Multiple myeloma, a type of blood cancer where malignant plasma cells accumulate in the bone marrow, leads to debilitating bone lesions in 80% of patients. These lesions result in severe pain and fractures that often fail to heal, creating a vicious cycle that supports tumor survival and regrowth. Now, a newly developed biomaterial has shown great promise in treating bone lesions and minimal residual disease in multiple myeloma patients, offering a potential approach for bone healing and tumor control.

A research team from the Translational Oncology Research Centre (TORC) at Vrije Universiteit Brussel (VUB, Brussels, Belgium), in collaboration with German universities, aimed to address the critical challenge of treating multiple myeloma. Their goal was to develop advanced bone repair materials that mimic the stability of healthy trabecular bone while promoting healing by reducing the activity of bone-resorbing cells (osteoclasts) and enhancing the function of bone-building cells (osteoblasts). These materials also needed to deliver localized drug treatments to suppress tumor activity and support bone regeneration.

The result of their work is "sicXer," a "mesoporous silica-collagen xerogel" designed to closely resemble mineralized collagen, the structural foundation of bone. By using innovative silica-based mineralization inspired by marine glass sponge spicules, the team tailored sicXer’s mechanical properties and degradation rates to closely match human bone. Building on this, they developed "boXer," a drug-loaded version of the material. BoXer incorporates bortezomib, an anti-myeloma drug known to stimulate bone formation while effectively killing tumor cells. The drug is released locally at the site of bone lesions, providing a dual therapeutic effect—bone regeneration and localized control of myeloma.

In their paper published in the Journal of Hematology & Oncology, the researchers demonstrated boXer’s ability to stimulate bone formation in preclinical models of both healthy and diseased bone. They also showed that boXer could suppress myeloma cells, including those resistant to systemic bortezomib treatment. The findings suggest significant potential for stabilizing and healing fracture-prone bone lesions. The team envisions sicXer and boXer as part of a new combined systemic and local treatment strategy for multiple myeloma. These materials may also have applications in treating non-malignant diseases involving bone degeneration or fractures.

“This innovation addresses a significant unmet need in multiple myeloma treatment by combining structural bone repair with targeted tumor control. We are eager to move towards clinical testing to realize the potential of sicXer and boXer in improving patient outcomes,” said TORC’s Professor Dirk Hose. 

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