system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why are Anti-Cancer drugs so expensive?
gpt
Cancer is a tremendous collection of wildly different conditions, each of which can require the development of very different cancer drugs to either treat or prevent.

Some anti-cancer drugs exist now and are very expensive. Others have yet to be developed, with many of those in their research and testing phases now. When they're available, they will be very expensive too. 

They're so expensive because they're being developed by private or public companies who have a responsibility to their own shareholders and owners to make a profit. To make a profit, the price you sell something at has to be greater than the price required to create it.

And this is the problem: the price to create and sell an anti-cancer drug is **ABSOLUTELY ENORMOUS**. Here's the steps:

* research and development to identify possible treatment vectors

* animal testing

* safety testing 

* clinical trials on volunteer patients, often over years.

* approval from government medicinal and drug organizations

Every one of those steps takes time and costs a lot of money, and your new drug could fail at any one of those stages, meaning all of that money you spent you get NOTHING for.

So companies in the anti-cancer drug business charge a lot because they have to pay for the drug they're producing, plus finance all the drug variants that are in development, and cover the lost costs of all of the drug variants that didn't pass their tests... and still earn a profit for their shareholders.