Adalimumab is a human TNF-α monoclonal antibody that acts as an inhibitor of inflammatory and immune responses often associated with chronic autoimmune-based conditions. In New Zealand, the reference adalimumab (Humira) has been listed on the Pharmaceutical Schedule since 2009 and has been funded under Special Authority criteria for use in:4,5
- rheumatoid arthritis
- polyarticular juvenile idiopathic arthritis
- psoriatic arthritis
- ankylosing spondylitis
- Crohn disease
- plaque psoriasis
- hidradenitis suppurativa
- uveitis (ocular inflammation).
Humira is currently used by approximately 6400 patients in the community and is routinely self-administered as a subcutaneous injection. Most patients using Humira who are seen in primary care either have rheumatoid or inflammatory bowel conditions.6
Evidence base and international experience with adalimumab biosimilars
Amgevita, an adalimumab biosimilar, has been approved by the European Medicines Agency (EMA) for use in the EU, by the Food and Drug Administration in the US, by the Therapeutic Goods Administration in Australia, and by Medsafe in New Zealand for all the indications of the reference adalimumab product (Humira).
A European study compared 29 biosimilar monoclonal antibody products and fusion proteins and their reference products (including adalimumab) and demonstrated comparable efficacy, safety and immunogenicity.7 The study used post-marketing surveillance data from European Public Assessment Reports (EPARs) and Periodic Safety Update Reports (PSURs) submitted to the EMA. The study claims that the safety and immunogenicity profiles of the biosimilars and their reference products are similar and do not change upon switching.7
More than 15 years’ use of biosimilars in the EU, over 2 billion treatment days worldwide, and reviews of more than 175 reference/biosimilar switch studies conducted up to 2018 have not revealed any safety problems. “An analysis of more than 1 million patient-treatment years of safety data raised no safety concerns.”7
Two phase III studies, in patients with rheumatoid arthritis8 and in patients with plaque psoriasis,9 both demonstrated non-inferiority between Amgevita and the reference adalimumab.
In Australia, on 1 April 2021, four adalimumab biosimilars were added to the Pharmaceutical Benefits Scheme. Amgevita was one of these and, of the four, it is the biosimilar providing the greatest range of dosage and delivery options (including prefilled syringe and pen, and a paediatric dose); these options are the ones also being made available in New Zealand.10
The 2018 Australian Public Assessment Report (AusPAR) for adalimumab noted that a single-dose pharmacokinetic study demonstrated bioequivalence of Amgevita and Humira.11 AusPAR also concluded that the two aforementioned phase III clinical equivalence studies were “well designed, used appropriate clinical endpoints, adequately justified the equivalence margins and convincingly demonstrated clinical equivalence for patients with rheumatoid arthritis and with plaque psoriasis”.11
New Zealand’s Pharmacology and Therapeutics Advisory Committee (PTAC) concluded that, based on available evidence, biosimilar adalimumab appears equally effective to reference adalimumab with no evidence to indicate any specific clinical risk or harm with switching from the reference product to a biosimilar.12
The committee also considered that there is currently no evidence that the rate of development of immunogenicity – including the identification of treatment antibodies leading to loss of treatment effectiveness – differed between reference and biosimilar adalimumab.12
See the He Ako Hiringa biological medicines resource hub for further reading.