Pfizer’s Xeljanz to enhance MMA was approved in March. Earlier in March, the FDA approved Rebif, made by Biogen, to enhance NHL. Both were approved for patients at high risk of developing an ulcerative colitis (UC) within three years. And they can be made available without the need for a costly biopsy test.

The U.S. Food and Drug Administration said it will offer new guidance for physicians prescribing experimental treatment to patients already at high risk of developing ulcerative colitis (UC).

The agency said in a statement on Monday that it’s working on the guidance following “intensive discussions with key experts” in clinical research and developing new medicines to treat inflammatory bowel disease (IBD).

In late March, Pfizer said it would halt enrollment in a so-called safety monitoring board study of Xeljanz after warnings about a discontinuation rate in hospitalized patients.

In late March, the FDA approved three new medicines, including one called Xeljanz which is an oral medication designed to help increase the activity of anti-inflammatory drugs. All three therapies were developed using cells genetically engineered to increase activity in specific parts of the immune system.

The three drugs, Pfizer said last month, have the potential to treat more than 130 million patients in more than 50 countries, with more than 150 million of those patients at high risk of developing ulcerative colitis.