Intra-patient variability in adalimumab drug levels within and between cycles in Crohn's disease.

BACKGROUND: Whether therapeutic drug monitoring for adalimumab needs to be performed at trough has not been defined. AIM: To determine intra-patient adalimumab drug-level variation and to identify modulating patient and disease factors. METHODS: In this prospective observational study, adult patients with Crohn's disease established on maintenance adalimumab had drug levels measured repeatedly according to pre-defined schedules (visit 1: day 4-6, visit 2: day 7-9, trough: day 13-14) across two consecutive fortnightly cycles. Disease activity was assessed using Harvey-Bradshaw Index, C-reactive protein and faecal calprotectin. For this analysis, trough levels ≥4.9 µg/mL were considered therapeutic. RESULTS: Nineteen patients underwent 111 evaluations. Mean intra-patient drug levels from paired visits between cycles did not differ (visit1 cycle1: 4.81, cycle2: 5.21 µg/mL, P = 0.24, visit2 cycle1: 4.86, cycle2: 4.82, P = 0.91 and trough cycle1: 3.95, cycle2: 3.95, P = 0.99), irrespective of disease activity. Drug levels were stable over the first 9 days (visit 1-2), but declined to trough by a mean 1.06 and 0.89 µg/mL between visit 1 or 2, respectively (P < 0.001). Models using nontemporal factors (smoking, syringe delivery device) and levels at earlier visits accounted for 66-80% of the variance in trough levels. On receiver-operating curve analysis, thresholds identified in the first 9 days that predicted a therapeutic trough level were similar to the trough threshold itself, with high sensitivity but modest specificity. CONCLUSION: While therapeutic drug monitoring should be performed at trough, a drug level ≥4.9 µg/mL obtained during the first 9 days predicts a therapeutic trough drug level with reasonable confidence.

Compassionate access anti-tumour necrosis factor-α therapy for ulcerative colitis in Australia: the benefits to patients.

BACKGROUND: The efficacy of infliximab has been demonstrated in patients with both acute severe and moderate-severe ulcerative colitis (UC). However, there is a need for 'real-life data' to ensure that conclusions from trial settings are applicable in usual care. We therefore examined the national experience of anti-tumour necrosis factor-α (TNF-α) therapy in UC. METHODS: Case notes review of patients with UC who had received compassionate access (CA) anti-TNF-α therapy from prospectively maintained inflammatory bowel disease databases of six Australian adult teaching hospitals. RESULTS: Patients either received drug for acute severe UC (ASUC) failing steroids (n = 29) or for medically refractory UC (MRUC) (n = 35). In ASUC, the treating physicians judged that anti-TNF-α therapy was successful in 20/29 patients (69%); in these cases, anti-TNF-α was able to be discontinued (after 1-3 infusions in 19/20 responders) as clinical remission was achieved. Consistent with this perceived benefit, only 7/29 (24%) subsequently underwent colectomy during a median follow up of 12 months (interquartile range (IQR) 5-16). Eight of the 35 patients with MRUC (23%) required colectomy during a median follow up of 28 months (IQR 11-43). The majority of these patients (20/35 or 57%) had anti-TNF-α therapy for ≥4 months, whereas, 27/29 (93%) of ASUC patients had CA for ≤3 months. CONCLUSIONS: These data show an excellent overall benefit for anti-TNF-α therapy in both ASUC and MRUC. In particular, only short-duration anti-TNF-α was required in ASUC. These real-life data thus support the clinical trial data and should lead to broader use of this therapy in UC.

Dose tailoring of anti-tumour necrosis factor-alpha therapy delivers useful clinical efficacy in Crohn disease patients experiencing loss of response.

BACKGROUND: 'Dose tailoring' of anti-tumour necrosis factor alpha (TNF-α) therapy in Crohn disease (CD), by dose escalation, or shortening of dosing intervals, has been suggested to regain clinical response following a flare in a proportion of patients. However, reported outcome data are sparse and none exists from Australia. METHOD: In an observational multicentre, retrospective study, the impact of anti-TNF-α dose tailoring on corticosteroid use, the need for surgery and physician perception of clinical efficacy was examined in a real-world setting at six Australian adult teaching hospitals. Demographics, disease characteristics, medications, indication for and duration of dose tailoring were documented. RESULTS: Fifty-five CD patients were identified as requiring dose tailoring and secondary loss of response was the indication in 96%. Either adalimumab (64%) or infliximab (36%) was dose escalated for a median of 5 months (range 1-47), with a median of 20 months follow up (range 3-65). At 3 months, dose tailoring reduced the mean number of days on high-dose corticosteroids (45 vs 23, P = 0.01). Most (78%) patients remained resection free, and 73% of physicians reported good clinical efficacy of dose tailoring. Of those who de-escalated therapy due to induction of remission, long-term (>12 months) follow up and complete data on steroid use were available in 15/28, with 12/15 (80%) remaining steroid free at 1 year. CONCLUSION: Short-term dose tailoring regains disease response in the majority of patients with CD. Of these, most will remain free of corticosteroids at 1 year after de-escalating therapy.