Peter C. Taylor, PhD

A recent study found that rheumatoid arthritis (RA) patients who continued their adalimumab (ADA) bio-originator treatment—instead of switching off to a biosimilar—had better outcomes and adherence than switchers.

The investigators noted that biosimilars are similar to their bio-originators in pharmacokinetic, immunogenic, safety, and efficacy profiles. Consequently, using them has the potential to lower treatment costs and give RA patients greater access to therapies.

The study was conducted to compare RA patient outcomes for those treated with ADA bio-originator to RA patients who switched over from the bio-originator to a biosimilar in real-world settings.

The investigative team was led by Peter C. Taylor, PhD, of the Nuffield Department of Orthopaedics at the University of Oxford’s Botnar Research Centre in the UK.

“The increasing economic burden of RA and of the availability of biosimilars has resulted in physicians switching some patients to biosimilars,” Taylor and colleagues wrote. “Reportedly, approximately 35% of European patients had been switched from the ADA bio-originator to an ADA biosimilar by the end of 2015.”

Background

The investigators used data from a European point-in-time survey—the Adelphi RA Disease Specific Programme—made up of data from both clinicians and patients in the countries of France, the UK, Spain, Germany, and Italy in 2020.

The research included in the study was drawn from a questionnaire given to clinicians regarding their next 10 adult RA patients and then followed by 4 additional patients. The 4 additional patients had reported switching to ADA biosimilars from ADA bio-originators and were labeled ‘switchers.’

The investigators compared the physician-and patient-reported outcomes (PROs) of switchers to those of non-switchers, with the team using propensity score matching.

The research team used a total of 303 rheumatologists, of which data from 160 non-switchers and 225 switchers was provided. They also noted that 140 RA patients provided the team with data, including 89 switchers and 51 non-switchers.

Findings

The study’s results indicated overall better outcomes for non-switcher RA patients over those who were switchers, with data indicating non-switchers were more likely over those who switched to improve on their ongoing ADA therapies (68%, n = 108 versus 26%, n = 59, P < 0.001).

The conditions of non-switching patients were found to be less likely to become worse (1%, n = 2 versus 9%, n = 20; P < 0.01), and adherence by RA patients was found to be substantially lower for those who switched compared to those who did not (0.66 versus 0.78, respectively; P = 0.04).

They also noted that those who switched were also found to be less consistent with their RA medicine than those who continued their normal treatments (P < 0.001).

Additionally, PRO ratings suggested that switchers had lesser quality-of-life rankings (EQ-5D Visual Analogue Scale: 62.9 versus 71.9; P < 0.001), and more impairments to activities (Work Productivity Activity Index: 31.0 versus 24.4; P = 0.02).

“In conclusion, this analysis of the Adelphi RA DSP demonstrated that the switching of patients with RA from ADA bio-originator to an ADA biosimilar, may have some unforeseen outcomes that should be considered by health decision makers, such as effects on patients’ disease severity, treatment adherence and (Quality of Life),” they wrote.

The study, “Outcomes Following Adalimumab Bio-originator to Biosimilar Switch—A Comparison Using Real-world Patient- and Physician-Reported Data in European Countries,” was published online by Springer Nature.