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Term of the Day

Natural history study

A natural history study is a preplanned observational study intended to track the course of a disease over time, identifying demographic, genetic, environmental and other variables that correlate with its development and outcomes in the absence of intervention, or under standard of care. Designs may be retrospective (chart review of existing records) or prospective (longitudinal follow-up of a cohort or registry).

Natural history data is particularly important in rare and paediatric diseases, where randomised placebo-controlled trials may be infeasible or unethical. The FDA (guidance on rare disease natural history studies, 2019) and the EMA accept well-designed natural history studies to define endpoints and biomarkers, identify patient subgroups, estimate sample sizes and, in some cases, serve as external or historical control arms for single-arm trials supporting orphan products.

Because they are non-interventional, natural history studies fall outside the CTR and are governed by national law (for example France's MR-003 or MR-004 reference methodologies) and by the GDPR. They typically involve secondary use of medical records, long-term follow-up, genetic data and small populations in which anonymisation is rarely achievable, so pseudonymisation, a DPIA and a robust research legal basis under Art. 9(2)(j) are essential. Registries maintained by patient organisations or academic consortia raise additional questions of joint controllership and data access governance.

I

Investigator

An investigator means an individual responsible for the conduct of a clinical trial at a clinical trial site (Art. 2(2)(15) EU Clinical Trials Regulation 536/2014). The investigator must be a medical doctor or a person following a profession recognised in the Member State as qualifying for the role by virtue of scientific knowledge and experience in patient care (Art. 49 CTR). Where a team conducts the trial, the responsible leader is the principal investigator; other members are sub-investigators.

Under ICH GCP section 4, the investigator is responsible for medical care of subjects, compliance with the protocol, obtaining informed consent, maintaining accurate source records and the investigator site file, reporting adverse events and serious adverse events to the sponsor, managing the investigational medicinal product, and supervising delegated staff. The investigator signs the protocol and a financial disclosure, and their CV and training records form part of the trial master file.

The investigator, or more precisely the institution employing them, is generally a controller under the GDPR for the medical records and the identifying source data, and holds the key that links subject codes to identities. Investigators are also data subjects themselves: their personal and professional data is processed by sponsors, CROs and regulators, published on the CTIS portal and ClinicalTrials.gov, and shared for feasibility and payment purposes, which requires a dedicated site-staff information notice.

Does an investigator need research ethics approval before starting participant activities?

Where the research is subject to ethics review, the required approval must be obtained before the covered activities begin. For example, HHS-regulated non-exempt human-subjects research requires prior IRB approval. Check the applicable jurisdiction and protocol, and keep evidence that the approved documents are the versions actually used by the site.