The ‘totality of evidence’ and ‘extrapolation’ of SB17, a ustekinumab biosimilar

Introduction: SB17 is a ustekinumab (UST) biosimilar targeting interleukin-12/23 for treating immune- mediated inflammatory diseases (IMIDs). The development of UST biosimilars like SB17 may help address the high cost of innovator biologics, offering affordable alternatives without compromising efficacy or safety. Areas covered: This review encompasses the totality of evidence supporting SB17’s similarity to UST, its regulatory approval, and indication extrapolation. It also discusses SB17’s lower immunogenicity relative to UST. Expert opinion: The approval of UST biosimilars represents a significant advancement in managing chronic IMIDs including psoriasis, plaque psoriasis, psoriatic arthritis, Crohn’s disease, and ulcerative colitis, providing cost-effective, efficacious alternatives. A randomized double-blind 28-week study involving over 500 patients with moderate-to-severe chronic plaque psoriasis demonstrated SB17’s equivalence to UST, with more than 80% of patients achieving over 90% improvement in psoriasis severity indices. Treatment-emergent adverse events were comparable between SB17 and UST. Despite their potential to transform clinical outcomes, economic burdens, and drug utilization patterns, the adoption of UST biosimilars faces challenges, including concerns about equivalence and regulatory inconsistencies. Addressing these issues through education, consistent regulatory frameworks, real- world data, and ongoing monitoring is crucial for their successful integration into clinical practice.