Dosage Adjustment During Long-term Adalimumab Treatment for Crohn's Disease: Clinical Efficacy and Pharmacoeconomics

Background: Data from CHARM, a 56-week, randomized controlled trial of adalimumab for patients with moderately to severely active Crohn's disease (CD), were used to evaluate outcomes of adalimumab dosage adjustment. Methods: Patients randomized to blinded adalimumab 40 mg every other week (EOW) in CHARM were the focus of the analysis. At >12 weeks, patients with flares or lack of response versus baseline (including patients who responded and then lost response) could move sequentially to open-label (OL) adalimumab EOW and then to OL adalimumab weekly. Results: Of 260 patients randomized to adalimumab EOW, 140 (54%) continued blinded EOW therapy and 120 (46%) moved to OL therapy. Of patients on OL therapy, 49 (19%) continued EOW therapy and 71 (27%) moved to weekly therapy; 36 (14%) completed the trial on weekly therapy. Of 71 patients on weekly therapy, 37% achieved clinical remission (Crohn's Disease Activity Index [CDAI] <150), 58% achieved CR-100 (CDAI decreased >= 100 points), and 63% achieved CR-70 (CDAI decreased >= 70 points). Of the 49 patients who remained on OL EOW therapy, 39% achieved clinical remission, 59% achieved CR-100, and 63% achieved CR-70. In a logistic regression, greater baseline CDAI predicted changing to weekly therapy. A model of dosage-adjustment cost indicated a modest per-patient drug-acquisition cost increase ($574 over yearly EOW dosing cost [$22,518]). Conclusions: Of patients randomized to blinded EOW therapy, 19% moved to OL EOW therapy and 27% moved to OL weekly therapy for flares or lack of response versus baseline. Weekly therapy was associated with clear clinical benefits and a small cost increase.