IRA Drug Price Negotiation: What Therapeutics Investors Need to Model

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The Inflation Reduction Act of 2022 fundamentally rewired the economics of branded therapeutics in the United States. Direct Medicare negotiation of drug prices—previously prohibited—is now law. The first ten negotiated drugs took effect in 2026. The next fifteen are negotiated by 2027. By 2029 the program covers up to twenty drugs per year. Any therapeutics investor who has not built IRA timing into their financial models is operating with stale assumptions.

The IRA does not affect every drug. It does affect every drug that becomes commercially material—and the threshold for materiality is lower than many sponsors assume.

The Selection Mechanism

CMS selects drugs for negotiation based on Medicare Part D spending (post-rebate, by manufacturer). The selection pool excludes drugs with generic or biosimilar competition, drugs less than 7 years from approval (small-molecule) or 11 years (biologics), and certain orphan-designated drugs. The window between launch and negotiation eligibility is fixed by statute and cannot be extended through life-cycle management.

The Maximum Fair Price

Once selected, a drug's maximum fair price (MFP) is set by CMS using a formula that considers the drug's clinical benefit, manufacturing costs, and prices in comparable countries. Initial MFPs for the first ten selected drugs ranged from 38% to 79% of list price. The reduction takes effect in the calendar year following negotiation.

Modeling the Revenue Impact

For a small-molecule blockbuster, the revenue impact looks roughly like this: year 1-6 normal pricing; year 7-9 negotiation eligibility plus potential MFP reduction; year 10+ continued MFP with generic competition typically entering year 10-11. The total US revenue compression compared to pre-IRA models is typically 25-40% in years 7-10. Biologics see a similar pattern shifted four years later.

Drug-Type Selection Bias

CMS selects from the top 50 highest-spending drugs that meet the eligibility criteria. This biases selection toward chronic-disease therapies with broad patient populations. Oncology and rare disease drugs are less likely to be selected in early cohorts, though they enter the pool as small-molecule oncology drugs accumulate Part D spend. Investors evaluating Phase 3 therapeutics in chronic disease must build IRA risk into models even when the drug has not been selected.

Strategic Responses That Work

Sponsors are responding to IRA in several ways: accelerating non-Medicare commercial channels to reduce Part D spend share; bringing biosimilars to market earlier (reducing the eligible pool); investing in life-cycle indications for drugs early in the eligibility window (additional indications enrich the per-patient value to soften the negotiation); and exiting the US market for drugs where MFP would make US commercialization uneconomic (rare but increasing).

Diligence Questions for Therapeutics Investors

When evaluating any therapeutics company with US-Medicare-eligible exposure: What is the projected Part D spend at year 5? Does the drug fall into the top 50 spending threshold? What is the eligibility entry year and how does the financing plan absorb the revenue compression? Is the sponsor pursuing biosimilar/generic mitigation strategies? Has the comparable-country pricing analysis been modeled?

The IRA is not a future risk—it is current law, with specific drugs already negotiated and specific revenue impacts already booked. Therapeutics investors who have not rebuilt their financial models with IRA mechanics built in are using assumptions from before the law took effect. The diligence question is not whether IRA will affect the asset—it is when and by how much.