Why CMC gaps are the most common reason regulatory submissions get delayed
When a regulatory submission takes longer than planned, the clinical or non-clinical data is rarely the problem.
The science, in most cases, has been done well. The delay almost always sits somewhere in Module 3.
Chemistry, manufacturing and controls remains the section that agencies scrutinise most heavily during initial review, where information requests are most frequent, and where the most avoidable clock stops originate. Understanding why that happens is the first step to preventing it.
Why CMC causes more delays than any other section
There are structural reasons why CMC is disproportionately represented in submission delays.
CMC spans multiple functions. Process development, analytical, manufacturing, regulatory affairs and quality all contribute data and documentation to the CMC package. When those functions work in silos, gaps appear at the boundaries, and no one person holds the complete picture.
CMC is also often treated as the last section to be completed. Programmes running behind schedule frequently compress the CMC writing timeline. The result is documentation that does not fully support the data, inconsistencies between sections, or missing justification that an agency reviewer will identify during their first pass.
Regulatory expectations have also risen. Agencies including the FDA, MHRA and EMA expect increasingly detailed CMC packages. A filing approach that cleared review five years ago may now generate a major amendment request.
The structural problem with CMC documentation
Multiple contributing functions, often working in silos, with gaps appearing at handover points
CMC writing frequently compressed under timeline pressure, leaving documentation behind the data
Rising agency expectations mean precedent from previous submissions is not always reliable
Consistency across sections requires oversight that individual function leads rarely have time to provide
Preparing a submission in the next 12 months?
TDP conducts pre-submission CMC reviews across IND, CTA, NDA and MAA filings. We identify the gaps most likely to generate agency questions before your filing goes in.
The most common CMC gaps we see
Across regulatory submissions in development-stage and commercial programmes, certain deficiencies appear repeatedly.
1. Insufficient process characterisation data
The data does not demonstrate adequate understanding of critical process parameters and their relationship to critical quality attributes. The control strategy cannot be fully justified.
2. Analytical method validation gaps
Methods lack full validation data, or validation reports do not align with the scope of method use in the submission. Particularly common where methods have been transferred between sites.
3. Specification justification absent or inadequate
Acceptance criteria are not tied to development data. Specifications appear set by convention rather than by evidence from the actual product and process.
4. Container closure documentation below current expectations
Container closure system documentation does not meet current ICH or agency guidance. Increasingly scrutinised, particularly for biologics and complex delivery systems.
5. Stability data gaps or unsupported shelf life claims
Stability packages with missing time points, insufficient data to support the proposed shelf life, or shelf life claims not adequately bracketed by the data presented.
6. Technology transfer documentation incomplete
Documentation does not demonstrate comparability at the receiving site. Particularly common when CDMO changes are made during development.
None of these gaps reflect poor science. They reflect programme pressure, compressed timelines, and the challenge of coordinating CMC documentation across teams with different priorities.
What regulators are looking for
Internal consistency: every CMC section tells the same story
Evidential support: every claim is backed by data presented in the dossier
Alignment with current guidance: FDA, MHRA and EMA expectations have continued to evolve
Transparency: gaps or limitations in the data are acknowledged and contextualised, not omitted
The cost of a gap identified during review
An information request from the FDA or a request for supplementary data from the MHRA does not simply cause a three-month delay.
Depending on what the agency finds, it can reset timelines entirely, trigger additional manufacturing or analytical work, require new stability studies, or prompt a request for a Type II variation or major amendment. For commercial-stage submissions, the downstream cost is measured in lost revenue and competitive position. For development-stage companies approaching key milestones, it can affect investor timelines and financing decisions.
The economics of investing in a thorough CMC review before submission are straightforward. The cost of finding a gap before filing is a fraction of the cost of managing it during review.
What a pre-submission CMC review actually involves
A structured pre-submission review, conducted by experienced consultants with direct agency submission experience, identifies the gaps most likely to generate questions before they become agency findings.
A rigorous review is not a light-touch document check. It requires technical depth and regulatory experience working together. The people conducting the review need to understand both what the science shows and how an agency reviewer will interpret it.
What a TDP pre-submission CMC review covers
Cross-checking all CMC sections for internal consistency
Comparing the dossier against current agency guidance and recent precedent for the product type
Reviewing data packages to confirm they support the claims being made
Identifying sections where additional justification, data or narrative would strengthen the package
Providing written findings with a clear prioritisation of what to address before submission
If your submission is within 12 months, now is the time
TDP conducts pre-submission CMC reviews for IND, CTA, NDA and MAA filings. If a gap exists, it is better to know before the filing goes in.
Building CMC quality into the programme from the start
The most effective approach is not to fix CMC gaps before submission. It is to avoid creating them in the first place.
This means involving CMC regulatory expertise early in the development process, not just at the writing stage. It means establishing clear documentation standards across all the functions contributing to the CMC package. And it means building in structured CMC review checkpoints as the programme moves through phases.
Programmes that treat CMC as a parallel workstream throughout development, rather than an end-stage documentation exercise, consistently produce cleaner submissions with fewer information requests. The investment in getting it right earlier is smaller than the cost of fixing it later.
If you want a direct view on where your CMC package stands, we are happy to take a look.