Pharmacokinetics of S1P receptor modulators in the treatment of ulcerative colitis.

INTRODUCTION: Ulcerative colitis is a chronic inflammatory bowel disease, affecting the colorectal mucosae, with a relapsing-remitting course, characterized by the trafficking and gathering of lymphocytes in the inflammatory intestinal mucosa. Sphingosine-1-phosphate (S1P) receptor modulators preventing lymphocytes egress from lymphoid tissues to the active inflammation site is an alternative therapeutic option in this condition. AREA COVERED: We carried out a comprehensive review of the literature available on Medline, Scopus and Embase regarding the pharmacokinetics of S1P receptor modulators. For each compound, we reviewed the mechanism of action, pharmacokinetic data and efficacy and safety data from phase 3 studies and real-life studies when available. EXPERT OPINION: S1P receptor modulators, including ozanimod and etrasimod (both currently on the market) as well as VTX002 (under development), are a new class of drugs for the treatment of moderate to severe ulcerative colitis, inducing and maintaining the remission. Due to its pharmacokinetic features, this class of drugs has certain advantages such as an oral administration, a short half-life, a high volume of distribution, and no immunogenicity. On the other hand, there are risks of cardiological and ophthalmological side-effects, as well as drug-drug interactions risk, that require special attention from the healthcare providers.

Efficacy and Safety of Sphingosine 1-Phosphate Receptor Modulators for Ulcerative Colitis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND AND AIMS: Sphingosine 1-phosphate receptor modulators (S1PRMs) are an effective treatment for ulcerative colitis (UC). This review summarizes all available randomized trial data on the efficacy and safety of S1PRM therapy. METHODS: Multiple publication databases were systematically searched for randomized control trials (RCTs) of adults with moderate to severe UC treated with S1PRMs. Random effects meta-analysis was performed. The risk of bias was assessed using the Cochrane Risk-of-Bias 2 tool, and the overall quality of evidence was rated using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. RESULTS: We identified 7 RCTs (1737 patients) involving the use of S1PRMs for moderate to severe UC. During induction, S1PRM therapy was efficacious when compared with placebo for clinical remission [RR: 2.65 (95% CI: 2.00, 3.53)], clinical response [RR: 1.68 (95% CI: 1.48, 1.91)], endoscopic improvement [RR: 2.17 (95% CI: 1.76, 2.68)], endoscopic normalization [RR: 2.56 (95% CI: 1.58, 3.83)], mucosal healing [RR: 2.88 (95% CI: 1.94, 4.26)], and histologic remission [RR: 2.42 (95% CI: 1.60, 3.66)]. Similar results were seen throughout the maintenance peroid, although fewer data were available to pool; notably, both sustained [RR: 3.57 (95% CI: 1.23, 10.35)] and steroid-free [RR: 2.92 (95% CI: 1.35, 6.33)] remission were significantly increased by S1PRM. There were no significant differences in adverse events [RR: 1.02 (95% CI: 0.90, 1.15)] and infections [RR: 1.15 (95% CI: 0.82, 1.60)] between S1PRM and placebo. CONCLUSION: Pooling of RCT data confirms that S1PRM therapy is both effective and safe for patients with moderate to severe UC.

Icanbelimod (CBP-307), a next-generation Sphingosine-1-phosphate receptor modulator, in healthy men: pharmacokinetics, pharmacodynamics, safety, and tolerability in a randomized trial in Australia.

