FDA Hopes to Leverage Regulatory Science to Protect Public from Nuclear, Radiologic Threats

Posted 13 August 2013 | By Alexander Gaffney, RAC 

The US Food and Drug Administration's (FDA) may be most known for its drug and device approvals intended to treat relatively common ailments-diseases, infections, cancer and inherited conditions-but every so often its activities venture into more exotic areas of regulation.

Regulation: The Exciting Stuff

Such an area was on display in a 12 August 2013 announcement in which FDA said it had awarded a $5.6 million contract to Harvard University to assess new medical countermeasures meant to treat radiation sickness by applying a "breakthrough" new regulatory science approach that allows microchips to mimic organ function.

That technology, more commonly referred to as "organs-on-chips" technology, has long been touted by FDA as a method to increase the quality of preclinical testing, allowing companies to have a better idea of how drugs will function once they are eventually used in humans. For example, an organ-on-a-chip that mimics liver function could be used to assess the long-term renal toxicity risks of a drug intended to be taken daily over a long period of time. Without such technologies, such risks might not be discovered until extensive premarket testing, or even long-term post-market testing, was conducted, placing patients at risk.

Of Ethics and Disasters

But when dealing with medical countermeasures, a whole new risk assessment paradigm comes into play. Under normal circumstances, there is a supply (though sometimes limited) of patients afflicted with a condition who agree to sign up for a clinical trial in return for a chance of obtaining an experimental treatment and some form of benefit.

But what happens when there are no unhealthy patients, and no prospect of any soon? That's where innovative regulatory models come into play, such as the organs on chips.

To be sure, there is precedence for this sort of activity. Under the 2002 Animal Efficacy Rule ("the Animal Rule"), sponsors can deviate from acceptable testing standards by conducting efficacy testing on animals if it is intended to treat a disease (e.g. anthrax, botulism, plague) that would otherwise be too dangerous to test on purposefully infected humans.

This logic is now being applied to radiological products as well, according to FDA's notice. With the threat of radiological and nuclear more pronounced in the US since the events of 11 September 2011, regulators have been taking a close look at using science to tentatively approve products when it is either unethical or unfeasible to test them on humans, or when animal models may have limited use to predicting a human response.

Combating Radiation Sickness

In the case of the new contract, FDA said it wants to create a product capable of assessing medical countermeasures for acute radiation syndrome (ARS), better known as radiation sickness.

As FDA explains, ARS is:

an illness affecting a combination of organs, occurs when the body receives a high dose of radiation over a short period of time-as would be expected to occur after a nuclear or radiological incident. The first symptoms of ARS typically are nausea, vomiting and diarrhea. These symptoms will start within minutes to days after the exposure, will last for minutes up to several days, and may come and go. Then the person usually looks and feels healthy for a short time, after which he or she will become sick again with loss of appetite, fatigue, fever, nausea, vomiting, diarrhea, and possibly even seizures and coma. This seriously ill stage may last from a few hours up to several months.

Calling the development of countermeasures to ARS a "high priority for the US government," FDA conceded that "complex scientific challenges" remain to be met given the myriad of organs affected by ARS that make testing the safety and efficacy of any product difficult. And, unlike some drugs approved under the Animal Rule, animal efficacy studies have little overlap with human models when it comes to radiation exposure, limiting their usefulness.

FDA said it hopes the contract with Harvard's Wyss Institute for Biologically Inspired Engineering will give it the capacity to evaluate new countermeasures, in turn spurring their development.

The contract comes on the heels of the signing of the Pandemic and All-Hazards Preparedness Reauthorization Act (PAHPRA) in March 2013, which afforded the agency the authority to grant tentative, limited approvals for products in cases where a "public health emergency" could exist in the future, based on the US Health and Human Service Secretary's determination. A November 2012 guidance on medical devices also established the agency's views on using diagnostic devices as part of a larger countermeasure program.

FDA Contract Announcement

Regulatory Focus newsletters

All the biggest regulatory news and happenings.


Most Viewed Articles