The performance of a hemostatic agent based on oxidized regenerated cellulose – polyglactin 910 composite in a liver defect model in immunocompetent and athymic rats

Many surgical methods and hemostatic agents can be used to achieve and maintain hemostasis in surgical fields. Numerous clinical situations exist where current treatment modalities are neither effective nor practical. Assessment of new hemostats primarily targets efficacy. However, the biocompatibility and healing properties associated with hemostats are crucial for regulatory approval and product acceptance. Standard biocompatibility and healing studies may not be appropriate for hemostats containing active biologics. Liver defects in NTac:NIH-Whn (athymic) and Sprague Dawley® ™ Outbred (immunocompetent) rats were treated with Fibrin Pad (absorbable matrix containing human-derived biologics) or the matrix only. Defects were evaluated at 14 and 28 days post-implantation. As expected, Fibrin Pad in immunocompetent rats induced a cellular immune response. Unexpectedly, biologically significant decreases in healing, material absorption, and local fibrin degradation were also present. Evaluation of Fibrin Pad in immunocompetent animal models must consider potentially significant alterations in healing, material absorption, and local fibrin degradation, in addition to the expected immune response; none of which may be relevant when Fibrin Pad is used in the clinical setting. These considerations are essential when standard efficacy and biocompatibility studies assessing Fibrin Pad are submitted for regulatory consideration or utilized as pre-clinical translational studies.