UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange act of 1934

Date of report (date of earliest event reported): February 21, 2015

RECEPTOS, INC.

(Exact name of registrant as specified in its charter)

3033 Science Park Road, Suite 300

San Diego, California 92121

(858) 652-5700

(Address, including zip code, and telephone number, including

area code, of registrant’s principal executive offices)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On February 21, 2015, Receptos, Inc. (the “Company”) reviewed in further detail the data from the induction period of its TOUCHSTONE trial, the Company’s Phase 2 study of ozanimod (RPC1063) in Ulcerative Colitis, in a presentation at a meeting of the European Crohn’s and Colitis Organization in Barcelona, Spain. The slides used at the presentation are furnished as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference. The Company does not undertake to update this presentation.

(d) Exhibits.

The information in this Current Report on Form 8-K, including the information contained in Exhibit 99.1, is being furnished to the Securities and Exchange Commission pursuant to Item 7.01 and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Exchange Act, except as shall be expressly set forth by a specific reference in such filing.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX

A Randomized, Double-Blind, Placebo-Controlled Induction Trial of an Oral S1P Receptor Modulator Ozanimod (RPC1063) in Moderate to Severe Ulcerative Colitis: Results of the TOUCHSTONE Study William Sandborn, MD 21 February 2015 Barcelona, Spain W. Sandborn¹, B. Feagan², D. Wolf³, G. D'Haens 4 , S. Vermeire 5 , S. Hanauer 6 , S. Ghosh 7 , H. Smith 8 , M. Cravets 8 , P. Frohna 8 , S. Gujrathi 8 , A. Olson 8 1 University of California San Diego, Division of Gastroenterology, La Jolla, United States 2 University of Western Ontario, Department of Gastroenterology, London, Canada 3 Atlanta Gastroenterology Associates, Emory Saint Joseph's, Atlanta, United States 4 Academic Medical Centre, Inflammatory Bowel Disease Centre, Amsterdam, Netherlands 5 University Hospital Leuven, Department of Gastroenterology, Leuven, Belgium 6 Northwestern University Feinberg School of Medicine, Digestive Health Center, Chicago, United States 7 University of Calgary, Department of Gastroenterology, Alberta, Canada 8 Receptos, Inc., Clinical Development, San Diego, United States Exhibit 99.1

Conflict of Interest Statements • W Sandborn- Financial support for research: Receptos, Jansen, Abbvie, Prometheus Laboratories, Pfizer, Amgen, Genentech, Takeda. Consultancy: Receptos, Jansen, Abbvie, UCB Pharma, Shire, Salix, Actavis, Prometheus Laboratories, Pfizer, Amgen, Genentech, Takeda • B Feagan- Consultancy: AbbVie, Actogenix, Albireo, Amgen, AstraZeneca, Avaxia Biologics, Baxter, Biogen Idec, Boehringer-Ingelheim, BMS, Calypso, Celgene, Elan, EnGene, Ferring Pharma, Roche/Genentech, GiCare, Gilead, Given Imaging, GSK, Ironwood, Janssen, JnJ, Lexicon, Lilly, Merck, Millennium, Nektar, Novonordisk, Pfizer, Prometheus, Protagonist, Receptos, Sanofi, UCB. Directorship: Robarts Clinical Trials • D Wolf- Financial support for research: AbbVie, Amgen, Elan, Given Imaging, Genentech, Janssen, Millennium, Pfizer, Prometheus, Receptos, UCB. Lecture fees: AbbVie, Janssen, Prometheus, Santarus, Salix, Takeda, UCB. Consultancy: AbbVie, Genentech, Given Imaging, Janssen, Prometheus, Salix, Takeda, UCB • G D’Haens- Consultancy: Abbvie, Ablynx, Actogenix, Amgen, AM Pharma, AstraZeneca, Boerhinger Ingelheim, Cosmo, Elan, Ferring, DrFALK Pharma, Celgene, Celltrion, Janssen, Engene, Galapagos, Giuliani, GivenImaging, GSK, Hospira, Takeda, Mitsubishi Pharma, MSD, Mundipharma, Novonordisk, Norgine, Otsuka, Pfizer, Photopill, PDL, Prometheus, Receptos, Robarts, Salix, Sandoz, Setpoint, Shire, TEVA, Tigenix, Tillotts, UCB, Versant, Vifor • S Vermeire- Financial support for research: Abbvie, MSD, Centocor. Consultancy: Abbvie, MSD, Takeda, Pfizer, Genentech/Roche,Ferring, Mundipharma, Receptos • S Hanauer- Consultancy: Receptos, AbbVie, Janssen, UCB, Shire, Actavis, Salix, BMS, Merck, Pfizer, Boehringer-Ingelheim, Sanofi-Aventis, Ferring, Celgene, Caremark • S Ghosh- Financial support for research: Abbvie. Lecture fees: Abbvie, MSD. Consultancy: Pfizer, Novo Nordisk BMS , Janssen, Abbvie, Receptos • H Smith, M Cravets, P Frohna, S Gujrathi, and A Olson are full-time employees of Receptos

