A Study to Evaluate the Efficacy, Safety, and Drug Levels of Oral Ozanimod in Pediatric Participants With Moderately to Severely Active Crohn's Disease With an Inadequate Response to Conventional Therapy

Percentage of Participants Who Achieve Simple Endoscopic Score for Crohn's Disease (SES-CD) Decrease From Baseline of ≥ 50% (ER-50) at Week 64

SES-CD assesses the degree of inflammation on the basis of 4 components: size of ulcers, ulcerated surface, affected surface, and presence of narrowing. Each of these 4 components are assessed in the five segments of the ileum and colon: ileum, right colon, transverse colon, left (descending and sigmoid) colon, and rectum, and is scored on a scale of severity 0 (Normal) to 3 (High). Sub-scores for each segment will be derived by adding component scores within segments. Total SES-CD score is the sum of the sub-scores across the five segments. The sum of each component across all segments ranges from 0 to 15, except for the presence of narrowing where it varies from 0 to 11. The range of the overall SES-CD score is 0-56, with larger scores indicating greater severity of disease.

Time frame: Week 64

Percentage of Participants Who Achieve Simple Endoscopic Score for Crohn's Disease (SES-CD) Decrease From Baseline of ≥ 50% (ER-50) at Week 12 Based on Data as Observed

SES-CD assesses the degree of inflammation on the basis of 4 components: size of ulcers, ulcerated surface, affected surface, and presence of narrowing. Each of these 4 components are assessed in the five segments of the ileum and colon: ileum, right colon, transverse colon, left (descending and sigmoid) colon, and rectum, and is scored on a scale of severity 0 (Normal) to 3 (High). Sub-scores for each segment will be derived by adding component scores within segments. Total SES-CD score is the sum of the sub-scores across the five segments. The sum of each component across all segments ranges from 0 to 15, except for the presence of narrowing where it varies from 0 to 11. The range of the overall SES-CD score is 0-56, with larger scores indicating greater severity of disease.

Time frame: Week 12

Percentage of Participants Who Achieve Reduction in Pediatric Crohn's Disease Activity Index (PCDAI) Score ≥ 12.5 and a Total PCDAI Score of < 30 Points at Week 64

The PCDAI is an instrument that was developed and validated for numerical assessment of disease activity in children and adolescents with CD. The PCDAI consists of the following 11 variables: Abdominal pain, stools per day, wellbeing, weight, height velocity, abdominal tenderness, peri-rectal disease, extra-intestinal manifestation, hematocrit, erythrocyte sedimentation rate and albumin. The category of severity for each index item is assigned a score: 0=normal;5=mild abnormality; 10= severe abnormality. For hematocrit and erythrocyte SR, the maximum score =5. For albumin level, the maximum score = 10. The PCDAI score is average of 11 variables scoring range of 0 to 100. Mild disease corresponds to scores of 11 to 30; moderate to severe disease corresponds to scores \> 30. Remission (no disease activity) is defined as a PCDAI score \< 10.

Time frame: Week 64

Percentage of Participants Who Achieve Reduction in Pediatric Crohn's Disease Activity Index (PCDAI) Score ≥ 12.5 and a Total PCDAI Score of < 30 Points at Week 12 Based on Data as Observed

The PCDAI is an instrument that was developed and validated for numerical assessment of disease activity in children and adolescents with CD. The PCDAI consists of the following 11 variables: Abdominal pain, stools per day, wellbeing, weight, height velocity, abdominal tenderness, peri-rectal disease, extra-intestinal manifestation, hematocrit, erythrocyte sedimentation rate and albumin. The category of severity for each index item is assigned a score: 0=normal;5=mild abnormality; 10= severe abnormality. For hematocrit and erythrocyte SR, the maximum score =5. For albumin level, the maximum score = 10. The PCDAI score is average of 11 variables scoring range of 0 to 100. Mild disease corresponds to scores of 11 to 30; moderate to severe disease corresponds to scores \> 30. Remission (no disease activity) is defined as a PCDAI score \< 10.

Time frame: Week 12

Percentage of Adolescents Who Achieve an Average Daily Abdominal Pain Score ≤ 1 Point and an Average Daily Stool Frequency ≤ 3 Points With Abdominal Pain and Stool Frequency no Worse Than Baseline at Week 12 Based on Data as Observed

Abdominal pain (AP) and stool frequency (SF) clinical remission was defined as average daily abdominal pain score ≤1 point, and average daily stool frequency ≤ 3 times with AP and SF no worse than baseline at Week 12. Participants entered responses in diaries daily. The 7 days entries prior to visit were considered for calculating average AP score and SF. The AP was graded on severity of 0 (none) to 3 (severe) scale and SF was defined number of liquid or soft stools per day.

