Does Medicare Cover Perjeta? Part B Costs and Prior Authorization

Medicare does cover Perjeta (pertuzumab) for people with HER2-positive breast cancer. Because the drug is given by intravenous infusion in a doctor’s office or infusion center rather than taken at home, it is covered under Medicare Part B as a physician-administered drug, not under Part D. Most plans require prior authorization before the first infusion, and a growing number now require you to try the subcutaneous combination drug Phesgo first.

Why Part B and Not Part D

Part B pays for drugs a provider administers to you in an outpatient setting. Perjeta fits that definition: it is delivered as an IV infusion, with an initial loading dose of 840 mg followed by 420 mg maintenance doses every 21 days.¹ Coverage rules are the same whether you have Original Medicare or a Medicare Advantage plan, though Advantage plans add their own prior authorization and step-therapy requirements on top.

Which Conditions Medicare Will Cover It For

Medicare generally follows the FDA-approved indications and nationally recognized compendia. Perjeta is approved in combination with trastuzumab and chemotherapy in three settings of HER2-positive breast cancer:

Neoadjuvant treatment, before surgery, for locally advanced, inflammatory, or early-stage disease.²
Adjuvant treatment, after surgery, for early breast cancer at high risk of recurrence.²
Metastatic disease, with trastuzumab and docetaxel, in patients who have not previously had anti-HER2 therapy or chemotherapy for metastatic disease.²

In December 2025, the FDA also approved pertuzumab in combination with fam-trastuzumab deruxtecan-nxki as a first-line treatment for unresectable or metastatic HER2-positive breast cancer.³ Some plans will also cover compendia-supported uses such as HER2-amplified colorectal cancer and HER2-positive recurrent salivary gland tumors.⁴

Prior Authorization and the Phesgo Hurdle

Nearly every Medicare plan requires prior authorization. The common requirements: confirmed HER2-positive disease, a baseline left ventricular ejection fraction within normal limits, and a diagnosis matching an approved or compendia-supported indication.⁵

Expect a step-therapy requirement as well. A growing number of Medicare Advantage plans now treat Phesgo, a subcutaneous fixed-dose combination of pertuzumab, trastuzumab, and hyaluronidase, as the preferred first-line product and classify Perjeta as a non-preferred “Step 2” drug. Under Aetna’s 2026 Medicare Part B policy, Perjeta is covered only if the patient has already received it within the past 365 days, has had a documented adverse reaction to Phesgo, has a contraindication to Phesgo, or needs it for an indication not covered under the standard breast cancer policy.⁶ Devoted Health’s 2025 plan uses the same structure.⁷

Initial approvals usually run six to twelve months. For neoadjuvant and adjuvant breast cancer, the total course of Perjeta is generally capped at 12 months, or up to 18 cycles.⁴ Renewal requires documentation that you are still benefiting, with no evidence of disease progression or unacceptable toxicity, plus continued heart function monitoring.⁵

What You Will Pay

Perjeta is expensive. The wholesale acquisition cost for a single 420 mg vial was about $6,889 as of January 2026.⁸ A maintenance infusion uses one vial; the loading dose uses two. Medicare pays Part B drugs at the Average Sales Price plus 6%. For the first quarter of 2026, the CMS payment limit for pertuzumab was $17.01 per milligram, which puts the Medicare-allowed amount at roughly $7,144 for a 420 mg maintenance infusion and roughly $14,288 for the loading dose.⁹

Under Original Medicare, you pay 20% coinsurance after meeting the annual Part B deductible, which is $283 in 2026.¹⁰ On a single maintenance infusion, that is about $1,400 out of pocket. Over a full course of treatment, the coinsurance runs into thousands of dollars, and Original Medicare has no annual cap on Part B out-of-pocket spending.¹¹

Medicare Advantage plans cannot charge more than 20% coinsurance (or an actuarially equivalent copay) for in-network Part B drugs, and they do include an annual out-of-pocket maximum. Once you reach that cap, the plan pays the rest for the year.¹¹

One boundary worth knowing: the Inflation Reduction Act’s $2,000 annual out-of-pocket cap, which took effect in January 2025, applies only to Part D pharmacy drugs. It does not help with Part B coinsurance for infused drugs like Perjeta.¹² Perjeta has not been selected for Medicare drug price negotiation in any of the first three rounds either.¹³

Ways to Reduce Your Coinsurance

If you have Original Medicare, a Medigap (Medicare Supplement) policy is the most direct way to shrink the bill. Plan G, for example, pays the full 20% Part B coinsurance after you meet the annual deductible, which for someone receiving Perjeta effectively reduces annual out-of-pocket drug costs to the $283 deductible.¹⁴

Low-income beneficiaries may qualify for a Medicare Savings Program such as QMB or SLMB, which can cover Part B premiums, deductibles, and coinsurance.¹¹

Federal anti-kickback rules prevent Genentech, Perjeta’s manufacturer, from offering copay assistance directly to Medicare patients. Instead, Genentech refers Medicare beneficiaries to independent charitable foundations.¹⁵ The foundations listed on the Perjeta website include CancerCare Co-Payment Assistance Foundation, Good Days, Patient Access Network Foundation, Patient Advocate Foundation, The Assistance Fund, and The HealthWell Foundation.¹⁶ Each has its own eligibility rules and open and closed funding periods, so apply early.

The New Biosimilar May Lower Future Costs

On November 13, 2025, the FDA approved Poherdy (pertuzumab-dpzb) as the first interchangeable biosimilar to Perjeta, with the same indications in metastatic, neoadjuvant, and adjuvant HER2-positive breast cancer.¹⁷ At least one major Medicare Advantage insurer’s medical coverage guidelines, as of April 2026, list Poherdy alongside Perjeta under the same medical necessity criteria.¹⁸ As biosimilars enter the market, the Medicare reimbursement rate is expected to fall, and your 20% coinsurance share will fall with it.

If Medicare Denies Your Perjeta

You have the right to appeal, and the first step depends on which Medicare you have. Under Original Medicare, file a redetermination with the Medicare contractor within 120 days of the denial. If that fails, the case moves to a Qualified Independent Contractor for reconsideration, and from there to an Administrative Law Judge, the Medicare Appeals Council, and ultimately federal court.¹⁹

Under Medicare Advantage, the plan reconsiders its own denial first. If it upholds the decision, the case is automatically forwarded to an independent review entity working under contract with CMS, with the same higher levels available after that.¹⁹

Your oncologist’s office is usually the one that drafts the appeal, since the medical necessity argument has to come from the treating provider. Genentech’s PERJETA Access Solutions program offers sample appeal letter templates and can help identify what a specific plan requires, though the company cannot file an appeal for you.²⁰ Free one-on-one counseling is also available through your State Health Insurance Assistance Program (SHIP).²¹

1
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2
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3
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4
CareFirst. Perjeta Standard Medicare Part B Management
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6
Aetna. Perjeta Medicare Part B Step Therapy Policy
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Genentech Drug Pricing Law. Genentech Perjeta WAC Pricing
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13
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14
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15
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16
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17
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18
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19
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20
Perjeta HCP. Helpful Resources for Your Practice
21
Medicare.gov. Medicare Appeals