Big Pharma's most extraordinary win came in 2003, when Congress passed a law that at once expanded government health insurance for the elderly, known as Medicare, to include prescription drugs. Martin Shkreli promised to lower the price of the life-saving drug, but reportedly never did. Credit:Bloomberg The law also – and this is not a joke – banned the government from negotiating the prices they would pay the drug companies. That is, once a drug had been approved for coverage, the government was forced to pay whatever the companies demanded. This bewildering concession – normally referred to as simply "Medicare Part D" – was made after a colossal lobbying effort under the Bush administration in 2003.

The pharmaceutical industry spent a staggering $US2.6 billion on lobbying activities between 1998 and 2012, according to OpenSecrets.org. That is four times as much as the defence and aerospace industries spend and almost twice the lobbying outlay of oil and gas companies. According to the Centre for Public Integrity, the pharmaceutical industry employs two lobbyists for each member of Congress and spends $US100 million a year to keep many of those members of Congress on its side. Medicare Part D was eventually passed after an ugly late-night battle on Capitol Hill. The vote was held at 3am, but after 15 minutes normally allowed for ballots to be cast, the legislation had failed, so Republican leadership kept the ballot open almost three hours while they twisted arms and offered inducements.

"The pharmaceutical lobbyists wrote the bill," one disgusted Republican congressman, Walter Jones, told CBS in 2007. "The bill was over 1000 pages. And it got to the members of the House that morning, and we voted for it at about 3 in the morning." The then House Majority Leader, Tom Delay, would later be reprimanded by the House Ethics Committee, which was dominated by his Republican colleagues. As a result drug prices in the United States are the most expensive in the world. The issue has now become a focus of the presidential campaign, at least on the Democratic side, and the industry is taking notice.

Hillary Clinton sent the stock price for drug companies plummeting on Monday when she reacted to news of Turing's hikes with a furious tweet, promising to introduce a plan to control drug prices. She announced details on Tuesday, vowing to stop "excessive profiteering" by imposing a $US250 monthly cap on prescription drugs. Biotech share prices sank as a result. Bernie Sanders, who is challenging Mrs Clinton from the left for the nomination, had already announced a similar plan, but in the wake of the Turing news he has added to it. "The pharmaceutical industry has become a health hazard for the American people," he thundered on Tuesday afternoon.

He would require generic drug companies to rebate money to the government if their prices go up higher than inflation. Like the Sanders legislation, Mrs Clinton's plan would allow the government to negotiate better prices for the drugs it buys and forbid brand-name companies from paying to keep low-cost competitors off the market. In addition, Mrs Clinton would allow Americans to buy prescription drugs abroad, most often in Canada, where prices are far lower. The case of Turing Pharmaceuticals and Daraprim​ is hardly unique. Congress is investigating Valeant Pharmaceuticals after the price for one of their drugs, Isuprel​, went from $US215 per vial to $US1346 per vial. How energetically that investigation will be prosecuted is anyone's guess.

Soon after buying the pain pill Vimovo​ from AstraZeneca​, Horizon Pharma​ bumped the price up by almost 600 per cent. For the CEO of Turing, this is nothing new. When Martin Shkreli​ served as chief executive with another drug company, Retrophin​, he increased the price of Thiola, a drug used to treat a disease that causes kidney stones, from $US135 a month to $US2700 a month. Follow FairfaxForeign on Twitter Follow FairfaxForeign on Facebook