Time frame: Week 12

Percentage of Adolescents Who Achieve an Average Daily Abdominal Pain Score ≤ 1 Point and an Average Daily Stool Frequency ≤ 3 Points With Abdominal Pain and Stool Frequency no Worse Than Baseline at Week 64

Abdominal pain (AP) and stool frequency (SF) clinical remission was defined as average daily abdominal pain score ≤1 point, and average daily stool frequency ≤ 3 times with AP and SF no worse than baseline at Week 12. Participants entered responses in diaries daily. The 7 days entries prior to visit were considered for calculating average AP score and SF. The AP was graded on severity of 0 (none) to 3 (severe) scale and SF was defined number of liquid or soft stools per day.

Time frame: Week 64

Change From Baseline in Stool Frequency (SF) Score at Week 64

SF was defined number of liquid or soft stools per day.

Time frame: Baseline and Week 64

Change From Baseline in Abdominal Pain (AP) Score at Week 64

Participants entered Reponses in diaries daily. The 7 days entries prior to visit were considered for calculating average AP score. The AP score was graded on severity of 0 (none) to 3 (severe) scale.

Time frame: Baseline and Week 64

Percentage of Adolescents Who Achieve Crohn's Disease Activity Index (CDAI) Score < 150 at Week 12 Based on Data as Observed

The CDAI is a composite score that is used to measure the clinical activity of Crohn's disease (CD). The CDAI uses a questionnaire with 8 disease activity variables: number of soft/liquid stools, severity of abdominal pain, general well-being, presence of complications, need for antidiarrheal drugs, presence of an abdominal mass, hematocrit, and deviation in body weight. The sub scores of number of soft/liquid stool, severity of abdominal pain (0 \[none\] to 3 \[Severe\]), general well-being (0 \[well\] to 4 \[terrible\] were summed over the 7 days prior to each visit. Additionally, the remaining predictors were also noted and weighted to create the total CDAI score which ranged from 0-600 with a higher score indicating a worse outcome.

Time frame: Week 12

Percentage of Adolescents Who Achieve Crohn's Disease Activity Index (CDAI) Score < 150 at Week 64

The CDAI is a composite score that is used to measure the clinical activity of Crohn's disease (CD). The CDAI uses a questionnaire with 8 disease activity variables: number of soft/liquid stools, severity of abdominal pain, general well-being, presence of complications, need for antidiarrheal drugs, presence of an abdominal mass, hematocrit, and deviation in body weight. The sub scores of number of soft/liquid stool, severity of abdominal pain (0 \[none\] to 3 \[Severe\]), general well-being (0 \[well\] to 4 \[terrible\] were summed over the 7 days prior to each visit. Additionally, the remaining predictors were also noted and weighted to create the total CDAI score which ranged from 0-600 with a higher score indicating a worse outcome.

Time frame: Week 64

Percentage of Adolescents Who Achieve Crohn's Disease Activity Index (CDAI) Reduction From Baseline of ≥ 100 Points or CDAI Score < 150 at Week 64

The CDAI is a composite score that is used to measure the clinical activity of Crohn's disease (CD). The CDAI uses a questionnaire with 8 disease activity variables: number of soft/liquid stools, severity of abdominal pain, general well-being, presence of complications, need for antidiarrheal drugs, presence of an abdominal mass, hematocrit, and deviation in body weight. The sub scores of number of soft/liquid stool, severity of abdominal pain (0 \[none\] to 3 \[Severe\]), general well-being (0 \[well\] to 4 \[terrible\] were summed over the 7 days prior to each visit. Additionally, the remaining predictors were also noted and weighted to create the total CDAI score which ranged from 0-600 with a higher score indicating a worse outcome.

Time frame: Week 64

Percentage of Adolescents Who Achieve Crohn's Disease Activity Index (CDAI) Reduction From Baseline of ≥ 100 Points or CDAI Score < 150 at Week 12 Based on Data as Observed

The CDAI is a composite score that is used to measure the clinical activity of Crohn's disease (CD). The CDAI uses a questionnaire with 8 disease activity variables: number of soft/liquid stools, severity of abdominal pain, general well-being, presence of complications, need for antidiarrheal drugs, presence of an abdominal mass, hematocrit, and deviation in body weight. The sub scores of number of soft/liquid stool, severity of abdominal pain (0 \[none\] to 3 \[Severe\]), general well-being (0 \[well\] to 4 \[terrible\] were summed over the 7 days prior to each visit. Additionally, the remaining predictors were also noted and weighted to create the total CDAI score which ranged from 0-600 with a higher score indicating a worse outcome.

