Background: Therapeutic drug monitoring (TDM) of anti-TNF in patients with inflammatory bowel disease (IBD) is an innovative practice used to support clinical decisions. First data on its usefulness in clinical practice has been obtained by Centres with much-experienced IBD-focused professionals. Is it possible that TDM might be more useful for decision making to less-experienced more-generalist GIs? To address this question we aimed to: a) determine concordance between foreseen selected treatment decision by physician's criteria and that selected according to TDM in two hospitals with different degree of experience on IBD; b) patient's clinical evolution according to the TDM-based management.
Methods: A prospective multicentre study (in two hospitals A and B) for a period of one year in patients with Crohn's disease (CD) or ulcerative colitis (UC) under treatment with infliximab or adalimumab and which need to modify their treatment.
It has been defined a different degree of experience (A more/B less) based on: a) years of clinical experience on IBD by involved professionals (A >10/B <10), counting on a specific IBD Unit (A Yes/B No) and number of patients visited on each centre (A 83/B 35).
The assessed variables were: drug levels plus anti-drug antibodies in blood, Harvey-Bradshaw index [HB≥5 active disease (AD), <5 clinical remission (CR)] and simple clinical colitis activity index (≥3 AD and <3 CR) at T0 (before treatment modification) and T1 (at six months)
Results: 34 patients, 50% men, 26 with CD and 8 with UC. Mean age: 48,8 years. Mean duration of anti-TNF treatment: 44,6 months.
Concordance between regimen selected according physician's criteria and that selected after TDM was 74% at hospital A vs 54% at hospital B.
In 32% (11/34) of the cases there was not any concordance between physician's criteria and TDM. According to levels based management, the following decisions were taken:
Intensification or switch (6/11): AD 100% at T0 – 50% at T1; CR 0% at T0 – 50% at T1.
De-escalation o maintenance (5/11): AD 20% at T0 – 20% at T1; CR 80% at T0 – 80% at T1.
In 68% (23/34) of the remaining cases (with concordance):
Intensification or switch (5/23): AD 80% at T0 – 40% at T1; CR 20% at T0 – 60% at T1
De-escalation, maintenance or cession (18/23): AD 11% at T0 – 11% at T1; CR 89% at T0 – 89% at T1.
Conclusions: Determination of anti-TNF drug levels in patients with IBD can improve the effectiveness of those treatments by helping on physician's decision making. It looks TDM is an especially useful tool for hospitals with lower degree of experience on IBD.
More studies should take into consideration TDM use on clinical practice in hospitals with less experienced GIs that actually accounts for a high rate of the real-life clinical practice on IBD throughout Europe.