investigational new drug

initialism: IND
https://doi.org/10.1351/goldbook.12673
Drug not yet approved for general use by the national authority, such as the Food and Drug Administration of the United States of America, but undergoing clinical investigation to assess its safety and efficacy.
Source:
PAC, 2013, 85, 1725. (Glossary of terms used in medicinal chemistry. Part II (IUPAC Recommendations 2013)) on page 1738 [Terms] [Paper]