Lower Doses of Infliximab Work Well in PsA

Glintborg B, Gudbjornsson B, Steen Krogh N, et al. Impact of different infliximab dose regimens on treatment response and drug survival in 462 patients with psoriatic arthritis: results from the nationwide registries DANBIO and ICEBIO. Rheumatology (2014) Jun 17. pii: keu252. [Epub ahead of print]

Giving a lower starting dose of infliximab (Remicade) than the 5 mg/kg every eight weeks recommended by current guidelines doesn’t appear to affect responses in psoriatic arthritis (PsA), according to a new study.

The observational cohort study among 462 PsA patients in the ongoing Danish Rheumatologic Database (DANBIO) and Icelandic Center for Rheumatology Research (ICEBIO) registries also finds that time in treatment (drug survival) is independent of low initial doses, particularly if infliximab is given in combination with methotrexate (MTX).

Half of the DANBIO and ICEBIO registry patients are women in their 40s with an average PsA duration of 7 years.

The Danes, who had higher body weights, received infliximab in doses ranging from less than 3 mg/kg (n=110) to 3-5 mg/kg (n=157) and over 5 mg/kg (n=38) every eight weeks. The Icelandic patients, who had lower disease activity, received less than 3 mg/kg infliximab (n=64) and 3-5 mg/kg (n=17). Around 60% of all patients received MTX.

After a year, 58% of the Danish patients and 68% of the Icelandic patients remained on infliximab.

Around half (53%) of the study patients maintained treatment at the initial dose, and 31% had increased the dose by one year, either due to shorter time intervals between infusions or higher doses per infusion.

Despite the dose escalation, the majority received infliximab at less than 5 mg/kg – with a median dose of 3.3 mg/kg for the Danes and 2.9 mg/kg for the Icelandic patients.  

Disease activity and physical function,  evaluated at the start of the study and at 3, 6 and 12 months, were not affected by the lower doses.

Patients were judged responders if they achieved any clinical response at 3 and 6 months -- either 20%, 50%, or 70% improvement by American College of Rheumatology Criteria (ACR20/50/70) criteria or European League Against Rheumatism (EULAR) good responses. Those who quit treatment within 10 weeks were judged non-responders; only 44 patients stopped infliximab.

Researchers conclude that, pending confirmation from further studies, a low infliximab starting dose with subsequent step-up therapy if needed appears to be effective in PsA.