# Cap what Original Medicare patients pay for Part B cancer drugs

Source: https://onco.cc/ideas/idea-cost-part-b-cap/  
OnCo record `idea-cost-part-b-cap` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Oral cancer drugs under Part D now have a yearly cap of $2,100, but infused drugs under Part B still carry 20% coinsurance with no limit; a Part B cap would close the biggest hole left in Medicare cancer coverage.

## Summary

The Inflation Reduction Act capped Part D out-of-pocket spending ($2,000 in 2025, $2,100 in 2026) but left Part B untouched. A patient on an infused checkpoint inhibitor without Medigap or Medicaid owes 20% of the Medicare-approved amount indefinitely. Options include a Part B out-of-pocket cap funded by a premium adjustment, or a guaranteed-issue window for Medigap after a cancer diagnosis so that people can buy the protection that already exists.

## Fields

- Kind: Idea
- Last checked: 2026-09-10
- Hypothesis: A Part B cap or diagnosis-triggered Medigap guaranteed issue will reduce the share of Original Medicare cancer patients with out-of-pocket drug spending above $5,000 a year by more than half.
- Rationale: Medicare Advantage plans already carry an in-network cap ($9,350 in 2025), so the actuarial mechanics are proven; the gap is in Original Medicare.
- Proposed test: Actuarial modelling by CMS and the Congressional Budget Office, followed by a state-level Medigap guaranteed-issue pilot (several states already require it) evaluated on take-up and out-of-pocket spending.
- Maturity: speculative
- Actor: policy

## Sources

- Medicare.gov: Chemotherapy coverage: https://www.medicare.gov/coverage/chemotherapy
- Medicare.gov: Medigap: https://www.medicare.gov/health-drug-plans/medigap

## Connected records

- terms: [Financial toxicity](https://onco.cc/terms/financial-toxicity/)
- bottlenecks: [Prices and value](https://onco.cc/bottlenecks/b-drug-pricing/)

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