Background: Icanbelimod (formerly CBP-307) is a next-generation S1PR modulator, targeting S1PR1. In this first-in-human study, icanbelimod was investigated in healthy men in Australia. Methods: Participants were randomized 3:1, double-blind, to icanbelimod or placebo in four single-dose cohorts (0.1 mg, 0.25 mg, 0.5 mg [n=8 per cohort], 2.5 mg [n=4]) or for 28-days once-daily treatment in two cohorts (0.15 mg, 0.25 mg [n=8 per cohort]). Participants in the 0.25-mg cohort received 0.1 mg on Day 1. Treatments were administered orally after fasting; following one-week washout, icanbelimod was administered after breakfast in the 0.5-mg cohort. Results: Icanbelimod exposure increased rapidly and dose-dependently with single and multiple dosing (Tmax 4-7 hours). Lymphocyte counts decreased rapidly after single (-11%, 0.1 mg; -40%, 0.25 mg; -71%, 0.5 mg; -77%, 2.5 mg) and multiple doses (-49%, 0.15 mg; -75%, 0.25 mg), and recovered quickly, 7 days after dosing. After single-dose 0.5 mg, although a high-fat breakfast versus fasting did not affect maximal decrease, lymphocyte counts tended to be lower after breakfast across most timepoints up to 72 hours. Twenty-eight participants (63.6%) experienced mainly mild treatment-emergent adverse events (TEAEs). After single-dose icanbelimod, the most common TEAEs were headache (28.6%, n=6) and dizziness (19.0%, n=4). Three participants experienced transient bradycardia, with one serious, following single-dose 2.5 mg icanbelimod. After multiple-dose icanbelimod, the most common TEAEs were headache (50.0%, n=6) and lymphopenia (41.7%, n=5), and two participants withdrew due to non-serious TEAEs. Up-titration attenuated heart rate reductions. Conclusion: Icanbelimod was well-tolerated up to 0.5 mg and effectively reduced lymphocyte counts. Clinical trial registration: ClinicalTrials.gov, identifier NCT02280434.b.

Presentation and Outcome in S1P-RM and Natalizumab-Associated Progressive Multifocal Leukoencephalopathy: A Multicenter Cohort Study.

BACKGROUND AND OBJECTIVES: Progressive multifocal leukoencephalopathy (PML) is a severe neurologic disease resulting from JC virus reactivation in immunocompromised patients. Certain multiple sclerosis (MS) disease-modifying therapies (DMTs) are associated with PML risk, such as natalizumab and, more rarely, sphingosine-1-phosphate receptor modulators (S1P-RMs). Although natalizumab-associated PML is well documented, information on S1P-RM-associated PML is limited. The aim of this study is to compare clinical presentations and outcomes between the 2 groups. METHODS: A retrospective multicenter cohort study included patients with PML from 2009 to 2022 treated with S1P-RMs or natalizumab. Data on clinical and radiologic presentation, outcomes, immune reconstitution inflammatory syndrome (IRIS), survival, disability (using the modified Ranking scale-mRS), and MS relapses post-PML were analyzed. RESULTS: Of 88 patients, 84 were analyzed (20 S1P-RM, 64 natalizumab). S1P-RM-associated PML was diagnosed in older patients (median age 52 vs 44 years, p < 0.001) and after longer treatment duration (median 63.9 vs 40 months, p < 0.001). Similarly, S1P-RM patients were more prone to show symptoms at diagnosis (100 vs 80.6%, p = 0.035), had more disseminated lesions (80% vs 34.9%, p = 0.002), and had higher gadolinium enhancement (65% vs 39.1%, p = 0.042). Natalizumab patients had a higher IRIS development rate (OR: 8.3 [1.92-33.3]). Overall, the outcome (mRS) at 12 months was similar in the 2 groups (OR: 0.81 [0.32-2.0]). Yet, post-treatment MS activity was higher in S1P-RM cases (OR: 5.7 [1.4-22.2]). DISCUSSION: S1P-RM-associated PML shows reduced IRIS risk but higher post-treatment MS activity. Clinicians should tailor post-PML treatment based on pre-PML medication.

[Translated article] Risk of Skin Cancer Associated with Disease-Modifying Therapies in Multiple Sclerosis: A Comprehensive Evidence Review.

The use of disease-modifying therapies (DMT) has led to a paradigm shift in the management of multiple sclerosis. A comprehensive narrative review was conducted through an extensive literature search including Medline and Google Scholar to elucidate the link between DMT and the propensity of cutaneous malignancies. Sphingosine-1-phosphate receptor modulators, such as fingolimod and siponimod are associated with a higher risk of basal cell carcinoma (BCC), but not squamous cell carcinoma, or melanoma. The associated physiopathological mechanisms are not fully understood. Alemtuzumab and cladribine show isolated associations with skin cancer. Regarding other DMT, no increased risk has ever been found. Given the evidence currently available, it is of paramount importance to advocate for necessary dermatological assessments that should be individualized to the risk profile of each patient. Nonetheless, additional prospective studies are still needed to establish efficient dermatological follow-up protocols.

Preventing and managing cardiovascular events in patients with inflammatory bowel diseases treated with small-molecule drugs, an international Delphi consensus.

