A 30-day notice for a manufacturing change on an approved Class III device is decided close to the time its name gives. Of the process-change supplements FDA received between 2015-01-01 and 2023-12-31 and decided as 30-Day Notices, 13,871 supplement records in FDA's PMA file, the median wait from receipt to decision was 27 calendar days and the 90th percentile was 30 calendar days. Only 8 of those records were decided more than 135 calendar days after receipt. The other outcome on the route runs on a slower clock. FDA converted 927 process-change supplement records to the 135 Review Track over the same receipt window, and those records were approved a median 187 calendar days after receipt of the original notice, 736 records (79.4%) of them more than 135 calendar days after receipt.
The regulatory affairs lead who files the notice owes operations a ship date for the changed product and a bridging-stock plan for the pre-change product, and the change-control board that approves the change window works from the same date as the planner who buys the safety stock. For the converted case, the figure to plan on is the recent one. For notices FDA received between 2018-01-01 and 2023-12-31, converted supplements were approved a median 204 calendar days after receipt, the 90th percentile of that wait was 484 calendar days, and 39.8% were approved within 180 calendar days, so a six-month hold from the receipt date covers under two in five recent conversions.
How often the slow clock starts is the other half of that plan. Of all 15,208 process-change supplement records FDA received in the window, 6.1% were converted to the 135 Review Track. Measured against the notices filed on the route, the converted share is 6.3%, and 6.8% once a change filed on several PMAs at once is counted a single time. Counting one record per distinct PMA number gives 735 records carrying a process-change supplement in the window, wide enough to use the share as an industry base rate, though a firm's own PMA history in FDA's database is the better predictor of what its next notice will do.
Two clocks on one filing
FDA's guidance on 30-day notices and 135-day PMA supplements for manufacturing method or process changes sets out both routes and the conversion between them, and gives no figure for how often conversion happens or how long a converted review runs. The fast half of the route is close to mechanical: under 21 CFR 814.39 the change may go ahead 30 days after FDA receives the notice unless FDA says otherwise, and the file shows a median of 27 calendar days and a 90th percentile of 30 calendar days from receipt to decision.
The converted half spreads much wider. Over the 927 converted records received in 2015-2023, the median was 187 calendar days from notice receipt to approval and the 90th percentile 413 calendar days. Of those records, 736 (79.4%) were approved more than 135 calendar days after receipt and 121 (13.1%) more than 365 calendar days after receipt. Collapsing rows that are the same change filed on more than one PMA gives 666 records, one per distinct change, with a median of 186 calendar days and 79.7% past 135 calendar days, so the shape holds at either grain.
The converted clock has lengthened
Inside the window the converted route got slower. For notices received between 2015-01-01 and 2017-12-31, converted supplements were approved a median 170.5 calendar days after receipt, and 53.8% within 180 calendar days. For notices received between 2018-01-01 and 2023-12-31, the median was 204 calendar days, the 90th percentile 484 calendar days, and 39.8% were approved within 180 calendar days.
That is the number a change plan should carry: 204 calendar days as the planning date from receipt, 484 calendar days as the contingency for the tail. The shift over time was measured on the same rows as everything else here, but the composition and concentration checks that support the pooled figures were not repeated on the change between the two periods, so treat the lengthening as a lead rather than a settled result.
How often a notice converts
The 15,208 process-change supplement records FDA received between 2015-01-01 and 2023-12-31 divide by supplement type as follows.
- 13,871 records were filed and decided as 30-Day Notices
- 927 records were converted to the 135 Review Track
- 207 records went by Special (Immediate Track)
- 117 records by Real-Time Process
- 79 records by the Normal 180 Day Track
- 5 records by Panel Track
- 2 records under FDA's legacy 'Special' string
The three conversion shares answer three different questions. The 6.1% is of every process-change supplement received in the window, and its denominator includes supplements filed directly on another track that could never have been converted. The 6.3% is of the supplements that entered on the notice route, which is the share an applicant filing a notice faces. The 6.8% is of distinct changes, once a change filed on several PMAs is counted once.
That last grain matters for anyone counting filings rather than projects. The 927 converted records are 666 distinct changes, and the 13,871 notice records are 9,144 distinct changes, because FDA records one change once per PMA it touches. A single Medtronic heart-valve detergent change accounts for a run of converted rows on its own.
The rate stepped down in 2012
The converted share did not drift down. In the first seven years of the route, notices received between 1998-01-01 and 2004-12-31, 7.4% were converted. Across 2005-2011 the share was 18.2%, peaking at 20.2% for notices received in 2005 and still 19.1% in 2011. For notices received in 2012 it was 9.4%, and across 2012-2019 it was 7.5%, falling to 6.2% in 2019. Across 2020-2023 the share was 5%, with 4.3% in 2020 and 3.5% in 2023.
