NextCure's Antibody Shows Promise for Rare Brittle Bone Disease

Maryland-based biotech company NextCure has made significant strides in developing a potential treatment for osteogenesis imperfecta (OI), commonly known as brittle bone disease. The company's antibody, NC605, has demonstrated promising results in preclinical studies, strengthening bones and reducing fractures in mice with the condition.

Breakthrough in Bone Density Improvement

NextCure's NC605 antibody has shown comparable efficacy to anti-sclerostin treatments in improving both trabecular and cortical bone density. Dr. Priyanka Kothari, NextCure's director of translational research, stated, "NC605 improved trabecular and cortical bone density and reduced fracture incidence comparable to anti-sclerostin." This development is particularly significant as there is currently no FDA-approved standard of care for OI patients.

The antibody targets Siglec-15, a receptor found on osteoclasts, cells responsible for bone tissue breakdown. By inhibiting Siglec-15, NC605 aims to halt the process of bone destruction, potentially offering a new mechanism of action for treating brittle bone disease.

Seeking Partners for Clinical Development

NextCure is actively seeking financial support and partnerships to advance NC605 into clinical trials. The company aims to submit an investigational new drug (IND) application within the next 12 to 18 months. This move aligns with NextCure's November 2024 announcement of refocusing efforts on tumor-targeting antibody-drug conjugates (ADCs).

The search for partners comes at a crucial time for NextCure, as the company navigates its pipeline following the discontinuation of another anti-Siglec-15 antibody, NC318, in 2022. Despite this setback, NextCure continues to support ongoing trials, including a study of NC318 in combination with Merck's Keytruda for advanced non-small cell lung cancer at Yale University.

Competitive Landscape in Rare Bone Disorders

NextCure's NC605 enters a field where other companies are also making progress. Notably, Ultragenyx and Mereo BioPharma are currently conducting a phase 3 trial for an anti-sclerostin treatment for OI. Additionally, Amgen's Evenity (romosozumab-aqqg), an anti-sclerostin antibody, is already approved for postmenopausal women with osteoporosis.

The development of NC605 represents a potential new approach to treating OI, a rare genetic disorder characterized by weakened bones that fracture easily. Current treatments focus primarily on symptom management and fracture prevention. If successful, NC605 could offer a targeted therapy that addresses the underlying bone fragility in OI patients.