Recently, I was working with a client on the strategy for a development program when access to a Complete Response Letter proved particularly valuable. It was a practical reminder that CRLs can be very important sources of regulatory insight and intelligence.

That experience also reminded me of the broader debate now taking place around CRL transparency.

In July 2025, the U.S. Food and Drug Administration made an important change in the transparency of its drug-review process. FDA published more than 200 Complete Response Letters, or CRLs, associated with applications submitted between 2020 and 2024. The Agency subsequently released additional previously unpublished letters and indicated that future CRLs would be published more promptly after issuance.

FDA presented the initiative as part of its commitment to “radical transparency”: an effort to give drug developers, patients, investors and the broader public greater visibility into why certain applications could not be approved.

By April 2026, however, publication had been paused while FDA considered a citizen petition challenging the legal basis for the initiative and the process used to protect confidential commercial information. In July 2026, FDA resumed publication, adding 14 CRLs and indicating that proactive disclosure would continue while the Agency strengthened its review, redaction and publication procedures.

This sequence of publication, pause and resumption illustrates why the issue is more complicated than a choice between transparency and confidentiality.

The central policy question is not simply whether FDA Complete Response Letters should be published. It is how CRL publication should be governed.

What is an FDA Complete Response Letter?

The terminology matters. A Complete Response Letter is sometimes described publicly as an FDA “rejection letter.” That description is understandable, but incomplete.

A CRL means that FDA has completed its review of an application and cannot approve it in its present form. The letter identifies deficiencies that must be addressed and may recommend actions that could place the application in a condition for approval.

The sponsor may respond through a resubmission, withdraw the application, request a meeting with FDA or pursue available dispute-resolution procedures.

Some CRLs identify fundamental questions about clinical efficacy or safety and may require one or more additional clinical trials. Others arise from manufacturing inspections, product-quality controls, analytical validation, facility readiness, bioequivalence, labeling, human factors or other potentially remediable issues.

A CRL is therefore an important regulatory decision, but it is not necessarily the final chapter in a product’s development.

That distinction becomes particularly important when the letter is published. Public disclosure can create the impression that FDA has made a final scientific judgment against a product when the letter may instead document one stage in an ongoing regulatory process.

What are the arguments for publishing Complete Response Letters?

There are legitimate public-policy arguments supporting greater CRL transparency.

CRLs can improve drug-development decisions

Complete Response Letters provide insight into how FDA applies statutory and scientific standards to actual development programs.

Guidance documents necessarily describe regulatory expectations at a relatively general level. CRLs show where particular applications did not meet those expectations.

Across multiple letters, developers may identify recurring deficiencies involving:

  • Clinical-trial design
  • Endpoint selection
  • Statistical analysis
  • Safety characterization
  • Dose justification
  • Manufacturing controls
  • Facility inspections
  • Comparability
  • Bioequivalence
  • Human factors
  • Labeling and risk management

Properly analyzed, this information could help companies identify regulatory risks earlier and avoid repeating preventable mistakes.

CRL publication can reduce information asymmetry

Historically, the public often learned about a CRL through a sponsor’s press release or securities filing.

Those communications may be accurate but necessarily selective. They are written for investors and other stakeholders and are not intended to reproduce a detailed regulatory document.

A 2015 analysis by FDA researchers compared CRLs with corresponding sponsor communications. The researchers found that company announcements frequently disclosed only part of FDA’s reasoning. In several cases, requirements for additional clinical trials were not publicly described.

This does not establish that every omission was misleading. It does, however, demonstrate the information imbalance that can arise when the sponsor controls nearly all public communication about an FDA decision.

CRL publication gives patients, investigators, healthcare professionals and investors access to FDA’s own account of the deficiencies.

Transparency can increase accountability on both sides

CRL publication does not expose only the sponsor’s decisions. It also exposes the regulator’s reasoning.

Sponsors know that their public descriptions of FDA feedback can be compared with the underlying letter. At the same time, FDA’s conclusions become more accessible for evaluation across review divisions, therapeutic areas and product categories.

That could support greater scrutiny of:

  • Scientific consistency
  • Proportionality of regulatory requests
  • Differences among review divisions
  • Changes in FDA expectations over time
  • Alignment between guidance and actual review practice

Transparency can therefore strengthen accountability for both industry and the Agency.

What are the risks of publishing Complete Response Letters?

Industry concerns should not be dismissed as simple opposition to transparency.

CRLs may contain commercially sensitive information

Marketing applications contain information about clinical-development strategies, manufacturing processes, formulations, analytical methods, product limitations and future development plans.

Even when individual facts do not independently qualify as trade secrets, competitors may be able to combine multiple disclosed elements to reconstruct a company’s development strategy.

Redaction is therefore not merely an administrative exercise. It requires scientific, legal and commercial judgment.

A redaction process that removes too much information may undermine the public value of disclosure. A process that removes too little may expose legitimate confidential commercial information.

FDA’s legal authority must be clear

Information contained in an unapproved marketing application has traditionally received significant protection from public disclosure.

FDA’s request for explicit statutory authority to disclose certain information from CRLs indicates that the boundaries of the Agency’s existing authority remain open to debate.

A durable transparency policy should not depend on shifting interpretations or informal agency practice. Congress and FDA should clearly define:

  • The legal authority supporting disclosure
  • Which applications and letters are covered
  • What information must remain protected
  • What procedures sponsors may use to challenge disclosure
  • Whether the policy applies prospectively, retrospectively or both

Transparency is more sustainable when the legal foundation is transparent as well.

Timing can affect fairness and accuracy

Immediate publication promotes timely access to information, but a CRL may contain issues that remain under active discussion.

