Gastrointestinal adverse drug reaction profile of etanercept: real world data from patients and healthcare professionals

Abstract
Objective We aimed to describe the nature and frequency of gastrointestinal adverse drug reactions (GI-ADRs) of etanercept (ETN) using patient-reported and healthcare professional (HCP)-registered data and compared this frequency with the GI-ADR frequency of the widely used TNFα-inhibitor adalimumab.
Methods Reported GI-ADRs of ETN for rheumatic diseases were collected from the Dutch Biologic Monitor and DREAM registries. We described the clinical course of GI-ADRs and compared the frequency with adalimumab in both data sources using a Fisher’s exact test.
Results Out of 416 patients using ETN for inflammatory rheumatic diseases in the Dutch Biologic Monitor, 25 patients (6%) reported 36 GI-ADRs. In the DREAM registries 11 GI-ADRs were registered for 9 patients (2.3%), out of 399 patients using ETN, with an incidence of 7.14 per 1000 patient years. Most GI-ADRs concerned diarrhoea, nausea and abdominal pain. GI-ADRs led to ETN discontinuation in one patient (4%) and dose adjustment in four (16%) in the Dutch Biologic Monitor. Eight GI-ADRs (73%) led to ETN discontinuation in the DREAM registries. The frequency of GI-ADRs of ETN did not significantly differ from GI-ADRs of adalimumab in both data sources (Dutch Biologic Monitor: ETN 8.7% vs. ADA 5.3%, p=0.07; DREAM: ETN 2.8% vs. ADA 4.7%, p=0.16).
Conclusion Most GI-ADRs associated with ETN concerned gastrointestinal symptoms. These ADRs may lead to dose adjustment or ETN discontinuation. The frequency of ETN associated GI-ADRs was comparable to the frequency of adalimumab associated GI-ADRs. Knowledge about these previously unknown ADRs can facilitate early recognition and improve patient communication.