Switching to Biosimilar Etanercept, Erelzi, Does Not Impact Efficacy, Safety, or Immunogenicity in RA

Sandoz’s biosimilar etanercept, approved in multiple territories as Erelzi, received FDA authorization in 2016 on the basis of a data package that included the phase 3 EGALITY study showing equivalent efficacy and comparable safety and immunogenicity of the biosimilar with its reference, Enbrel, in patients with psoriasis.

Now, researchers are reporting switching data from the phase 3 EQUIRA study in patients with rheumatoid arthritis (RA), demonstrating that a single switch from the reference to the biosimilar had no impact on efficacy, safety, or immunogenicity of etanercept.

The EQUIRA study was conducted from 2015 to 2017 in 83 centers in 16 countries. Adult patients who had moderate or severe RA and an inadequate response to conventional therapy were randomized to receive 50 mg of either the reference (n = 190) or the biosimilar (n = 186) for 24 weeks. The primary objective of the study—demonstrating therapeutic equivalence of the 2 products at week 24—was met, as described elsewhere.

At week 24, those who had a moderate treatment response or better continued the biosimilar (n = 175) or switched from the reference to the biosimilar (n = 166) for up to 48 weeks.

The least squares mean change in Disease Activity Score in a count of 28 joints with C-reactive protein (DAS28-CRP) was comparable between the biosimilar-only group (−2.90 [standard error (SE), 0.12]) and the switch group (−2.78 [SE, 0.130]). Additionally, the proportions of patients who had a good European League Against Rheumatism (EULAR) response was 54.4% and 51.9% in the 2 groups, respectively. A moderate response was achieved by 41.5% and 44.2%, respectively.

The proportion of patients who achieved American College of Rheumatology (ACR) criteria for 20%, 50%, and 70% improvement was comparable between groups; ACR50 and ACR70 response rates were numerically higher in the switched group at all time points, though this difference was not clinically relevant.

At week 48, the mean change from baseline in Health Assessment Questionnaire Disability Index (HAQ-DI) was −0.62 (standard deviation [SD], 0.55) in the biosimilar-only group and −0.66 (SD, 0.55) in the switch group. The proportion of patients who achieved a HAQ-DI score in the normal range up to week 48 was comparable between the 2 groups (34.7% and 39.5%, respectively).

The proportion of patients with at least 1 serious adverse event (AE) was low, and numbered 4 patients in each group. Treatment-related AEs occurred in 23 patients in the biosimilar-only group and 19 patients in the switch group.

After week 24, no patients in the switch group developed anti-drug antibodies (ADAs). Four patients in the biosimilar-only group developed single-event, low-titer, non-neutralizing ADAs.

These 48-week results, write the authors, show that a switch to the biosimilar from the reference etanercept did not impact safety, efficacy, or immunogenicity of etanercept therapy in patients with RA.

Reference

Jaworski J, Matucci-Cerinic M, Schulze-Koops H, et al. Switch from reference etanercept to SDZ ETN, an etanercept biosimilar, does not impact efficacy, safety, and immunogenicity of etanercept in patients with moderate-to-severe rheumatoid arthritis: 48-week results from the pahse 3, randomized, double-blind EQUIRA study. Arthritis Res Ther. 2019;21:130. doi: 10.1186/s13075-019-1907-x.