Combination product development alone is very tricky because of the FDA’s rudimentary policies on combination products. Manufacturers are often left scratching their heads as to which regulatory pathway to follow for their combination product even before it is complete; they are asking themselves, which FDA center has responsibility over my product? Is my product a device or is it really a drug? For example, an antibacterial adhesive bandage is both a medical device because it controls minor bleeding but the antibiotic used to prevent infection also makes it a drug. I would rather have my product be considered a device because they are managed by risk classification (more flexibility) while all new drugs must go through pre-market approval and a new drug application. The FDA’s current determination criteria is, what is the major mode/purpose of this product? For a device leaning combination product, the manufacturer must then prove that its purpose is not achieved through a chemical reaction.

Now combine human factor studies into this and the headache becomes bigger. To answer your question, combination products need a combination of human factor studies and nonconventional reliability tests, i.e. a combination of product control and clinical studies. The issue with this is that clinical tests can only be done at the very end, once the product is finished. Combination products may change design after HF validation because of failure during clinical trials for pre-market approval. This means product revision is an arduous time and paperwork consuming process (that also impedes medical innovation). The FDA should rework their policies on combination product development.

References:
http://www.fda.gov/downloads/RegulatoryInformation/Guidances/UCM484345.pdf
http://thehill.com/blogs/pundits-blog/healthcare/250280-fixing-the-fdas-broken-combination-products-policies