerning the method of confirming male partner sterilization from the protocol to the Study Procedure Manual, to remove the exclusion prohibiting subjects with fistulae likely to require surgery from entering the study, to clarify that subjects who have been withdrawn early from study CCX114157 due to disease worsening and have received, or are receiving, certain rescue treatments shall be excluded from entry into study CCX114644, to clarify that enteral or parenteral nutritional supplementation to treat malnutrition is permitted, to clarify that any biologic or investigational agent, including – but not limited to - janus kinase ihibitors, vedolizumab and ustekinumab are prohibited medications, to revise the Time & Events table to provide for ongoing assessments from week 108 to week 216, to extend the visit window for visits from week 16 onward, to clarify the definition of the safety population, to clarify the analysis of data by subgroups, to clarify the purpose of the interim analyses that will be performed, to clarify the definition of baseline for statistical analysis purposes, to clarify how the extent of treatment exposure will be defined and summarized. To clarify that the incidence rate of adverse events will be summarized by overall duration of exposure as well as by 6-month intervals of exposure. To clarify that ECG data will be summarized separately for data calculated manually and by machine. To clarify the efficacy analyses that will be performed based on CDAI score and fistulae closure. To clarify how the CRP concentration data will be summarized and analyzed for statistical purposes.