3.2 Navigating regulatory pathways

in practice

3.2A Medical device trials

This subsection is for you if:

You are developing or evaluating a medical device and using an sDHT to capture endpoint data

The sDHT itself qualifies as a medical device (e.g., Software as a Medical Device, a regulated wearable sensor)

You need to clarify device classification, Significant Risk/Non-Significant Risk (SR/NSR) status, or validation requirements with CDRH

New to CDRH? Visit the Regulatory Accelerator Resource Index

If you’re unfamiliar with FDA’s medical device pathways, FDA’s Regulatory Accelerator provides a visual map of CDRH resources organized by product lifecycle phase.

This guide curates tools, engagement opportunities, and guidance across the development lifecycle from market research through post-launch monitoring. It includes many resources detailed below plus additional CDRH-specific materials.

Start here: Is your sDHT a medical device?

FDA provides resources to help you make this determination:

How to Determine if your Product is a Medical Device provides a helpful overview.

After reviewing How to Determine if your Product is a Medical Device, be sure to visit the Digital Health Policy Navigator.

Developers
Complete this assessment early and document your rationale. If your sDHT’s regulatory status is ambiguous, the Navigator’s output can serve as a starting point for discussions with DICE or DHCoE.

Adopters
If you’re evaluating an sDHT developed by someone else, ask the developer if they’ve completed the Digital Health Policy Navigator assessment. Their determination (device vs. non-device) should be documented and justifiable.

Guidance matures, and quality frameworks endure

Regulatory guidance will continue to evolve, but the fundamental principles of rigorous evidence generation, codified in the V3+ framework, remain constant. Whether your sDHT is regulated as a device or not, demonstrating it is fit-for-purpose requires systematic attention to:

• Technical verification (does the sensor capture accurate data?)

• Analytical validation (does the algorithm reliably produce the intended output?)

• Clinical validation (does the measure reflect meaningful clinical phenomena?)

• Usability validation (can users successfully deploy the technology?)

This Roadmap provides detailed, actionable context on each of these domains (see Section 4: Your Validation Strategy). Each is essential for generating credible evidence that will satisfy regulators, clinical partners, and ultimately, patients.

FDA’s guidance “Software as a Medical Device (SaMD): Clinical Evaluation” was finalized December 8, 2017 and was withdrawn from FDA’s website in early 2026 alongside updates to the the Clinical Decision Support and General Wellness guidances. In addition to following the updated guidances, developers seeking additional recognition of comprehensive quality can apply for DiMe’s Software Evidence and Analysis Library (SEAL) program, which awards recognition to digital health software products that demonstrate performance against a comprehensive framework of standards and best practices in evidence, usability, privacy, and security—with equity woven throughout. SEAL is not a regulatory program and is not intended to replace regulatory review.

Learn more: DiMe SEAL Program

Review sDHT medical devices authorized for marketing in the U.S.

The Medical Devices that Incorporate Sensor-Based Digital Health Technology List
“is a resource intended to identify sDHT medical devices that are authorized for marketing in the United States. Digital health innovators can refer to this list to gain insights into the current device landscape and regulatory expectations, which helps foster innovation of safe and effective devices. This list can also provide transparency to health care providers and patients to clearly identify when medical devices use sDHT. In addition, this list can further support the incorporation of sDHTs in medical product development programs, as appropriate.” – FDA

This list may help you:

Developers:

• Benchmark your technology against authorized devices

• Understand current regulatory expectations and precedent

• Identify potential predicate devices for 510(k) pathway

Adopters:

• Evaluate whether candidate sDHTs have FDA authorization

• Assess the regulatory maturity of available technologies

• Make informed vendor selection decisions

PRO TIP

If your sDHT is on this list, it has marketing authorization as a medical device, but you may still need additional validation evidence for your specific context of use in clinical trials (see Section 4: Your validation strategy).

Touchpoint options

FDA spotlight

Digital Health Center of Excellence (DHCoE) – DigitalHealth@fda.hhs.gov.

The Digital Health Inbox is a helpful opportunity to receive informal answers to your digital health policy questions. For example, you might ask questions specific to digital health technologies, software as a medical device (SaMD), or novel digital measurement approaches.

Once you have a reasonably characterized device concept, intended use, and preliminary development plan, a Pre‑Submission can be used to seek feedback on key elements (e.g., study design, validation strategy, and evidence expectations). An initial email inquiry to the Digital Health Center of Excellence (DHCoE) can help confirm the right review contacts and refine the focus of your Pre‑Submission so that you ask targeted questions and provide sufficient context.

Timing your engagements: Medical device development map

Plan your FDA interactions to align with your development milestones. Earlier engagement generally allows more flexibility to incorporate feedback; later engagement focuses on confirming readiness for submission.

The medical device development pathway allows for earlier clinical validation compared to drug development.

Stakeholder considerations

Developer: This earlier validation timeline means sDHT developers partnering with device sponsors should be prepared with preliminary validation data (verification, analytical validation, initial usability testing) before or during EFS. Unlike drug development, where validation often occurs in Phase 2 or later, medical device sponsors may need validated measures much earlier in the development process.

