USFDA Guidance: ANDA Submissions – Amendments & Requests and Study Data Technical Conformance Guide - Technical Specifications

For generic drug developers, receiving tentative approval (TA) for an Abbreviated New Drug Application (ANDA) is a major milestone—but it is not the end of the regulatory journey. Moving from tentative approval to final FDA approval requires careful planning, timely submissions, and technically compliant study data. To support applicants, the FDA has issued two complementary guidance documents:

• ANDA Submissions — Amendments and Requests for Final Approval to Tentatively Approved ANDAs (Revision 2, December 2025), and

• Study Data Technical Conformance Guide (SDTCG): Technical Specifications Document (Version 6.1, December 2025).

ANDA Submissions – Amendments and Requests for Final Approval to Tentatively Approved ANDAs

An ANDA allows a generic drug applicant to rely on FDA’s prior finding of safety and effectiveness for a Reference Listed Drug (RLD). Instead of repeating clinical efficacy studies, ANDA applicants must demonstrate:

• pharmaceutical equivalence,

• bioequivalence (BE), and

• adequate product quality.

However, even when an ANDA meets all scientific and regulatory requirements, FDA may be legally unable to grant final approval due to patent protections or exclusivities associated with the RLD.

Understanding Tentative Approval

Tentative approval means FDA has determined that an ANDA meets all scientific and regulatory requirements for approval, except for outstanding legal issues such as patents or exclusivities associated with the reference listed drug (RLD).

A tentatively approved ANDA is not an approved drug, cannot be marketed, and is not listed as approved in the Orange Book.

Final approval is granted only after legal barriers expire and the applicant submits a proper request for final approval.

Amendments After Tentative Approval

Following TA, applicants may need to submit amendments to reflect changes before final approval. These can include updates to product quality, manufacturing sites, bioequivalence data, labeling changes due to RLD updates, or patent and exclusivity information.

FDA reviews these amendments under GDUFA III performance goals, classifying them as minor or major depending on their complexity and whether inspections are required. Some amendments may be deferred if the ANDA cannot be approved in the near term.

Requesting Final Approval: Key Timing Considerations

FDA does not automatically grant final approval when patents or exclusivities expire. Applicants must submit a formal request for final approval, which is treated as an amendment.

If the request is submitted less than three years after TA and includes no substantive changes, FDA generally recommends submitting it at least three months before the expected approval date, and it is usually reviewed as a minor amendment.

If the ANDA has been tentatively approved for three years or more, FDA expects applicants to reassess whether standards have changed. In these cases, the request for final approval is generally submitted as a major amendment, ideally no later than ten months before the desired approval date.

What to Include in a Final Approval Request

A request for final approval should clearly state that final approval is requested, identify the legal basis for approval, list all changes since TA, include an updated Form FDA 356h, and provide updated labeling where applicable. Poorly prepared requests may result in review delays or continued tentative approval.

Study Data Technical Conformance Guide - Technical Specifications Document

Even when regulatory timing is well managed, final approval can be delayed if supporting study data are not submitted in a technically compliant format. The Study Data Technical Conformance Guide (SDTCG) describes FDA’s expectations for how clinical and nonclinical study data must be structured, formatted, and validated for electronic submission.

The SDTCG applies across submission types, including ANDAs, and ensures FDA reviewers can efficiently load, analyse, and interpret study data. Non-conforming data can lead to technical rejection or requests for resubmission, regardless of scientific adequacy.

By aligning with both guidances, applicants can reduce review cycles, avoid unnecessary delays, and achieve approval as close as possible to the earliest lawful date—supporting faster access to affordable generic medicines. For full details, readers should consult the official FDA guidance documents linked above.