NEWS OF THE WEEK
LONGER-LASTING ARTIFICIAL JOINTS MATERIALS SCIENCE: Multilayered thin film could improve replacement joints
O
F THE 700,000 knee replacement surgeries
the Centers for Disease Control & Prevention says are conducted each year in the U.S., 12% of them have to be redone within 10 years. The same is true for hip replacements, according to a 2011 study by a group of European orthopedic surgeons. Part of the reason for the do-overs is bad glue. The goto method currently used by doctors to stick a titanium or plastic implant to the bone in a person’s joint is to apply polymethyl methacrylate (PMMA) cement, says Paula T. Hammond, a chemical engineer at Massachusetts Institute of Technology. This polymeric glue erodes over time, she says, loosening the implant and
EUROPE DEBATES SHARING TRIAL DATA PHARMACEUTICALS: Competitive
SA NOF I
threat seen in open access to clinical trial data
A Viehbacher
PROPOSAL BY Europe’s drug regulatory au-
thority to make data from clinical trials public met with immediate criticism from industry when it was announced last week. The head of the European Federation of Pharmaceutical Industries & Associations, a trade group known as EFPIA, warned that the European Medicines Agency’s proposal could expose competitively sensitive data on research done in Europe to drugmakers around the world. At a press conference in Brussels, Christopher A. Viehbacher, CEO of the French drugmaker Sanofi who was elected president of EFPIA last week, questioned whether European taxpayers want publicly supported research and development “suddenly available to all and at a disadvantage to European companies. ... We’re certainly open to doing things in a different way, but let’s do it intelligently.” CEN.ACS.ORG
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SCI. TRANSL. MED.
A multilayered coating helps glue artificial joints to real bone by slowly releasing BMP-2 (blue blobs), a protein that triggers bone growth.
shedding bits that can cause joint inflammation. To create a stronger, longer-lasting interface between bone and an implant, Hammond and her colleagues developed a two-part multilayer implant coating that sticks well and stimulates bone growth (Sci. Transl. Med. 2013, DOI: 10.1126/scitranslmed.3005576). On the implant surface, the researchers deposit alternating base layers of polyacrylic acid and a mixture of hydroxyapatite, a mineral found in natural bone, and chitosan, a polysaccharide derived from crustacean shells. They then add outer layers of a water-degradable amino ester polymer and a mixture of polyacrylic acid and bone morphogenetic protein-2 (BMP-2), which triggers bone growth. When surgically inserted into the shinbones of rats, a coated implant controllably released BMP-2 slowly, over a 30-day period, which stimulated steady tissue growth between the implant and the rat shinbone. In tests of the mechanical strength of the implants, the researchers found they couldn’t easily remove them—the new coating is two to three times as strong as PMMA cement. Given the number of people needing joint replacements, this new coating could have “considerable humanitarian impact,” says Nicholas A. Kotov, a chemical engineer at the University of Michigan who studies nanocomposites and implantable devices. Hammond and her team have patented the multilayer coating and are seeking funds to test it in larger animals.—LAUREN WOLF
In releasing the draft policy, EMA said it is acting to “balance out the commitment to give widest possible access to data for independent scrutiny with the need to protect personal data as well as legitimate commercially confidential information.” The draft will be open for public comment for three months, and EMA says it expects enactment by Jan. 1, 2014. Some European drugmakers—GlaxoSmithKline, for example—have already committed to publishing clinical trial data. GSK claims to have information on its website on all clinical trials under way, with about 5,000 trial summaries currently available. And in the U.S., the Food & Drug Administration is developing a framework to make available to the public safety and effectiveness data that have been masked to protect patient privacy. The agency already makes clinical summaries of its extensive drug reviews available to the public on its website. And FDA’s advisory committee process provides previews of its initial interpretation of submitted drug information. Meanwhile, EFPIA is at work on its own plan for publishing clinical trial data. “We are currently studying the [EMA] proposal, and at the same time we are finalizing an industry commitment to share patient-level and study-level data with researchers,” the association said in a statement.—RICK MULLIN
JU LY 1 , 2013
