FDA's Modular PMA Review: Submitting Early Doesn't Start the Clock Early

FDA's modular PMA and HDE review program lets an applicant submit nonclinical and manufacturing information as discrete modules while still collecting and analyzing clinical data on the final device design. FDA reissued the final guidance on January 13, 2025, more than two decades after the agency first introduced the approach and Congress codified it into the statute. The program is widely treated as a way to shave time off the overall approval timeline. It isn't one. It is a way to get FDA working on your nonclinical and manufacturing data before your clinical program finishes — and the statutory review clock still waits for the module that completes the file.

What modular review actually buys you

Congress codified the modular approach into the FD&C Act in 2002, amending Section 515(c) to authorize FDA to review PMA modules as they arrive and to assess user fees against modular applications. The mechanics are flexible by design: an applicant proposes how to group review disciplines into modules — biocompatibility and bench testing together, for instance — subject to the review team's agreement. One exception holds across every modular application: manufacturing information and Bioresearch Monitoring (BIMO) data are handled on their own track rather than folded into another module. What that buys the applicant is early engagement — FDA reviewers flag deficiencies in nonclinical or manufacturing data while the clinical program is still running, instead of after a complete PMA has already been filed.

Why “earlier” isn't “faster”

21 CFR 814.44(c) sets FDA's review period at the later of 180 days from the date of filing under 21 CFR 814.42, or an adjusted count when a major amendment extends it. Filing is the trigger — and for a modular PMA, filing doesn't happen at the first module. It happens when the completing module, the one that carries the clinical data FDA needs to evaluate the complete application, arrives and FDA accepts it. Everything submitted before that point is real review work, not wasted effort, but it does not advance the date the 180-day clock starts running.

• Filing, not submission, starts the clock. 21 CFR 814.44(c) runs FDA's 180-day review period from the date of filing under §814.42 — and a modular PMA isn't filed until the completing module arrives.
• The completing module has to carry the clinical data. Nonclinical and manufacturing modules can go in early; the module that triggers filing is the one FDA can review as a complete application.
• The cover letter has to say so. FDA's guidance expects the final module's cover letter to flag the application as the completed modular PMA or HDE.
• Manufacturing and BIMO modules stand apart. Most modules can be grouped by discipline with the review team's agreement; manufacturing and Bioresearch Monitoring information are handled on their own track.

Modular review buys you FDA's attention on your nonclinical and manufacturing data before your clinical program is done. It does not buy you an earlier filing date. What the 180-day clock actually measures

Where modular review backfires

The failure mode is not the clock — it's the design. Manufacturing and nonclinical modules submitted early assume the device design behind them is settled. FDA's own framing treats modular review as a fit for applicants who are still collecting and analyzing clinical data but are otherwise far enough along that the design isn't expected to move. An applicant who submits a manufacturing module against a design that later changes doesn't get a faster review — they get a module FDA already reviewed that now has to be resubmitted, on top of whatever the design change cost elsewhere in the program. Modular review is a poor fit at the opposite end too: an applicant close to having a complete, submission-ready package gains little from splitting it into modules FDA will review on roughly the same timeline anyway.

None of this makes modular review a bad tool — it's a sequencing tool, not a shortcut. Teams that treat the PMA submission strategy as a single filing decision, rather than a module-by-module negotiation with the review team, end up resubmitting manufacturing data against a design that moved. The modular program rewards teams who already know their design is close to final and want FDA working in parallel — not teams hoping an early module buys them a head start on the clock. Once the device is approved, that discipline doesn't end: the same filing logic shapes how post-approval changes get reviewed too.