FDA Guidance on Considerations for Neurodevelopmental Safety Studies: Measurements

The Food and Drug Administration (FDA) finalized its guidance entitled “Considerations for Long-Term Clinical Neurodevelopmental Safety Studies in Neonatal Product Development” on October 17, 2024. This final guidance finalizes the draft guidance originally issued on February 13, 2023, following a public comment period during which FDA received and considered industry feedback. For medical device manufacturers, drug sponsors, and biologics developers, the finalization of this guidance marks a significant milestone; converting what was previously advisory draft content into the FDA’s current, settled thinking on how to approach long-term neurodevelopmental safety evaluations for neonatal products.

Treatment with medical products during the neonatal period coincides with a time of critical growth and physiologic development. Although short-term safety evaluations may be appropriate for adults or other populations, such short-term evaluations may not identify important adverse events in the neonatal population, as latent effects may follow early-life exposures. Historically, most medical products used to treat neonates and young infants were not approved for use in these populations, and thus have not undergone comprehensive evaluation of safety or efficacy for use in neonates.

The guidance provides a framework for considering whether, and what type of, long-term neurologic, sensory, and developmental evaluations are needed to support a safety determination. Provisions remain non-binding in legal nature, and an alternative approach may be applied provided it aligns with existing law and has been agreed with FDA in advance.

Timing of Safety Evaluations

Comprehensive neurodevelopmental outcomes should be evaluated at a minimum of 2 years of age, adjusted for prematurity, though earlier and/or later evaluations of certain outcomes may also be warranted.

The three-stage timing framework the guidance establishes is:

Early and Longitudinal (0–2 years): Assessments including head growth measurements, hearing and vision tests, neurological exams, and developmental milestones can be reliably performed during the first two years of life and should be monitored longitudinally; providing critical early safety signals and baseline neurodevelopmental health data.

Comprehensive Outcomes at Two Years: A comprehensive evaluation at a minimum of two years adjusted age captures critical cognitive, motor, and sensory development that may not be apparent in earlier stages.

Later Childhood Follow-Up (4–6 years): Subtle cognitive, language, and behavioral outcomes (including learning difficulties and behavioral disorders) may not emerge until later childhood. Even in the absence of concerns at two years, longer follow-up may be warranted depending on the product and population.

Key Characteristics of Measurement Tools

The five key factors guiding selection and implementation of Clinical Outcome Assessments (COAs) minimizing participant burden, accounting for confounding factors, selecting appropriate score types, ensuring strong psychometric properties, and applicability to both term and preterm infants remain the core framework from the draft guidance.

The final guidance strengthens the multi center and global applicability requirement: tools should be validated for use across different demographic groups and available in languages suitable for global study sites, ensuring results are generalizable across diverse populations. For sponsors running multinational neonatal studies, this validation requirement should be assessed at the instrument selection stage; not retrofitted after site activation.

A practical note on score types: in populations at high risk for impairment, using multiple score types (standardized norm-referenced scores alongside raw scores) is explicitly recommended to avoid floor or ceiling effects, ensuring both severely impaired and developmentally advanced children are appropriately captured in study results.

Domains of Assessment

When a comprehensive neurodevelopmental evaluation is needed, it should encompass physical, mental, and social health domains organized across three categories: General Health (physical health, quality of life, developmental interventions and educational services); Neurodevelopment (sensory, motor function, cognition, emotional and behavioral health, communication/language, social functioning, and adaptive functioning); and Relevant Covariates (demographic variables, socioeconomic status, environmental exposures, and other factors that may change over time).

A practical note from the final guidance: the decision to conduct a comprehensive multi-domain evaluation versus a focused domain-specific assessment is not arbitrary, it flows directly from the product-specific and population-specific considerations addressed in the earlier sections of the guidance. Sponsors should document the rationale for their domain selection in the study protocol, as reviewers will evaluate whether the chosen domains are appropriately justified given the product’s mechanism of action and CNS exposure profile.

Adjunctive Assessments

While adjunctive assessments and biomarkers may not substitute for direct neurodevelopmental outcomes, they can provide useful supplementary information. These assessments are often product-specific and may be especially relevant when there is a known signal of concern from earlier nonclinical studies or studies in different populations.

I. Neuroimaging

Neuroimaging studies, such as brain MRI, can provide anatomical evidence of toxicity, such as disruptions in myelination. However, these imaging findings should be correlated with clinical outcomes to ensure they are meaningful.

