Medical equipment manufacturing company Allegra Orthopaedics (ASX: AMT) reveals further evidence of safety of its bone regeneration device after completing a large animal study. 

The animal study was undertaken at SAHMRI-PIRL (South Australian Health and Medical Research Institute – Preclinical, Imaging and Research Laboratories) under good laboratory practice (GLP) conditions. The research has now progressed to full fusion and histological analysis.

The medical devices—3D printed bioceramic scaffolds—were also used to conduct an animal testing at NAMSA (North American Science Associates) USA. Biological testing revealed that SrHT-Gahnite Cervical Spinal Fusion Cage was non-cytotoxic (did not contaminate cells), non-sensitising, non-irritating, and nonpyrogenic (did not induce a fever). It was implanted in rabbits for 13 weeks, and it did not elicit a reaction from local tissue. The studies proved the biological safety of the Sr-HT-Gahnite device.

Currently, most synthetic bone substitutes either regenerate bone or weight-bear, i.e. handle significant amounts of body weight of the person. Allegra’s Sr-HT-Gahnite device does both, as evidenced in the animal studies. 

The device duplicates the strength and elasticity provided by bone grafts, the traditional transplant surgery to repair damaged bones. In grafting, orthopaedics need to utilise the existing bone in the patient’s body, which can have a range of side effects, including rejection of the bone graft. Additionally, this surgery is all the more challenging when it comes to long bone regeneration as it might not bear the load. 

That’s what makes Allegra’s studies so crucial. Sr-HT-Gahnite’s osteoconductive and osteoinductive properties help to overcome these limitations. The device is made of 90% calcium sulphate, a biocompatible material that is already used in orthopaedic surgery. It can be moulded into any shape and size, which makes it suitable for a wide range of surgeries. Additionally, it is resorbable, meaning that as the new bone starts to grow, Sr-HT-Gahnite degrades and gets absorbed by the body. Essentially, the device mimics the qualities of natural bone.

Furthermore, the lack of serious side-effects and biological acceptance of the grafts are a step in the right direction. Reduced infection risks, medication and morbidity are other positive signs. Based on their current evidence, the Sr-HT-Gahnite device has the potential to accelerate bone growth with optimum efficiency.

Allegra’s Sr-HT-Gahnite device was developed by Professor Hala Zreiqat and her team at The University of Sydney. The Company has licensed the exclusive patent rights from the University, and they comprise the formulation, production techniques and application of the material.

In March of this year, Allegra announced the first published article demonstrating the systemic safety of the material, Sr-HT-Gahnite, under GLP conditions. The study focused on the systemic safety results of implanting the Sr-HT-Gahnite Cervical Fusion Cage in sheep. It revealed that there were no major changes in blood haematology, no systemic distribution of strontium to the blood and wool, and no histopathological abnormalities in the distant organs, compared to baseline and control values. 

The Company is still conducting more tests but if all goes as planned, Allegra expects they are on track to obtain a 90 day FDA 510(k) clearance for the United States in early 2023 for Sr-HT-Gahnite.