Findings
Fragmented and inconsistent measurement approaches currently hinder the generation of decision-grade evidence for pediatric rare diseases. Small and geographically dispersed patient populations make traditional site-based clinical assessments operationally difficult and burdensome for families. Digital health technologies can capture subtle functional changes and "functional fingerprints" in home settings that are often missed during infrequent clinic visits. Standardized core digital measures across conditions allow for the aggregation of data and the creation of a shared evidence base for rare disorders. Meaningful aspects of health identified by patients and caregivers include motor function, communication, sleep quality, and autonomic stability.

Recommendations
Sponsors should adopt the core set of digital clinical measures to reduce trial timelines, lower development costs, and decrease participant burden. Researchers should prioritize passive and objective data collection to minimize the need for manual tracking by caregivers. Clinical trial designs should transition toward decentralized or hybrid models to improve access for children and families regardless of their location. Stakeholders should use the project's conceptual model to identify and customize digital measures that align with the specific health priorities of their target population. Developers should focus on human-centered design to ensure digital tools are usable and sustainable for pediatric patients and their support networks.

Regulatory Considerations
The FDA and EMA provide specific pathways and interaction opportunities to accelerate the acceptance of digital endpoints in rare disease trials. Digital measures must be validated as "decision-grade" endpoints to meet the evidentiary requirements for regulatory submission and marketing approval. Alignment with industry standards for data elements and interoperability is necessary to ensure data integrity across multi-site studies. Early engagement with regulatory bodies through meetings and formal submissions is critical for confirming the suitability of new digital biomarkers. Compliance with data privacy and ethical standards is paramount when collecting continuous, real-world data from vulnerable pediatric populations.

Findings
The guidance applies to four types of Clinical Outcome Assessments (COAs): Patient-Reported Outcomes (PROs), Observer-Reported Outcomes (ObsROs), Clinician-Reported Outcomes (ClinROs), and Performance Outcomes (PerfOs). A COA is considered fit-for-purpose when the validation evidence is sufficient to support its context of use (COU). To determine if a COA is fit-for-purpose, sponsors must clearly describe the Concept of Interest (COI) and the COU, and present sufficient evidence to support a clear rationale for the COA's proposed interpretation and use. The rationale for using a COA should include up to eight components, such as justification for the COA type, capturing the important parts of the COI, appropriate administration and scoring, minimal influence from irrelevant factors or measurement error, and correspondence with the Meaningful Aspect of Health (MAH). The most direct assessment of how a patient feels or functions (MAH) should be used as the COI whenever possible.

Recommendations
Sponsors should use the Roadmap to Patient-Focused Outcome Measurement to guide the selection, modification, or development of a COA. The process begins with understanding the disease/condition (including patient perspectives) and conceptualizing clinical benefits and risks (defining the MAH, COI, and COU). When feasible, existing COAs are generally preferred, especially for well-established COIs, as this approach is often the least burdensome. If an existing COA is modified or used in a different context, additional evidence (e.g., cognitive interviews, psychometric studies) must be collected to justify its fitness for the new context of use. For new COA development, sponsors should involve patients, document all steps, and generally avoid using the new COA for the first time in a registration (pivotal) trial; a standalone observational study or early phase trial is recommended for evaluation.

Regulatory Considerations
Sponsors are encouraged to interact early and throughout medical product development with the relevant FDA review division to ensure COAs are appropriate for the intended COU. Sponsors should communicate their proposed COA-based endpoint approach, including the MAH, COI, COA type/name/score, and the final COA-based endpoint, ideally using the suggested format. The type and amount of evidence required to support the rationale for a COA's use is weighed against the degree of uncertainty regarding that part of the rationale. For ClinROs, it is recommended to use an assessor masked to treatment assignment and study visit for primary endpoints, if feasible. FDA strongly discourages proxy-reported measures for concepts known only to the patient (e.g., pain) and recommends using an ObsRO to measure observable behaviors instead when the patient cannot self-report.

Recommendations
Clearly define the concept of interest and its context of use to ensure COAs align with trial objectives.
Use conceptual and measurement frameworks to communicate how COAs measure patient experiences and generate interpretable scores.
Leverage existing COAs where possible, modifying them only when justified, and document all modifications rigorously.
Ensure COAs are accessible and inclusive, incorporating features like large fonts, touch interfaces, or audio assistance for diverse populations.
Conduct early engagement with FDA to discuss COA selection, development, and validation plans.

Regulatory Considerations
Fit-for-purpose validation requires evidence of conceptual alignment, scoring reliability, and sensitivity to clinically meaningful changes.
Digital health technologies used for COAs must comply with FDA’s guidance on data integrity, usability, and technical performance.
COAs intended for regulatory submissions must be developed and validated before pivotal trials to avoid jeopardizing trial outcomes.
Modifications to COAs or scoring methods during trials necessitate justification and revalidation.
Sponsors should submit comprehensive documentation on COA development, including scoring algorithms and item tracking matrices.

Findings
There is a notable lack of reports on the use of digital health technology in pediatric patients.
Challenges exist in selecting the design, metrics, and types of sensors best suited for disease evaluation.
False positive detection remains problematic in seizure detection using DHTs.
There is a lack of information on the use of DHTs in infants.
Unique design challenges for pediatric DHTs arise from size, anatomy, physiology, activity levels, and cognitive development.

Recommendations
Further research and evaluation are needed to realize the full potential of remote monitoring in pediatric trials.
Creative approaches, including machine learning, should be employed to identify optimal measurement methods.
Training for caregivers is necessary to ensure DHTs are worn correctly and data are complete.

Regulatory Considerations
Confirming the reliability and clinical relevance of DHT measurements is essential.
Ensuring privacy and confidentiality of patient data must be prioritized.

Findings
The process of obtaining Informed Consent (IC) involves providing adequate information to facilitate comprehension and must allow subjects the opportunity to ask questions, continuing throughout the research. Electronic Informed Consent (eIC) systems, which can use various electronic media, are increasingly used to supplement or replace paper-based IC processes. The eIC process may be conducted on-site or remotely, but the legal responsibility for obtaining consent cannot be delegated to the electronic system. For FDA-regulated clinical investigations, electronic signatures must comply with 21 CFR Part 11 to be considered equivalent to a handwritten signature.

Recommendations
Presentation & Comprehension: eIC information should be easy to navigate, convey information in understandable language, and may use interactive electronic-based technology (e.g., diagrams, video) to facilitate comprehension. Optional questions can be used to assess a subject's understanding of key study elements.
Remote Consent: If consent is obtained remotely, the electronic system must include a reliable method to verify the identity of the subject (e.g., official identification, biometric methods).
Signature & Documentation: Electronic signatures are permitted and can be created using methods like biometrics or username/password, provided they are uniquely linked to the individual. The subject must be given a copy of the signed eIC, which can be electronic or paper.
Privacy & Security: The eIC system must be secure with restricted access and include methods to ensure confidentiality of subject information. If HIPAA applies, information must be encrypted unless otherwise documented.

Regulatory Considerations
IRB Responsibility: IRBs must review and approve all eIC materials and any subsequent amendments, including optional comprehension questions and the usability of the eIC materials. IRBs must maintain records (electronic or hard copy) of the approved versions of the eIC materials.
Submissions & Inspection: For IDE applications, copies of all eIC materials must be submitted to the FDA. During inspections, investigators must have site-specific signed eICs, amendments, and materials available (electronic or paper) for FDA review.
HIPAA: HIPAA authorizations may be obtained electronically, provided the signature is legally valid, and a copy must be provided to the subject.