See the definition of 'Clinical Trails' (https://www.nhlbi.nih.gov/studies/clinicaltrials):
"Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. These studies also may show which medical approaches work best for certain illnesses or groups of people."
At clinical trials, human beings are used, no more animals. Please see a concised description of how a drug is developed from lab to clinical trials on the website provied above.