NDA vs BLA: the two kinds of US drug application

Before a new medicine can be sold in the US, its maker has to file one of two applications with the FDA: a New Drug Application (NDA) or a Biologics License Application (BLA). Which one depends on what the product is, not on how important or novel it is. For the review timeline the difference barely matters. For competition after approval it matters a lot.

The short version

NDA: for drugs, mostly small molecules made by chemical synthesis. The legal basis is section 505 of the Federal Food, Drug, and Cosmetic Act.
BLA: for biological products made from living systems, such as antibodies, therapeutic proteins, vaccines, blood products, and cell and gene therapies. The legal basis is section 351 of the Public Health Service Act.

Both are reviewed under the same PDUFA goals, so a standard review is about 10 months from filing and a priority review about 6, whichever application it is. (How the PDUFA date is set explains the clock.)

What counts as a biologic

The line is mostly about size and how the product is made. Small molecules have a defined chemical structure that can be copied exactly. Biologics are large, complex molecules or living cells, made in cell lines or from human or animal sources, and two batches are never quite identical.

The boundary has a few precise edges worth knowing:

Proteins versus peptides. FDA rules define a "protein" as a chain of more than 40 amino acids (21 CFR 600.3). Longer chains are biologics; shorter peptides are regulated as drugs and go through an NDA.
Oligonucleotides. Antisense and siRNA medicines are made by chemical synthesis, so they are drugs and use NDAs, even though they act on genes.
Gene and cell therapies are biologics, whether the gene is delivered by a virus, a non-viral vector or engineered cells.
The 2020 transition. Some proteins historically approved as drugs, such as insulin and human growth hormone, were moved over and "deemed to be" BLAs in March 2020 under the Biologics Price Competition and Innovation Act.

From the tracker

The upcoming submissions show the split. Candel plans a BLA for aglatimagene besadenovec, a gene-based therapy delivered in an adenovirus (Candel page); Annexon a BLA for the antibody tanruprubart (Annexon page). PMV Pharmaceuticals plans an NDA for rezatapopt, a small molecule (8-K exhibit, 31 August 2026), as does Atea for its hepatitis C combination (Atea page).

Who reviews it

Two FDA centres share the work:

The Center for Drug Evaluation and Research (CDER) reviews NDAs, and also most therapeutic biologics such as monoclonal antibodies and therapeutic proteins, which were transferred to it in 2003.
The Center for Biologics Evaluation and Research (CBER) reviews vaccines, blood products, and cell and gene therapies.

So "BLA" doesn't automatically mean CBER. An antibody BLA is usually a CDER review; a gene therapy BLA is a CBER review. The two centres have separate advisory committees, which matters if a meeting is called.

Variations you'll see in filings

505(b)(1) and 505(b)(2) NDAs

A standard NDA, under section 505(b)(1), contains full reports of studies the company ran or paid for. A 505(b)(2) NDA relies partly on data the company doesn't own, such as published literature or the FDA's earlier findings about an approved drug. It's common for new formulations, new routes of delivery or new combinations of known drugs, and it can mean a smaller clinical programme.

Supplements: sNDA and sBLA

Once a product is approved, adding a new use, a new population or a significant label change needs a supplemental application. An "efficacy supplement" for a new indication gets its own PDUFA date like an original application.

From the tracker

Cytokinetics' supplemental NDA for aficamten, based on the MAPLE-HCM trial, has a PDUFA date of 14 November 2026 (8-K exhibit); ImmunityBio's supplemental BLA for ANKTIVA in papillary disease has one of 6 January 2027 (ImmunityBio page). Arcutis has an sNDA for ZORYVE cream in infants (Arcutis page).

Rolling submissions

Normally the whole application goes in at once. Products with Fast Track designation can submit completed sections as they're ready, a "rolling submission". The review clock doesn't start until the last section is in, so the date that matters is when the company says the submission is complete.

From the tracker

Palvella announced on 31 August 2026 that it had completed its rolling NDA for QTORIN rapamycin gel (press release). Its PDUFA date wasn't public when this guide was written, so the tracker showed the company's own expectation of a decision in H1 2027 rather than a date. See the Palvella page.

The four-letter suffix

Since 2017, the FDA has given newly approved biologics a non-proprietary name with a random four-letter suffix, to tell apart products that might otherwise share a name, such as an original biologic and its biosimilars. If you see a name like that, it's a biologic.

From the tracker

Three recent approvals in the decided archive: Vera's atacicept-vymj, Outlook's bevacizumab-vikg and Jazz's zanidatamab-hrii. All three are biologics approved through BLAs.

Why it matters after approval

The biggest practical difference is how competitors can follow.

Generics copy approved small-molecule drugs through an Abbreviated New Drug Application (ANDA) under section 505(j). A new chemical entity generally gets five years of exclusivity before a generic application can be submitted.
Biosimilars follow approved biologics through the abbreviated 351(k) pathway, but a new biologic gets twelve years of exclusivity before a biosimilar can be approved. Biosimilars are also harder and more expensive to develop than generics.

Patents and other exclusivities, such as the seven-year orphan drug exclusivity, sit on top of these, so the real period without competition varies a lot. The pathway sets the baseline.

How this shows up on the site

When a company guides to filing an application, the tracker records it as a "Regulatory submission" row with the window the company gave. When the FDA accepts it and assigns a date, a PDUFA row follows, and the row's note quotes the filing so you can see whether it's an NDA, a BLA or a supplement.

More guides

What a PDUFA date is, and why the FDA doesn't publish themThe PDUFA target action date is the FDA's own deadline for deciding on a drug application. Here is where it comes from, how it moves, and why you only hear about it from the company.
What happens at an FDA advisory committee meetingWho sits on an FDA advisory committee, how the day runs, what the vote means and doesn't mean, and where to find the documents beforehand.
What a Complete Response Letter means, and what usually followsA Complete Response Letter is the FDA's "not yet" on a drug application. What it contains, the company's options, how resubmission clocks work, and how to read the announcement.
How to read a Phase 3 topline readoutEndpoints, p-values, effect sizes, safety tables and the phrase "met its primary endpoint": a practical guide to reading the press release a company puts out when pivotal trial results land.
Clinical trial phases explained: Phase 1 to Phase 4What each phase of clinical development is for, roughly how big the trials are, what the in-between labels like 1b, 2a and 2/3 mean, and what a readout at each stage can and can't tell you.
Fast Track, Breakthrough, Priority Review and Accelerated Approval explainedThe FDA's expedited programmes are often lumped together, but they do different things at different stages. What each one is, what it changes about the timeline, and what it doesn't promise.
How to verify a catalyst date yourself on SEC EDGARA step-by-step walkthrough of the method behind this site: finding the filing that announced a PDUFA date or readout window, reading it properly, and spotting the traps that catalyst calendars fall into.
8-K vs 6-K vs press release: where catalyst dates are disclosedWhy almost every row on this site links to an 8-K exhibit, what the 6-K is for, when a press release has no filing behind it, and how the item numbers and "furnished vs filed" affect what you're reading.
Why catalyst windows like "H2 2026" are vague, and how they narrowMost biotech catalysts don't have a date, only a window the company guided to. Why that is, what the common phrases mean, how windows tighten or slip, and how this site handles them.
Glossary of FDA and biotech catalyst termsPlain-English definitions of the regulatory, clinical and SEC-filing terms used across the tracker and the guides, from AdComm to Type A meeting.