A Study of E6011 in Participants With Active Crohn's Disease

The primary purpose of this study is to examine the efficacy and safety of E6011 at 12 weeks after administration by means of double-blind placebo-controlled trial.

Participants with moderate to severe Crohn's disease will be enrolled in this study.

The study will include screening period, remission-induction period (double-blind), rescue period (open-label), extension period (open-label), post-observation period, and a follow-up period.

At the end of remission-induction period, participants with reduction in Crohn's disease activity index (CDAI) score of 70 points or more when compared to baseline will move on to the open-label extension period, and participants with less than 70 points reduction in CDAI score will move on to the rescue period. At the end of the rescue period, participants with a reduction in the CDAI of 70 points or more will move on to the open-label extension period and with less than 70 points reduction in the CDAI score will be discontinued.

The post-observation period will include in-person assessment after the completion or discontinuation of the extension period, and participants will be contacted by telephone, etc. after the last dose of study drug administration. Participants will be contacted over phone after the last dose of study drug administration for follow up assessments.

Eligibility Criteria:
Inclusion Criteria:

1. Has diagnosed on basis of clinical findings, endoscopic findings, etc. with small intestine-type, small and large-intestine type, or large-intestine type Crohn's disease at least 12 weeks before giving consent.
2. With a baseline (at week 0 before the start of investigational medicinal product \[IMP\] administration) disease severity ranging from moderate to severe. CDAI score between 220 and 450, and a PRO2 score between 14 and 34.
3. With a SES-CD \>=7 (or for participants with isolated ileal disease, \>=4 in ileum segment) in the screening period, with one or more ulcers (in SES-CD score, ulcer presence subscore \>=1 in any segment) assessed by colonoscopy and confirmed by a centralised review.
4. Who received adrenocorticosteroids or immunomodulators in the past, but showed no therapeutic response (insufficient response) or the drugs were not tolerated (intolerance). Alternatively, participants who cannot taper adrenocorticosteroids (dependence). Alternatively, participants who showed no therapeutic response after administering biologic(s) (primary nonresponse), participants who initially showed therapeutic response but it lessened or disappeared afterwards (secondary nonresponse), or participants who did not tolerate the drug (intolerance).
5. If the participants are taking aminosalicylic acid (5-ASA), salazosulfapyridine, or antibiotics for the treatment of Crohn's disease (metronidazole, ciprofloxacin, etc.), the dosage and administration have not changed for at least 4 weeks prior to the start of the IMP administration.
6. If the participants are taking under 30 milligram per day (mg/day) of oral prednisolone (or equivalent adrenocorticosteroid) or 9 mg/day or less of oral budesonide, the dosage and administration have not changed for at least 4 weeks prior to the start of the IMP administration.
7. If the participants are taking azathioprine (AZP), 6-mercaptopurine (6-MP) or methotrexate (MTX), the dosage and administration have not changed for at least 8 weeks prior to the start of the IMP administration.

Exclusion Criteria:

1. Diagnosed with ulcerative colitis or indeterminate colitis.
2. Diagnosed with gastrointestinal epithelial dysplasia.
3. Who have an abscess or are suspected to have one.
4. With an artificial anus, ileo-anal pouch or fistula.
5. With symptomatic or high-grade gastrointestinal stenosis (participants who require expansion by endoscopy or who require have SES-CD score stenosis sub-score of 3, etc.).
6. Who, after undergoing small bowel resection, have been diagnosed with a short bowel syndrome, which makes maintaining caloric intake difficult.