Clinical Features and HLA Association of 5-Aminosalicylate (5-ASA)-induced Nephrotoxicity in Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Nephrotoxicity is a rare idiosyncratic reaction to 5-aminosalicylate (5-ASA) therapies. The aims of this study were to describe the clinical features of this complication and identify clinically useful genetic markers so that these drugs can be avoided or so that monitoring can be intensified in high-risk patients. METHODS: Inflammatory bowel disease patients were recruited from 89 sites around the world. Inclusion criteria included normal renal function prior to commencing 5-ASA, ≥50% rise in creatinine any time after starting 5-ASA, and physician opinion implicating 5-ASA strong enough to justify drug withdrawal. An adjudication panel identified definite and probable cases from structured case report forms. A genome-wide association study was then undertaken with these cases and 4109 disease controls. RESULTS: After adjudication, 151 cases of 5-ASA-induced nephrotoxicity were identified. Sixty-eight percent of cases were males, with nephrotoxicity occurring at a median age of 39.4 years (range 6-79 years). The median time for development of renal injury after commencing 5-ASA was 3.0 years (95% confidence interval [CI] 2.3-3.7). Only 30% of cases recovered completely after drug withdrawal, with 15 patients requiring permanent renal replacement therapy. A genome-wide association study identified a suggestive association in the HLA region (p = 1×10(-7)) with 5-ASA-induced nephrotoxicity. A sub-group analysis of patients who had a renal biopsy demonstrating interstitial nephritis (n = 55) significantly strengthened this association (p = 4×10(-9), odds ratio 3.1). CONCLUSIONS: This is the largest and most detailed study of 5-ASA-induced nephrotoxicity to date. It highlights the morbidity associated with this condition and identifies for the first time a significant genetic predisposition to drug-induced renal injury.

Ulcerative colitis patients with an inflammatory response upon mesalazine cannot be desensitized: a randomized study.

BACKGROUND AND AIMS: Mesalazine is a key drug in the treatment of ulcerative colitis (UC). Intolerance to mesalazine has been described, including fever and gastrointestinal symptoms. Several case reports reported successful desensitization of patients with mesalazine intolerance. The aim was to assess the number of UC patients who are persistently intolerant to mesalazine after single-blinded rechallenge and to test the effectiveness of a rapid desensitization protocol in UC patients demonstrated mesalazine intolerance. METHODS: This is a prospective, single-blind randomized study in UC patients who discontinued mesalazine because of intolerance. Patients with severe reactions were excluded. Eligible patients underwent a skin patch test with mesalazine followed by a single-blinded randomized crossover rechallenge with 500 mg mesalazine or placebo. Patients with symptoms upon rechallenge were admitted to the hospital for 3 days oral desensitization. RESULTS: Nine of the 37 identified UC patients who discontinued mesalazine because of intolerance were included. All nine patients had negative patch tests, seven patients had symptoms (fever, nausea, vomiting and diarrhea) within 2 h upon rechallenge. Four of these seven patients participated in the desensitization protocol and in none a successful desensitization could be performed. All four had an inflammatory intolerance reaction with rise in C-reactive protein. There were no elevations in serum tryptase or urinary-methylhistamine levels observed and no signs of immediate type allergic reactions, like urticaria, bronchial obstruction or anaphylaxis. CONCLUSION: We recommend not to rechallenge UC patients with an inflammatory response upon mesalazine and these patients will not benefit from a rapid desensitization protocol.