Biosimilar SB17 versus reference ustekinumab in moderate to severe plaque psoriasis after switching: phase 3 study results up to week 52

Introduction: SB17 is a biosimilar to reference ustekinumab (UST). We compared the efficacy, safety, and immunogenicity of SB17 to UST up to Week 52, including switching from UST to SB17. Methods: Subjects were randomized to receive 45 mg of SB17 or UST subcutaneously up to Week 40. At Week 28, subjects from the UST treatment group were re-randomized to either switch to SB17 or continue UST. Efficacy, safety, and immunogenicity were assessed up to Week 52. Results: Among baseline randomized 503 subjects, 481 subjects were re-randomized at Week 28; continuing SB17 (SB17 + SB17, n = 237), switching from UST to SB17 (UST+SB17, n = 122) or continuing UST (UST+UST, n = 122). The percent change from baseline in Psoriasis Area and Severity Index (PASI) was comparable between treatment groups up to Week 52 (SB17 + SB17: 95.8%, UST+SB17: 95.6%, UST+UST: 94.5% at Week 52). Other efficacy endpoints were also comparable. The incidence of treatment-emergent adverse events (SB17 + SB17: 16.5%, UST+SB17: 13.9%, UST+UST: 23.8%) and the overall incidence of anti-drug antibodies occurring after transition were comparable between treatment groups (SB17 + SB17: 5.6%, UST+SB17: 5.1%, and UST+UST: 6.7%). Conclusion: SB17 demonstrated clinical biosimilarity to UST after switching from UST, and maintained long-term comparable efficacy and safety with UST up to Week 52.