Anti-infliximab antibodies in inflammatory bowel disease: prevalence, infusion reactions, immunosuppression and response, a meta-analysis

Adverse events of tumor necrosis factor inhibitors

BACKGROUND/AIMS

Adverse events in anti-TNF treatment can be divided into allergic reactions with an acute and delayed onset, infectious complications in relation to the underlying disease, and without. Last but not least, there is the unresolved question of tumor induction and propagation. All of these may account for morbidity and eventually mortality.

METHODS

Literature-based review to update current knowledge about safety and adverse events of TNF blockers.

RESULTS

Major drawbacks are infectious complications with the use of anti-TNF-α antibodies. The risk is increased in inflammatory bowel disease in general and in the perioperative setting of Crohn's disease patients. The number of tuberculosis cases has decreased since meticulous testing prior to treatment start is mandatory. An excess mortality that has been reported from referral centers is neither documented in randomized controlled trials nor in real-life settings. Regarding malignancies, lymphoma and skin cancer are a concern. The incidence of lymphoma may be raised, but this has also been debated with the use of thiopurines. Skin cancer, especially melanoma, is more common in inflammatory bowel disease and may be associated with the use of biologics. Overall, most studies do not address the influence of active inflammation or co-administration of other drugs. Hence, the risk attributable to TNF blockers alone is currently ill-defined.

CONCLUSION

Treatment with anti-TNF-α antibodies is an option with substantial risks. Most problems can be prevented by thorough workup of the patient.

Pre-existing IgG antibodies cross-reacting with the Fab region of infliximab predict efficacy and safety of infliximab therapy in inflammatory bowel disease

BACKGROUND

Infliximab (IFX) is a chimeric murine/human anti-TNF antibody (Ab) used for the treatment of Crohn's disease (CD) and ulcerative colitis (UC). Loss of response is common and associated with development of anti-IFX Abs during ongoing therapy. However, human anti-murine immunoglobulin Abs are common and may cross-react with the murine part of IFX.

AIM

To investigate if Abs binding to IFX's Fab region (IFX-Fab) are present in IBD patients before exposure to IFX, and whether they predict efficacy and safety of IFX therapy.

METHODS

Observational, retrospective cohort study of patients with CD (n = 29) and UC (n = 22).

RESULTS

Pre-treatment levels of IFX-Fab reactive IgG Abs were significantly lower in CD patients in remission after 1 year of maintenance IFX (median 91 mU/L, n = 8) than in the rest of the patients (639 mU/L, n = 21; P < 0.01), and lower than in patients with secondary loss of response in particular (692 mU/L, n = 7; P < 0.01). A cut-off concentration of <439 mU IFX-Fab reactive IgG Ab per litre comprised all patients who later obtained long-term sustained remission on IFX (sensitivity 100%, specificity 67%). Similar trends were observed in UC. The pre-treatment levels of IFX-Fab reactive IgG Abs were markedly higher in patients developing infusion reactions to IFX (1037 mU/L, n = 7) than in the remaining patients (349 mU/L, n = 44; P = 0.036).

CONCLUSIONS

IFX-Fab reactive IgG antibodies present in serum from IBD patients before infliximab therapy associate with lack of long-term efficacy and safety. Assessments of such antibodies may help clinicians to choose between treatment with infliximab and more humanised agents.