Hillary Clinton proposes to impose a monthly cap of $250 on out-of-pocket prescription drug costs for patients with chronic or serious medical conditions.

She also proposes a programme to encourage the wider use of generic rather than branded drugs and to end pharmaceutical companies’ ability to write off the cost of ads targeted directly at consumers.

Good. https://t.co/UkOr0vfeHX

— Hillary Clinton (@HillaryClinton) September 22, 2015

She had promised to outline such a programme in a tweet on Monday where she expressed her outrage at the way Turing Pharmaceuticals, a startup biotech company, had raised the price of a treatment for parasitic infections from $13.50 to $750 overnight - an increase of over 5,000%.

Hillary Clinton referenced Turing again in her speech yesterday, "That is not the way the market is supposed to work. That is bad actors making a fortune off of people’s misfortune,'' she said.

"Pharmaceutical companies can charge astronomical fees, far beyond anything it would take to recoup their investment and far beyond’’ - adding that they charge higher prices in the US than in other territories.

Turing has since pledged to reduce the price, but the Nasdaq biotechnology sector fell by another 1.7% in value yesterday after dropping 4.5% on Monday.