Janus kinase (JAK) inhibitors and sphingosine 1 phosphate (S1P) receptor modulators are small molecule drugs (SMDs) approved for IBD treatment. Their use in clinical practice might be limited due to cardiovascular concerns. We aimed to provide guidance on risk assessment, monitoring, and management strategies, aiming to minimize potential cardiovascular risks of SMDs and to facilitate an adequate shared decision-making. A systematic literature search was conducted, and proposed statements were prepared. A virtual consensus meeting was held, in which eleven IBD physicians and two cardiovascular specialists from ten countries attended. Proposed statements were voted upon in an anonymous manner. Agreement was defined as at least 75 % of participants voting as 'agree' with each statement. Consensus was reached for eighteen statements. Available evidence does not show a higher risk of cardiovascular events with JAK inhibitors in the overall IBD population, although it might be increased in patients with an unfavorable cardiovascular profile. S1P receptor modulators may be associated with a risk of bradycardia, atrioventricular blocks, and hypertension. Cardiovascular risk stratification should be done before initiation of SMDs. Although the risk of cardiovascular events in patients with IBD on SMDs appears to be low overall, caution should still be taken in certain scenarios.

Sphingosine 1-phosphate receptor modulators in multiple sclerosis treatment: A practical review.

Four sphingosine 1-phosphate (S1P) receptor modulators (fingolimod, ozanimod, ponesimod, and siponimod) are approved by the US Food and Drug Administration for the treatment of multiple sclerosis. This review summarizes efficacy and safety data on these S1P receptor modulators, with an emphasis on similarities and differences. Efficacy data from the pivotal clinical trials are generally similar for the four agents. However, because no head-to-head clinical studies were conducted, direct efficacy comparisons cannot be made. Based on the adverse event profile of S1P receptor modulators, continued and regular monitoring of patients during treatment will be instructive. Notably, the authors recommend paying attention to the cardiac monitoring guidelines for these drugs, and when indicated screening for macular edema and cutaneous malignancies before starting treatment. To obtain the best outcome, clinicians should choose the drug based on disease type, history, and concomitant medications for each patient. Real-world data should help to determine whether there are meaningful differences in efficacy or side effects between these agents.

Safety, Pharmacokinetics, and Pharmacodynamics of Etrasimod: Single and Multiple Ascending Dose Studies in Healthy Adults.

Etrasimod is an investigational, once-daily, oral, selective sphingosine 1-phosphate receptor 1,4,5 modulator in development for immune-mediated inflammatory diseases (IMIDs). Here, we report the human safety, pharmacokinetics, and pharmacodynamics of etrasimod obtained from both a single ascending dose (SAD; 0.1-5 mg) study and a multiple ascending dose (MAD; 0.35-3 mg once daily) study. Overall, 99 healthy volunteers (SAD n = 40, MAD n = 59) completed the 2 studies. Evaluated single and multiple doses were well tolerated up to 3 mg without severe adverse events (AEs). Gastrointestinal disorders were the most common etrasimod-related AEs. Over the evaluated single- and multiple-dose ranges, dose-proportional and marginally greater-than-dose-proportional etrasimod plasma exposure were observed, respectively. At steady state, etrasimod oral clearance and half-life mean values ranged from 1.0 to 1.2 L/h and 29.7 to 36.4 hours, respectively. Dose-dependent total peripheral lymphocyte reductions occurred following etrasimod single and multiple dosing. Etrasimod multiple dosing resulted in reductions from baseline in total lymphocyte counts ranging from 41.1% to 68.8% after 21 days. Lymphocyte counts returned to normal range within 7 days following treatment discontinuation. Heart rate lowering from pretreatment baseline on etrasimod dosing was typically mild, with mean reductions seen after the first dose of up to 19.5 bpm (5 mg dose). The favorable safety, pharmacokinetic, and pharmacodynamic properties of etrasimod in humans supported its further development and warranted its investigation for treatment of IMIDs.

Ozanimod: A First-in-Class Sphingosine 1-Phosphate Receptor Modulator for the Treatment of Ulcerative Colitis.

