You should be careful about suggesting that vanilla libertarians should abandon it. I'll explain why.

The problem with non-aggression principle libertarianism is sociopaths like Martin Shkreli. On one side of it, those guys are regulated to do less harm, and on the other, they get murdered for a bounty. But right there in the middle of NAP-libertarianism, a sociopathic rent-seeker can be as much of a selfish asshole as he wants, because one man's asshole is another's visionary leader, and NAP-libertarians judge all deviant behaviors by identifiable and measurable harm to victims. Shkreli is not actually causing harm here, so he's A-OK by NAP standards.

In this case, sick people are not able to compel the involuntary services of physicians and chemists, so they do not have the right to be provided with life-saving drugs. But nor does any other party have the right to prevent those people from acquiring them. So it would be inevitable for economic conditions to align on one drug or another such that the pricing rubs the median person's sense of justice the wrong way. The startup costs are just too high to be recovered, considering the marginal cost of production and the existing demand, so a natural monopoly forms. And there's the asshole in the middle of it, charging other people rent on their own health.

From one point of view, he is charging them less than what it would cost them to treat themselves. But from another, he is profiting from human misery.

Hard-core NAP-libertarians would probably suggest that other people should charge Shkreli $10000/night for hotel rooms, $100/gallon for gasoline, and $500/slice for pie, a solution that requires extensive reputation tracking systems and broad community support. After all, he has no more right to cheap food than others have a right to cheap drugs.

For a preview of how this would work, look at any social justice warriors' controversy of the last decade. Both actual assholes and those merely accused would be tried in the court of public opinion, then sentenced to a lifetime of petty reprisals from every angle. People get fired and blackballed for one ill-considered phrase or act that follows them for a long, long time. In this, jacking up pill prices by 1000% would be very much like refusing to marry homosexuals, or carelessly saying forbidden words.

You may not be aware of this, but NAP-libertarians are actually very reasonable moderates in the realm of libertarianism. Those who think it unworkable in practice have other options beyond a return to mainstream politics. They could sidestep into other moderate forms that better handle any one specific issue, or they could move on into the various forms of structured anarchism.

Every political philosophy has its weaknesses, but I'm not certain that this case is enough for a NAP-libertarian to justify altering any core values. Price gouging in very small niche markets just does not seem all that bad of a problem, in comparison to the related problems that could stem from the solutions that similar political philosophies would provide. I have to say that NAP-libertarianism produces better outcomes in this specific case than even my own politics. (That's not an endorsement.)