If you’re an sDHT developer without a device sponsor partner, you can still use Q-Subs to clarify classification, discuss validation strategies, or explore MDDT qualification.

Adopter: Use Pre-Submissions before EFS to align with FDA on validation strategy. Early feedback can prevent costly redesigns and increase the chances your pivotal IDE will generate acceptable evidence.

When an sDHT captures endpoint data for your device trial, you (not the sDHT developer) typically lead the regulatory engagement. However, close coordination with the developer ensures technical accuracy and prevents surprises.

Note on the Digital Health Advisory Committee (DHAC): DHAC is an external expert advisory panel that advises FDA on complex digital health policy and scientific questions. Unlike the touchpoints described above (which you initiate), DHAC meetings are convened by FDA when external expert input would inform policy development or review of novel issues. You can participate by attending public meetings or submitting comments, but DHAC is not a mechanism for product-specific regulatory advice. For more on DHAC, see below in Section 3.2B.

Q-Submissions: a closer look

The Q-Submission program is CDRH’s primary mechanism for pre-submission feedback. 

Which Q-Submission type do you need?

The Q-Submission program includes several meeting types. For sDHT endpoint work, three are particularly relevant:

Pre-Submission (Pre-Sub) Study Risk Determination Agreement Meeting: For high-stakes programs

Use for:	Feedback on endpoint acceptability, validation plans, trial design, data handling strategy
When:	Before finalizing your IDE protocol or initiating pivotal studies
Output:	Written feedback and/or meeting discussion on your specific questions

Most common for sDHT endpoint work

Use for:	Determining if your sDHT-enabled study is significant risk (SR), nonsignificant risk (NSR), or IDE-exempt
When:	You’re uncertain whether the sDHT’s role triggers IDE requirements
Output:	Formal risk determination letter for your IRB

Critical if your sDHT function is investigational or affects risk classification

Use for:	Agreement on clinical protocol, endpoints, and statistical plans for pivotal trials
When:	Your sDHT endpoints are central to PMA-level evidence or multi-study programs
Output:	Written minutes documenting FDA’s feedback

Less common but valuable for de-risking large investments

Other Q-Sub types (Informational Meetings, Submission Issue Requests) are also options. For novel technologies, CDRH offers Informational Q-Subs where you present and demonstrate your technology to FDA rather than asking specific questions. FDA asks questions of you, which provides valuable signals about your likely regulatory path and validation requirements. This pathway is most useful when your technology represents a genuinely novel approach that FDA reviewers need time to understand before you commit to expensive validation studies.

For most sDHT endpoint questions, start with a Pre-Submission. If you’re unsure about study risk classification, consider requesting a Study Risk Determination first or concurrently.

What to include in a Q-Sub package:

Element	Purpose
Cover letter	Identify submission as a Q-Sub; state purpose clearly
sDHT description	What it is, how it works, intended use or context of use, target population. Bring a complete protocol with clearly defined endpoints. Clearly articulate the clinical utility and how you’re using the sDHT to capture the endpoint(s).
Regulatory history	Prior FDA interactions, cleared predicates if applicable
Validation summary (V3+)	Completed and planned verification, analytical validation, clinical validation, usability validation. For sDHTs, explicitly address what validation will occur during EFS vs. what will be deferred to pivotal IDE. If clinical validation will be embedded in EFS, describe the substudy design. Ideally this is a complete protocol, not a list of intentions.
Specific questions	3–4 focused questions per substantial topic; frame around decisions you need to make
Supporting materials	Protocol excerpts, data summaries, literature references as relevant

Formatting guidance: FDA recommends targeted, focused submissions. Include enough background for reviewers to understand your context, but avoid extraneous detail. If substantial background is necessary, indicate which information relates to which questions.

What NOT to do:

• Don’t provide only high-level information. If you give FDA high-level information, they’re likely going to give you high-level feedback. Simply listing things you plan to do (software documentation, cybersecurity) without specifics gives FDA nothing concrete to respond to.

• Don’t expect FDA to design your study for you. Don’t ask the FDA to help you decide which path to take or which device to use or design. That’s not their role.

• Don’t come before you’re ready. If you haven’t decided what your device actually will be and are still in an exploratory mindset, you’re too early for a productive Q-Sub.

Alignment matters: FDA conducts “comparative review”—reviewers look at how you describe your device in one part of the Q-Sub and compare it to how you describe it elsewhere (protocol, other materials). Inconsistencies raise red flags. When FDA talks about “alignment,” this is what they mean: consistency across your entire submission.

FDA’s Pre-Sub acceptance checklist (see Appendix 1 of the Q-Submission Program Guidance, FDA, Final (2025)) highlights what you should include for a successful submission. The guidance covers accepted formats, timelines, meeting types, and submission components. 

The more specific your questions, the more actionable feedback FDA can provide.  For example:

“Is our planned analytical validation sample size sufficient to demonstrate heart rate accuracy for the intended population?”

