As part of its Critical Path Initiative, launched in 2004, the US Food and Drug Administration is encouraging public-private collaborations to more fully explore the physical and chemical characteristics of nanoparticles. The goal is to develop new test methods, characterization protocols, and standards that will help manufacturers move nanoproducts from preclinical testing to commercialization.
GREAT POTENTIALThe federal government spends more than $1 billion a year on its National Nanotechnology Initiative, established in 2001. Some of this funding supports the National Institutes of Health Roadmap Initiative, launched in September 2003, to discover how nanotechnology can enhance our basic understanding of biological concepts and cellular processes. National Cancer Institute officials are particularly enthusiastic about the great potential of nanotechnology to detect cancer at very early stages. Such methods could enable clinical trials to assess efficacy in anticancer therapies much earlier. And "smart" nanotherapeutics could time the release of a drug or deliver multiple drugs sequentially, as well as provide sustained therapy for chronic cancers.
Biomedical nanoscience strategies may facilitate gene therapy development, which has been stymied by difficulties in finding suitable transport agents to carry nucleic acid to the diseased target cell. New nanoscale structures designed to bind and neutralize anthrax toxins may protect people from infectious diseases. Researchers at Montana State University are using disarmed viruses and protein "cage" technology to deliver therapeutic and imaging agents to specific tissues, an approach that may have multiple applications for carrying antibodies, peptides, and other therapies to cells.
FDA has approved nanoscale liposomes and microemulsions, as well as magnetic resonance imaging agents and targeting agents. A treatment for metastatic breast cancer, Abraxane, (Abraxis BioScience, http://www.abraxisbio.com/) uses human albumin to create nanoparticles of Taxol (paclitaxel); the resulting injectable suspension does not require any solvent and thus reduces serious side effects and permits a higher doses for patients. Similarly, Cell Therapeutics of Seattle, WA ( http://www.celltherapeutics.com/) is testing a nanotherapy for lung cancer (Xyotax) that binds Taxol to a polyglutamate polymer, to more efficiently deliver the drug to tumor cells.
These developments are expected to yield more combination products with multiple components, including a delivery system, therapy, and imaging agent. Such complex therapies will challenge FDA's Office of Combination Products in determining the primary mode of action, of which the FDA center has primary regulatory oversight. FDA's Office of Science and Health Coordination oversees nanotechnology activities throughout the agency, including its participation on government-wide nanotechnology committees.
A coalition of environmental and health organizations, led by Center for Technology Assessment, considers these products to be dangerous. The group filed a petition with FDA in May 2006, calling for the agency to pull all over-the-counter nanosunscreens off the market until manufacturers can prove they are safe. The petition seeks new regulations for drugs containing nanoparticles, along with changes in FDA's 1999 sunscreen monograph to require additional analysis of nanoparticles in these products and labeling all nanoingredients.