FDA-Required Drug Safety Studies Remain Behind Schedule

FDA-mandated safety studies for drugs remain incomplete despite years of market presence, creating unverified risk exposure for patients.

The FDA requires long-term safety monitoring for drugs after approval, but as of its July 31, 2026 database update, nearly 600 postmarket studies are behind schedule. This includes Tavneos, which began a required safety study in 2021 with 21 patients enrolled in a planned 300-patient cohort by late 2026. The FDA documented liver damage cases in patients 'possibly' or 'probably causally associated' with Tavneos, while other studies like the CustomFlex Artificial Iris trial for aniridia patients showed zero enrollments by August 2026. KFF Health News analysis identified hundreds of FDA-mandated studies delayed across drugs and biologics, with 250 studies having final reports due before July 31, 2026.

This friction occurs because delayed studies prevent verification of long-term drug effects. When safety data remains unconfirmed, patients face unquantified health risks from medications approved years ago. The Trump administration’s policy shift to require one clinical trial instead of two for approvals may have contributed to this pattern, though the FDA clarifies delays do not indicate unresolved safety issues.

This creates a critical friction point for health access: patients cannot fully trust medication safety without completed studies. As studies lag, the burden of unverified risks falls on individuals using drugs that may cause harm. Next, we’ll watch whether Amgen completes Tavneos’ study and how policy changes affect study timelines. The FDA notes delays can stem from product discontinuation or legitimate study adjustments—not safety concerns—so the full context requires deeper review of each case. The source’s data shows 600 studies are behind schedule, but this is a rounded figure from the database’s last update in July 2026.

Source: KFF Health News