NextCure's NC605 Shows Promise in Treating Osteogenesis Imperfecta with Enhanced Bone Quality
Key Insights
NextCure's anti-Siglec-15 (search) antibody NC605 demonstrated significant reduction in fractures in preclinical osteogenesis imperfecta (search) models, with 90% of treated male mice and 80% of treated female mice showing no fractures post-sacrifice.
The treatment enhanced bone quality by increasing trabecular and cortical tissue mineral density while improving mechanical properties, contrasting with current anti-resorptive treatments that increase density but compromise bone quality.
Male mice showed particularly pronounced benefits including increased trabecular bone volume, cortical thickness, and improved mechanical bone strength measures of max load and stiffness.
NextCure, Inc. announced promising preclinical data for NC605, a novel anti-Siglec-15 (search) antibody, demonstrating enhanced bone quality and reduced fracture incidence in osteogenesis imperfecta (search) (OI) models. The data were presented at the Osteogenesis Imperfecta Federation Europe virtual Investigator Meeting on November 15, 2024, marking a significant advancement in addressing this rare bone disorder.
Addressing Critical Unmet Medical Need
Osteogenesis imperfecta (search), also known as brittle bone disease, is a rare disorder characterized by high bone turnover, abnormal bone formation, bone fragility and recurrent fractures. Currently, there is no cure for OI, and existing anti-resorptive treatments present significant limitations by inhibiting both bone loss and bone formation, leading to increased bone density but overall poor bone quality.
NC605 offers a differentiated mechanism of action by inhibiting bone loss while enhancing osteoblast recruitment to produce new bone, resulting in the generation of quality bone with increased density. This approach addresses the fundamental shortcoming of current therapeutic options.
Significant Fracture Reduction Demonstrated
The preclinical study evaluated fracture incidence and bone quality in male and female OI mice treated with 20 mg/kg of surrogate antibody NP159, the murine monoclonal antibody parent to NC605. The results showed dramatic improvements in fracture prevention across both sexes.
In the treated population, 90% of male OI mice and 80% of female OI mice had no fractures post-sacrifice, compared to 85% and 55% in the control groups, respectively. This represents a substantial improvement, particularly notable in the female population where the control group showed significantly higher fracture rates.
Enhanced Bone Quality Across Multiple Parameters
Both male and female treated mice demonstrated increased trabecular and cortical tissue mineral density, along with increased cortical bone mineral density. These changes collectively resulted in overall enhanced bone quality with better mechanical properties, addressing the core pathology of osteogenesis imperfecta (search).
The treatment showed particularly pronounced benefits in male mice, which exhibited increased trabecular bone volume fraction, including an increase in the number of trabeculae and decreased separation between trabeculae. Additionally, male mice showed increased cortical thickness, with these changes resulting in increased max load and stiffness—critical measures of mechanical bone strength.
Sexual Dimorphism Considerations
"We have again demonstrated that, NP159, a surrogate murine antibody for NC605, reduces fracture incidence in both male and female OI mice. Given sexual dimorphism seen with OI, we noted improved bone quality in the treated male mice specifically," said Solomon Langermann, Ph.D., NextCure's chief scientific officer.
The observed sexual dimorphism in treatment response reflects the complex nature of osteogenesis imperfecta (search) and highlights the importance of considering sex-specific effects in therapeutic development. Despite these differences, Langermann emphasized the broad therapeutic potential: "We continue to believe that NC605 has the potential to be a transformative agent for both female and male OI patients."
Clinical Development Pathway
The preclinical data were generated in collaboration with Dr. Cathleen Raggio from Hospital for Special Surgery, New York, lending additional credibility to the research findings. NextCure, a clinical-stage biopharmaceutical company focused on discovering and developing novel therapies to treat cancer, is expanding its therapeutic focus to address rare bone disorders through its anti-Siglec-15 (search) platform.
The company's approach leverages its core strengths in understanding biological pathways and biomarkers, particularly the interactions of cells and their role in biological responses. This expertise positions NextCure to advance NC605 through clinical development for osteogenesis imperfecta (search) patients who currently have limited therapeutic options.