There are over six million fractures per year in the US with direct costs in the billions, not to mention lost productivity. The only drug currently available to accelerate the healing process must be applied directly to the fracture surface during surgery, but not all breaks require such intervention

New research, Bone Fracture-Targeted Dasatinib Conjugate Potently Enhances Fracture Repair In Vivo, presented today at the 2018 American Association of Pharmaceutical Scientists (AAPS) PharmSci 360 Meeting highlights a novel bone anabolic agent, when injected, intravenously reduces femur fracture healing time by 60% without impacting the surrounding healthy tissue.

Researchers from Purdue University designed a new chemical entity (to dasatinib-aspartate10 conjugate, DAC) that employs a targeted peptide to dasatinib, an anti-cancer drug that has been shown to promote the growth of new bones.

Following systemic injection, DAC is observed to concentrate on the fracture surface, resulting in accelerated repair and increased bone density. The data shows that the healing process that takes eight weeks for full recovery of mechanical strength is reduced to three to four weeks when treated with the targeted drug.

"We foresee a significant need for this type of therapy," said presenting author, Mingding Wang, Purdue University. "Even though many broken bones do not need surgery, most require a prolonged  healing process that can lead to morbidity, loss of work productivity, and in some cases even death. or tissues, we can hopefully address these critical issues. "

Best treatment

The study results indicate that treatment with DAC, yielding at a 114% increase in bone density, and was found to be the best treatment interval. Reducing this dosing interval to every four days, however, resulted in a measurable decline in potency. Since the blood supply to the fracture area is often disrupted, after a fracture, waiting for a week or two for blood vessels to stabilize prior to administering DAC did not negatively impact its effectiveness or the healing speed.

While administration of nontargeted dasatinib provided some improvement in healing rate, DAC was dramatically better, doubling the bone density. In addition, since the nontargeted form of dasatinib is administered chronically to cancer patients without significant toxicity, the fracture-targeted form is expected to be even safer. That is, when dasatinib is selectivity targeted to the bone fracture surface, its presence in all other tissues should be greatly reduced.

Philip Low, principal investigator and Presidential Scholar for Drug Discovery, Purdue Institute for Drug Discovery noted, "While the use of casts, rods, or pins may be required in some cases, the ability of this therapy to accelerate the return of a fracture patient to normal function and lifestyle could have widespread benefits to the entire orthopedic community. "

The next stage of the investigation is proof of the efficacy of DAC in additional fractures, including long  bone  fractures, hip fractures, nonunion fractures, spinal fusions, and craniofacial  fractures .