The chief executive of health watchdog Nice told ITV News he is "disappointed" that drug manufacturer Roche has not offered the NHS a discount on a breast cancer drug that costs around £90,000 per patient.
Kadcyla, which extends women's lives by almost six months, could be blocked from routine NHS access because it is too expensive.
"Companies can discount their prices and they frequently do. Given the list price. I would have expected the company to have at least considered (a discount)," Andrew Dillon said.
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The chancellor now faces the prospect of forming a minority government or calling for a snap election.
The 73-year-old said a return is unlikely "given the politicised atmosphere that seems to have afflicted our set."
Chancellor Philip Hammond said the UK will make a financial proposal to the EU in the next three-and-a-half weeks.