Results of the study, which focused on patient-reported outcomes in addition to clinical measurements, mirror findings from other large-scale studies evaluating the safety and efficacy of biosimilars in patients with rheumatoid arthritis.
Swapping adalimumab with an adalimumab biosimilar did not significantly increase disease activity or result in worse patient-reported outcomes in patients with rheumatoid arthritis (RA), leading to favorable feelings towards switching to the new therapy, according to a study published in Pharmacology Research and Perspectives.1
Larger studies have previously investigated the safety and efficacy of biosimilars in this patient population with positive results, in addition to the cost-related benefits.
“However… most of the evidence to date is based on extensions of randomized controlled trials in selected patients, like the PLANETRA and Imraldi® extension studies, which may not be comparable to patients treated in the setting of real-world practice,” investigators noted. “Moreover, little is known yet about patients' satisfaction and experience with switching to a biosimilar.”
A hospital-wide switch from adalimumab to an adalimumab biosimilar prompted investigators to conduct the single-center, retrospective, observational study, performed at Rheumatology Department of the Medisch Spectrum Twente hospital in Enschede, the Netherlands, evaluating any changes in disease activity, functional disability, and quality of life in patients with RA starting treatment with the biosimilar. Patients were eligible to participate in the 12-month study if they were aged 18 years or older, had a clinical diagnosis of RA, and had been receiving adalimumab for 3 or more months prior to switching to the biosimilar.
Data was enhanced with a cross-sectional survey in which patients rated their satisfaction and reported any side effects at approximately the 18-month mark. The Disease Activity Score 28 joints (DAS28), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) assessed disease activity, the short form 36 (SF-36) was used to determine quality of life, and the Health Assessment Questionnaire Disability Index (HAQ-DI) measured functional disability.
Sufficient data was available in 52 patients with RA. The mean age of participants was 62.4 years, 80.8% were women, and the median disease duration was 15 years. Although 3 patients (7.9%) discontinued the biosimilar due to side effects, overall patient satisfaction was high. On a scale of 0-10, in which 10 meant “totally agree,” the mean score from patients regarding the switch to the biosimilar was 7.53 (±2.78). Of the 38 patients who completed the survey, 84.2% were still being treated with the biosimilar.
Disease activity did not significantly increase from baseline measurements (mean DAS28 = 2.25) and those taken at 3 months (mean DAS28 = 2.29; p = 0.780). Similar results were seen at the 6-, 9-, and 12-month evaluations. Patient-reported outcome measures, determined using SF-36 and the HAQ-DI scores, did not significantly change from prior to the initiation of the biosimilar.
During the study period, 31.6% (n = 12) experienced side effects, including oral sores, eyelid inflammation, cystitis, urticaria, coughing, fatigue, bruising at the injection site, and flu-like symptoms. The prevalence of side effects did not increase during the 12-month period.
As patients self-reported side effects, investigators could not clinically verify the symptoms, thus limiting the study. Additionally, since patients knew they were receiving the biosimilar, there is a possibility that a nocebo effect may have skewed the results.
“By demonstrating in the current study that patients who are already using an originator biological can effectively and safely switch to a biosimilar, the decision to switch these patients to the biosimilar may be made more often in the future,” investigators concluded. “This can further help to reduce healthcare costs and keeping healthcare accessible for everyone.”
Brouwer R, Ten Klooster PM, Masselink JB, Vonkeman HE. Continuous effectiveness and safety after a hospital-wide switch to adalimumab biosimilar: An observational study in rheumatoid arthritis patients. Pharmacol Res Perspect. 2022;10(6):e01025. doi:10.1002/prp2.1025