Elevated aminotransferases during treatment with interferon-beta for multiple sclerosis: actions and outcomes.

The authors report further analysis of a six-year retrospective chart review of multiple sclerosis (MS) patients prescribed interferon-beta (IFNB) in British Columbia, Canada. Actions and outcomes taken when 284/835 (34%) of the patients developed de novo elevated aminotransferases are presented; 239/284 (84%) of patients were continued on treatment despite these elevations; 216/246 (88%) of patients reaching grade 1 toxicity (greater than the upper limit of normal) continued IFNB treatment; of these, 167/216 (77%) returned to within normal limits. Of the 22/29 (76%) reaching grade 2 toxicity (> 2.5 times the upper limit of normal) and continuing treatment, 14/22 (64%) returned to within the normal range. One of the nine patients reaching grade 3 toxicity ( > 5 times the upper limit of normal) was allowed continue treatment and their aminotransferase levels returned to within normal limits. However, one patient reaching grade 3 toxicity went on to develop liver failure (previously reported).