Enzalutamide, sold under the brand name Xtandi, is a nonsteroidal antiandrogen (NSAA) medication which is used in the treatment of

prostate cancer Prostate cancer is cancer of the prostate. Prostate cancer is the second most common cancerous tumor worldwide and is the fifth leading cause of cancer-related mortality among men. The prostate is a gland in the male reproductive system that su ...

. It is indicated for use in conjunction with

castration Castration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharm ...

in the treatment of metastatic castration-resistant prostate cancer (mCRPC), nonmetastatic castration-resistant prostate cancer, and metastatic castration-sensitive prostate cancer (mCSPC). It is taken

by mouth Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...

Side effect In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...

s of enzalutamide when added to castration include

asthenia Weakness is a symptom of a number of different conditions. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, i ...

back pain Back pain is pain felt in the back. It may be classified as neck pain (cervical), middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. The lumbar area is the most common ...

diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...

arthralgia Arthralgia (from Greek ''arthro-'', joint + ''-algos'', pain) literally means ''joint pain''. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication. According to MeSH, ...

, and

hot flash Hot flashes (also known as hot flushes) are a form of flushing, often caused by the changing hormone levels that are characteristic of menopause. They are typically experienced as a feeling of intense heat with sweating and rapid heartbeat, an ...

es. Rarely, it can cause

seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with lo ...

s. It has a high potential for

drug interaction Drug interactions occur when a drug's mechanism of action is disturbed by the concomitant administration of substances such as foods, beverages, or other drugs. The cause is often the inhibition of the specific receptors available to the drug, ...

s. Enzalutamide is an antiandrogen, and acts as an

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, ri ...

of the

androgen receptor The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone in ...

, the

biological target A biological target is anything within a living organism to which some other entity (like an endogenous ligand or a drug) is directed and/or binds, resulting in a change in its behavior or function. Examples of common classes of biological targets ...

androgen An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This in ...

s like

testosterone Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testes and prostate, as well as promoting secondar ...

and

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 includi ...

. In doing so, it prevents the effects of these

hormone A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...

s 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 ...

and elsewhere in the body. Enzalutamide was first described in 2006, and was introduced for the treatment of prostate cancer in 2012. It was the first second-generation NSAA to be introduced. It is on the

World Health Organization's List of Essential Medicines The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health ...

Medical uses

Prostate cancer

There is good evidence that enzalutamide is an effective treatment for increasing overall survival among people with high-risk non-metastatic castration-resistant prostate cancer, particularly those with a

PSA PSA, PsA, Psa, or psa may refer to: Biology and medicine * Posterior spinal artery * Primary systemic amyloidosis, a disease caused by the accumulation of abnormal proteins * Prostate-specific antigen, an enzyme used as a blood tracer for pros ...

doubling time ≤ 6 months.

Other uses

Enzalutamide can be used as an antiandrogen in

feminizing hormone therapy Feminizing hormone therapy, also known as transfeminine hormone therapy, is hormone therapy and sex reassignment therapy to change the secondary sex characteristics of transgender people from masculine or androgynous to feminine. It is a comm ...

for

transgender women A trans woman or a transgender woman is a woman who was assigned male at birth. Trans women have a female gender identity, may experience gender dysphoria, and may transition; this process commonly includes hormone replacement therapy and som ...

Available forms

Enzalutamide is provided in the form of a 40 mg Capsule. It is taken orally at a dosage of 160 mg once per day (four capsules).

Contraindications

Enzalutamide is

contraindicated In medicine, a contraindication is a condition that serves as a reason not to take a certain medical treatment due to the harm that it would cause the patient. Contraindication is the opposite of indication, which is a reason to use a certain tre ...

in women during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ca ...

. It may cause fetal harm.

Side effects

Notable

side effect In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...

s of enzalutamide seen in

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, dietar ...

s have included

gynecomastia Gynecomastia (also spelled gynaecomastia) is the abnormal non-cancerous enlargement of one or both breasts in males due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Updated by Brent Wisse (1 ...

, breast pain/tenderness,

fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...

es,

headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...

sexual dysfunction Sexual dysfunction is difficulty experienced by an individual or partners during any stage of normal sexual activity, including physical pleasure, desire, preference, arousal, or orgasm. The World Health Organization defines sexual dysfunction as ...

, and, less commonly,

s. Other "common" side effects reported in clinical trials have included

neutropenia Neutropenia is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood. Neutrophils make up the majority of circulating white blood cells and serve as the primary defense against infections by destroying bacteria ...

visual hallucination A hallucination is a perception in the absence of an external stimulus that has the qualities of a real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space. Hallucination is a combinatio ...

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

cognitive disorder Cognitive disorders (CDs), also known as neurocognitive disorders (NCDs), are a category of mental health disorders that primarily affect cognitive abilities including learning, memory, perception, and problem solving. Neurocognitive disorders in ...

memory impairment Amnesia is a deficit in memory caused by brain damage or disease,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be caused temporarily by the use ...

hypertension Hypertension (HTN or HT), also known as high blood pressure (HBP), is a long-term medical condition in which the blood pressure in the arteries is persistently elevated. High blood pressure usually does not cause symptoms. Long-term high bl ...

dry skin Xeroderma, xerosis or xerosis cutis, or simply dry skin, is a skin condition characterized by excessively dry skin. The medical term ''xeroderma'', meaning "dry skin", derives from modern Latin, ''xero-'' 'dry' + Greek ''derma'' 'skin'. In most ...

, and

pruritus Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasant ...