Time frame: Week 12

Percentage of Participants Who Achieve a Pediatric Crohn's Disease Activity Index (PCDAI) Score < 10 at Week 64 While Remaining Corticosteroid Free in the Prior 12 Weeks

The PCDAI is an instrument that was developed and validated for numerical assessment of disease activity in children and adolescents with CD. The PCDAI consists of the following 11 variables: Abdominal pain, stools per day, wellbeing, weight, height velocity, abdominal tenderness, peri-rectal disease, extra-intestinal manifestation, hematocrit, erythrocyte sedimentation rate and albumin. The category of severity for each index item is assigned a score: 0=normal;5=mild abnormality; 10= severe abnormality. For hematocrit and erythrocyte SR, the maximum score =5. For albumin level, the maximum score = 10. The PCDAI score is average of 11 variables scoring range of 0 to 100. Mild disease corresponds to scores of 11 to 30; moderate to severe disease corresponds to scores \> 30. Remission (no disease activity) is defined as a PCDAI score \< 10.

Time frame: Week 64

Percentage of Adolescents Who Achieve a Pediatric Crohn's Disease Activity Index (PCDAI) Score < 10 at Week 64 While Remaining Corticosteroid Free in the Prior 12 Weeks

The PCDAI is an instrument that was developed and validated for numerical assessment of disease activity in children and adolescents with CD. The PCDAI consists of the following 11 variables: Abdominal pain, stools per day, wellbeing, weight, height velocity, abdominal tenderness, peri-rectal disease, extra-intestinal manifestation, hematocrit, erythrocyte sedimentation rate and albumin. The category of severity for each index item is assigned a score: 0=normal;5=mild abnormality; 10= severe abnormality. For hematocrit and erythrocyte SR, the maximum score =5. For albumin level, the maximum score = 10. The PCDAI score is average of 11 variables scoring range of 0 to 100. Mild disease corresponds to scores of 11 to 30; moderate to severe disease corresponds to scores \> 30. Remission (no disease activity) is defined as a PCDAI score \< 10.

Time frame: Week 64

Percentage of Participants Who Achieve a Crohn's Disease Activity Index (CDAI) Score < 150 at Week 64 While Remaining Corticosteroid Free in the Prior 12 Weeks

The CDAI is a composite score that is used to measure the clinical activity of Crohn's disease (CD). The CDAI uses a questionnaire with 8 disease activity variables: number of soft/liquid stools, severity of abdominal pain, general well-being, presence of complications, need for antidiarrheal drugs, presence of an abdominal mass, hematocrit, and deviation in body weight. The sub scores of number of soft/liquid stool, severity of abdominal pain (0 \[none\] to 3 \[Severe\]), general well-being (0 \[well\] to 4 \[terrible\] were summed over the 7 days prior to each visit. Additionally, the remaining predictors were also noted and weighted to create the total CDAI score which ranged from 0-600 with a higher score indicating a worse outcome.

Time frame: Week 64

Percentage of Participants Achieving Simple Endoscopic Score for Crohn's Disease (SES-CD) ≤ 2 or SES-CD ≤ 4 Points With no SES-CD Subscore > 1 Point at Week 12 Based on Data as Observed

SES-CD assesses the degree of inflammation on the basis of 4 components: size of ulcers, ulcerated surface, affected surface, and presence of narrowing. Each of these 4 components are assessed in the five segments of the ileum and colon: ileum, right colon, transverse colon, left (descending and sigmoid) colon, and rectum, and is scored on a scale of severity 0 (Normal) to 3 (High). Sub-scores for each segment will be derived by adding component scores within segments. Total SES-CD score is the sum of the sub-scores across the five segments. The sum of each component across all segments ranges from 0 to 15, except for the presence of narrowing where it varies from 0 to 11. The range of the overall SES-CD score is 0-56, with larger scores indicating greater severity of disease.

Time frame: Week 12

Steady State Systemic Exposures of Ozanimod at Week 20 and Throughout the Study

Blood samples were collected to assess steady state exposure of ozanimod.

Time frame: Week 20 and up to end of study (Week 64)

Absolute Lymphocyte Count at Week 12 Based on Data as Observed

Blood samples were collected to assess lymphocyte count.

Time frame: Baseline (Day 1) and Week 12

Absolute Lymphocyte Count at Week 64

Blood samples were collected to assess lymphocyte count.

Time frame: Week 64

Number of Participants With Adverse Events

An Adverse Event (AE) is defined as any new untoward medical occurrence or worsening of a preexisting medical condition in a clinical investigation participant administered study treatment and that does not necessarily have a causal relationship with this treatment. Serious Adverse Events (SAEs) is any untoward medical occurrence that, at any dose: results in death; is life-threatening; requires inpatient hospitalization; results significant disability; or is a congenital anomaly/birth defect.

Time frame: From first dose (Day 1) and up to Week 12