phase I/IIA

Definition of phase I/II clinical trial
National Cancer Institute

phase I/II clinical trial

(fayz … KLIH-nih-kul TRY-ul)
A study that tests the safety, side effects, and best dose of a new treatment. Phase I/II clinical trials also test how well a certain type of cancer or other disease responds to a new treatment. In the phase II part of the clinical trial, patients usually receive the highest dose of treatment that did not cause harmful side effects in the phase I part of the clinical trial. Combining phases I and II may allow research questions to be answered more quickly or with fewer patients. Also called phase 1/phase 2 clinical trial.

Source: NCI Dictionary of Cancer Terms