OBJECTIVE: To review the pharmacological and clinical profile of ozanimod in the treatment of ulcerative colitis (UC). DATA SOURCES: A PubMed search was conducted from inception to July 2021 using the keywords ozanimod, ulcerative colitis, and sphingosine 1-phosphate receptor modulator. Information was also extracted from published abstracts and the package insert. STUDY SELECTION AND DATA EXTRACTION: Phase 2 and 3 studies and relevant literature on ozanimod pharmacological and clinical profiles were reviewed. DATA SYNTHESIS: Ozanimod approval was based on True North, a phase 3 trial evaluating ozanimod's efficacy and safety in the treatment of moderate to severe UC. Compared with placebo, ozanimod led to clinical remission in a significantly higher proportion of patients in both the induction and maintenance phase. Additionally, for secondary end points of clinical response, endoscopic improvement, corticosteroid-free remission, and mucosal healing, ozanimod performed significantly better than placebo. Common adverse events included infections, headaches, hypertension, bradycardia, and liver enzyme elevations. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Ozanimod is the first sphingosine 1-phosphate modulator to be approved for UC and is administered orally. Its efficacy profile is comparable with other UC medications. However, its safety profile is unique, requiring extensive assessments prior to initiation of and during treatment. Thus, it is unclear how ozanimod will be positioned in UC treatment. CONCLUSION: Ozanimod is another option in the growing arsenal of UC treatment. Although it offers a novel mechanism of action and is administered orally, there are important safety, dosing, and pharmacokinetic factors to consider prior to initiation and use.

Risk for Cardiovascular Adverse Events Associated With Sphingosine-1-Phosphate Receptor Modulators in Patients With Multiple Sclerosis: Insights From a Pooled Analysis of 15 Randomised Controlled Trials.

Background: All agents engaging sphongosine-1-phospate receptors (S1PRs) will have some cardiovascular effect. This study aimed to elucidate the risk of cardiovascular adverse events (AEs) in patients with multiple sclerosis (MS) treated with S1PR modulators (S1PRMs). Methods: We systematically searched the PubMed, EMBASE, and Cochrane Library databases for randomised controlled trials (RCTs) published through January 5, 2021. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated using the random-effects model. Sensitivity analyses and meta-regression were performed. Results: Seventeen RCTs (12 for fingolimod; 3 for ozanimod; 2 for siponimod) involving 13,295 patients were included. Compared with the control treatment, S1PRMs significantly increased the risk of cardiovascular AEs (RR, 2.21; 95% CI, 1.58-3.10; I2, 75.6%). Notably, the high-risk cardiovascular AEs associated with S1PRMs were primarily bradyarrhythmia (RR, 2.92; 95% CI, 1.91-4.46; I2, 30.8%) and hypertension (RR, 2.00; 95% CI, 1.49-2.67; I2, 56.5%). Subgroup analysis results were consistent with the primary outcomes except that ozanimod was associated with a higher risk of hypertension only (RR, 1.76; 95% CI, 1.10-2.82; I2, 0.0%), while siponimod was associated with a higher risk of bradyarrhythmia only (RR, 2.75; 95% CI, 1.75-4.31; I2, 0.0%). No significant inter-subgroup differences were observed (Pinteraction > 0.05). Conclusions: S1PRM use increased the risk of cardiovascular AEs by 1.21 times in patients with MS, and increased risks for bradyarrhythmia and hypertension were at 2.92- and 2.00-fold, respectively. These findings can help clinicians assess the risk of cardiovascular AEs in patients treated with S1PRMs. Systematic Review Registration: The PROSPERO ID is CRD42020183215.

Ozanimod as Induction and Maintenance Therapy for Ulcerative Colitis.

BACKGROUND: Ozanimod, a selective sphingosine-1-phosphate receptor modulator, is under investigation for the treatment of inflammatory bowel disease. METHODS: We conducted a phase 3, multicenter, randomized, double-blind, placebo-controlled trial of ozanimod as induction and maintenance therapy in patients with moderately to severely active ulcerative colitis. In the 10-week induction period, patients in cohort 1 were assigned to receive oral ozanimod hydrochloride at a dose of 1 mg (equivalent to 0.92 mg of ozanimod) or placebo once daily in a double-blind manner, and patients in cohort 2 received open-label ozanimod at the same daily dose. At 10 weeks, patients with a clinical response to ozanimod in either cohort underwent randomization again to receive double-blind ozanimod or placebo for the maintenance period (through week 52). The primary end point for both periods was the percentage of patients with clinical remission, as assessed with the three-component Mayo score. Key secondary clinical, endoscopic, and histologic end points were evaluated with the use of ranked, hierarchical testing. Safety was also assessed. RESULTS: In the induction period, 645 patients were included in cohort 1 and 367 in cohort 2; a total of 457 patients were included in the maintenance period. The incidence of clinical remission was significantly higher among patients who received ozanimod than among those who received placebo during both induction (18.4% vs. 6.0%, P<0.001) and maintenance (37.0% vs. 18.5% [among patients with a response at week 10], P<0.001). The incidence of clinical response was also significantly higher with ozanimod than with placebo during induction (47.8% vs. 25.9%, P<0.001) and maintenance (60.0% vs. 41.0%, P<0.001). All other key secondary end points were significantly improved with ozanimod as compared with placebo in both periods. The incidence of infection (of any severity) with ozanimod was similar to that with placebo during induction and higher than that with placebo during maintenance. Serious infection occurred in less than 2% of the patients in each group during the 52-week trial. Elevated liver aminotransferase levels were more common with ozanimod. CONCLUSIONS: Ozanimod was more effective than placebo as induction and maintenance therapy in patients with moderately to severely active ulcerative colitis. (Funded by Bristol Myers Squibb; True North ClinicalTrials.gov number, NCT02435992.).

