# First-in-human (FIH) trial

Source: https://onco.cc/terms/first-in-human/  
OnCo record `first-in-human` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The first time a new drug is given to people, after animal and laboratory testing and clearance of an Investigational New Drug application. In oncology these are phase 1 trials in patients with advanced cancer who have exhausted standard options, starting at a fraction of the dose predicted to be safe; modern designs run straight through to registrational cohorts.

## Summary

An Investigational New Drug application (or EU clinical trial authorisation) summarising toxicology, manufacturing and the protocol must be cleared before dosing. Starting doses derive from animal no-adverse-effect levels or, for immune agonists after the TGN1412 disaster, from minimal anticipated biological effect levels. First-in-class drugs (a new mechanism) carry more uncertainty than follow-on agents. Modern FIH trials are seamless: escalation, expansion and sometimes registrational cohorts in one protocol, so a first-in-human study can lead directly to accelerated approval (sotorasib, tarlatamab). 'Entering the clinic' marks a programme's transition from preclinical to clinical stage.

## Fields

- Kind: Term
- Last checked: 2026-09-09
- Also known as: first-in-human; first in human; FIH; first-in-human trial; first-in-human study; first-in-class; first in class; first-in-patient; phase 0; microdose; investigational new drug; IND-enabling; IND clearance; clinical entry; entered the clinic; clinical-stage; preclinical; pre-clinical; preclinical-stage; first-in-human studies; first-in-human trials

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Phase_I_clinical_trial
- Wikipedia: https://en.wikipedia.org/wiki/Phase_I_clinical_trial

## Connected records

- terms: [Dose-escalation designs (3+3, BOIN, dose-expansion)](https://onco.cc/terms/dose-escalation-design/), [Ethics review (IRB, research ethics committee)](https://onco.cc/terms/ethics-review/), [Informed consent](https://onco.cc/terms/informed-consent/), [Maximum tolerated dose (MTD)](https://onco.cc/terms/mtd/), [Phase 1, 2 and 3 trials](https://onco.cc/terms/trial-phases/), [Seamless, adaptive and Bayesian trial designs](https://onco.cc/terms/seamless-adaptive/), [Trial lifecycle: from protocol to label](https://onco.cc/terms/trial-lifecycle/), [Window-of-opportunity trial](https://onco.cc/terms/window-of-opportunity-trial/)
- fronts: [Drug Discovery Platforms](https://onco.cc/fronts/drug-discovery/)
- journals: [Medical oncology](https://onco.cc/journals/medical-oncology/), [Oncology research](https://onco.cc/journals/oncology-research/)
- trials: [TARGET National](https://onco.cc/trials/target-national/)

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