Carmell Therapeutics’ Bone Putty Reduces Infections, Speeds Bone Healing

Data presented in early September from a recently completed clinical trial with Carmell Therapeutics Corp.’s Repair bone putty show the blood plasma-based putty reduced infections, sped bone healing, and promoted more rapid wound closure of open tibia fractures. David North, M.D., an orthopedic surgeon associated with the University of Cape Town, presented the findings at the South African Orthopaedic Association Congress held Sept. 1-4 in Cape Town, South Africa.

The Repair putty incorporates a material made from blood plasma containing a concentration of natural healing factors that bathe the injured tissue as the material degrades. This first study was designed to assess the safety and performance of the putty in augmenting the healing of fractures.

“We were very pleased and a bit surprised by the results,” said Brian Bernstein, M.D., principal investigator for the study, director of the Orthopaedic Trauma Group in Cape Town and chairman of the South African Orthopaedic Trauma Society. “We are always concerned about infections with open bone fractures, and the idea of using a concentration of natural growth factors to augment healing and reduce infections is especially attractive, particularly if such a product can be offered at a reasonable cost.”

Open fractures are problematic to treat as infections, delayed bone healing, and wound closure/sepsis are significant challenges. In this 30 patient trial, 70 percent of the patients enrolled had more severe type IIIA and IIIB (Gustilo classification for large orthopedic injuries more than 10 cm in size) injuries involving comminuted bone, high levels of contamination and severe soft tissue injuries. Additionally, 67 percent were smokers, a factor known to retard healing, and 70 percent received external fixation that uses pins to penetrate the skin and stabilize the fracture, with an associated high rate of pin-tract infections.

Patients agreeing to participate in the study were randomly placed into either a control or treatment group. The Repair putty was placed into the fracture site during fracture reduction of the treatment patients, and both groups were followed for one year. No adverse events associated with the use of the putty were observed for the 20 treatment patients. A statistically significant acceleration of bone healing occurred at 180 days with more rapid wound closure at 30 days approaching significance for the treatment patients compared to the controls.

While the Carmell anticipated that the putty would accelerate bone healing and wound closure, a big surprise was the reduction in infections. Eighty percent of control patients experienced at least 1 infection during the study compared to only 22 percent of the putty treated injuries, a statistically significant difference.

“We are very excited about the outcomes of this first clinical trial,” said Alan West, Carmell’s CEO. “We had hoped to see accelerated bone healing with faster wound closure, but perhaps the most important outcome of the study was the infection reduction observed. The Repair Bone putty safely and naturally reduced infections and accelerated both bone healing and wound closure. No competitive product can accomplish all three endpoints.”

With the most severe type III injuries, the infection reduction was even more significantly reduced with 100 percent of controls versus 25 percent of treatment patients experiencing at least 1 infection. The relatively high rates of infection for the controls (80 percent & 100 percent) were due to the use of external fixation. When pin related infections were removed from the data, the control group had a 43 percent infection rate for the more severe injuries, which compares well with the reported literature; by contrast, the putty group in this subset had only a 17 percent infection rate.

Carmell officials believe that the infection reduction is largely due to the blood plasma component of the putty not only eluting natural regenerative factors but also recruiting the body’s immune system to the area of the injury over several weeks as it degrades, thereby leveraging the body’s own ability to fight off infections. This result is most significant for trauma patients – high doses of antibiotics are typically given prophylactically to prevent infection, but the rise of antibiotic-resistant bacteria is raising new concerns about antibiotic overuse. The Repair Bone putty may become a game changer in the way these fractures are treated.

Pittsburgh, Pa.-based Carmell Therapeutics develops products manufactured from blood plasma containing a concentration of natural regenerative factors that accelerate the repair of injured tissues.