How is a person "harmed" by someone creating a drug that can save their life?
If you spend some logical thought time on it, when politicians take away the profit incentive and because of that a drug does NOT get invented, the politicians themselves are the one doing harm.
Have you ever heard of an "Adhesion Contract?" That is where one person has all the power in a bargaining position and the other party is free to pay what is demanded or walk away. Such contracts are controlled and rightly so.
A person would certainly be harmed if the drug company used its bargaining power viv-a-vis the consumer. The flaw in the Libertarian argument is their failure to recognize there is a vast difference in bargaining power among various persons, firms or entities. Imagine you personally going to a giant drug company and trying to bargain their price down for a drug that would save your five year olds life.