Trastuzumab biosimilars

Medicare

Part B (clinician-administered)

Given by infusion or injection in a clinic or hospital outpatient department, so it is a Part B drug: Medicare pays 80% after the Part B deductible and the patient owes 20% coinsurance, uncapped in Original Medicare unless a Medigap policy applies. Biosimilars are paid at their own average sales price plus 8% of the reference product's price under Medicare Part B, an incentive to prescribe them; patient coinsurance is generally lower than for Herceptin.

Commercial insurance

covered on label

Preferred products on most commercial medical-benefit formularies; plans pick one or two preferred biosimilars and may require a switch.

20% Part B coinsurance on a high-cost infusion adds up quickly: Medigap Plan G or N, Medicare Advantage maximum out-of-pocket, Medicaid dual eligibility, or a charity fund are the usual buffers.

Sources: Medicare.gov: Chemotherapy · Medicare.gov: Prescription drugs (outpatient, Part B) · FDA: Biosimilars. Not medical or financial advice; verify with your plan.

Notes

Biosimilars are not appraised separately: they fall under the originator's TAs (TA34, TA107, TA208). NHS England's biosimilar commissioning framework drove rapid switching from 2018.

NHS England

Routinely funded for the appraised indication (or via managed access)

Sources: NICE search: trastuzumab biosimilars. Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.