As I've written before, antibiotics are too cheap. Drug companies simply can't get sufficient ROI on a product that is used once and costs a few hundred dollars. They would much rather develop drugs that patients take every day for the rest of their lives, or develop cancer medications that bring in $50-100K for a course of therapy.
Via David Shlaes, I see that Brad Spellberg and John Rex have looked into the question of how much a course of antibiotics could cost, and still return a net benefit to all parties. Their hypothetical drug is narrowly targeted toward carbapenem-resistant Acinetobacter baumanii (CRAB), a bug for which all current therapies are ineffective or highly toxic.
They find that at $10K for a course of therapy, an Acinetobacter-specific drug which reduced mortality from 20% to 10% would end up costing some $3000 per year of life saved. The comparable value for Avastin, a best-selling cancer drug, is $168,000. In other words, even a $10K antibiotic is actually pretty cheap.
What Spellberg and Rex don't address is how that cheap/expensive antibiotic gets prescribed in the first place. Since the hypothetical drug is narrowly targeted, there first needs to be an identification that the infectious agent is indeed Acinetobacter, and that it is in fact carbapenem resistant. Standard hospital micro lab procedures can do this, but it typically takes 3 days to get a result. In that time the patient is being treated with ineffective antibiotics, and may well be past the point of recovery by the time the correct diagnosis is made.
The obvious answer - and I know Brad is an advocate of this - is to develop rapid diagnostics that would identify Acinetobacter and determine carbapenem resistance in a few hours from a patient sample or positive blood culture. The first part of this is very doable using nucleic acid technologies. Verigene has a research-use test that ID's Acinetobacter spp, and other platforms surely have the same capacity. However, carbapenemase genes come in lots of varieties and developing a gene sequence test for them that has high sensitivity is no trivial task. And it's necessary, because 25-50% of Acinetobacter infections are still susceptible to carbapenemase, and you don't want to use the new, expensive antibiotic unless it is known that other agents won't work.
But let's say it's doable - what then? To have an impact, the hospital micro lab will have to test every Gram-negative blood culture with this test. Acinetobacter infections are on the rise, but they are still only a few percent of bloodstream infections in the US. Let's say they are 4%. That means that the micro lab will have to run - and pay for - 25 tests to catch a single positive case. Current PCR tests for MRSA, which are much simpler than a prospective carbapenemase test, cost $50-100. A dedicated CRAB test would have to cost at least $200, when fully capitalized and staffed. So the micro lab will have to spend $5000 to make a single diagnosis that drives use of the new $10,000 antibiotic.
That's a lot, but it still makes good economic sense, from a societal standpoint, to spend that money and treat the infection effectively. But society (at least in the US) doesn't make the spending decision - individual actors, such as doctors and microbiology lab managers do, and their incentives do not always align with society's.
We found this out the hard way at MicroPhage. Our test allowed patients with methicillin-susceptible S aureus infections (about half of all S aureus infections) to be taken off empiric vancomycin, and be treated with more-effective and less-toxic beta-lactams. It cost $50, and a typical hospital would have to spend about $2000 in testing to get an actionable result. The savings in health care costs would be $10,000+, making the test very cost-effective.
It was an utter flop in the marketplace, with sales of about $50K in its first and only year on the market. The problem? The micro lab manager, who had to buy the test, paid all of the costs and saw none of the savings. That was pretty much a deal-breaker.
Absent significant structural reform, the hypothetical CRAB test would likely meet the same fate. And without the test, the antibiotic would have much less impact, and likely fail to generate a decent ROI.
None of this is meant as a criticism of Spellberg and Rex. But it points out another layer of structural barriers that we have unwittingly erected to the development of new antibiotics. Unfortunately, until all of these problems are solved, it's as if none of them are solved.
Posted with Blogsy
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