Phase 1/2 Trial

phase 1/2 trial

A phase 1/2 trial is an early-stage clinical study that combines the goals of both phase 1 and phase 2 research. The first part focuses on safety and finding the right dose, usually enrolling a small number of participants to see how their bodies react. The second part expands to more people to look for early signs that the treatment actually works and to collect more safety data. By combining these steps, researchers can move more quickly from learning whether a drug is safe to understanding whether it might help patients. These trials often use an adaptive design, meaning the study can change based on early results—like adjusting doses or the number of participants—to improve learning and safety. Results from a phase 1/2 trial are important but still preliminary: they guide whether a treatment should go on to larger, more definitive studies. Because they are small and focused, these trials can’t prove a drug works for everyone, but they can reveal promising effects worth testing further. For people considering participation, a phase 1/2 trial can offer early access to a new therapy, but it also carries uncertainty and potential risks. Clinicians, regulators, and investors use information from these trials to decide whether to support larger studies and eventual approval.