Clinical Edge Journal Scan Commentary: RA November 2021

Arundathi Jayatilleke, MD

Biosimilar medications have received significant attention recently in the treatment of rheumatoid arthritis (RA), though the effects of switching from the reference drug to a biosimilar is not known. The study by Fleischmann et al ¹ looks at the safety and efficacy, as well as immunogenicity, of biosimilar adalimumab (ADL-PF) compared to the reference ADL-EU (European Union sourced adalimumab) in a randomized double-blind study. Patients were randomized to start and continue ADL-PF or start ADL-EU and switch to ADL-PF at week 26 or 52. Immunogenicity was measured using anti-drug antibodies (ADA). American College of Rheumatology (ACR20) response rates were similar among all groups, while ACR50 and ACR70 response rates were numerically lower in the week 52 switch group. ADA development was comparable between groups. Data were analyzed using descriptive statistics, but overall, safety, efficacy, and immunogenicity were similar between patients maintained on ADL-PF and those switched from ADL-EU at week 26 or 52.

Statins have long been associated with musculoskeletal symptoms in patients, but have also been postulated to have anti-inflammatory and immunomodulatory effects. Complicating the relationship is the knowledge that inflammation increases cardiovascular risk in RA patients. In a case-control study, Peterson et al ² used an administrative database to examine the influence of statin use on development of RA. Cases were identified based on ICD-9 coding as well as a prescription for methotrexate after diagnosis. They were matched 1:1 with controls based on demographics and year of diagnosis. Statin use was evaluated. Statin use was associated with a small increase in risk of RA, which was diminished after adjusting for hyperlipidemia; a trend towards increase in risk with higher dose and duration of statin use was not statistically significant. Beyond this, the reduced risk after adjustment for hyperlipidemia is hard to interpret as an explanation of cause or effect of autoimmunity, and, given the small magnitude of increases and decreases in risk, may not be clinically meaningful.

In addition to patients with RA having a higher burden of cardiovascular disease necessitating use of statins, they also have a high risk of progressive secondary osteoarthritis requiring joint replacement surgery. Chang et al ³ used a national claims-based dataset from China to examine risk of total knee or hip replacement (TKR and THR, respectively) in patients with RA. From 2000-2013 (ie, the onset of the biologic era), TKR and THR rates were examined in a cohort of biologic disease-modifying antirheumatic drug (bDMARD) users compared to conventional synthetic DMARD (csDMARD) users. Adjusted hazard ratios (HR) were lower for both TKD and THR in bDMARD users. Though RA activity was not examined, combined with the knowledge of the association of disease severity with bDMARD use, this study lends evidence to the benefits of more aggressive treatment .

Finally, much is made of the link between bDMARD and targeted synthetic DMARD use and malignancy due to reduced immunosurveillance, but concrete evidence is conflicting. Wetzman et al ⁴ performed a systematic review of studies of patients with inflammatory arthritis (RA, psoriatic arthritis, and Ankylosing spondylitis ) looking at cancer relapse or occurrence of new cancer. An increase in skin cancers (HR 1.32) was noted, but reassuringly no other increase in risk of recurrent or new cancer was seen.

References

1. Fleischmann R et al. Long-term efficacy, safety, and immunogenicity of the adalimumab biosimilar, PF-06410293, in patients with rheumatoid arthritis after switching from reference adalimumab (Humira®) or continuing biosimilar therapy: week 52–92 data from a randomized, double-blind, phase 3 trialArthritis Res Ther. 2021(Sep 25);23:248.
2. Peterson MN et al. Risk of rheumatoid arthritis diagnosis in statin users in a large nationwide US study. Arthritis Res Ther. 2021(Sep 18):23:244.
3. Chang YS et al. Effects of biologics on reducing the risks of total knee replacement and total hip replacement in rheumatoid arthritis. Rheumatology (Oxford). 2021(Sep 17):keab671.
4. Wetzman A et al. Risk of cancer after initiation of targeted therapies in patients with rheumatoid arthritis and a prior cancer: systematic review with meta-analysis. Arthritis Care Res (Hoboken). 2021(Sep 21): acr.24784.