Health system specialty pharmacies have grown rapidly over the past decade. More systems have built in-house capabilities, invested in integration, and proven they can deliver a better patient experience.
And yet, one challenge keeps coming up in every conversation with pharmacy leaders: access to payer networks.
At face value, it does not make much sense. These pharmacies are embedded in care teams, closer to the patient, and often outperform on adherence and coordination. So why are they still left out of many commercial specialty networks?
The answer has less to do with performance and more to do with how the system is built.
To understand the issue, you have to start with how drug costs are managed. Payers and PBMs rely heavily on manufacturer rebates to offset specialty drug spend. In many cases, rebate guarantees are not just part of the model, they drive the model.
Those guarantees are built into contracts with employers and health plans. Teams model them, negotiate them, and defend them in competitive bids. When performance falls short, the consequences are real. PBMs can face financial penalties or lose business altogether.
That reality creates a strong incentive to protect rebate performance.
This is where 340B enters the picture.
When a drug is dispensed under 340B, manufacturers often do not pay a rebate on that claim. From the manufacturer’s perspective, this avoids paying both a discount and a rebate on the same unit. From the payer’s perspective, it removes expected value.
That gap shows up quickly in the total cost picture.
Health system specialty pharmacies tend to dispense a higher share of 340B-eligible prescriptions. When plans include them in networks, they increase exposure to rebate erosion. That puts pressure on financial guarantees and makes network performance harder to predict.
At that point, the decision shifts. It becomes less about clinical quality and more about financial certainty.
Part of the problem is structural. The industry still lacks a consistent way to identify which claims are 340B. Without a shared standard or central source of truth, stakeholders are forced to make assumptions.
Manufacturers rely on their own methods to determine which claims qualify as 340B when they review rebate invoices. Those methods are imperfect. They sometimes withhold rebates on claims that should qualify, and in other cases, they pay rebates where they should not.
That inconsistency creates risk across the system.
Payers and PBMs cannot confidently predict rebate performance. Health systems cannot fully demonstrate the value of non-340B volume. And manufacturers continue to operate without clean visibility.
Health system specialty pharmacies consistently deliver strong patient outcomes. That is not in question.
The challenge is that patient experience rarely drives network decisions unless something breaks. When financial performance and clinical performance are not aligned, financial performance tends to win.
That is why we see broader inclusion in categories like oncology, where rebates are limited and the economics are more straightforward. Outside of those areas, the barriers become much harder to overcome.
The system is doing what it was designed to do. It prioritizes predictability, even when that limits more integrated care models.
If we want a different outcome, we have to change how value shows up in the model.