P497 Injection Site Reactions and Injection Site Pain for the Adalimumab Biosimilar ABP 501: Results from Two Double-Blind, Randomised, Controlled Studies

Adalimumab (40 mg/0.8 ml strength) is a commonly used, subcutaneously administered anti-TNF therapy for inflammatory bowel disease. Clinical studies of adalimumab in rheumatoid arthritis (RA) have documented that the injection site reactions (erythema, itching, haemorrhage, pain or swelling) were the most common adverse events and that the immediate post administration pain from the injection to be 3.7 cm on a 10-cm visual analogue scale (VAS). ABP 501 (AMGEVITA®; adalimumab) was recently approved in the EU as the first biosimilar to adalimumab, a fully human recombinant monoclonal antibody. Formulation excipients of a biosimilar can differ provided there is no impact to product quality. ABP 501 is, therefore, formulated with different set of excipients that do not include citrate as that is known to cause pain or stinging. The main objective of this study was to compare injection site pain and injection site reactions between ABP 501 and adalimumab. Two randomised, double-blind, active-controlled clinical trials were conducted; one in patients with moderate to severe RA (n = 526) and the other in patients with moderate to severe plaque psoriasis (PsO; n = 350). The details of the two study designs and their efficacy, safety, and immunogenicity results have been previously reported. In both studies, injection site pain perception was assessed at baseline and at Weeks 4, 8, and 12 using a 100-mm horizontal VAS measured within 5 min after injection. In the RA study nine injection site reactions treatment-emergent adverse events (TEAEs) occurred in 6 of 264 subjects (2.3%) in the ABP 501 group and 39 events occurred in 13 of 262 subjects (5.0%) in the adalimumab reference product (RP) group. In the PsO study 4 injection site reactions TEAEs occurred in 3 of 174 subjects (1.7%) in the ABP 501 group and 26 events occurred in 9 of 173 subjects (5.2%) in the adalimumab RP group through Week 16. In the RA study, mean injection site pain perception scores were lower in the ABP 501 group (range: 10.0–10.7 mm) vs. the adalimumab RP group (range: 16.1–21.4 mm) at each evaluated visit. In the PsO study, mean injection site pain perception scores were also lower in the ABP 501 group (range: 3.3–4.5 mm) compared with the adalimumab RP group (range: 12.4–19.3 mm) at each of the four time-points. These results confirm that in addition to having clinically equivalent efficacy, the frequency of injection site reactions and perception of injection site pain were lower with ABP 501 compared with adalimumab RP. Results are attributed to the different excipients in the ABP 501 formulation.