Complete response letters for generic drugs

In fiscal 2025, FDA sent 1,281 complete response letters to companies seeking approval of generic drugs, according to the agency's monthly activity report⁵. It approved 689 generic applications in the same period. For every approval, the Office of Generic Drugs wrote nearly two letters explaining why an application could not be approved as filed.

A complete response letter, or CRL, is the most common outcome of a generic drug review. It is also among the least visible. When FDA began publishing CRLs in 2025, the database it built covered new drug applications and biologics license applications. Letters to generic applicants stayed private.

What is public comes from FDA's own aggregate analyses. Those show that most first-round failures trace to manufacturing and product quality, and that a large share involve plants already in trouble with FDA.

What the regulation requires

Federal regulation 21 CFR 314.110 governs these letters for both new drug applications and abbreviated applications for generics. FDA sends a CRL when it "will not approve the application or abbreviated application in its present form," the regulation¹ says. The letter must "describe all of the specific deficiencies" the agency found, and "when possible" recommend steps that would put the application in condition for approval. FDA may issue one without first inspecting facilities or reviewing labeling if the data are already inadequate.

An applicant then has three options under the regulation. It can resubmit, addressing every deficiency. It can withdraw the application without prejudice to a later filing. Or it can request an opportunity for a hearing on whether there are grounds to deny approval. If it does nothing for a year, FDA may treat the silence as a request to withdraw, though the regulation says FDA will grant any reasonable request for more time.

For generics, the user fee agreement sets the review clock for a resubmission, the same system of ANDA review goal dates that governs first filings. Under the GDUFA III commitment letter², FDA classifies the response as a major or minor amendment and must state its basis for calling it major. Major amendments get a goal date of six to 10 months and minor ones three months, under the user fee program described in our GDUFA explainer. A minor response filed more than a year after the CRL is reclassified as major, except for drugs on FDA's shortage list or tied to a declared public health emergency.

How many letters FDA sends

Sources are FDA's activity reports for fiscal 2023³, 2024⁴ and 2025⁵ and the FDA-TRACK dataset⁶ for fiscal 2026. The ratio is GxRadar's arithmetic. CRLs and approvals in a year do not involve the same applications, since many approvals follow letters sent in earlier years.

Rejected applications pile up. At the end of August 2026, 1,235 ANDAs sat in complete response status, meaning FDA was waiting on the applicant, according to FDA-TRACK. A year earlier, at the end of September 2025, the figure was 1,325.

What the letters cite

FDA has published aggregate breakdowns at its annual Generic Drugs Forum. A 2025 presentation by FDA staff in the Office of Pharmaceutical Quality⁷ examined the 284 first-cycle CRLs classified as major that FDA issued in fiscal 2023. Those letters cited 429 major deficiencies, and more than 70 percent were quality-related. Shares below do not sum to 100 because the presentation did not list every smaller category.

Within the drug product category, the leading problems were impurities without the toxicology data to qualify them, inadequate safety assessments of extractables and leachables from packaging, and insufficient data to show that a complex active ingredient such as a peptide was the same as the brand's. Of the drug product deficiencies tied to critical quality attributes, 56 percent involved nitrosamine drug substance-related impurities, the contaminant class described in our nitrosamine explainer. On the drug substance side, 82 percent of major deficiencies came from problems in the referenced Drug Master File, the confidential file an ingredient supplier keeps with FDA (see DMF in our glossary).

Bioequivalence problems, the studies described in our piece on the 80-125 rule, made up 18 percent.

When the plant is the problem

Facility issues dominate the manufacturing category. In its fiscal 2025 quality report⁸, FDA analyzed nearly 10,000 original applications and supplements across brand, generic and biologic programs that required a facility assessment and were received in fiscal 2024 and 2025. As of May 2026, 28 percent had received a CRL. Of those, 43 percent were due to "facility withholds," a hold placed on approval because of concerns about the plant. More than half of the withholds involved facilities that already had an Official Action Indicated or potential OAI status when the application arrived.

FDA's conclusion was direct. "Many of these CRLs could have been prevented had the submission included only facilities with a compliant status," the report said. It listed three inspection citations most often behind withholds: inadequate investigation of discrepancies and batch failures, quality control unit procedures not written or followed, and inadequate control of microbial contamination in sterile products. How inspections reach those outcomes is covered in our guide to inspections, 483s and warning letters.

A CRL that is major only because of a facility problem can be downgraded. If the applicant shows the issue is resolved and no further inspection is needed, FDA can reclassify the response as minor, shortening the review. FDA granted 56 such requests and denied nine in fiscal 2025, and granted 84 and denied five from October 2025 through August 2026, the activity data show.

Talking to FDA after a letter

Applicants can ask for a post-CRL teleconference to clarify deficiencies. FDA's goal is to schedule 90 percent within 14 days and hold them within 30 days of the request. In fiscal 2025 applicants requested 65, and FDA granted 48, according to its GDUFA performance report to Congress⁹. Applicants with a bioequivalence problem can request a post-CRL scientific meeting; 19 were requested and 14 granted that year. Developers can also raise questions before filing, through controlled correspondence and pre-ANDA meetings, or by following FDA's product-specific guidances.

Why generic letters stay private

On July 10, 2025, FDA published more than 200 CRLs¹⁰ tied to applications submitted between 2020 and 2024 and since approved, saying the public would gain insight into "the most common deficiencies cited that sponsors must address." On Sept. 4, 2025, it said it would release new CRLs promptly¹¹ after issuing them and posted 89 more tied to pending or withdrawn applications.

FDA's openFDA database¹² describes its contents as CRLs "associated with approved and unapproved New Drug Applications (NDAs) and Biologics License Applications (BLAs)." It held 458 letters as of its last update on Aug. 13, 2026, GxRadar found by querying the API. ANDAs are not in its scope, so the roughly 1,000 to 1,500 letters a year that generic applicants receive remain unpublished.

A user fee renewal may change how those letters are discussed even if they stay private. FDA's proposed GDUFA IV commitment letter¹³ for fiscal 2028 through 2032 would make clarification of CRL deficiencies one use of a new "TYPE 30" meeting, requested within 15 days of the letter and held or answered in writing within 30 days. The current agreement runs through fiscal 2027. Our explainers on how a generic drug gets approved and the Office of Generic Drugs cover the rest of the process.