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Is living with ulcerative colitis or Crohn’s disease making you suffer behind the selfies?

Inflammatory bowel disease (IBD) can be life-changing with symptoms often being as controlling as they are invisible, which can leave many people hiding how they really feel.

We are looking for qualified participants with ulcerative colitis (UC) or Crohn’s disease to join one of our clinical studies investigating a potential new treatment option.*

Can I take part?

What are clinical studies?

A clinical study (also known as a clinical trial) is a research study that is designed to help answer questions about the safety of investigational medicines and to find out how well they work.

These studies must be performed, and the study results must demonstate that the investigational medicine is effective and safe for the patients it is intended for, before being approved for use in patients and sold in pharmacies.

It is important to test investigational medicines in the people they are meant to help. It is also important to conduct research in a variety of people because different people may respond differently to treatments.

Clinical study phases

In order to reach patients, every investigational medicine may make its way through three clinical study phases before being approved. It may then go through one further phase to review its long-term effects. Each phase has a different goal and separate hurdles to clear before a potential new treatment can be taken forward.

Phase 1

  • Number of participants is usually around 20-80
  • The aim is to see how safe the investigational medication is
  • Participants in Phase 1 studies are usually healthy volunteers

Phase 2

  • Usually involves 100-600 participants
  • Tests how safe the investigational medication is, as well as how effective it is, and several doses of the investigational medicine may be evaluated
  • Phase 2 studies tend to look at the effects of the investigational medicine in patients with the condition the medicine is intended to treat

Phase 3

  • Participant numbers can range from several hundred to several thousand
  • These studies aim to gather lots of data on the safety and effectiveness of an investigational medicine
  • The results of Phase 3 studies are used to request approval to market the medication

Phase 4

  • Can involve less than a hundred to thousands of participants
  • Conducted after a medication has been approved
  • Focuses on the long-term effects of the medication by monitoring it over an extended period of time or investigating the safety or effectiveness of the medicine in different patient types

The Arena IBD studies

Evaluating a potential new treatment for ulcerative colitis and Crohn’s disease

In the Arena IBD studies, etrasimod, an investigational medicine that is taken by mouth once a day, will be investigated to see whether it could help some people manage the signs and symptoms of their ulcerative colitis or Crohn's disease.


Phase 3 trials for patients with moderate-to-severe ulcerative colitis

Find out more


Phase 2 study for patients with moderately-to-severely active Crohn’s disease

Find out more

About Arena

Arena Pharmaceuticals was founded in 1997 and now operates from three locations - San Diego, California and Boston, Massachusetts in the US and Zug, Switzerland.

It is our mission to improve the lives of those suffering from IBD around the world. We know that living with IBD isn't always easy and this drives our commitment to discover new treatments and help them to become available to patients.

* This investigational medicine has been tested before in small numbers of healthy volunteers and in patients with medical conditions, including ulcerative colitis. For these studies, the investigational medicine is being tested in a larger group of patients. This investigational medicine has not been approved for commercial use for any specific condition by the United States Food and Drug Administration (FDA) or any other Health Authority. In previous Phase 2 clinical research studies with etrasimod, improvement was noted in UC symptoms and the appearance of the lining of the intestine.