Clinical Validation of Allogeneic Morphogenetic Protein: Donor Intervariability, Terminal Irradiation and Age of Product is not Clinically Relevant Christopher Yeung 1* , Justin Field 1 and Jeffrey Roh 2 1 Desert Institute for Spine Care, Phoenix, AZ, USA 2 Orthopedics International, Kirkland, WA, USA * Corresponding author: Christopher Yeung, Desert Institute for Spine Care, 1635 E Myrtle Ave, Phoenix, AZ, USA, Tel: 602-944-2900; E-mail: christopheryeungmd@gmail.com Rec date: Jan 14, 2014, Acc date: Jun 26, 2014, Pub date: Jun 29, 2014 Copyright: © 2014 Yeung C, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Donor to donor variation has long been a concern of the allograft industry. DBM and stem cell products have been particularly susceptible to intervariability between donors, regardless of the process used to manufacture these products. Manufacturers of allograft based products have often utilized in vitro or small animal models to help predict reliability, yet little data is available correlating preclinical outcomes with clinical efficacy. OsteoAMP is a commercially available allograft-derived growth factor rich in osteoinductive, angiogenic, and mitogenic proteins. An analysis of radiographic results comparing fusion outcomes was conducted for 285 consecutive cervical and lumbar spinal fusion patients utilizing OsteoAMP bone grafts from 114 donors of varying ages. A blinded radiological fusion assessment, performed by an independent radiologist, showed all patients, except one, fused within 18 months (average time to fusion was 189.9 days). This evidentiary analysis shows that OsteoAMP fusion success did not show donor intervariability and that fusion rate/time is not dependent on donor age. In addition, the implant retained bioactivity over time and terminal sterilization via low-dose gamma irradiation did not impair the bioactivity of the grafts. Keywords: Donor intervariability; Allograft; OsteoAMP; Spine fusion Introduction Clinical efficacy between donors has been a challenge in the allograft industry for many decades [1,2]. Compounding the problem, research has shown that there is in fact more variability between donors than between products and the processes used to manufacture these products [3,4]. Variables contributing to these concerns include donor age and gender, processing techniques and sterilization methods [2,5]. According to the U.S. Department of Health & Human Services approximately 60% of deceased donors recovered in the US between 1988 and 2013 were male with the majority of all donors ranging in age between 35 and 64 years. To try and predict efficacy of the tissue recovered, demineralized bone matrix (DBM) products and stem cell products often utilize in vitro or ectopic rat in vivo assays. There have been little data correlating preclinical outcomes with clinical efficacy, limiting the value of such testing [2]. Quite often, the donor material tested preclinically is at an intermediary processing step, prior to terminal sterilization and storage. Sterilization is a critical process to ensure graft preservation [6]. There have been a number of product recalls in recent years for products that do not undergo terminal sterilization. In particular, allograft-derived stem cell products have been reported to the US Food and Drug Administration for contamination of hepatitis [7] and multiple strains of clostridium [8-10]. Terminal sterilization provides the surgeon with an additional safeguard against microbial contaminates, although the perceived detrimental effects of irradiation have caused uncertainty in its overall clinical value [11]. Studies have shown that irradiation with 25 kGy reduces osteoblast differentiation and expression of BMP-7 when compared to non-irradiated human bone allograft implanted in a nude rat model [12]. Other studies have shown that irradiation used by bone banks did not influence the inductive properties of DBM [13,14]. In addition, adding a carrier like lecithin to a DBM could negatively influence biological activity after sterilization [11]. This study attempted to identify the effects of processing and donor selection used for a novel allograft growth factor by analyzing the fusion rates of patients that underwent spine surgery. It was hypothesized that the growth factors remained bioavailable and were not affected by the age of the donor, the age of the product or whether the product was irradiated. Methods and Materials A retrospective radiographic analysis was conducted to evaluate the fusion success rate in patients receiving allograft material from donors of different genders, ages and preparations utilizing a commercially available allogeneic morphogenetic protein, OsteoAMP® (Advanced Biologics, Carlsbad, CA). The study involved two sites with three treating physicians total. The indications for surgery were symptomatic patients diagnosed with degenerative disc disease (DDD), stenosis, and/or spondylolisthesis. OsteoAMP bone allograft was processed from human cadavers cleared for implantation utilizing a proprietary processing technique. OsteoAMP was selected as the biologic and used in conjunction with the centers’ preferred spinal spacer and fixation system. All products were prepared per the instructions for use. No other biologic product Spine Yeung, et al., J Spine 2014, 3:3 http://dx.doi.org/10.4172/2165-7939.1000173 Research Article Open Access J Spine ISSN:2165-7939 JSP, an open access journal Volume 3 • Issue 3 • 1000173