An Overview of the Efficacy and Safety of Ozanimod for the Treatment of Relapsing Multiple Sclerosis.

Multiple sclerosis (MS) is a complex disease of the central nervous system that can cause permanent disability in young adults. A large armamentarium is available for its management and is increasing over time. Ozanimod is an oral drug belonging to the sphingosine-1-phosphate receptor (S1PR) modulator family recently approved in different countries for MS with active disease. It selectively modulates S1PR1 and S1PR5 to prevent autoreactive lymphocytes from entering the central nervous system (CNS), where they can determine inflammation and neurodegeneration. Ozanimod was tested in one Phase II and two Phase III pivotal trials and was shown to be effective and well tolerated. Moreover, further investigations, including comparative trials with other S1P modulators and MS disease-modifying drugs, are needed to better define placement in MS treatment. Furthermore, ozanimod is currently under evaluation for inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, in international phase III studies. This article retraces the itinerary leading to the approval of ozanimod for MS treatment and its peculiarities and potentiality inside the S1PR modulator family.

Concentration-QTc Modeling of Ozanimod's Major Active Metabolites in Adult Healthy Subjects.

Ozanimod, approved by regulatory agencies in multiple countries for the treatment of adults with relapsing multiple sclerosis, is a sphingosine 1-phosphate (S1P) receptor modulator, which binds with high affinity selectively to S1P receptor subtypes 1 and 5. The relationships between plasma concentrations of ozanimod and its major active metabolites, CC112273 and CC1084037, and the QTc interval (C-QTc) from a phase I multiple-dose study in healthy subjects were analyzed using nonlinear mixed effects modeling. QTc was modeled linearly as the sum of a sex-related fixed effect, baseline, and concentration-related random effects that incorporated interindividual and residual variability. Common linear, power, and maximum effect (Emax ) functions were assessed for characterizing the relationship of QTc with concentrations. Model goodness-of-fit and performance were evaluated by standard diagnostic tools, including a visual predictive check. The placebo-corrected change from baseline in QTc (ΔΔQTc) was estimated based on the developed C-QTc model using a nonparametric bootstrapping approach. QTc was better derived using a study-specific population formula (QTcP). Among the investigated functions, an Emax function most adequately described the relationship of QTcP with concentrations. Separate models for individual analytes characterized the C-QTcP relationship better than combined analytes models. Attributing QT prolongation independently to CC1084037 or CC112273, the upper bound of the 95% confidence interval of the predicted ΔΔQTcP was ~ 4 msec at the plateau of the Emax curves. Therefore, ΔΔQTcP is predicted to remain below 10 msec at the supratherapeutic concentrations of the major active metabolites.

Siponimod: A Review in Secondary Progressive Multiple Sclerosis.

Oral siponimod (Mayzent®), a next-generation, selective sphingosine 1-phosphate receptor (S1PR) 1 and 5 modulator, is approved in several countries for the treatment of secondary progressive multiple sclerosis (SPMS), with specific indications varying between individual countries. In the pivotal EXPAND trial (median duration double-blind treatment 18 months) in a broad spectrum of patients with SPMS, once-daily oral siponimod 2 mg (initial dose titration over 6 days) was significantly more effective than placebo in reducing clinical and MRI-defined outcomes of disease activity and disability progression, including 3-month confirmed disability progression on the Expanded Disability Status Scale (EDSS), and was generally well tolerated in the core phase of the study. These beneficial effects of siponimod appeared to be sustained during up to 5 years of treatment in the ongoing open-label extension phase of EXPAND. The safety profile of siponimod is similar to that of other agents in its class, including adverse events of special interest (i.e. those known to be associated with S1PR modulators). No new safety signals were identified during up to 5 years' treatment in the open-label extension phase. Albeit further long-term efficacy and safety data from the real-world setting are required to fully define its role, given the paucity of current treatment options and its convenient dosage regimen, siponimod represents an important emerging option for the treatment of adult patients with SPMS with active disease evidenced by relapses or imaging-features of inflammatory activity.