• S1P 1R signaling on CCR7+ lymphocytes (central memory T cells) facilitate their exit from lymph nodes  along an S1P gradient • Ozanimod induces S1P 1R internalization so lymphocytes do not respond to S1P and are retained in the lymph node • Protective immunity is generally preserved since CCR7- lymphocytes (effector memory T cells) do not circulate through the lymph nodes S1P 1R Modulation Results in Sequestration of Select Lymphocyte Subsets

S1P 1R Modulators • Fingolimod is the first S1P receptor modulator (S1P 1,3,4,5R ) and oral agent approved in 2010 for the treatment of Relapsing Multiple Sclerosis (RMS) • Well established efficacy and safety profile • Over 100,000 patients have been treated with Fingolimod • No increase in serious infections, opportunistic infections, TB, PML or malignancies over time • Warnings and Precautions include first dose cardiac effects (HR reduction and cardiac conduction abnormalities), LFT elevations, and macular edema • Ozanimod (RPC1063) is a next generation oral S1P receptor modulator • Increased selectivity for the S1P 1R and S1P 5R • Improved pharmaceutic properties that allow for enhanced tissue penetration and faster clearance • Demonstrated efficacy in a Phase 2 trial in RMS patients • Clinical trial experience to date has demonstrated an improved cardiovascular profile, reduced LFT elevations, no macular edema and rapid lymphocyte recovery

Patient Population: Key Inclusion/Exclusion Criteria • Inclusion: • Adults with moderate to severe UC defined by a Mayo score of 6- 12 inclusive with endoscopic subscore 2 by central read • Receiving treatment with oral aminosalicylates and/or prednisone • Patients were allowed to receive MTX, 6-MP or AZA until the day of dosing with Ozanimod • Exclusion: • Treatment with biologics within 5 half-lives • History of clinically relevant cardiovascular disease • Resting heart rate 55 bpm

Study Design Induction Period Maintenance Period Randomization Placebo (N=65) Ozanimod 0.5 mg (N=65) Ozanimod 1 mg (N=67) Mayo Responders Open-Label Primary Endpoint: Induction Disease Relapse Week 32 Maintenance Endpoint 1 Week Dose Titration 8 Weeks Treatment 24 Weeks Treatment • Conducted at 57 sites in 13 countries • Induction period completion rate: 95%

Study Endpoints and Methods • Primary Efficacy Endpoint • Proportion of patients in clinical remission at Week 8, defined as a Mayo score 2 points with no subscore > 1 point • Key Secondary Efficacy Endpoints • Proportion of patients with clinical response at Week 8 • Change from Baseline in Mayo score at Week 8 • Proportion of patients with mucosal improvement/mucosal healing (endoscopic subscore 1) • Methods • All endoscopies were read centrally by a blinded evaluator for both eligibility confirmation and endpoint scoring • Subjects with different central and local endoscopic sub- scores had an additional central read and adjudication

