The US Food and Drug Administration filed a Level 1 draft guidance on September 1, 2026 that withdraws the agency's May 2003 final guidance on pharmacokinetics in patients with impaired hepatic function and replaces it with updated recommendations on study design, data analysis, and the impact on dosing and labeling. The draft, docket FDA-2026-D-8693, entered Federal Register public inspection as document 2026-17961, with formal publication scheduled for September 2, 2026 and a 90-day public comment window opening on that date.
Issued by the FDA's Center for Drug Evaluation and Research (CDER), the guidance targets sponsors and applicants running pharmacokinetic (PK) studies, and where appropriate pharmacodynamic (PD) studies, in hepatically impaired patients for both drugs and therapeutic biological products. The 2003 final it retires was 23 years old, and the replacement has been industry-anticipated since at least the 2020 FDA and University of Maryland M-CERSI hepatic impairment PK workshop. The full draft is available as a direct download from the FDA (PDF of the draft guidance).
What does the new draft change for hepatic impairment studies?
The draft retires the 2003 final guidance and reissues CDER's recommendations across the three dimensions named in its title: how hepatic impairment PK studies should be designed, how the resulting data should be analyzed, and how the findings should drive dosing and labeling. As a Level 1 guidance it carries non-binding recommendations ("not for implementation") that reflect the agency's current thinking, and sponsors that align with them can expect a more predictable review. Because the 2003 document predates two decades of advances in model-informed drug development and population PK analysis, the update carries real weight for how protocols, modeling plans, and labeling templates are built. The draft text and issuing details are on the FDA guidance document page.
Who must act on this draft, and why now?
Every CDER and CBER sponsor with an NDA or BLA in flight, plus the CROs that run hepatic impairment studies for them, has work to do. Clinical pharmacology, regulatory affairs, labeling, and clinical operations teams at major US filers (Pfizer, Merck, Eli Lilly, Johnson and Johnson/Janssen, Roche/Genentech, Novartis, GSK, Bristol Myers Squibb, Amgen, Gilead, AbbVie, Sanofi, AstraZeneca) and at EU, Japanese, and Chinese sponsors filing in the US all need to map the draft against their current programs. The CROs that run these studies (IQVIA, PPD, Fortrea) should brief their clinical pharmacology units. The urgency is the 90-day comment clock: the window that shapes the final guidance closes 90 days after the September 2, 2026 Federal Register publication.
How should sponsors prepare comments and protocols?
Three concrete steps. First, pull every in-flight hepatic impairment PK protocol and check it against the draft's study design and data analysis sections before the next milestone. Second, review modeling and simulation plans, including any population PK approaches, against the new expectations and flag where a protocol may need amendment. Third, audit labeling templates, especially the hepatic impairment language in "use in specific populations," since the draft's title names dosing and labeling as a direct output. Comments go to docket FDA-2026-D-8693 via Regulations.gov; written comments are accepted at Dockets Management, FDA, 5630 Fishers Lane, Rm 1061, Rockville, MD 20852. FDA accepts comments on guidance at any time under 21 CFR 10.115(g)(5), but only comments filed within the 90-day window carry weight in the finalization.
| Milestone | Date |
|---|---|
| Federal Register public inspection (document 2026-17961) | September 1, 2026 |
| Federal Register publication (comment clock starts) | September 2, 2026 |
| 90-day comment window closes | December 1, 2026 |
| 2003 final guidance withdrawn | On finalization of the new guidance |
Continuous, per-jurisdiction monitoring surfaces a guidance change like this the moment it lands in public inspection, before it reaches the trade press.
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What to do next: confirm whether your in-flight NDAs and BLAs carry a hepatic impairment PK component, brief your clinical pharmacology and labeling leads on the draft this week, and calendar the 90-day comment deadline so your submission lands inside the window.