Ponesimod for the treatment of relapsing multiple sclerosis.

INTRODUCTION: Multiple Sclerosis (MS) is an immune-mediated, complex, chronic inflammatory, and neurodegenerative disease of the central nervous system. Among the several therapeutic options developed over the last decade for relapsing MS (RMS), fingolimod, a sphingosine 1-phosphate receptor (S1PR) modulator, was the first oral treatment. The adverse events associated with fingolimod have limited its use in certain populations, thus further stimulating the search for other S1PR modulators. AREAS COVERED: The authors reviewed the English-published literature on ponesimod using the PubMed database. The search terms used were 'ponesimod' or 'ACT-128,800' and 'multiple sclerosis.' Available data on the pharmacological profile of ponesimod and the information on clinical efficacy and safety drawn from clinical trials in comparison with other S1PR modulators are presented and discussed. EXPERT OPINION: Published peer-reviewed data on long-term safety and efficacy are still lacking but have been collected and regulatory authorities expressed a favorable opinion to market access. At present, we believe that ponesimod has little chance of becoming a leading treatment for RMS due to the availability of many alternative options and the timing of market access. Given its favorable risk-benefit and convenience profile, however, ponesimod might become a leading option among S1P receptor modulators used for RMS.

Ozanimod induction therapy for patients with moderate to severe Crohn's disease: a single-arm, phase 2, prospective observer-blinded endpoint study.

BACKGROUND: Although treatment of Crohn's disease has improved with development of tumour necrosis factor antagonists, fewer than 50% of patients have sustained benefit. Durable maintenance therapy with orally administered alternative treatments remains an unmet need. We aimed to evaluate the effects of ozanimod, an oral agent selectively targeting sphingosine-1-phosphate receptor subtypes 1 and 5, on endoscopic disease activity in Crohn's disease. METHODS: STEPSTONE was a phase 2, uncontrolled, multicentre trial in adults with moderately to severely active Crohn's disease recruited at 28 hospital and community research centres in Canada, the USA, Hungary, Poland, and Ukraine. All patients began treatment with a 7-day dose escalation (4 days on ozanimod 0·25 mg daily followed by 3 days at 0·5 mg daily). Patients then received ozanimod 1·0 mg oral capsule daily for a further 11 weeks, for a 12-week induction period, followed by a 100-week extension. The primary endpoint was change in Simple Endoscopic Score for Crohn's Disease (SES-CD) from baseline to week 12, as determined by a blinded central reader. Data are reported for the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT02531113 and EudraCT, number 2015-002025-19, and is completed. FINDINGS: 69 patients were enrolled between Nov 17, 2015, and Aug 18, 2016. At week 12, the mean change from baseline in SES-CD was -2·2 (SD 6·0); 16 (23·2%, 95% CI 13·9-34·9) patients experienced endoscopic response. A reduction from baseline in Crohn's Disease Activity Index (CDAI) score also was observed (mean change -130·4 [SD 103·9]). Clinical remission (CDAI <150 points) was shown in 27 (39·1%, 95% CI 27·6-51·6) patients and response (CDAI decrease from baseline ≥100) in 39 (56·5%, 95% CI 44·0-68·4) of patients. The mean change from baseline in two-item patient-reported outcome (PRO2, stool frequency, abdominal pain scores) score was -66·1 (SD 65·4). Mean change from baseline in Geboes Histology Activity Score (GHAS) was -5·9 (SD 11·0) and in Robart's Histopathology Index (RHI) -10·6 (25·1). Adverse events were most frequently those attributed to Crohn's disease, most commonly Crohn's disease (flare) in 18 (26%) patients. The most commonly reported serious treatment-related adverse events were Crohn's disease (six [9%]) and abdominal abscess (two [3%]). INTERPRETATION: Endoscopic, histological, and clinical improvements were seen within 12 weeks of initiating ozanimod therapy in patients with moderately to severely active Crohn's disease. Phase 3 placebo-controlled trials have been initiated. FUNDING: Celgene Corporation.