Is it OK for a drug to cost $450,000?

That’s what we asked readers yesterday, in light of how much Alnylam Pharmaceuticals intends to charge for its rare disease drug, and the results were split.

About 56 percent of respondents said Alnylam’s list price was indefensible, regardless of how much the company invested in science and how rare the disease is. The remaining 44 percent said the cost was justified by the drug’s benefit.

As is always the case in drug pricing, the story is complicated. For one, most patients will get the drug at a discount that will likely bring the net price to around $350,000 a year. And then there’s Alnlyam’s plan for a money-back guarantee: The company said it wants to strike deals with insurers in which it will refund the cost of medicine if patients don’t benefit. Just how that will work remains to be seen.