Patient Demographics and UC Disease History Placebo (N=65) Ozanimod 0.5 mg (N=65) Ozanimod 1 mg (N=67) Demographics Male – n (%) 35 (53.8) 32 (49.2) 48 (71.6) Age (years) – mean (SD) 41.9 (12.3) 38.8 (12.1) 41.8 (11.0) UC Disease History Years since UC diagnosis – mean (SD) 6.1 (5.5) 5.9 (5.4) 6.7 (6.8) Mayo Score by central read – mean (SD) 8.6 (1.5) 8.3 (1.5) 8.5 (1.6) Prior anti-TNF medication – n (%) 10 (15.4) 12 (18.5) 15 (22.4) Prior use of AZA/6-MP/MTX – n (%) 17 (26.2) 24 (36.9) 22 (32.8) Baseline use of corticosteroids – n (%) 23 (35.4) 22 (33.8) 26 (38.8)

1° Endpoint: Proportion of Patients in Remission at Week 8 (Adjudicated Central Read) p = 0.1422 p = 0.0482 6.2% 13.8% 16.4% 0% 5% 10% 15% 20% Treatment Group Placebo (N=65) Ozanimod 0.5 mg (N=65) Ozanimod 1 mg (N=67)

p = 0.0698 p = 0.0114 p = 0.1422 p = 0.0482 Comparison of 1° Endpoint: Original Central Read vs. Adjudicated Central Read 4.6% 6.2% 13.8% 13.8% 17.9% 16.4% 0% 5% 10% 15% 20% Original Central Read Adjudicated Central Read Placebo (N=65) Ozanimod 0.5 mg (N=65) Ozanimod 1 mg (N=67)

2° Endpoint: Proportion of Patients in Clinical Response at Week 8 (Adjudicated Central Read) p = 0.0648 p = 0.0140 36.9% 53.8% 58.2% 0% 10% 20% 30% 40% 50% 60% 70% Treatment Group Placebo (N=65) Ozanimod 0.5 mg (N=65) Ozanimod 1 mg (N=67)

2° Endpoint: Proportion of Patients With Mucosal Improvement/Mucosal Healing (Endoscopy score of 1 at Week 8, Adjudicated Central Read) p = 0.0348 p = 0.0023 12.3% 27.7% 34.3% 0% 10% 20% 30% 40% Treatment Group Placebo (N=65) Ozanimod 0.5 mg (N=65) Ozanimod 1 mg (N=67)

Safety: Treatment Emergent Adverse Events Number of Subjects Placebo (N=65) Ozanimod 0.5 mg (N=65) Ozanimod 1 mg (N=67) 1 TEAE 22 (33.8) 23 (35.4) 19 (28.4) Most Common TEAEs Placebo Ozanimod 0.5 mg Ozanimod 1 mg Anemia / Decreased HgB 4 (6.2) 4 (4.6) 0 Worsening of UC 3 (4.6) 2 (3.1) 1 (1.5) Serious TEAEs Placebo Ozanimod 0.5 mg Ozanimod 1 mg Number of Subjects with 1 Serious TEAE 4 (6.2) 1 (1.5) 1 (1.5) Colitis ulcerative 2 (3.1) 0 1 (1.5) Hyperpyrexia 0 1 (1.5) 0 Iron deficiency anemia 1 (1.5) 0 0 Jaundice (due to cholestasis) 1 (1.5) 0 0

No notable cardiac, ophthalmologic, or infectious TEAEs observed 24-hr Holter Monitoring Findings Placebo (n=65) Ozanimod 0.25 mg (n=132) Subjects with 2 Degree AVB 0 0 Subjects with Sinus Pause 0 0 Safety: Holter Monitoring and Transaminase Elevations ALT elevation > 3xULN Placebo (n=65) Ozanimod 0.5 mg (n=65) Ozanimod 1 mg (n=67) ALT elevation 0 2 (3.1) 1 (1.6) ALT elevations were asymptomatic, transient, not associated with elevations in bilirubin and improved while receiving Ozanimod nd

Conclusions • Ozanimod 1 mg induced clinical remission at Week 8 (1 ° EP) • All 3 secondary endpoints were met for Ozanimod 1 mg at Week 8 • Proportion of patients with a clinical response • Change from baseline in Mayo score • Proportion of patients with mucosal improvement • A dose response relationship was observed for all primary and key secondary efficacy endpoints • Ozanimod was well tolerated with a favorable benefit-risk profile