Pos0085 a Randomized, Double-Blind, Phase Iii Study to Compare Sb16 (Proposed Denosumab Biosimilar) to Reference Denosumab in Patients With Postmenopausal Osteoporosis: 18-Month Results

Background: SB16 has been developed as a proposed biosimilar to reference denosumab (DEN hereafter). Objectives: We have previously reported the biosimilarity of SB16 to DEN in terms of efficacy, pharmacokinetics (PK), pharmacodynamics (PD), safety, and immunogenicity up to 12 months.[1] Here we present the switching period results up to Month 18. Methods: Postmenopausal osteoporosis patients were randomized in a 1:1 ratio to receive either 60 mg of SB16 or DEN subcutaneously at Month 0 and Month 6. At Month 12, patients were re-randomized into switching period to continue their treatment (SB16+SB16 or DEN+DEN) or switch from DEN to SB16 (DEN+SB16). Efficacy, PK, PD, safety, and immunogenicity were assessed up to Month 18. The study received ethical approval, and all participating patients gave informed consent. Results: Among 457 patients, 407 patients were re-randomized at Month 12 and entered the switching period; SB16+SB16 (n=206), DEN+DEN (n=101), DEN+SB16 (n=100). A total of 404 patients completed the switching period. The mean %change from baseline in lumbar spine bone mineral density (BMD) at Month 18 was comparable between treatment groups. The least squares mean (LSM) of %change from baseline in lumbar spine BMD at Month 18 was 6.77 (standard error: 0.286) for SB16+SB16. The LSM difference in the lumbar spine BMD change for the full analysis set was –0.03% (90% CI [–0.85, 0.79]) between SB16+SB16 and DEN+DEN, and –0.52 (90% CI [–1.48, 0.43]) between DEN+SB16 and DEN+DEN. The mean %change from baseline in total hip BMD and femoral neck BMD at Month 18 were comparable between treatment groups. The PK, PD, safety, and immunogenicity profiles were also comparable up to Month 18. Conclusion: The efficacy, PK, PD, safety, and immunogenicity among the treatment groups (SB16+SB16, DEN+DEN, and DEN+SB16) were comparable up to Month 18. REFERENCES: [1] Eastell R et al., ASBMR 2023, SUN-432. Acknowledgements: NIL. Disclosure of Interests: Richard Eastell Meeting presentations for Pharmacosmos, Alexion, UCB, Amgen, Consultant for Immunodiagnostic Systems, Sandoz, Samsung Bioepis, CL Bio, CureTeQ, Biocon, Takeda, UCB, Grant funding from Alexion, Osteolabs, Bente Langdahl Speaker for Amgen, UCB, Gedeon-Richter, Astellas, Astra-Zenica, Advisory boards for Amgen, UCB, Consultancy for Samsung Bioepis, Grant/research support from Samsung Bioepis, Yoon-Sok Chung Speakers bureau for Amgen, Consultant for Samsung Bioepis, Grant/research support from Samsung Bioepis, Rafal Plebanski Grant/research support from Samsung Bioepis, Edward Czerwinski Speaker for Amgen, Consultant for Amgen, Grant/research support from Samsung Bioepis, Eva Dokoupilova Grant/research support from Abbvie, Eli Lilly, GSK, Novartis, Biopharma SPRL, Pfizer, Sanofi, Hexal AG, Gilead, Janssen, Galapagos, Samsung Bioepis, Jerzy Supronik Grant/research support from Samsung Bioepis, Jan Rosa Speakers bureau for Amgen, Grant/research support from Samsung Bioepis, Andrzej Mydlak Grant/research support from Samsung Bioepis, Anna Rowinska-Osuch Grant/research support from Samsung Bioepis, Ki-Hyun Baek Grant/research support from Samsung Bioepis, Audrone Urboniene Grant/research support from Samsung Bioepis, Robert Mordaka Grant/research support from Samsung Bioepis, Sohui Ahn Shareholder of Samsung Biologics, Employee of Samsung Bioepis, Young Hee Rho Shareholder of Samsung Biologics, Employee of Samsung Bioepis, Jisuk Ban Shareholder of Samsung Biologics, Employee of Samsung Bioepis.