MS Drug Candidate Could Also Help Treat Ulcerative Colitis

January 2015

Ulcerative colitis is a form of inflammatory bowel disease characterized by chronic inflammation in the colon and rectum, and its global incidence and prevalence seem to be increasing with time. While existing medications do help some patients, 23 to 45 percent of ulcerative colitis sufferers eventually require surgical removal of all, or part of, the colon.

Scripps Research Institute Professor Hugh Rosen (above) collaborated with his colleague Professor Ed Roberts on the initial development of RPC-1063.

Now, a drug candidate discovered at Scripps Florida and developed by Scripps California Professors Hugh Rosen and Ed Roberts has shown potential to significantly improve the treatment paradigm for ulcerative colitis patients. In a Phase 2 study of the drug candidate, called RPC1063, 16.4 percent of patients taking the treatment experienced clinical remission after eight weeks, compared to 6.2 percent of those on placebo. RPC1063 had previously shown promise in treating multiple sclerosis.

“We are delighted that RPC1063 is showing promise for ulcerative colitis patients in addition to its already significant efficacy and safety data in multiple sclerosis,” said Dr. Rosen. “Research carried out at TSRI since 2002 has led to the discovery of fundamental mechanisms that can be modulated for potential treatments of a variety of autoimmune diseases, including ulcerative colitis and multiple sclerosis, and the unique multidisciplinary environment in chemistry and biology at TSRI allowed this progression to clinical trials.” The clinical trial, sponsored by Receptos, Inc., the San Diego biotechnology company now developing the drug, also showed that RPC1063 was generally well tolerated.

Ulcerative colitis is a chronic condition that involves inflammation and sores in the inner lining of the digestive tract. Along with Crohn's disease, the other main form of inflammatory bowel disease, the condition affects more than one million people nationwide, according to the U.S. Centers for Disease Control and Prevention. Some people have a mild case, while others are affected with life-threatening complications.

The drug candidate RPC1063 was derived from a screening “hit” from the National Institutes of Health molecular library at Scripps Florida's Molecular Screening Center, using assay technology from the Rosen lab in La Jolla. The Roberts and Rosen labs then developed significant medicinal chemistry to turn that hit into a validated lead and, ultimately, a drug candidate.

TSRI then licensed the compound to Receptos, which is developing RPC1063 for approval by the U.S. Food and Drug Administration.

The latest results come from Receptos's multi-national, multi-center, double-blind, randomized, placebo-controlled study, which is investigating the effect of two active doses of RPC1063 versus placebo for the treatment of moderately to severely active ulcerative colitis. In light of the current positive results, Receptos plans to initiate a Phase 3 trial of RPC1063 for ulcerative colitis, as well as a Phase 2 study of the drug candidate for Crohn's disease.

The mechanism of RPC1063 (Sphingosine 1-Phosphate Receptor modulation) may also be significant in the treatment of other autoimmune diseases. Receptos is currently evaluating the drug candidate in a Phase 3 study for the treatment of multiple sclerosis, as well.

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