Publication before those issues are addressed may present an interim regulatory position as though it were final.

Other regulators have attempted to balance these interests through delayed publication, appeal periods or public assessment reports that incorporate the final outcome of an internal review.

Publication could change sponsor-regulator interactions

Drug development depends on candid communication between regulators and sponsors.

Development teams must be able to discuss failed analyses, uncertain findings, alternative interpretations and potential remediation strategies. FDA reviewers must also be able to communicate concerns directly.

A system that makes every written exchange part of an immediate public record could encourage more defensive communications on both sides.

This risk should not be overstated, but it should be considered.

How do other global regulators disclose negative decisions?

The United States is not the first jurisdiction to publish information about unsuccessful marketing applications. However, international practices vary considerably.

European Medicines Agency

The European Medicines Agency publishes information following negative opinions by the Committee for Medicinal Products for Human Use and following refusals of marketing-authorisation applications.

The public record may include a question-and-answer document and a refusal European Public Assessment Report explaining the scientific basis for the decision.

The European model is not simply the publication of correspondence sent to the applicant. Disclosure is integrated into a defined regulatory assessment process.

Medicines and Healthcare products Regulatory Agency

The United Kingdom’s MHRA publishes Public Assessment Reports for certain refused marketing-authorisation applications.

These reports are intended to explain the regulatory decision and the evidence considered, while protecting commercially confidential information.

Therapeutic Goods Administration

Australia’s TGA publishes Australian Public Assessment Reports for wholly rejected applications.

Publication generally occurs after the relevant appeal period has expired and any internal review has been completed. The final public record can therefore reflect both the original decision and the outcome of the review.

Health Canada

Health Canada publishes Regulatory Decision Summaries covering positive and negative decisions and certain cancelled submissions.

Its broader disclosure framework also addresses when clinical information ceases to qualify as confidential business information following a final regulatory decision.

Pharmaceuticals and Medical Devices Agency

Japan’s PMDA publishes extensive review reports for approved products but does not operate an equivalent system of routinely publishing detailed rejection correspondence for unsuccessful applications.

What can FDA learn from global regulatory practice?

The lesson is that regulators have made different policy choices concerning:

  • The document that is published
  • The stage of the process at which publication occurs
  • Whether an appeal period must first expire
  • How confidential information is identified and protected
  • Whether the public document includes subsequent regulatory outcomes
  • Whether the regulator publishes correspondence or prepares a separate assessment report

These distinctions matter.

International experience demonstrates that transparency can be designed as a regulatory process rather than treated as document disclosure.

Could CRL publication advance global regulatory science?

The potential value of CRL publication extends beyond accountability for individual decisions.

Drug development produces an enormous amount of knowledge, but much of what becomes publicly visible is associated with approved products, positive trials and successful regulatory strategies.

The lessons from unsuccessful programs are considerably less accessible. That creates a form of regulatory publication bias.

Complete Response Letters contain information about:

  • Study designs that were considered inadequate
  • Endpoints that did not support the proposed indication
  • Safety questions that remained unresolved
  • Statistical analyses that did not adequately support effectiveness
  • Manufacturing and quality systems that failed to meet approval standards
  • Facilities that were not considered inspection-ready
  • Development assumptions that did not withstand regulatory review

This regulatory knowledge may be as important to innovation as information about successful approvals.

A sufficiently broad and well-organized CRL dataset could help researchers, regulators and developers identify recurring weaknesses in current scientific methods. It could show where regulatory expectations are evolving and where additional guidance, methodological research or international harmonization may be needed.

The benefits could be particularly important for smaller biotechnology companies, academic developers and emerging markets.

Large pharmaceutical companies often possess decades of internal regulatory intelligence derived from previous submissions and interactions with multiple agencies. Smaller organizations may not have access to the same institutional memory.

A governed public system could reduce some of that asymmetry and make regulatory learning more broadly available.

What would a durable FDA CRL publication policy require?

A sustainable U.S. policy should address several issues explicitly.

  • Clear legal authority and scope
  • Defined publication timing
  • A structured redaction process
  • Context and version control
  • Consistency across products and sponsors
  • Periodic regulatory-science analyses

Global interoperability

Over time, FDA and other regulators could explore common taxonomies and data standards that allow public regulatory decisions to be compared across jurisdictions.

This would not require regulators to reach identical conclusions. Different authorities operate under different statutes, procedures and public-health priorities.

The objective would be to make areas of regulatory convergence and divergence more visible and scientifically intelligible.

The question is no longer simply whether CRLs should be published

Complete Response Letters contain information with real public value.

They can improve development programs, provide greater context to patients and investors, and allow the public to evaluate both sponsor communications and FDA decision-making.

They also contain information created within a confidential regulatory process, often concerning applications that remain under development and decisions that may not yet be final.

A policy based entirely on confidentiality no longer reflects evolving international expectations for regulatory transparency.

But immediate disclosure without clear legal authority, a predictable redaction process, appropriate procedural protections and sufficient context is also unlikely to be durable.

The best answer is governed transparency: publication supported by clear authority, defined scope, consistent safeguards, appropriate timing and enough context for the information to be understood rather than simply released.

The larger opportunity is to move from governed transparency to a global regulatory-science learning system.

With structured data, longitudinal outcomes and responsible use of artificial intelligence, CRLs could help the development community learn systematically from regulatory failure, not to reduce drug review to an algorithm, but to ask better questions earlier, design stronger development programs and avoid repeating preventable mistakes.

CRL publication should therefore be evaluated not only as a transparency policy, but also as a potential innovation policy to convert accumulated regulatory experience into shared scientific progress.