Adalimumab Biosimilar Performs Well in RA Trial

Rheumatoid arthritis patients who received the adalimumab biosimilar, adalimumab-atto, performed slightly better than patients receiving adalimumab in a phase three randomized, double-blind, controlled trial.

Though only 26 weeks long, the findings demonstrate clinical efficacy, safety and immunogenicity in patients who were randomized to receive adalimumab or its biosimilar. The study, which was led by Stanley B. Cohen, M.D., of the University of Texas Southwestern Medical School, appears in the June 5 online issue of the Annals of the Rheumatic Diseases.

Adalimumab is a recombinant human IgG1 monoclonal antibody that binds to TNF-α. It is approved to treat rheumatoid arthritis, juvenile idiopathic arthritis (JIA), psoriatic arthritis, ankylosing spondylitis, Crohn's disease and plaque psoriasis. Adalimumab-atto (Amjevita/Amgen) is the first biosimilar to adalimumab (Humira/AbbVie) and was approved by the Food and Drug Administration in 2016.

Previously known as ABP 501, adalimumab-atto has been proven to be highly similar to its reference product, adalimumab. 

The study

In this study, researchers report the results of a phase three trial in patients with moderate to severe rheumatoid arthritis who were randomized to receive either adalimumab-atto or its reference product, adalimumab 40 mg every two weeks. The primary endpoint was a risk ratio of ACR20 between both groups at 24 weeks. The treatments were deemed equivalent if the 90% CI for risk ratio of ACR20 at 24 weeks fell between .738 and 1.355.

The study included 526 patients:  264 were randomized to adalimumab-atto and 262 were randomized to adalimumab. Of those, 93.9% of patients in the trial (494) completed the study (243 and 251), respectively.

The percentages of ACR20, ACR50 and ACR70 responders were comparable across groups throughout the study. At week 24, 74.6% of patients in the adalimumab-atto group and 72.4% (189/261) in the adalimumab group met the ACR20 response criteria. The risk ratio (2-sided 90% CI) of ACR20 at week 24 for adalimumab-atto versus adalimumab was 1.039 (0.954, 1.133). Clinical equivalence between the two treatments were demonstrated with a 90% CI of (0.954, 1.133), which was within the equivalence margin (0.738, 1.355). The risk differences (two-sided 90% CI) between the two groups for ACR20 at 24 weeks was 2.604 (−3.728, 8.936).

At week 24, 49.2% of adalimumab-atto patients and 52% of adalimumab reached ACR50. With a RR (90% CI) for ABP 501 versus adalimumab of 0.948 (0.819, 1.097) and RD (90% CI) of −2.836% (−10.220%, 4.547%). At 24 weeks, 26% and 22.9% of adalimumab-atto and adalimumab patients, respectively, achieved ACR70. The RR (90% CI) for ACR70 at week 24 was 1.130 (0.872, 1.464) and the RD (90% CI) was 3.147% (−3.177%, 9.470%).

There were more similarities in the study:  The percentage of patients reporting more than one treatment-emergent adverse event was similar for both groups (50 and 54.6%, respectively) as was the number of patients reporting serious adverse events (3.8% and 5%, respectively).

Other biosimilars

Other biosimilars that have been approved by the FDFA include filgrastim-sndz (Zarxio/Sandoz); infliximab-abda (Renflexis/Samsung Bioepis); and, etanercept-szzs (Erelzi/Sandoz). In the European Union, the European Medicines Agency has granted marketing authorization to several rheumatoid arthritis biosimilars:  Inflectra, Remsima, Flixabi, (infliximab biosimilars) and Benepali (etanercept biosimilar).

Take-home points

• ABP 501 (adalimumab-atto) is equivalent in efficacy to the reference product, adalimumab, in patients with RA.
• Similar efficacy results were observed for ABP 501 and adalimumab for ACR20 (primary endpoint), ACR50 and ACR70 (secondary endpoints).
• The mean changes from baseline in DAS28-CRP results were also similar between groups at all study time points.
• The clinical safety results from this study indicate that ABP 501 and adalimumab have similar safety profiles. No new safety signals were detected in this study compared with other adalimumab clinical trials in patients with RA.

References:

Cohen S, Genovese MC, Choy E, et al. “Efficacy and safety of the biosimilar ABP 501 compared with adalimumab in patients with moderate to severe rheumatoid arthritis: a randomised, double-blind, phase III equivalence study,” Annals of the Rheumatic Diseases. Published Online First: 05 June 2017. DOI: 10.1136/annrheumdis-2016-210459