Patents are a monopoly. Efficient resource allocation is therefore impossible.
If you have some magical formula that would avoid doing I'm sure that NICE would love to hear from you.
If governments were making their own generic drugs and sold them at cost then it would help avoid situations like Martin Shkreli. The drug wasn't protected by a patent, it's just that nobody else produced that drug. In my opinion this seems like a reasonable thing for governments to do.
Also, the best treatments aren't always available in this first place. Eg (at least a few years ago, don't know today) Adderall was illegal as a treatment here. Some EU countries, until recently, even treated methylphenidate like that.
It's been put at about $10 million, for the purposes of EPA regulations. Insurance companies have their own formula, from a couple hundred thousand into the millions, and healthcare users QUALYs - quality-adjusted life years, and those are priced at $50,000-$150,000.