The U.S. Food and Drug Administration has granted orphan drug status to INN-108 as a treatment for children with ulcerative colitis, its maker, Innovate Biopharmaceuticals, announced in a press release.

Regulators grant orphan drug designation to treatments that preliminary research indicates are better than current therapies, particularly for diseases with high unmet medical needs.

With orphan status, FDA approval of the drug would give Innovate Biopharmaceuticals seven years of exclusivity in marketing the treatment.

INN-108 is a small molecule that combines two existing drugs. The FDA has approved one of them, 5-ASA or mesalamine, as an ulcerative colitis therapy. Japan has approved the other, 4-APAA (4-aminophenylacetic acid), as a rheumatoid arthritis treatment.

At the moment, more than 80 percent of people with mild to moderate ulcerative colitis are being treated with various formulations of 5-ASA or mesalamine. 5-ASA fails to help a lot patients, however, and there are few alternatives to it besides steroids.

Some doctors try treating patients who fail the treatment with expensive biologics that suppress tumor necrosis factor, a cell signaling protein involved in inflammation. They include AbbVie’s HUMIRA and J&J’s REMICADE.

The compounds in INN-108 are joined together through a chemical bond known as an azo-bond. This bond breaks only when INN-108 enters the colon through the action of bacteria that reside in the gut.

Innovate Biopharmaceuticals said two Phase 1 clinical trials suggest that the drug combo is more effective at treating ulcerative colitis than mesalamine/5-ASA alone.

The trials demonstrated the effectiveness and safety of the drug in adults with mild to moderate ulcerative colitis. Phase 2 trials will start in 2018.

Innovate is developing a liquid oral formulation of INN-108 that will make it easier for children to take.