RD-162 is a second-generation

nonsteroidal antiandrogen A nonsteroidal antiandrogen (NSAA) is an antiandrogen with a nonsteroidal chemical structure. They are typically selective and full or silent antagonists of the androgen receptor (AR) and act by directly blocking the effects of androgens like ...

(NSAA) which was developed for the treatment of prostate cancer but was never marketed. It acts as a potent and selective

silent antagonist A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. Antagonist drugs interfere in the natural operation of recep ...

of the androgen receptor (AR). The drug is a di

aryl In organic chemistry, an aryl is any functional group or substituent derived from an aromaticity, aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar ...

thio hydantoin

derivative In mathematics, the derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value). Derivatives are a fundamental tool of calculus. ...

. It is closely related to

enzalutamide Enzalutamide, sold under the brand name Xtandi, is a nonsteroidal antiandrogen (NSAA) medication which is used in the treatment of prostate cancer. It is indicated for use in conjunction with castration in the treatment of metastatic castrat ...

and

apalutamide Apalutamide, sold under the brand name Erleada among others, is a nonsteroidal antiandrogen (NSAA) medication which is used in the treatment of prostate cancer. It is specifically indicated for use in conjunction with castration in the treatme ...

. Both RD-162 and enzalutamide show 5- to 8-fold higher

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Par ...

for the AR than the first-generation NSAA

bicalutamide Bicalutamide, sold under the brand name Casodex among others, is an antiandrogen medication that is primarily used to treat prostate cancer. It is typically used together with a gonadotropin-releasing hormone (GnRH) analogue or surgical remo ...

, and only 2- to 3-fold lower affinity than

dihydrotestosterone Dihydrotestosterone (DHT, 5α-dihydrotestosterone, 5α-DHT, androstanolone or stanolone) is an endogenous androgen sex steroid and hormone. The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues includ ...

(DHT), the major endogenous

ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elec ...

of the receptor in the

prostate gland The prostate is both an accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found only in some mammals. It differs between species anatomically, chemically, and physio ...

. RD-162 and enzalutamide were developed together and were derived from the nonsteroidal androgen RU-59063, which itself was derived from the first-generation NSAA

nilutamide Nilutamide, sold under the brand names Nilandron and Anandron, is a nonsteroidal antiandrogen (NSAA) which is used in the treatment of prostate cancer.https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/020169s008lbl.pdf It has also been ...

. RD-162 and enzalutamide were selected as the

lead compound A lead compound (, i.e. a "leading" compound, not to be confused with various compounds of the metallic element lead) in drug discovery is a chemical compound that has pharmacology, pharmacological or biological activity likely to be therapeutical ...

s from a group of over 200 compounds that were synthesized and assayed for

antiandrogen Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body. They act by blocking the ...

ic activity. Enzalutamide was ultimately selected from the two for further

clinical development Drug development is the process of bringing a new pharmaceutical drug to the market once a lead compound has been identified through the process of drug discovery. It includes preclinical research on microorganisms and animals, filing for reg ...

and was eventually marketed. RD-162 is also very closely related to apalutamide, with the two compounds differing only by the replacement of a single atom (a

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

atom in one of the

phenyl ring In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula C6 H5, and is often represented by the symbol Ph. Phenyl group is closely related to benzene and can be viewed as a benzene ring, minus a hydrogen ...

s of RD-162 swapped with a

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

atom in apalutamide). Apalutamide was approved for the treatment of prostate cancer in 2018.

References

Abandoned drugs Benzamides Fluoroarenes Hormonal antineoplastic drugs Ketones Nitriles Nonsteroidal antiandrogens Spiro compounds Thioureas Trifluoromethyl compounds {{Genito-urinary-drug-stub