FDA approves Zepbound single-dose vials

The U.S. Food and Drug Administration approved a supplement to Eli Lilly's application for Zepbound (tirzepatide) injection on March 28, 2024, adding a single-dose vial as a second container type for the obesity drug ^[1]. Until then, Zepbound had been supplied only as a single-dose pen ^[1].

The approval came through a prior approval supplemental new drug application, NDA 217806/S-003, which Lilly submitted and FDA received on November 20, 2023 ^[1]. According to the agency's letter, the supplement "provides for the addition of a single-dose vial container closure system for tirzepatide drug product" and for expanding the testing role of a quality control testing site for the vial presentation ^[1]. The manufacturing and testing site names are redacted in the public version of the letter ^[1].

What the letter actually changed

The document posted by FDA is a corrected approval letter. The original March 28 letter listed the wrong Medication Guide — the version previously approved on November 8, 2023 ^[1]. FDA wrote that this guide "is superceded by the Medication Guide dated March 2024 which includes single-dose pen and single-dose vial" ^[1]. The corrected letter fixed that error but kept the effective action date of March 28, 2024 ^[1].

The enclosures list shows what patients and pharmacists would see change: updated Prescribing Information, the March 2024 Medication Guide, the existing Instructions for Use for the single-dose pen (unchanged from November 8, 2023), a new Instructions for Use for the single-dose vial, and new carton and container labeling for the vial ^[1]. In other words, the vial arrived with its own separate step-by-step instructions, because the handling is not the same as with a pen.

FDA directed Lilly to submit the content of labeling in electronic format within 14 days of the letter and final printed carton and container labeling within 30 days of printing ^[1]. The letter also notes that Zepbound is a combination product under 21 CFR 3.2(e), so Lilly must follow postmarketing safety reporting rules that apply to combination products — a category that covers a drug packaged with a delivery device ^[1].

The letter was signed by John Sharretts, M.D., director of FDA's Division of Diabetes, Lipid Disorders, and Obesity, with an electronic signature dated April 2, 2024 ^[1].

Why it matters for patients

The practical difference between the two presentations is how the medicine gets from the package into the body. A single-dose pen is a self-contained injector. A single-dose vial requires drawing the liquid into a syringe first, which is why FDA approved a separate Instructions for Use document specifically for the vial ^[1]. That separate document is the official source for how the vial is meant to be handled, and it is part of the approved labeling rather than optional guidance ^[1].

This approval also means that from March 28, 2024 forward, "Zepbound" no longer describes a single product format. Prescriptions, pharmacy stock, and insurance claims can involve either a pen or a vial, and the Medication Guide patients receive is supposed to be the March 2024 version that covers both ^[1].

Several things people commonly ask about are not addressed in the approval letter and remain unknown from this source: the price of the vials, which strengths are offered in vial form, how the vials are distributed, whether syringes and needles are included, and whether availability differs by pharmacy. The letter covers only the regulatory and labeling actions ^[1]. It also does not change what Zepbound is approved to treat — the supplement was about the container closure system and quality control testing, not a new indication or new clinical data ^[1].

What happens next

March 28, 2024 is the effective approval date for the single-dose vial ^[1]. Within 14 days of the letter, Lilly was required to file the approved labeling electronically so it would appear in public labeling repositories, which is how prescribing information and the Instructions for Use become searchable online ^[1]. Patent information tied to the supplement was due to FDA on Form FDA 3542 within 30 days of approval ^[1]. Questions about the review were directed to regulatory project manager Arati B. Kamath, Ph.D. ^[1].