Golimumab biosimilar BAT2506 vs reference golimumab in PsA: A phase III extension study

Results from an extension phase of a multicenter, double-blind, randomized, phase III (NCT05046431) study evaluating the golimumab biosimilar BAT2506 vs reference golimumab (Ref-GLM) in patients with active psoriatic arthritis (PsA) were published in Expert Opinion on Biological Therapy by Tang et al. Patients were randomized (1:2:1) to receive Ref-GLM or BAT2506 for 48 weeks or Ref-GLM from Week 0 to Week 24 followed by BAT2506 from Week 24 to Week 48 (Ref-GLM/BAT2506). Efficacy endpoints included: American College of Rheumatology 20%/50%/70% improvement in response (ACR20/50/70); change from baseline in Disease Activity Score 28 using C-reactive protein (DAS28-CRP), individual ACR components, and health assessment questionnaire disability index (HAQ-DI); and Psoriasis Area and Severity Index (PASI) and nail psoriasis severity index (NAPSI) responses. Additional endpoints included safety, pharmacokinetics (PK), and immunogenicity through Week 52. 

Key data: At Week 52, ACR20 response rates were 88.3% with Ref-GLM (n = 172), 89.8% with BAT2506 (n = 341), and 85.1% with Ref-GLM/BAT2506 (n = 166); ACR50 response rates were 71.7%, 69.7%, and 67.0%, respectively; and ACR70 response rates were 50.6%, 50.4%, and 44.9%, respectively. PASI responses and mean changes from baseline in DAS28-CRP, individual ACR components, NAPSI score, and HAQ-DI score were comparable across the three treatment groups. Treatment-emergent adverse events (TEAEs) were reported in 62.2% of patients in the Ref-GLM group, 66.3% in the BAT2506 group, and 66.9% in the Ref-GLM/BAT2506 group. From Weeks 24 to 52, mean serum concentrations overlapped across all three groups, with similar increases from Weeks 36 to 52 and declines at the end of dosing follow-up. In the Ref-GLM, BAT2506, and Ref-GLM/BAT2506 groups, positive anti-drug antibodies (ADAs) were reported in 39.3% 37.2%, and 42.1% of patients, respectively, while positive neutralizing antibodies (NAbs) were reported in 37.5%, 36.6%, and 39.0%, respectively. The presence of ADAs did not impact efficacy or safety outcomes. 

Key learning: Results from the extension period of this phase III study demonstrated comparable efficacy, safety, PK, and immunogenicity between BAT2506 and Ref-GLM, as well as following a switch from Ref-GLM to BAT2506, through Week 52. These findings support the comparable clinical performance of BAT2506 vs Ref-GLM in patients with PsA.