II. Neurophysiologic Testing

Neurophysiologic tests, such as visual-evoked responses or auditory brainstem-evoked responses, may help differentiate between central and peripheral nervous system injuries. Other potential tests include somatosensory evoked potentials, electromyography, and electroencephalography.

Adjunctive assessments and biomarkers, including neuroimaging (brain MRI) and neurophysiologic testing (visual-evoked responses, auditory brainstem-evoked responses, somatosensory evoked potentials, electromyography, and electroencephalography) may provide useful supplementary information but do not substitute for direct neurodevelopmental outcomes.

A key regulatory principle the final guidance reinforces: adjunctive assessments are generally product-specific and most relevant when there is a known safety signal from earlier nonclinical studies or studies in different populations. Sponsors should not rely on adjunctive biomarker data as a substitute for primary outcome assessments; particularly neuroimaging findings, which the guidance explicitly states should be correlated with clinical outcomes to ensure they are meaningful rather than anatomically isolated data points. This correlation requirement is a common area of reviewer scrutiny in neonatal product submissions.

Conclusion

FDA’s October 2024 final guidance on long-term neurodevelopmental safety studies in neonatal product development provides sponsors; including medical device manufacturers, drug developers, and biologics companies with a definitive, settled framework for planning, designing, and executing these evaluations. From determining whether a study is needed, to selecting appropriate measurement tools, timing assessments across the developmental lifecycle, and documenting domain selection rationale, the guidance covers the full spectrum of considerations relevant to neonatal product safety programs.

For manufacturers whose products may be used in neonatal populations; either as an approved indication or as a foreseeable off-label use now is the time to review whether the guidance’s three-question framework triggers neurodevelopmental study obligations for your development program.

FAQ

Q: Is the FDA guidance on neonatal neurodevelopmental safety studies final or still in draft?

A: The guidance is final. FDA published the final guidance on October 17, 2024, finalizing the draft guidance originally issued on February 13, 2023. FDA considered comments received on the draft guidance before issuing the final version. The final guidance represents FDA’s current settled thinking while it remains non-binding, it is the standard against which FDA reviewers will evaluate neonatal study designs.

Q: Does this guidance apply to medical devices, or only to drugs and biologics?

A: The guidance explicitly applies to drugs, biological products, and medical devices, all referred to collectively as “medical products” in the guidance. Medical device manufacturers developing products intended for neonatal use (including monitoring systems, therapeutic devices, and invasive or semi-invasive instruments) should assess whether their products trigger long-term neurodevelopmental safety study requirements under this framework, particularly where CNS exposure or neurological risk is present.

Q: How do I determine whether my product requires a long-term neurodevelopmental safety evaluation?

A: The guidance describes three categories of considerations: general considerations (degree of CNS exposure, timing of exposure relative to vulnerable developmental stages, duration of exposure); patient and population-specific considerations; and product-specific considerations. A key addition in the final guidance addresses the impact of route of administration on CNS exposure and the need for neurodevelopmental evaluation. Sponsors should work through all three consideration categories and document their rationale; this determination is a foundational element of the regulatory submission.

Q: What is the minimum age for neurodevelopmental outcome assessment under the guidance?

A: Comprehensive neurodevelopmental outcomes should be evaluated at a minimum of 2 years of age, adjusted for prematurity, though earlier and/or later evaluations of certain outcomes may also be warranted. The final guidance clarifies that the minimum follow-up duration depends on different population- and product-specific factors; meaning the two-year minimum should not be interpreted as a ceiling. Follow-up to age 4–6 may also be warranted for detecting learning difficulties and behavioral disorders that do not emerge until later childhood.

Q: What are the most important changes from the 2023 draft to the October 2024 final guidance?

A: Changes from draft to final include: the background section now addresses the recommended minimum duration of follow-up and notes it depends on population- and product-specific factors; new text was added in the product-specific considerations section addressing the impact of route of administration on CNS exposure and the need for neurodevelopmental evaluation. These changes give sponsors more nuanced product-specific guidance on when and how long evaluations are required and reduce the risk of under-designing study follow-up based solely on the two-year minimum.

Source

https://www.fda.gov/regulatory-information/search-fda-guidance-documents/considerations-long-term-clinical-neurodevelopmental-safety-studies-neonatal-product-development

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