Introduction
Every drug that exists today was once administered to a human being for the very first time. That pivotal moment is called a First-In-Human (FIH) trial — and it represents one of the most scientifically rigorous and ethically significant milestones in all of medicine.
FIH trials mark the transition from pre-clinical laboratory research to actual human subjects. Getting this transition right is not just a regulatory requirement — it is a fundamental obligation to patient safety and scientific integrity.
This guide explains what FIH trials are, how they are designed, what risks are managed, and why working with an experienced CRO like Conduct Research dramatically improves outcomes.
What is a First-In-Human Trial?
A First-In-Human (FIH) trial is a Phase I clinical study in which an investigational compound — typically a new drug, biologic, or device — is administered to humans for the first time. These trials are primarily designed to evaluate safety, tolerability, pharmacokinetics (how the body processes the drug), and pharmacodynamics (how the drug affects the body).
FIH trials are NOT designed to prove that a drug works — that is the job of Phase II and III trials. The goal is to determine whether the compound can be safely given to humans at all, and at what doses.
Key Components of a FIH Trial Design
1. Starting Dose Determination
The starting dose is calculated from pre-clinical animal study data and safety pharmacology results. It is set far below the anticipated therapeutic dose to minimize initial risk. Common methods include the Minimal Anticipated Biological Effect Level (MABEL) approach, particularly for biologics.
2. Dose Escalation Strategy
FIH trials escalate doses incrementally across cohorts of participants. Common escalation designs include:
- Traditional 3+3 Design — cohorts of 3–6 patients with pre-defined stopping rules
- Accelerated Titration Design — faster escalation in early, low-risk dose ranges
- Bayesian Adaptive Designs — uses real-time data to inform escalation decisions
3. Safety Monitoring Committees
An independent Data Safety Monitoring Board (DSMB) reviews interim safety data between dose escalation cohorts. This oversight is a critical safeguard against unexpected toxicities.
Who Participates in FIH Trials?
FIH trials are typically conducted in one of two populations, depending on the investigational compound:
- Healthy Volunteers — used when the compound has no therapeutic target in healthy people and risk is low
- Patients with the Target Disease — used in oncology, where the risk-benefit profile justifies exposing patients rather than healthy individuals
Conduct Research specializes in oncology FIH trials, where participant selection, informed consent processes, and ethical considerations are especially complex.
| “A well-executed First-In-Human trial is the foundation upon which all subsequent development is built. Getting it right the first time saves years of development time.”
— Clinical Pharmacology Expert, Conduct Research Advisory Network |
Regulatory Requirements for FIH Trials in Canada
In Canada, FIH trials require a Clinical Trial Application (CTA) submitted to Health Canada’s Clinical Trial Division. Key requirements include:
- Complete pre-clinical safety pharmacology and toxicology data package
- Investigator Brochure (IB) summarizing all pre-clinical findings
- Protocol reviewed and approved by a Research Ethics Board (REB)
- Adherence to Division 5 of the Food and Drug Regulations and ICH E6(R2) GCP guidelines
Conduct Research’s regulatory affairs team handles all aspects of CTA preparation and submission, minimizing delays and ensuring first-pass approval wherever possible.
Planning a First-In-Human trial? Conduct Research brings specialized FIH expertise. Visit conductresearch.ca/first-in-human-clinical-trials/
How Conduct Research Supports FIH Trials
- Protocol design and dose escalation strategy development
- Health Canada CTA preparation and submission
- Site selection and investigator training
- DSMB coordination and real-time safety monitoring
- Patient recruitment and informed consent management
- PK/PD data collection and integrated reporting
Conclusion
First-In-Human trials are among the most consequential and carefully orchestrated studies in all of clinical research. They require precision, deep regulatory knowledge, and an unwavering commitment to patient safety. With Conduct Research as your CRO partner, your FIH program will be built on a foundation of expertise, compliance, and care — from the very first dose to the last data point.
Frequently Asked Questions
Q: How long does a First-In-Human trial typically take?
FIH trials generally take 12–24 months to complete, depending on dose escalation cohort sizes, enrollment rates, and the number of dose levels being evaluated.
Q: What is the difference between a FIH trial and a Phase I trial?
All FIH trials are Phase I trials, but not all Phase I trials are FIH. Phase I also includes studies in patients with the target disease, multiple ascending dose studies, and food-effect or drug-drug interaction studies conducted after the initial FIH study.
Q: What happens if a serious adverse event occurs in a FIH trial?
A serious adverse event (SAE) triggers mandatory reporting to Health Canada within defined timelines (typically 7 or 15 days depending on severity), a review by the DSMB, and a temporary halt to dose escalation pending investigation.
Q: Can Conduct Research conduct FIH oncology trials?
Yes. Conduct Research has specialized expertise in oncology FIH trials, including dose escalation in solid tumor and hematologic malignancy studies.
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