Rheumatoid Arthritis Patients More Often Discontinue Infliximab Treatments

Patients with rheumatoid arthritis (RA) are more likely to discontinue medicating with infliximab versus adalimumab and etanercept, according to a study published in the Annals of Rheumatic Diseases.

Researchers from the Karolinska Institutet in Stockholm, Sweden identified 9,139 RA patients who began their first tumour necrosis factor (TNF) between 2003 and 2011 from the Swedish Biologics Register (ARTIS) in order to compare drug survival on adalimumab, etanercept, and infliximab. The patients were 76 percent women with a mean age of 56 years. The researchers collected data on the patients’ age, sex, education, period, health assessment questionnaire (HAQ), disease duration, concomitant disease modifying anti rheumatic drug (DMARD) treatment, and general frailty.

There were a total of 9,139 patients included in the study: 26 percent started adalimumab, 43 percent etanercept, and 32 percent infliximab. The researchers found that during the follow up period, 3,782 patients discontinued their first biological treatment. This was primarily found to be for 2 reasons: 51 percent due to inefficacy and 36 percent due to adverse events. Similar distributions were noted by the investigators across adalimumab, etanercept, and infliximab initiators.

After 0.8 years, 25 percent of patients had discontinued using adalimumab and infliximab initiators, while it took 1.3 years for the same percentage of patients to discontinue etanercept. Half of infliximab initiators had discontinued the drug after 2.6 years, while half of adalimumab users had discontinued after 5 years. After a 5 year follow up, patients who remained on their first drug numbered 38 percent, 50 percent, and 55 percent of infliximab, adalimumab, and etanercept initiator users, respectively.

The discontinuation rates were greater in women than in men, the researchers commented. The discontinuation rates were also greater in patients with lower education compared with higher education. During the periods of 2006-2009 and 2010-2011, the discontinuation rates were higher than during the period of 2003-2005. Another difference the researchers noted was patients with higher baseline HAQ discontinued more often, as well as patients with greater general frailty. However, concomitant DMARD use and longer disease duration were associated with a lower risk of discontinuation.

“Discontinuation rates were higher for infliximab compared with adalimumab and etanercept initiators, as well as for adalimumab versus etanercept initiators during the first year,” the authors concluded. “Discontinuation rates increased with calendar period of TNF initiation, as did the share of discontinuations due to inefficacy.”

The authors also commented that prior research into this topic did not compare periods of time when all 3 drugs were available simultaneously. European studies tended to demonstrate shorter drug survival on infliximab, while studies from the United States have shown the opposite. Typically, the researchers found that Medicare compensates the cost of infliximab as an intravenous infusion and did not reimburse adalimumab or etanercept.