Number of Drugs in Phase I
This equals the total number of drugs undergoing the first stage of clinical testing on humans at a particular time.
Phase I is part of the Drug pipeline, following other tests on animals or other subjects and includes testing of the drug's safety, tolerance, and so forth. Phase I testing involves paying human volunteers to test a range of doses of the drug. Following Phase I testing, the drug passes on to Phase II and then Phase III if it passes the subsequent tests.