FDA Drug Approval Process: CDER Regulatory Guide

The FDA drug approval process is the pathway through which the U.S. Food and Drug Administration decides whether a new drug may be marketed, based on evidence of safety and effectiveness. The Center for Drug Evaluation and Research (CDER) runs the review of most human drugs, working under Section 505 of the Federal Food, Drug, and Cosmetic Act (FD&C Act). For teams in regulatory affairs in the pharmaceutical industry, the main rules are 21 CFR Part 312 (investigational new drugs) and 21 CFR Part 314 (new drug applications).

What it is and who runs it

CDER is the FDA center that regulates human prescription and over-the-counter drugs. Its review teams include medical officers, pharmacologists, toxicologists, statisticians and chemistry, manufacturing and controls (CMC) reviewers. The overall FDA drug development process runs from laboratory and animal testing, through clinical testing in people, to FDA review of the evidence and proposed labeling.

Eligibility and starting requirements

Any commercial sponsor or investigator who holds enough nonclinical data can submit an Investigational New Drug (IND) application under 21 CFR Part 312; both commercial and investigator-initiated INDs exist. Before human testing, laboratory and animal safety studies are expected to follow Good Laboratory Practice (21 CFR Part 58). Sponsors often use contract research organizations for this work, described in the pharmaceutical CRO industry sector overview.

What it requires

The process is a regulatory framework, not a funding program. A new drug application (NDA) is submitted in the electronic Common Technical Document (eCTD) format, organized into five modules covering regional administrative information, summaries, quality (CMC), nonclinical reports and clinical study reports.

Application and compliance steps

Step 1: IND filing

Before clinical trials begin, the sponsor submits an IND. Under 21 CFR 312.40(b), an IND goes into effect 30 days after FDA receives it, unless FDA notifies the sponsor that the investigations are on clinical hold, or earlier tells the sponsor they may begin.

Step 2: Clinical trials

Trials must follow Good Clinical Practice; see what changed in ICH E6(R3) Good Clinical Practice and clinical trial protocol design. Participants give informed consent.

Step 3: NDA submission

Under Section 505(b) of the FD&C Act, the sponsor sends the evidence to CDER, where a team reviews the data and proposed labeling. FDA generally expects results from two well-designed clinical trials, although convincing evidence from one trial may suffice for rare diseases.

Step 4: FDA review and action

FDA acts on the application with an approval letter or a Complete Response Letter (CRL, 21 CFR 314.110) that sets out deficiencies to resolve before approval.

Typical timeline phases

What are the 4 phases of FDA approval?

Preclinical testing is followed by clinical trials in phases (Phase 1 for early safety, Phase 2 for preliminary effectiveness and side effects, Phase 3 for pivotal confirmatory trials), then FDA review, then post-market safety monitoring. FDA’s goal for the FDA drug approval process timeline at review is to act within 10 months for a standard review and within 6 months for a Priority Review.

Common reasons for a clinical hold

Under 21 CFR 312.42, FDA may place a proposed or ongoing study on clinical hold when:

• subjects would face an unreasonable and significant risk of illness or injury;
• the named investigators lack the scientific training and experience for the study;
• the investigator brochure is misleading, erroneous or materially incomplete;
• the IND lacks enough information to assess risks to subjects; or
• for Phase 2 or 3, the protocol is clearly deficient in design for its objectives.

Related programs

Mechanism	Authority	What it is
Investigational New Drug (IND)	21 CFR Part 312	Application required before clinical investigation of an unapproved drug begins
Priority Review	FDA review designation	FDA goal to act within 6 months, against 10 months for standard review
Orphan Drug Designation	21 CFR Part 316	For conditions affecting fewer than 200,000 people in the United States, with defined exceptions

FAQ

What is the difference between an IND and an NDA?

An IND (21 CFR Part 312) lets clinical investigation of an unapproved drug begin. An NDA (21 CFR Part 314) asks FDA to approve the drug for marketing.

What triggers an FDA clinical hold?

The grounds are listed in 21 CFR 312.42, including unreasonable risk to subjects, unqualified investigators, a misleading investigator brochure and insufficient information to assess risk.

How long does FDA review take?

FDA’s stated goals are action within 10 months for a standard review and within 6 months for a Priority Review.

What happens after a Complete Response Letter?

A CRL (21 CFR 314.110) describes deficiencies that must be resolved before the application can be approved.

Sources

Checked 2026-11-07.

• U.S. Food and Drug Administration, The Drug Development Process: https://www.fda.gov/drugs/development-approval-process-drugs
• 21 CFR 312.40 (IND effective date): https://www.law.cornell.edu/cfr/text/21/312.40
• 21 CFR 312.42 (clinical holds): https://www.law.cornell.edu/cfr/text/21/312.42
• 21 CFR 316.20 (orphan drug designation): https://www.law.cornell.edu/cfr/text/21/316.20
• FDA, Priority Review: https://www.fda.gov/patients/fast-track-breakthrough-therapy-accelerated-approval-priority-review/priority-review