As the National Academies of Sciences, Engineering, and Medicine calls for aggressive action to curb the national drug pricing crisis, the Initiative for Medicines, Access & Knowledge (I-MAK) filed two additional patent challenges against Sovaldi  (sofosbuvir), the backbone of Harvoni and Epclusa. These challenges build on their challenges against six sofosbuvir patents filed in October.

If Gilead’s eight patents are overturned, US taxpayers will save more than $10 billion and generics will come to market 16 years earlier. The challenges come as Argentina rejected the prodrug patent on sofosbuvir based on challenges filed by Fundación Grupo Efecto Positivo (FGEP). China rejected the same prodrug patent on sofosbuvir in response to legal challenges by I-MAK in 2015, and other patient advocacy groups have also filed challenges on sofosbuvir patents in Brazil, Russia, Thailand and Ukraine. In Europe, Gilead's patent rights on the prodrug have been narrowed following a patent challenge by medical humanitarian groups, and this decision is currently under appeal.

“Americans with hepatitis C simply cannot wait decades to be able to afford and access life-saving treatment,” said Tahir Amin, co-founder and co-executive director at I-MAK. “For too long, Gilead has abused our patent system to preserve its stranglehold on the hepatitis C market and keep prices astronomically high. It’s no surprise that more and more patent offices across the world are ruling that Gilead’s patents are unmerited.”

A recent I-MAK white paper found that unmerited pharmaceutical patents on Revlimid, Sovaldi and Gleevec—combined with other industry strategies used to delay competition—cost payers and taxpayers more than $55 billion. As the opioid crisis fuels transmission, the hepatitis C infection rate sits at an all-time high. There are an estimated 3.5 million people with hepatitis C in the US, and more than 85 percent of Americans diagnosed with chronic hepatitis C will not receive treatment this year, largely due to the exorbitant cost of treatment.

I-MAK recently filed the first-ever US hepatitis C legal challenges with the Patent Trial and Appeal Board against six different patents relating to Sovaldi. The two additional patent challenges filed today include:

The Tablet Form of Sovaldi: It has been standard practice for decades across the pharmaceutical industry to make tablets for oral consumption by mixing the active ingredient with inert materials. This commonly practiced technique allows for large scale manufacturing, maintains a tablet’s physical appearance, improves stability and aids the delivery of the drug in a human. Gilead has obtained a patent by simply claiming that it has combined the active ingredient, Sovaldi, with various commonly used inert excipients in a particular weight percentage to make a tablet. Given that the percentage range claimed in this patent is common industry standard for making tablets and is already implied by some of Gilead’s earlier patents on Sovaldi, this is a classic case of how pharmaceutical companies try to extend their patent exclusivity. In this case, Gilead’s tablet patent extends its monopoly beyond the base compound of Sovaldi by an additional four years to 2029.

Combination of two patented compounds: Harvoni consists of two compounds covering the active ingredients, sofosbuvir and ledipasvir. Both compounds have individual patents granted on these active ingredients. It is commonly practiced in the industry to combine two active ingredients, particularly in the field of antivirals such as for HIV treatments. Earlier patents already granted on these active compounds, as well as general literature, state that they can be used in combination with other anti-viral HCV compounds. Combination patents are a part of the pharmaceutical industries toolbox for extending patent exclusivity in order to manage the lifecycle of existing products. In this case, Gilead’s combination patent extends its monopoly beyond the base compound of sofosbuvir by seven years and ledipasvir by two years, until 2032.

Earlier this week, Argentina’s National Institute of Industrial Property (INPI) rejected a patent application on the sofosbuvir prodrug after a legal challenge filed by the Fundación Grupo Efecto Positivo (FGEP) with legal support from I-MAK. Since 2006, I-MAK has challenged unmerited patents worldwide, winning over 80 percent of its cases.

“Across the globe, people with treatable diseases are dying because they cannot access treatment,” said Priti Krishtel, co-founder and co-executive director at I-MAK. “The pharmaceutical industry exploits the patent system to prolong their monopolies on vital medication, and patients pay the price. As our case work advances, more and more patent offices around the world are growing wise to their anticompetitive tricks and overturning Gilead’s unmerited hepatitis C patents.”

I-MAK’s previous challenges and wins on cases on four HIV drugs alone have helped save countries over $500 million—money that can be reinvested to treat more than one million people. Several countries have already rejected or not granted patents for Gilead’s hepatitis C treatments.