ERC-RMB Represents the State of the Art in the Absorbable Magnesium Alloy Research Space at ASTM-FDA Workshop on Absorbable Medical Devices

Outcome / accomplishment: On November 28, 2012, ASTM and FDA co-sponsored a workshop to provide a forum for industry, academia and FDA to discuss test methods for establishing correlations between in vitro and in vivo degradation of absorbable implant devices, and the interaction of mechanical loading and mechanical performance with degradation, with a particular focus on cardiovascular devices.   This workshop (ASTM-FDA Workshop on Absorbable Medical Devices: Lessons Learned from Correlations of Bench Testing and Clinical Performance) was held at the FDA’s White Oak, MD, campus, was unique in that it brought researchers working in the absorbable polymers and metals fields together to share their experiences and challenges. ERC-RMB was invited to represent the state of the art in the absorbable magnesium alloy space.
Impact / benefits: This workshop was attended by ~150 expert academic and industrial researchers, clinicians and regulators actively engaged in absorbable materials R&D from around the globe. This forum enriched the absorbable metals community through drawing meaningful comparisons with the challenges faced by the absorbable polymer community and discussing the manner in which they are being addressed. It was determined that this interaction was useful, and additional meetings between the absorbable polymers and metals communities should be held.
Explanation / background: The use of absorbable materials poses risks due to the critical fatigue and mechanical loading demands that the implant must withstand and perform. However, the optimal preclinical/bench testing paradigm to predict clinical performance of fully absorbable cardiovascular devices is not yet defined.   This workshop discussed the use of absorbable materials (including synthetic polymers as well as erodible metals) in medical devices across a broad range of indications with the aim of defining successful and unsuccessful methods to predict clinical performance.   Topics discussed included correlations of in vitro and in vivo absorption, quantitative characterization of absorption kinetics, test methods to identify interactions of absorption with mechanical loading and, test methods to assess mechanical performance of the absorbable product. 
       Dr. Frank Witte, Associate Professor of Experimental Orthopedics at the Hannover Medical School and Global Coordinator for ERC-RMB, represented the collective views of the absorbable metals community in a presentation titled “Current Opinion of the Science Community on Guidelines and Testing of Biodegradable Metals”. This presentation was based on findings from the 1st Minimum Consensus on Standardization in Biodegradable Metals at the 4th Biometals Conference, held in Maratea, Italy from August 28 to September 1, 2012. Suggestions for standard materials screening tests, device performance tests and reference standard alloys were discussed.
       Dr. Yeoheung Yun, Associate Professor of Bioengineering at North Carolina A&T state University and leader for the ERC-RMB’s studies towards standardization of corrosion characterization studies gave a presentation titled: “Testing Corrosion for Biodegradable Mg alloys: Science, Current Methods, and Limitation”. In his talk, Dr. Yun discussed the challenges faced in testing materials absorption, particularly in correlating in-vitro test results with in-vivo performance. Confounding factors include local perfusion, exposure to proteins, and the impact of solutes on degradation product composition.
       Dr. Lisa Ferrara, Owner and President of OrthoKinetic Testing Technologies and Chair of the ERC-RMB Industrial Advisory Board, discussed “Mechanical Evaluation of Biodegradable Magnesium and Magnesium Alloys: Identifying the Necessary Testing, Challenges, and Pitfalls for Biomaterial Characterization”. Dr. Ferrara shared her experience in testing biomaterials testing with the group, emphasizing the potential pitfalls resulting from poor study design and the need for a team approach to test development to avoid these problems. 
In addition to these presentations, ERC leadership and PIs had the opportunity to build and strengthen relationships with key industrial colleagues, ISO, ASTM and FDA.