This is a guest post by Taylor J. Christensen, M.D. (@taylorjayc). Dr. Christensen is an internal medicine physician and health policy researcher with a background in business strategy and health services research.

Since any mystery in the healthcare system intrigues me, I’ve been working on understanding pharmacy benefit managers (PBMs) lately.

Why did PBMs arise in the first place, and how did they come to have this somewhat strange role in the drug market? Let’s look at the evolution of PBMs, which I will categorize into three distinct phases.

Forewarning: There isn’t a lot of publicly available information on this stuff, so some of this is my best piecing together of things I’ve read plus supplemented by direct communications with people who work for insurers or PBMs.

Phase 1

Way back before PBMs, people used to pay for medications 100% up front out of pocket. They’d keep their receipts and then submit them all to their insurer later for partial reimbursement according to their insurance plan’s formulary.

That clearly had some downsides. If a patient couldn’t afford the full price up front, they would be stuck choosing which of their meds they’re not going to get, which is bad for both patients (nonadherence) and pharmacies (lost sales). Insurers also had to spend tons of time reconciling shoeboxes full of receipts.

If only there were a way to integrate an insurer’s formulary into the pharmacy’s computer system so that patients only pay their exact copay at the time they fill a prescription! Everyone would be a lot happier. Patients wouldn’t have to forego quite so many medications, pharmacies wouldn’t lose out on as many medication sales, and insurers wouldn’t have to deal with people sending in shoeboxes full of receipts. Win win win.

Enter the precursors to pharmacy benefit managers—they were essentially groups of software engineers tasked with working with pharmacies to get insurers’ formularies into the pharmacies’ computer systems. And they succeeded! After that, when a patient showed up to fill a prescription, the pharmacy would simply enter the patient’s insurance information into their system and the exact co-pay for that medicine would magically appear on the cash register’s screen. The patient paid their amount, and the transaction was then sent to the insurer to reimburse the rest.

But how did these precursor PBMs evolve into today’s PBMs that, among other things, “manage benefits”? My guess is that it went something like this .  . .

Phase 2

These precursor PBMs got pretty good at integrating formularies into pharmacies’ systems, so they began to expand their customer base by helping lots of other insurers do the same thing.

Soon they became more familiar with all the complexities and intricacies of formularies than anyone else. And, as companies are wont to do, they leveraged that competency to make more money by offering a new service, which they maybe pitched to insurers like this: “Hey insurer, we already know all the details of your formulary. And we know where you could save money since formularies are kind of our thing. Why don’t you outsource your formulary-making efforts to us? We’ll make you a better formulary and charge less than it’s costing you to do it in-house right now. No-brainer, right?” And thus, not too long after their inception, PBMs officially started managing pharmacy benefits.

But that’s not where the story ends.

Phase 3 (dun dun dun)

Soon these PBMs found that they had amassed significant indirect control over which medicines patients get. Set a lower copay for a medicine and, sooner or later, more patients will end up taking it. And the one making the formulary is the one who sets the copays.

What did PBMs do with that power? They tried to leverage it to get better drug prices from manufacturers, which would allow them to offer an equivalent but cheaper formulary to their customers (insurers). But how, if they are not actually in the drug supply chain (that goes from drug manufacturers à drug wholesalers à pharmacies à patients) could they do that?

They cleverly reached out to the drug manufacturers directly and said something like this: “Hey drug manufacturer, we don’t actually have a direct financial relationship with you (yet). But we have significant control over how many sales you get because we set patients’ copays. How about we guarantee that your drug will, from now on, be the only one from its category in the lowest-copay tier? This will increase your sales quite a bit! And, in exchange for helping you get more sales, you can send us a “rebate” on every sale. So this is how it will work. We already keep track of every drug transaction, so every quarter we will send you the data to show how many patients using our formulary bought your drug, and you will send us a $10 rebate for each one.”

Contrary to popular belief, PBMs don’t keep all of this rebate money. Remember, their goal is to outbid other PBMs to offer the best formulary for the cheapest. And if the PBM market is competitive, they will have some degree of price competition that will force them to pass along some of those rebates on to their customers (insurers) in the form of lower fees.

I spoke with someone who works at an insurer and is in charge of contracting with their insurer’s PBM, and this person indicated that it is very possible for an insurer to get multiple bids from PBMs and identify which one is the best deal. Although, with the complexity involved, this process generally requires a specialist healthcare consultant who is an expert on navigating PBM contracts. I spoke with such a consultant, who had also worked for PBMs directly before becoming a consultant to insurers, and this person estimated that PBMs only keep about 20% of the rebates they receive from drug manufacturers. Other studies have been done on this topic, but attribution is tricky since PBMs are able to rename the monies they are receiving from drug manufacturers to fudge the numbers, which is probably why the Government Accountability Office reported in 2019 that PBMs only retain about 1% of rebates.

Well, there you have it. Phase 3 was the start of all the wheeling-dealing complexities that give PBMs their shady reputation.

I believe this is helpful background to have when you’re trying to improve the drug market (i.e., solve the problem of expensive drugs) because without understanding the incentives of the parties involved, you cannot get to the root of the problems with that system.