SPD8 is GlycoNex’s denosumab biosimilar, co-developed with Mitsubishi Gas Chemical. Denosumab is a fully human IgG2 monoclonal antibody targeting RANKL, and is marketed as Prolia® for osteoporosis and Xgeva® for the prevention of skeletal complications associated with malignancy. Following database unblinding in June 2026, the trial achieved positive top-line results and met its primary endpoint, supporting clinical comparability with the reference product. GlycoNex plans to submit a marketing authorization application to Japan’s Pharmaceuticals and Medical Devices Agency in the third quarter of 2026 subject to regulatory review. In December 2024, GlycoNex licensed the Japanese commercialization rights for SPD8 to an undisclosed pharmaceutical partner under an agreement that includes upfront and milestone payments, while retaining commercialization rights in markets outside Japan, which remain available for partnership.
SPD8
Denosumab Biosimilar
About SPD8
Targeting the RANKL pathway
Denosumab and its biosimilars work by binding to RANKL (Receptor Activator of Nuclear Factor κB Ligand), a key signaling protein that activates osteoclasts — the cells responsible for bone resorption. By neutralizing RANKL, denosumab inhibits osteoclast formation, function, and survival, thereby reducing bone resorption and increasing bone mineral density in osteoporosis. In oncology contexts, the same mechanism prevents the bone destruction caused by tumor cells, reducing skeletal-related events in patients with bone metastases. SPD8 is engineered to deliver this same mechanism with biosimilar levels of analytical, nonclinical, and clinical equivalence to denosumab.
Demonstrating biosimilarity to denosumab
Biosimilar development requires demonstrating equivalence to the reference product across three distinct comparability layers. GlycoNex's approach leverages its proprietary integrated glycan analytical platform — particularly important for denosumab, where glycan composition is a critical quality attribute — alongside conventional structural, functional, and clinical characterization. SPD8's development program is designed around full alignment with ICH Q6B principles and the regulatory expectations of Japan's PMDA, Taiwan's TFDA, and additional target markets.
Comparability
Structural and physicochemical characterization including primary sequence, post-translational modifications, N-glycan profile, and higher-order structure.
Key platforms: LC-MS, ion chromatography, capillary electrophoresis, and intact mass spectrometry — covering the critical quality attributes regulators expect for an IgG2 with complex glycosylation.
Comparability
In vitro functional assays, receptor binding, signaling pathway inhibition, and osteoclast function assays in cell-based systems.
Validated against reference denosumab in head-to-head studies, demonstrating equivalent potency, binding kinetics, and downstream biological response across the relevant assay panel.
Comparability
Pharmacokinetic equivalence, pharmacodynamic equivalence, and clinical efficacy and safety trial in patients — Phase 3 trial in Japan completed October 2025.
Primary endpoint: percent change in bone mineral density at the lumbar spine, the standard regulatory measure for postmenopausal osteoporosis biosimilarity readouts.
Supported by GlycoNex's GMP-compliant manufacturing facility (50L + 200L scales) and an external advisory team with deep expertise in PMDA and FDA CMC regulatory pathways.
Phase 3 Trial
SPD8's pivotal Phase 3 trial was conducted in Japan to evaluate clinical equivalence with reference denosumab in patients with osteoporosis. Enrollment completed on October 29, 2025. The trial was unblinded in June 2026 with positive top-line results, meeting the primary endpoint (percent change in bone mineral density) and confirming clinical comparability to reference denosumab.
Development & regulatory pathway
SPD8's Phase 3 unblinding in June 2026 — positive top-line results meeting the primary endpoint — is the program's key value-creation milestone, de-risking the subsequent regulatory and commercial path.
Bone health: a sustained therapeutic need
Osteoporosis remains a major global health burden, with fracture-related morbidity and mortality particularly elevated in older populations.
Cancer-related skeletal events also affect a substantial patient population with metastatic bone disease.
Amgen's 2025 denosumab sales reflect emerging biosimilar competition, down from prior-year levels.
Two paths for collaboration
SPD8's development has been validated by a Japan commercialization agreement signed in December 2024. Two distinct partnership opportunities remain — and we welcome inquiries on both.
Proven biosimilar execution
GlycoNex has demonstrated full biosimilar development capability through SPD8, from analytical characterization through Phase 3 clinical trial completion.
- MGC co-development since 2018
- Phase 3 enrollment completed October 2025
- Japan commercialization rights out-licensed December 2024
- BLA filing planned Q3 2026
Companies seeking a development partner with proven end-to-end biosimilar capability — particularly for complex monoclonal antibodies where glycan analytical capability matters.
ex-Japan rights available
GlycoNex retains all ex-Japan commercialization rights for SPD8. With Phase 3 complete and a clear regulatory path, the asset is positioned for partnership discussions with global or regional commercialization partners outside Japan.
- Phase 3 trial complete (October 2025)
- Positive Phase 3 top-line (June 2026) — primary endpoint met
- Regulatory dossier mature for Japan filing (Q3 2026); ex-Japan filing strategy adaptable to partner preferences
- Manufacturing supported by GlycoNex GMP facility
Pharmaceutical and biopharmaceutical companies seeking commercial-stage biosimilar assets in markets outside Japan, including Asia-Pacific, Europe, North America, and emerging markets.
A clinical-stage biosimilar, validated by Japan licensing
SPD8's positive Phase 3 top-line results (June 2026) mark a key value-creation milestone ahead of BLA filing.