The reality of out-of-pocket maximums and the catastrophic phase for Part D beneficiaries.

There is a moment that happens in pharmacies across the country every day. A Medicare beneficiary hands over their insurance card for a specialty medication, and the number that comes back is not what they expected. They did everything right. They signed up for Part D. They have coverage. And the drug still costs more than they can pay.

This is not a coverage gap story. The coverage gap, the old "donut hole," has been largely closed. What this is, instead, is a structural problem that sits inside Part D by design. It has a name most beneficiaries have never heard: the catastrophic phase. And for patients on specialty medications, it is one of the most consequential parts of their coverage year.

How Part D actually works

Part D does not work like most insurance. Instead of a simple deductible and then coverage, it has phases. Each phase has different cost-sharing rules. Each phase has thresholds that change year to year. And most beneficiaries move through them without ever understanding what phase they are in or what it means for what they owe.

The structure, in plain terms, looks like this.

The deductible phase. At the start of the plan year, the beneficiary pays full drug costs up to the annual deductible. In 2024, that ceiling was $545. Until that threshold is crossed, the insurance is essentially not paying for anything.

The initial coverage phase. Once the deductible is met, the plan starts sharing costs. The beneficiary pays a copay or coinsurance. The plan pays the rest. This phase continues until total drug spending reaches a set threshold.

The catastrophic phase. After out-of-pocket costs hit $8,000 in 2024, the beneficiary enters the catastrophic phase. Under the Inflation Reduction Act changes taking full effect in 2025, beneficiaries no longer owe cost-sharing in this phase. Before that change, the math was brutal: patients were still paying 5 percent of drug costs with no cap, which on a $15,000 specialty drug meant hundreds of dollars per month even after crossing into "catastrophic" coverage.

The name catastrophic was never meant to describe the coverage. It describes the spending level that triggers it. The coverage itself, until recently, was anything but protective.

What this looks like for a specialty patient

Take a Medicare beneficiary with rheumatoid arthritis on a biologic that costs $3,000 per month. In January, they start the year in the deductible phase, paying full cost until they hit $545. Then they move into initial coverage, paying their plan's coinsurance, often 25 to 33 percent of the drug cost. By spring, they may have crossed into the catastrophic phase.

Before 2025, crossing into the catastrophic phase felt like relief but delivered only partial protection. The 5 percent coinsurance on a $3,000 drug is $150 per month. Every month. For the rest of the plan year. For a patient on a fixed income, that is not a small number.

For patients on multiple specialty medications, the math compounds. A Medicare beneficiary managing cancer, MS, or a complex autoimmune condition may be running through multiple high-cost drugs simultaneously. The phases do not reset between drugs. The total spending across all Part D drugs is what determines which phase the patient is in.

The catastrophic phase does not mean the patient is protected. Until recently, it meant the patient had already spent thousands of dollars and was still paying a percentage with no ceiling.

The Inflation Reduction Act changes the math, but not the whole problem

The Inflation Reduction Act introduced a $2,000 out-of-pocket cap for Part D beneficiaries starting in 2025. For the first time, there is an annual ceiling on what a Medicare patient owes for their prescription drugs. This is a genuine and significant improvement. Patients who previously faced uncapped catastrophic phase costs now have a hard stop.

But the cap does not solve everything.

The $2,000 cap is still $2,000. For a beneficiary on Social Security with limited income, reaching that threshold can happen in the first quarter of the year on a single specialty medication. The months that follow are covered, but the early months are not, and the damage to a fixed-income budget can happen before the protection kicks in.

The cap also does not address the upstream problem. Benefit verification still needs to happen. Prior authorizations still need to be filed. Step therapy requirements do not go away because the out-of-pocket structure improved. A patient who cannot get their medication approved never reaches the cap in the first place.

And the cap applies only to Part D, the pharmacy benefit. Specialty medications administered in a physician's office or infusion center typically fall under Part B, the medical benefit, which has a separate and different cost structure. A patient who thinks the $2,000 cap covers everything they owe for their biologics may discover mid-year that their infused medication has been billing under Part B the entire time, with different cost-sharing that the cap does not touch.

Where the access failure actually lives

The Part D structure is not a secret. The phase thresholds are published. The cost-sharing rules are documented. But the patient sitting across from their physician at the point of prescription does not know any of this. They know they have Medicare. They know they have Part D. They do not know which phase they are in, how close they are to the next threshold, or what their cost-sharing will look like in six months when the phases shift.

This is an information failure as much as a structural one. The system does not tell patients what it is going to cost them before it costs them. It tells them at the pharmacy counter, in real time, when there is no good option except to pay or walk away.

What closes this failure is not a pamphlet about Part D phases. It is a practice that does benefit verification at the time of prescribing, flags patients who are approaching phase transitions, screens for PAP eligibility when cost becomes a barrier, and treats the financial pathway to treatment as a clinical responsibility, not an afterthought.

Most practices do not do this. The gap between what Medicare covers and what a specialty patient can actually access is not primarily a policy problem. It is an infrastructure problem. And it sits in the back office.

What a practice can actually do

The practices that protect their specialty patients from Part D cost surprises are doing a few things consistently.

They are running benefit verification that includes phase status. Not just whether the drug is covered, but where the patient is in their Part D benefit year and what their projected cost-sharing looks like through the rest of the plan year. A patient who is two months from hitting their out-of-pocket cap needs to know that before they consider stopping the medication because of cost.

They are screening for manufacturer assistance programs at the time of denial and at the time of any significant cost event. For Medicare beneficiaries, commercial copay cards are typically not available. But PAP eligibility for low-income patients is real and underutilized. The Extra Help program, also called the Low Income Subsidy, can dramatically reduce a beneficiary's Part D costs and is missed constantly by practices that do not have a screening protocol.

They are communicating proactively. A patient who understands that their cost-sharing is going to be high in January and February, and near zero by April, can make different decisions than a patient who discovers the January bill unprepared.

The $2,000 cap is a real improvement. It is not a solution. The access gap for Medicare Part D beneficiaries still runs through the back office.

The bigger picture

Part D reform is real and ongoing. The Inflation Reduction Act changes represent the most significant structural improvement to Medicare drug coverage in years. But policy improvements do not automatically translate into access improvements at the patient level. The infrastructure to connect a beneficiary to the coverage they are entitled to still has to exist at the practice level.

The patients most harmed by Part D cost-sharing are the ones least equipped to navigate it: older adults on fixed incomes, patients with complex conditions requiring multiple specialty medications, and beneficiaries who do not know they qualify for assistance programs that could cut their costs to nearly zero.

The system is not going to tell them. The practice has to.

Taylor McKinney · The Access Gap · @theaccessgap