Clinical outcome and pharmacokinetics after addition of low-dose cyclosporine to methotrexate: a case study of five patients with treatment-resistant inflammatory bowel disease.

Introduction: This study reports the clinical outcome, toxicity, and methotrexate pharmacokinetics after the addition of low-dose cyclosporine to methotrexate in patients with ulcerative colitis or Crohn's disease.

Methods: Three patients with steroid-refractory ulcerative colitis and two patients with steroid refractory Crohn's disease who failed monotherapy with subcutaneous methotrexate 25 mg/week for 16 weeks were treated with the combination of methotrexate and low-dose oral cyclosporine (3 mg/kg/day) for an additional 16 weeks. Clinical response was measured with the Inflammatory Bowel Disease Questionnaire (IBDQ) score. Concentrations of erythrocyte methotrexate, plasma methotrexate, and plasma 7-hydroxymethotrexate were also determined.

Results: Both patients with Crohn's disease withdrew from the study for toxicity (headaches, seizure). The three patients with ulcerative colitis experienced clinical improvement with a mean increase in the IBDQ score from 164 to 190 points, p = 0.01. The mean serum creatinine in the three patients who completed the study increased from 0.9 mg/dL at baseline to 1.2 mg/dL at week 16. p = 0.04. One patient developed hypertension. There was no significant change from baseline in the concentrations of erythrocyte methotrexate, plasma methotrexate, and plasma 7-hydroxymethotrexate.

Conclusions: Combination therapy with methotrexate and low-dose oral cyclosporine did not alter methotrexate pharmacokinetics and resulted in high rates of cyclosporine-associated toxicity.