New Research Highlights the Role of Biosimilar Etanercept in Treating Ankylosing Spondylitis

While the United States continues to await the launch of the first FDA-approved biosimilar etanercept (Erelzi), in other parts of the world biosimilars of the reference etanercept (Enbrel) are being widely used in clinical practice, and recent research reports on the role that biosimilar etanercept plays in the treatment of ankylosing spondylitis (AS).

One new study reports that, in patients with AS, tapering biosimilar etanercept is comparable with full-dose therapy in treating hip arthritis, a key feature of AS.¹

The study enrolled 136 patients with AS, all of whom were given treatment with biosimilar etanercept at a dose of 50 mg per week for 12 weeks. Then, 80 participants were assigned to taper their treatment to 50 mg every other week from week 13 to 24. The remaining participants continued to receive the full dose of biosimilar etanercept to week 24.

The investigators found no significant differences in disease activity between the tapering arm and the full-dose arm, and both arms saw equivalent decreases in acute inflammation as revealed by magnetic resonance imaging at week 24 versus baseline.

According to the investigators, a tapered treatment for hip arthritis in AS is comparable to full-dose treatment.

Another study of biosimilar etanercept in AS, conducted in Chinese patients, found that detecting serum drug levels and antidrug antibody (ADA) levels could help providers estimate the clinical efficacy of the therapy.²

The study enrolled 60 patients with AS, all of whom were being treated with biosimilar etanercept. The patients’ serum and clinical data were collected at baseline and weeks 4, 12, and 24.

The researchers found that patients who achieved and all of whom had achieved an AS Disease Activity Score with C-reactive protein (ASDAS-CRP) score of less than 2.1 had significantly higher drug levels than patients whose ASDAS-CRP scores were over 2.1. Patients with higher drug levels also had lower Bath AS Disease Activity Index scores and lower levels of tumor necrosis factor (TNF).

Patients who had ADAs had lower drug levels and higher TNF levels, but ADAs did not have an effect on remission rates. According to the investigators, serum drug levels and ADAs may be useful in assessing the clinical efficacy of biosimilar etanercept in patients with AS, and could help guide modification of patients’ treatment regimens during therapy.

Finally, a third study reports that, despite the benefits of using biosimilar etanercept in treating AS, the drug may not be the most cost-effective option.³

The study, conducted from the perspective of a Canadian healthcare system over a 60-year time horizon for biologic-naïve adults with AS, evaluated the cost-effectiveness of an interleukin-17A inhibitor (secukinumab) versus other available options: the anti-TNF agents adalimumab, certolizimab pegol, golimumab, reference and biosimilar infliximab, and reference and biosimilar etanercept.

The researchers found that treating patients with AS with 150 mg of secukinumab achieved 16.46 quality-adjusted life years (QALYs) at a cost of CaD $533,010 (approximately US $402,439); the investigators wrote that secukinumab produced more QALYs at a lower cost than any of the other products considered, including biosimilar etanercept, which produced 15.19 QALYs at a cost of CaD $574,062 (approximately US $433,474).

According to the authors, using secukinumab rather than anti-TNFs to treat biologic-naïve patients in Canada “translates into substantial benefits for patients and the healthcare system.”

References

1. Huang ZX, Deng WM, Guo X, Huang ZP, Lin CL, Li TW. Clinical and MRI response to dose reduction of an etanercept-biosimilar for hip arthritis in patients with ankylosing spondylitis: an observational, retrospective cohort study [published online February 12, 2019]. Clin Rheumatol.

2. Dong Y, Li P, Xu T, Bi L. Effective serum level of etanercept biosimilar and effect of antidrug antibodies on drug levels and clinical efficacy in Chinese patients with ankylosing spondylitis [published online February 12, 2019]. Clin Rheumatol. doi: 10.1007/s10067-018-04424-x.

3. Goeree R, Chiva-Razavi S, Gunda P, Jain M, Jugl SM. Cost-effectiveness analysis of secukinumab in ankylosing spondylitis from the Canadian perspective [published online November 13, 2018]. J Med Econ. doi: 10.1080/13696998.2018.1539400.