A Plos One paper by Beall et al.
This paper analyses medicine/device patent combinations in Athma, Diabetes, COPD and severe allergic reactions to look for evidence of device patents being used to extend market exclusivity.
The paper found that patents on devices, which result in longer patent protection of the medicines they are given with, are very common. The median additional years of patent protection afforded by device patents was 4.7 years (range: 1.3–15.2 years).
“Incremental, patentable innovation in devices to extend the overall patent protection of medicine/device product combinations is very common.”
“Our study demonstrates that medicines for which patents have long expired in the United States can be placed behind a second tier of patent protection for their delivery devices.”
“In the health-specific definition, evergreening occurs when a secondary patent extends the product’s exclusivity period without a proportionate therapeutic benefit. Under this definition, many of the products in this study were arguably evergreened, because the medicines would have the same (or very nearly so) therapeutic benefit if administered by an alternative device.”
Beall RF, Nickerson JW, Kaplan WA, Attaran A (2016) Is Patent “Evergreening” Restricting Access to Medicine/Device Combination Products? PLoS ONE 11(2): e0148939. doi:10.1371/journal. pone.0148939