Is Generic Insulin's Absence Interfering with Patient Adherence?

The lack of generic insulin may keep patients from using the medicine, even though they risk life-threatening complications, new research from Johns Hopkins University School of Medicine suggests.

Incremental tweaks to insulin formulations have allowed manufacturers to extended patent protection, according to study authors Jeremy Greene, MD, PhD, and Kevin Riggs, MD, MPH. The evergreening practice creates less incentive for generic manufacturers to make insulin versions because those versions can be perceived as being obsolete.

Although insulin was discovered in 1921, the university manufacturing it at the time gave drug companies the right to manufacture it and patent any improvements in 1923. Patents on the first synthetic insulin expired in 2014; however, a complicated manufacturing process makes creating generic versions more difficult. As a result, generic insulin versions must undergo a lengthy approval process, and they cost more to make than other, simpler generic medications. According to Drs. Riggs and Greene, any generic insulin entering the market may cost 20% to 40% less than brand name products.

The study, which appeared in the March 19, 2015, edition of The New England Journal of Medicine, highlights the limits on generic competition and its effect on public health.

“We see generic drugs as a rare success story, providing better quality at a cheaper price,” said Dr. Greene, a practicing internist and associate professor of the history of medicine. “And we see the progression from patented drug to generic drug as almost automatic. But the history of insulin highlights the limits of generic competition as a framework for protecting the public health.”

Insulin can cost between $120 and $400 per month if a patient’s insurance does not cover prescription drugs or if a patient does not have insurance, the researchers said. Patients who cannot afford the medicine face painful, costly complications, including blindness, kidney failure, gangrene, and limb loss, they added.

Coupling insulin cost with the inconvenience some patients have when taking the drug can lead to nonadherence.

“Insulin is an inconvenient medicine even for people who can afford it,” Dr. Riggs, a general internal medicine research fellow, said in a press release. “When people can’t afford it, they often stop taking it altogether.”