Pharmacokinetics and safety of candidate biosimilar CT-P55 versus reference secukinumab: a three-arm, randomized, double-blinded, single-dose, multicenter, Phase I study

This first-in-human study compared the pharmacokinetics, safety, and immunogenicity of candidate biosimilar CT-P55 to both European Union (EU)-approved and United States (US)-licensed secukinumab in healthy participants. Three-arm, double-blinded, parallel-group, single-dose, Phase 1 study conducted across four centers in Japan over 22 weeks. Healthy adult males were randomized (1:1:1) to a single 150-mg subcutaneous dose of CTP55, EU-approved, or US-licensed secukinumab. Primary endpoints were area under the concentration–time curve from time zero to infinity (AUC0–inf) and maximum serum drug concentration (Cmax). Baseline characteristics were comparable across groups (CT-P55 [n = 57], EU-approved secukinumab [n = 59], and US-licensed secukinumab [n = 56]). The 90% confidence intervals for the geometric least squares mean ratios of AUC0–inf and Cmax were within the equivalence margin (80–125%). Safety profiles were comparable. 218 treatment-emergent adverse events were reported for 110 (65.5%) participants; most were Grade 1/2. One serious adverse event was reported (US-licensed secukinumab group). The low immunogenic profile of CT-P55 was comparable to both reference secukinumab groups, with no neutralizing antibodies detected. CT-P55 exhibited equivalent pharmacokinetics as well as comparable safety and immunogenicity to both EU-approved and US-licensed secukinumab in healthy Japanese males. Generalizability may be limited beyond Asian males. The study is registered at Clinicaltrials.gov (NCT07054970). Secukinumab is a medicine that is used to treat some inflammatory diseases, in which the body is harmed by its own immune system (natural defenses). Secukinumab is a ‘biologic’ medicine, which means it is a complex medicine made from living cells. Biologic medicines can be expensive. A ‘biosimilar’ is a type of medicine that is very similar to an existing biologic medicine (known as the ‘reference’ biologic). Biosimilars are typically cheaper than reference medicines yet provide similar results. This can mean treatment is cheaper and easier for patients to access. Currently, there are no secukinumab biosimilars available to patients in the European Union (EU) or the United States (US), but a potential biosimilar called ‘CTP55’ is being developed. This study is important because it was the first time that CT-P55 was tested in humans. The study aimed to show that CT-P55 is equivalent to reference secukinumab when given to healthy adults. Study participants were split into three groups at random. Each group received a single injection of CT-P55, EU ‘reference’ secukinumab, or US ‘reference’ secukinumab. The study showed that the pharmacokinetics (how the body processes the drug) of CT-P55 were equivalent to those of ‘reference’ secukinumab. Safety and immunogenicity (unwanted immune reactions) were also comparable between the treatments. These results support CT-P55 as a potential biosimilar of secukinumab. A new clinical trial is underway to compare how well CT-P55 and ‘reference’ secukinumab work in patients with an inflammatory disease.