Two checks say the 2012 drop is a change in what FDA did with notices rather than a change in who was filing them. Restricted to the 38 applicant strings with at least 10 notice or 135-track rows in both 2010-11 and 2012-13, the converted share went from 15.4% to 7.2%, so the fall happened inside the same firms. Standardising later conversion rates to the 2005-2011 mix of advisory committee panels gives 7.1% for 2012-2019 and 4.5% for 2020-2023, close to the unadjusted figures. The converted supplements did not reappear under another supplement type or another reason string.
What caused the step is outside this file. The candidates worth checking by date are FDA's revision of its 30-day-notice guidance, MDUFA III taking effect, and a change in how FDA records a conversion in its database. None of those can be settled from the PMA file, and this piece attributes the step to none of them.
What FDA already publishes about these reviews
FDA reports submission performance in FDA Days, the review clock that stops while an applicant answers a deficiency letter. The MDUFA performance goals for fiscal years 2023 through 2027 are written in those terms, and whether any goal there covers 30-day notices or supplements on the 135 Review Track was not established for this piece. Review days and calendar days part company on the same submission, and every duration here is calendar days from FDA's receipt of the original notice to the decision date on the record.
FDA does publish aggregate decision-time charts for some submission classes in its quarterly reports, such as the 3rd quarter FY 2023 MDUFA V performance report. Those tables and the CDRH annual report were not read by hand for a 30-day-notice or 135-day-supplement breakout. If one of them carries decision times for 135-day supplements, the calendar-day half of what is here is already in print and the conversion rate is the part that is new.
How the numbers were counted
Every figure comes from FDA's PMA file, export 2026-09-04. One row in that file is one PMA supplement record with a receipt date, a decision date, a supplement type and a supplement reason. The counted population is every row whose supplement reason is 'Process Change - Manufacturer/Sterilizer/Packager/Supplier'. The main window is date_received from 2015-01-01 to 2023-12-31 inclusive. The trend figures use receipt windows back to 1998-01-01, and the recent-clock figures use receipt dates from 2018-01-01.
Route comes from the supplement type string: '30-Day Notice' for a notice decided as filed, '135 Review Track For 30-Day Notice' for a converted one. On a converted row the receipt date is the original notice's receipt date, and no converted row in the window sits out of S-number order against the notice it came from. Each duration is the decision date minus the receipt date in calendar days, taken per row, and the medians and percentiles are over those row-level durations. The 90th percentile of the pooled converted wait is 413.2 days, printed here as 413.
Change-grain counts collapse rows sharing an applicant, a receipt date, a decision date and the same approval-order statement, which groups one change filed on several PMAs into one change. The continuing-filer comparison keeps applicant strings with at least 10 notice or 135-track rows in both 2010-11 and 2012-13, 38 strings in all, and recomputes the converted share inside that set. The standardised rates weight each advisory committee panel's later conversion rate by that panel's 2005-2011 notice count, for panels present in both periods.
The window ends at 2023-12-31 and the export is 2026-09-04, a gap of 978 days. Of converted supplements received between 2005-01-01 and 2019-12-31, 0.83% were decided more than 978 days after receipt, and the file carries no row without a decision date, so the 2023 receipt cohort is close to complete.
What these files cannot say
The statute's 135 days are FDA review days, and that clock stops while the applicant answers FDA. This file records calendar dates only, so it cannot show whether FDA met or missed 135 review days on any supplement. The 736 records (79.4%) approved more than 135 calendar days after receipt are the wait the applicant lived through. FDA's own review-clock data, or a MDUFA performance report that breaks out 135-day supplements, would settle the review-day question.
The PMA file carries approved supplements only. A converted notice that the applicant withdrew, or that FDA denied, has no row anywhere in it. The 6.1% conversion share is therefore a floor, and the duration figures describe conversions that ended in approval. FDA's internal supplement tracking, or a FOIA request for 30-day-notice dispositions, would size that gap.
The cause of the 2012 step cannot be recovered from these rows, only ruled out as a recoding. Nothing here supports naming a guidance revision, a user-fee agreement or a database practice as the reason, and the documents would have to be checked by issue date first.
The prior that a converted notice takes 135 days is inferred from FDA's guidance text and the route's name, not from any survey of filers. No published conversion rate or duration for this route was located, but the search was not exhaustive.
The pooled conversion share also hides real variation between firms and between change types. Conversion rates differ enough by applicant that the industry figure is a starting point for a change plan, and the firm's own record of notices and conversions on its own PMAs, which is public in the same database, is the number that should set the contingency.
