The first Australian audit directly comparing infliximab and adalimumab as induction and maintenance therapy in Crohn’s disease has concluded that the TNF inhibitors lead to similar clinical and biochemical outcomes, but infliximab may have the edge in controlling fistulising disease.
Dr Poornima Varma and colleagues in Melbourne audited 81 patients treated at the Alfred Hospital, of whom 63 started infliximab and 18 were commenced on adalimumab, at the discretion of their treating doctors, after their disease was judged as refractory to conventional therapies.
Both agents were effective. “Significant CDAI [Crohn’s Disease Activity Index] reductions were noted within both groups at 3 months and 12 months,” they said, reporting their findings in the Internal Medicine Journal.
“Similarly, significant reductions were noted in steroid doses within groups at 3 months and 12 months, with notable reductions in CRP at 3 months.”
There were no significant differences between the two medications in these parameters. However, fistula-related admissions were significantly reduced in infliximab patients (100%) compared to adalimumab patients (62.5%).
Patients starting adalimumab were significantly older (43 vs 34 years) and more likely to have an active perianal fistula at baseline (67% vs 40%).
Adverse events occurred in 14.8% of the infliximab group and 11.1% of the adalimumab group.
Single cases of testicular seminoma, melanoma, and diffuse large B-cell lymphoma were reported in infliximab-treated patients (the latter in a patient on long-term concurrent azathioprine therapy), as well as one case of drug-induced lupus.
“The only serious adverse event in the adalimumab group was a case of congestive cardiac failure in a patient with no pre-existing cardiac disease,” they said.
“Other reported adverse events in the infliximab group included chest infections in two patients, one minor acute infusion reaction, and two delayed hypersensitivity reactions, as compared to a single case of perianal sepsis in the adalimumab group.”
Infliximab was often chosen in clinical practice as the first-line anti-TNF agent despite a lack of data showing any superiority to adalimumab, they said.
“In fact, available evidence suggests that efficacy is comparable between both agents.”
Significantly more infliximab patients were no longer on concurrent therapy at 12 months compared to adalimumab patients.
“The exact reasons for withdrawal of immunomodulators at 12 months could not be established through medical records however the study included a time period when concerns about adverse events to combination therapy (in particular hepatosplenic Tcell lymphoma) led to the use of anti-TNF monotherapy in some patients, especially young males,” they said.
The researchers acknowledged the limitations of the audit, including the small sample size (especially the number treated with adalimumab), the single-centre database which reflected institution-specific management protocols, and missing follow-up data for some patients.