Read CRLs, review documents for human factors insights, experts say

PROVIDENCE, RI – The US Food and Drug Administration’s (FDA) recently released trove of complete response letters (CRL) is a valuable resource for companies to understand the agency’s thinking on human factors. A panel of experts say that they have used the documents to evaluate human factors of their own products and avoid potential regulatory pitfalls.

Earlier this year, FDA announced it would publish CRLs for drugs promptly, laying out the reasons for the products’ rejection. The agency initially published around 200 CRLs that were previously available for products that were later approved in July, followed by 89 CRLs for drugs that have been rejected since 2024 and are no longer being pursued by their sponsors. (RELATED: FDA to publish CRLs ‘promptly’ as drugs are rejected, Regulatory Focus, 4 September 2025)

During a discussion on human factors and use-related risk analysis (URRA) considerations at the AFDO/RAPS Healthcare Products Collaborative Combination Products Summit, a panel of experts said they have been using the CRLs to evaluate what issues regulators may have regarding human factors of their products.

Matt Marber, a senior usability engineer at Novo Nordisk, said the letters have been a “blessing in disguise” that has helped his team understand what has been happening at other companies and FDA’s expectations.

“That was a nice opportunity to learn a little bit more about what was going on in other companies,” said Marber. “Being able to get a little bit of a pulse of what are common challenges that other teams are facing when it comes to their submissions helps move your compass in the right direction in terms of making sure that, ‘Oh, the agency is concerned about X, Y, Z when it comes to human factors, how are you evaluating those same exact things in your human factors activities?’

“That actually will then save on agency interaction, perhaps, if you're taking the feedback that is already publicly available and already implementing it into your own processes,” he added.

Jiaying Shen, executive director for medical device and combination product development for regulatory and quality at Merck, echoed those sentiments. She said that her company’s human factors team also analyzed human factors issues in the CRLs to see if they have similar products in development with similar problems and what lessons they can learn to avoid them.

“More important for me, I use that as a tool to promote human factors within Merck,” said Shen. “Sometimes people would look at human factors as a service group. No, we are not.

“I would like to promote the human factors function as we are a strategic partner,” she added. “So, I use this to scare them a little bit.”

Tina Rees, director for human factors at Regeneron, agreed and noted that CRLs have been very effective in getting companies to pay attention to human factors issues.

“Nothing gets their attention more than a CRL,” she said. “One of the most effective things I've had at companies is if you get a CRL on human factors. All of a sudden, you get all the support you need.

Besides CRLs, Rees also encouraged companies to dig through review documents posted on FDA’s website. She noted that human factor information is categorized under the “other” section of the files and may be redacted; however, the available information is still very useful.

“CRLs are really valuable but also don't overlook the fact that the reviews are available,” said Rees. “When you go on to drugs at FDA, and you can actually see the reviews, that is extremely helpful.

“A lot of times, while the information is redacted, there is a tremendous amount of information there into what the company's validation approaches were and what specific questions the agency had for them, and how the agency interpreted that data,” she added.

Combination Products Summit

Read CRLs, review documents for human factors insights, experts say

Related topics

Recommended content

Welcome to the new RAPS Digital Experience