Nanomedicine is the application of nanotechnology to the discipline of medicine: the use of nanoscale materials for the diagnosis, monitoring, control, prevention, and treatment of disease. Nanomedicine holds tremendous promise to revolutionize medicine across disciplines and specialties, but this promise has yet to be fully realized. Beyond the typical complications associated with drug development, the fundamentally different and novel physical and chemical properties of some nanomaterials compared to materials on a larger scale (i.e., their bulk counterparts) can create a unique set of opportunities as well as safety concerns, which have only begun to be explored. As the research community continues to investigate nanomedicines, their efficacy, and the associated safety issues, it is critical to work to close the scientific and regulatory gaps to assure that nanomedicine drives the next generation of biomedical innovation.

There is enormous excitement and expectation surrounding the multidisciplinary field of nanomedicine - the application of nanotechnology to healthcare - which is already influencing the pharmaceutical industry. This is especially true in the design, formulation and delivery of therapeutics. Currently, nanomedicine is poised at a critical stage. However, regulatory guidance in this area is generally lacking and critically needed to provide clarity and legal certainty to manufacturers, policymakers, healthcare providers as well as public. There are hundreds, if not thousands, of nanoproducts on the market for human use but little is known of their health risks, safety data and toxicity profiles. Less is known of nanoproducts that are released into the environment and that come in contact with humans. These nanoproducts, whether they are a drug, device, biologic or combination of any of these, are creating challenges for the Food and Drug Administration (FDA), as regulators struggle to accumulate data and formulate testing criteria to ensure development of safe and efficacious nanoproducts (products incorporating nanoscale technologies). Evidence continues to mount that many nanoproducts inherently posses novel size-based properties and toxicity profiles. Yet, this scientific fact has been generally ignored by the FDA and the agency continues to adopt a precautionary approach to the issue in hopes of countering future potential negative public opinion. As a result, the FDA has simply maintained the status quo with regard to its regulatory policies pertaining to nanomedicine. Therefore, there are no specific laws or mechanisms in place for oversight of nanomedicine and the FDA continues to treat nanoproducts as substantially equivalent ("bioequivalent") to their bulk counterparts. So, for now nanoproducts submitted for FDA review will continue to be subjected to an uncertain regulatory pathway. Such regulatory uncertainty could negatively impact venture funding, stifle nanomedicine research and development (R&D) and erode public acceptance of nanoproducts. The end-result of this could be a delay or loss of commercialized nanoproducts. Whether the FDA eventually creates new regulations, tweaks existing ones or establishes a new regulatory center to handle nanoproducts, for the time being it should at least look at nanoproducts on a case-by-case basis. The FDA should not attempt regulation of nanomedicine by applying existing statutes alone, especially where scientific evidence suggests otherwise. Incorporating nanomedicine regulation into the current regulatory scheme is a poor idea. Regulation of nanomedicine must balance innovation and R&D with the principle of ensuring maximum public health protection and safety.

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Pigs provide a highly sensitive animal model for pseudoallergic infusion reactions, which are mild-to-severe hypersensitivity reactions (HSRs) that arise following intravenous administration of certain nanoparticulate drugs (nanomedicines) and other macromolecular structures. This model has been used in research for three decades and was also proposed by regulatory bodies for preclinical assessment of the risk of HSRs in the clinical stages of nano-drug development. However, there are views challenging the human relevance of the model and its utility in preclinical safety evaluation of nanomedicines. The argument challenging the model refers to the “global response” of pulmonary intravascular macrophages (PIM cells) in the lung of pigs, preventing the distinction of reactogenic from non-reactogenic particles, therefore overestimating the risk of HSRs relative to its occurrence in the normal human population. The goal of this review is to present the large body of experimental and clinical evidence negating the “global response” claim, while also showing the concordance of symptoms caused by different reactogenic nanoparticles in pigs and hypersensitive man. Contrary to the model’s demotion, we propose that the above features, together with the high reproducibility of quantifiable physiological endpoints, validate the porcine “complement activation-related pseudoallergy” (CARPA) model for safety evaluations. However, it needs to be kept in mind that the model is a disease model in the context of hypersensitivity to certain nanomedicines. Rather than toxicity screening, its main purpose is specific identification of HSR hazard, also enabling studies on the mechanism and mitigation of potentially serious HSRs.