Clinical Development

Phase 1 Clinical Trial(Phase 1)

The first stage of clinical testing in humans, primarily assessing safety, tolerability, and pharmacokinetics.

Usage Examples

The Phase 1 study enrolled 48 healthy volunteers.
First-in-human dosing began after FDA cleared the IND.
The SAD study identified the maximum tolerated dose.

What is Phase 1?

Phase 1 clinical trials are the first studies of a new drug in humans, typically conducted in 20-100 healthy volunteers (or patients for certain drugs like oncology). The primary objectives are to assess safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD).

Phase 1 studies include single ascending dose (SAD), multiple ascending dose (MAD), and food effect studies. These trials help determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), and appropriate dosing for subsequent phases.

First-in-human (FIH) studies require careful starting dose selection based on preclinical data and may use adaptive designs to efficiently explore the dose range.

Regulatory Context

This term appears most often in clinical development workflows where submission quality, regulatory evidence, and audit readiness depend on consistent language. It is commonly referenced alongside 21 CFR 312, ICH E8, ICH M3.

FDAEMAPMDA

When This Matters

The Phase 1 study enrolled 48 healthy volunteers.
First-in-human dosing began after FDA cleared the IND.
The SAD study identified the maximum tolerated dose.

Common Mistakes

Applying one-region clinical assumptions to global submission strategies.
Missing protocol-to-regulation traceability for pivotal studies.
Underestimating how regional guidance updates impact trial documentation.

Related Regulations

21 CFR 312ICH E8ICH M3

Frequently Asked Questions

Phase 1 trials typically take several months to 1-2 years, depending on the number of dose levels, study design, and enrollment speed.

No, for drugs with significant expected toxicity (e.g., oncology drugs), Phase 1 studies are conducted in patients with the target disease who may benefit from treatment.

Starting doses are typically derived from preclinical toxicology studies using approaches like the no-observed-adverse-effect level (NOAEL) with safety factors, or minimum anticipated biological effect level (MABEL).