The Medicare Modernization Act of 2003

Medicare started paying for outpatient prescription drugs on January 1, 2006, under a benefit created by the Medicare Prescription Drug, Improvement, and Modernization Act of 2003. The law, Public Law 108-173¹, was signed December 8, 2003. In 2025, 54.8 million of the 68.8 million people on Medicare were enrolled in Part D plans, and 13.9 million of them received the low-income subsidy, according to KFF².

Deep inside the same law sits Title XI, “Access to Affordable Pharmaceuticals.” In a few dozen pages it limited brand companies to one 30-month stay per generic application, wrote six ways a first generic filer can lose its 180-day exclusivity and required drug companies to file patent settlements with the Federal Trade Commission and the Justice Department.

Both halves still shape the generic market. Generics filled 84.5 percent of Part D claims in the year GxRadar examined in its analysis of Part D, and Title XI's rules still decide when many of those generics can launch. This history covers the drug benefit as Congress first wrote it and the Hatch-Waxman changes that rode along.

The drug benefit as written in 2003

The statute set the 2006 standard benefit in dollar terms. Enrollees paid a $250 deductible, then 25 percent of costs up to an initial coverage limit of $2,250. Above that limit, coverage stopped until the enrollee's own spending reached an out-of-pocket threshold of $3,600, after which catastrophic coverage began. That stretch became known as the coverage gap, covered in GxRadar's history of the doughnut hole.

Figures for 2026 and 2027 come from the CMS announcement of April 6, 2026³. The gap closed and the out-of-pocket cap arrived through the Inflation Reduction Act redesign that took effect in 2025, explained in Part D changes in 2025, 2026 and 2027.

Congress also wrote in a “noninterference” clause. The Secretary of Health and Human Services “may not interfere with the negotiations between drug manufacturers and pharmacies and PDP sponsors” and “may not require a particular formulary or institute a price structure” for covered drugs, the enacted text¹ says. Congress carved an exception into that clause for Medicare drug price negotiation in 2022. Most Part D enrollees are now in Medicare Advantage drug plans, 58 percent in 2025 against 42 percent in stand-alone plans, KFF reported.

One 30-month stay per application

Under the 1984 Hatch-Waxman Act, a brand company that sued within 45 days of receiving a generic's patent challenge triggered a 30-month delay in FDA approval, as FDA's patent certification page⁷ explains. The problem regulators saw was repetition. Brand companies could list new patents after a generic application was filed and set off new stays. In July 2002 the FTC published a study recommending that federal law “permit only one automatic 30-month stay per drug product per ANDA,” as FDA recounted in its June 18, 2003 final rule⁴.

FDA acted first by regulation. The 2003 rule allowed a full opportunity for only one 30-month stay per generic application, and the agency estimated the benefit to consumers at $34.8 billion over 10 years, or about $3.3 billion a year. Six months later section 1101 of the Medicare law put the limit in the statute. A stay now attaches only to patents whose information the brand submitted to FDA before the generic application was filed. The generic applicant must send its notice within 20 days of FDA's acknowledgment that the application has been filed, and a generic that is sued can counterclaim for an order making the brand correct or delete Orange Book patent information when the patent claims neither the approved drug nor an approved use. In March 2004 FDA revoked parts of its own rule⁵, citing the new law signed December 8, 2003.

GxRadar's explainer on the 30-month stay covers how stays run now, and Orange Book patent listing challenges covers the counterclaim and later fights over what belongs in the book.

Six ways to lose the 180 days

Before 2003, as GxRadar's 180-day exclusivity explainer describes, a first filer that delayed its own launch could keep later generics off the market with it. Section 1102 answered with a list of “forfeiture events.” If a first applicant triggers one, it loses the exclusivity, and if every first applicant forfeits, no later applicant inherits the 180 days.

That list survives in the current text of 21 U.S.C. 355(j)(5)(D)⁹. The failure-to-market clock runs to “the later of” two dates. One is the earlier of 75 days after approval or 30 months after submission; the other is 75 days after court decisions or patent withdrawals resolve each qualifying patent.

None of this applied everywhere at once. Under FDA's draft guidance on 180-day exclusivity⁶, the 2003 provisions apply only to generic applications filed after December 8, 2003, for a reference drug that had no Paragraph IV certification before that date. If even one challenge to that drug was submitted earlier, the older rules govern every generic referencing it. FDA's Paragraph IV list⁷ still marks those drugs “pre-MMA.” A first filer that has not won tentative approval by the deadline can get stuck, a situation covered in tentative approvals explained.

Settlements go to the FTC

Subtitle B of Title XI requires a generic company with a Paragraph IV application and a brand company that reach an agreement about the brand drug, the generic or the 180-day period to file the agreement with the FTC and the Justice Department's antitrust chief. Agreements between two generic filers about the 180 days must be filed too. Filings are due within 10 business days of signing, are exempt from public disclosure and carry a civil penalty of up to $11,000 for each day a company is out of compliance, according to the enacted text¹.

Those filings feed the FTC's yearly counts. In fiscal 2021 the agency received 199 final patent settlements covering 86 brand products, and 33 of them combined explicit compensation from the brand company with a restriction on when the generic could enter, the FTC’s fiscal 2021 report⁸ said. GxRadar's article on pay-for-delay settlements covers what those numbers mean.

The rest of the 2003 law that touches generics

Section 303 moved most Medicare Part B drug payments toward a formula based on average sales price, the system described in average sales price and Part B generics. Section 1121 rewrote the drug importation provisions now known as section 804. Title XII created health savings accounts, covered in using an HSA or FSA for prescriptions. FDA's list of food and drug law milestones¹⁰ adds a smaller item, a required study of how technology could make prescription drug information available to people who are blind or visually impaired.

Part D is now in its 21st year. The next change on the calendar is January 1, 2027, when the Part D deductible rises to $700 and the out-of-pocket threshold to $2,400, per CMS³.