“Does the agency agree that the proposed endpoint (daily step count measured by the wearable) can serve as a primary efficacy endpoint in the intended indication?”

PRO TIP

For examples of well-framed Q-Sub questions, see Appendix 2 of Requests for Feedback and Meetings for Medical Device Submissions: The Q-Submission Program, Final, 2025 (FDA).

Requests for Feedback and Meetings for Medical Device Submissions: The Q-Submission Program

Requests for Feedback and Meetings for Medical Device Submissions: The Q-Submission Program

2023 FDA

FDA guidance – final

Authors

Center for Devices and Radiological Health, Center for Biologics Evaluation and Research

This guidance explains the FDA's Q-Submission (Q-Sub) Program, which facilitates structured feedback and meetings for medical device development and submission preparation. It covers various Q-Sub types, including Pre-Submissions, Submission Issue Requests, Study Risk Determinations, and Informational Meetings. It highlights submission processes, timelines, and key expectations for feedback or interaction. The document also offers checklists and examples to help submitters prepare their requests effectively, ensuring efficient and transparent regulatory interactions.

Findings
Pre-Submissions (Pre-Subs) allow submitters to obtain FDA feedback on specific questions before submitting formal IDEs, 510(k)s, PMAs, or other applications. Early feedback can improve submission quality and streamline the review process.
Submission Issue Requests (SIRs) provide a mechanism for addressing issues raised in FDA hold letters (e.g., 510(k) deficiencies) to help expedite resolutions.
Study Risk Determinations help sponsors clarify whether clinical studies are significant risk (SR), non-significant risk (NSR), or exempt from IDE regulations.
Informational Meetings are non-feedback sessions aimed at familiarizing FDA staff with new devices or sharing updates on ongoing development.
The program encourages timely submissions, including supplements for ongoing discussions and amendments to update materials.

Recommendations
Clearly define the purpose and goals of the Q-Sub in the submission to facilitate effective FDA review.
Include specific, well-formulated questions that focus on a limited number of topics to ensure actionable feedback.
For Pre-Subs, align planned testing and submissions with FDA guidance and include detailed device descriptions, testing protocols, and relevant background information.
Use SIRs to discuss proposed solutions to deficiencies raised in FDA hold letters, focusing on timely resolution.
Draft and submit meeting minutes promptly (within 15 days of meetings) to ensure accurate documentation of FDA feedback.

Regulatory Considerations
Submitters should adhere to the timelines specified for different Q-Sub types, including 70 days for Pre-Sub feedback or 21 days for SIRs submitted promptly after a hold letter.
Q-Subs should include all relevant regulatory history and references to prior FDA communications to streamline the review process.
FDA feedback through the Q-Sub program is non-binding and based on the information available at the time; subsequent submissions must align with the provided feedback to maintain consistency.
Informational Meeting requests should clearly state that feedback is not expected and may be used to track interactions outside other formal Q-Sub types.
Confidentiality of Q-Subs is maintained in compliance with FDA’s disclosure regulations and the Freedom of Information Act (FOIA).

Keywords

Breakthrough Devices Program Clinical trials Combination products De Novo process Device design FDA guidance Humanitarian device exemption (HDE) Investigational device exemptions (IDE) Labeling considerations Medical device development Pre-submission (Pre-Sub) Premarket notification (510(k)) Premarket submissions Q-Submission Regulatory framework Regulatory guidance Risk management Total Product Lifecycle (TPLC)

Technologies

Combination & integrated products

Open Resource

Some summaries are generated with the help of a large language model; always view the linked primary source of a resource you are interested in.

key takeaways

Regardless of whether you’re working in a medical device or drug/biologic context, several principles apply:

1. Match the mechanism to your question
Informal touchpoints (email inquiries, DHT Steering Committee outreach) are appropriate for early orientation. Formal mechanisms (Q-Subs, PDUFA meetings) generate documented feedback that shapes your program. Choose based on what you need and what you’re ready to discuss.

2. Time your engagements to your development stage
Earlier engagement provides more flexibility to incorporate feedback. Later engagement confirms readiness. Plan interactions at natural milestones rather than waiting until problems arise.

3. Prepare focused, well-organized materials
Whether you’re submitting a Q-Sub package or a PDUFA briefing document, clarity and focus matter more than volume. Frame questions around the decisions you need to make, and provide enough context for FDA to respond meaningfully.

4. Coordinate across functions internally and with partners
Regulatory engagement is most effective when clinical, technical, and regulatory perspectives are aligned. If you’re an adopter working with an sDHT developer (or vice versa), ensure your materials tell a coherent story and that all parties are aligned on the endpoint strategy.

5. Document and build on prior interactions
Where applicable, reference earlier FDA feedback in subsequent submissions. This creates continuity and helps reviewers understand how your program has evolved.

Next steps

If you’re considering formal qualification for broad reuse across programs, see Section 3.3: Formal Qualification Programs

For real-world examples and potential engagement scenarios, see Section 3.4: Examples in practice