Does Medicare Part D Cover Keytruda?
Yes — Keytruda (Pembrolizumab) is covered under Medicare Part D, filled by 82,000 beneficiaries across 398,000 claims in the latest year. It typically sits on tier 4-5 (specialty) of standard Part D formularies. Specialty drugs use coinsurance (25-33% of plan-negotiated price), not flat copays. The 2025 Part D annual out-of-pocket cap is $2,000.
Keytruda Medicare Coverage & Out-of-Pocket Cost
Keytruda is covered under Medicare Part D, with the program paying an average of $18,176 per prescription fill. Keytruda typically falls on Tier 4-5 (specialty) of standard Part D formularies. Specialty drugs use coinsurance (25-33% of plan-negotiated price), not flat copays. The 2025 Part D annual out-of-pocket cap is $2,000.
Your actual out-of-pocket cost depends on three factors: (1) formulary tier — your plan's specific placement; (2) deductible status — most plans require you to meet up to a $590 deductible (2025) before copays kick in; (3) coverage phase — initial coverage, then the donut hole was eliminated in 2025, replaced by a hard $2,000 annual out-of-pocket cap under the Inflation Reduction Act. Once you hit $2,000 in true out-of-pocket spending, the rest of your Part D drugs are free for the year.
No generic is currently available for Keytruda. Medicare beneficiaries cannot use manufacturer copay cards (anti-kickback statute prohibits them for federal program enrollees), but charity foundations such as the PAN Foundation, NeedyMeds, and the HealthWell Foundation offer copay grants for many cancer drugs. The Medicare Extra Help (LIS) program also reduces Part D costs to near-zero for income-qualified beneficiaries (under 150% of the federal poverty level).
For cash-pay or commercial insurance scenarios, compare prices using GoodRx, SingleCare, or Cost Plus Drugs before filling — discount-program prices sometimes beat Part D copays for lower-cost generics.
How to Confirm Keytruda Coverage & Handle a Denial
Medicare Part D coverage of Keytruda is set plan-by-plan, not nationally. To confirm your plan covers it, look up Keytruda in the Medicare Plan Finder or your plan's online drug list, and check three flags: the formulary tier (drives your copay), prior authorization (PA), and step therapy (ST) or quantity limits.
Because Keytruda is a higher-cost drug, plans are more likely to require prior authorization or step therapy — meaning you may need to try a lower-cost alternative first, or your prescriber must document why Keytruda is medically necessary. If your plan denies coverage, you have the right to a formulary exception: your prescriber submits a statement of medical necessity, and the plan must respond within 72 hours (24 hours if expedited).
A denial can be appealed through five levels — redetermination by the plan, an independent review entity, an Administrative Law Judge, the Medicare Appeals Council, and finally federal court. Coverage resets every January, so re-check Keytruda on your formulary during open enrollment (October 15 – December 7) even if it was covered this year.
Key Facts: Keytruda Cost
- Medicare Part D avg
- $18,176/claim
- Likely Part D tier
- Tier 4-5 (specialty)
- Annual cost/patient
- $88,220
- Generic available
- No
- Manufacturer
- Merck
- Treats
- Cancer
- Patent expires
- 2028-06-28
- YoY price change
- +28.6%
Source: CMS Medicare Part D Spending Dashboard. Tier placement inferred from typical formulary norms — confirm with your specific Part D plan.
Keytruda is manufactured by Merck and prescribed primarily for Cancer. In the most recent Medicare Part D data, 398,000 claims were filed for 82,000 unique beneficiaries, at an average cost of $18,176 per claim. Average annual cost per beneficiary is $88,220.
Year over year, Medicare spending on Keytruda has increased by +28.6%. No generic substitute is available, so the brand-name price reflects the full market cost. Its patent expires 2028-06-28.
Keytruda belongs to the Cancer Immunotherapy & Targeted Therapy class. Checkpoint inhibitors (Keytruda, Opdivo) unleash the immune system to attack cancer by blocking proteins (PD-1/PD-L1) that cancer cells use to hide. Kinase inhibitors (Ibrance, Xtandi) block specific enzymes that drive cancer cell growth. IMiDs (Revlimid) modify the immune system and directly kill cancer cells. CDK4/6 inhibitors (Ibrance, Kisqali) stop cancer cells from dividing.
Key Data
| Metric | Value |
|---|---|
| Avg Cost Per Claim | $18,176 |
| Total Medicare Spending | $7234.0M |
| Total Claims | 398,000 |
| Beneficiaries | 82,000 |
| Generic Available | No |
| Year-Over-Year Change | +28.6% |
Other Drugs for Cancer
Frequently Asked Questions
Yes. Keytruda appears in Medicare Part D claims data, with 82,000 beneficiaries filling 398,000 prescriptions in the latest year. Whether your specific plan covers it depends on that plan's formulary, so confirm on your plan's Summary of Benefits.
It can. Many Part D plans apply prior authorization, step therapy, or quantity limits to Keytruda — higher-cost drugs like this one are the most likely to carry these requirements. Prior authorization means your prescriber must document medical necessity before the plan pays. Check your plan's formulary "PA," "ST," or "QL" flags, or ask your pharmacist to run a test claim.
You have appeal rights. Start with a coverage determination / formulary exception request from your plan (your prescriber submits a supporting statement). If denied, you can escalate through five levels: redetermination, an independent review entity, an Administrative Law Judge, the Medicare Appeals Council, and federal court. Expedited 72-hour decisions are available when waiting could jeopardize your health.
Most Medicare Advantage plans include Part D drug coverage (MA-PD), so Keytruda is generally available — but each Advantage plan sets its own formulary, tier, and pharmacy network. Coverage and copay can differ from Original Medicare plus a standalone Part D plan, so compare the specific plan's drug list before enrolling.
Keytruda is typically placed on Tier 4-5 (specialty) of standard Part D formularies. Specialty drugs use coinsurance (25-33% of plan-negotiated price), not flat copays. The 2025 Part D annual out-of-pocket cap is $2,000. Your exact tier and cost-sharing are set by your individual plan and can change each plan year.
Use the Medicare Plan Finder at medicare.gov, enter Keytruda, and review each plan's formulary, tier, and restrictions. You can also call the number on your insurance card or check the plan's online drug lookup. Coverage is reset every January, so re-check during open enrollment (Oct 15 – Dec 7).
More about Keytruda
Yes — Keytruda (Pembrolizumab) is covered under Medicare Part D, filled by 82,000 beneficiaries across 398,000 claims in the latest year. It typically sits on tier 4-5 (specialty) of standard Part D formularies. Specialty drugs use coinsurance (25-33% of plan-negotiated price), not flat copays. The 2025 Part D annual out-of-pocket cap is $2,000.
The data source behind this answer is CMS Medicare Part D Drug Spending data. Every figure on the page traces back to that source; the methodology page describes the inputs and the refresh cadence in full detail.
A practical caveat: the headline answer above reflects the most recent CMS Medicare Part D Drug Spending data vintage; underlying data is often revised for months after first publication, and the right reference for any specific decision is whichever vintage is current at the time of the decision. The as-of date is stamped on every page.
Source: CMS Medicare Part D Spending, 2026.