From the article: "In the years following albendazole's price hike in 2011, Medicaid spending on the drug went from under $100,000 in 2008 to more than $7.5 million in 2013." To most Congressional Republicans, this is beautiful music begause it means one of their constituents is getting rich by ripping off taxpayers. (Indeed, it may be the only form of music they can appreciate.)
It seems to be because their payments are benchmarked to what private insurers pay and the private insurers don't fight price hikes on drugs with (for them) small total costs.
One fix might be to use a benchmark that is less dependent on whether private insurance bothers to negotiate. Another would be to allow HHS (working with FDA) to arrange for import of certain drugs.