(itching). Enzalutamide monotherapy is regarded as having a moderate negative effect on sexual function and activity, significantly less than that of GnRH analogues but similar to that of other NSAAs such as bicalutamide.

Central adverse effects

Seizures have occurred in approximately 1% of patients treated with enzalutamide in clinical trials. This is thought to be due to enzalutamide crossing the

blood–brain barrier The blood–brain barrier (BBB) is a highly selective semipermeable membrane, semipermeable border of endothelium, endothelial cells that prevents solutes in the circulating blood from ''non-selectively'' crossing into the extracellular fluid of ...

and exerting off-target binding to and inhibition of the GABA_A receptor in the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...

(it has been found to inhibit the GABA_A receptor ''

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...

'' ( = 3.6 μM) and induces

convulsion A convulsion is a medical condition where the body muscles contract and relax rapidly and repeatedly, resulting in uncontrolled shaking. Because epileptic seizures typically include convulsions, the term ''convulsion'' is sometimes used as a s ...

s in animals at high doses). In addition to seizures, other potentially GABA_A receptor-related side effects observed with enzalutamide treatment in clinical trials have included

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

vertigo Vertigo is a condition where a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties w ...

paresthesia Paresthesia is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. Paresthesia may be transient or chronic, and may have any of dozens of possible underlying causes. Paresthesias ar ...

, and headache. Due to its ability to lower the

seizure threshold The term seizure threshold is used to describe the balance between excitatory (glutaminergic) and inhibitory ( GABA-ergic) forces in the brain which affect how susceptible a person is to seizures. Those diagnosed with epilepsy or certain other neur ...

, patients with known

seizure disorder Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...

s or

brain injury An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or o ...

should be closely monitored during enzalutamide treatment. NSAA-induced seizures are responsive to

benzodiazepine Benzodiazepines (BZD, BDZ, BZs), sometimes called "benzos", are a class of depressant drugs whose core chemical structure is the fusion of a benzene ring and a diazepine ring. They are prescribed to treat conditions such as anxiety disorders, ...

treatment, and it has been suggested that GABA_A receptor inhibition by enzalutamide could be treated with these drugs. In dose-ranging studies, severe

was observed with enzalutamide at doses of 240 mg/day and above.

Rare adverse reactions

There is a single

case report In medicine, a case report is a detailed report of the symptoms, signs, diagnosis, treatment, and follow-up of an individual patient. Case reports may contain a demographic profile of the patient, but usually describe an unusual or novel occurrence ...

posterior reversible encephalopathy syndrome Posterior reversible encephalopathy syndrome (PRES), also known as reversible posterior leukoencephalopathy syndrome (RPLS), is a rare condition in which parts of the brain are affected by swelling, usually as a result of an underlying cause. Some ...

(PRES) with enzalutamide treatment. The

mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targe ...

of the side effect is unknown, but it was proposed to a consequence of inhibition of the GABA_A receptor by enzalutamide.

Overdose

Enzalutamide may cause

s in

overdose A drug overdose (overdose or OD) is the ingestion or application of a drug or other substance in quantities much greater than are recommended.

Interactions

Enzalutamide is a moderate to strong inducer of multiple

cytochrome P450 Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

s including

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from t ...

CYP2C9 Cytochrome P450 family 2 subfamily C member 9 (abbreviated CYP2C9) is an enzyme protein. The enzyme is involved in metabolism, by oxidation, of both xenobiotics, including drugs, and endogenous compounds, including fatty acids. In humans, the prote ...

, and

CYP2C19 Cytochrome P450 2C19 (abbreviated CYP2C19) is an enzyme protein. It is a member of the CYP2C subfamily of the cytochrome P450 mixed-function oxidase system. This subfamily includes enzymes that catalyze metabolism of xenobiotics, including some pr ...

and hence has a high potential for clinically relevant

s. Circulating concentrations of enzalutamide may be altered by inhibitors and

inducer In molecular biology, an inducer is a molecule that regulates gene expression. An inducer functions in two ways; namely: *By disabling repressors. The gene is expressed because an inducer binds to the repressor. The binding of the inducer to the r ...

s of

CYP2C8 Cytochrome P4502C8 (abbreviated CYP2C8), a member of the cytochrome P450 mixed-function oxidase system, is involved in the metabolism of xenobiotics in the body. Cytochrome P4502C8 also possesses epoxygenase activity, i.e. it metabolizes long-cha ...

and CYP3A4, and should be avoided if possible. In a clinical study of enzalutamide for -positive

breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a re ...

in women, enzalutamide was found to decrease serum concentrations of the

aromatase inhibitor Aromatase inhibitors (AIs) are a class of drugs used in the treatment of breast cancer in postmenopausal women and in men, and gynecomastia in men. They may also be used off-label to reduce estrogen conversion when supplementing testosterone exog ...

anastrozole Anastrozole, sold under the brand name Arimidex among others, is a medication used in addition to other treatments for breast cancer. Specifically it is used for hormone receptor-positive breast cancer. It has also been used to prevent breast ca ...

and

exemestane Exemestane, sold under the brand name Aromasin among others, is a medication used to treat breast cancer. It is a member of the class of antiestrogens known as aromatase inhibitors. Some breast cancers require estrogen to grow. Those cancers h ...

by 90% and 50%, respectively, which could reduce their effectiveness.

Pharmacology

Pharmacodynamics

Enzalutamide acts as a selective silent

of the

(AR), the

s like

and

(DHT). Unlike 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 ...

, enzalutamide does not promote translocation of AR to the

cell nucleus The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, h ...

and in addition prevents binding of AR to deoxyribonucleic acid (DNA) and AR to

coactivator A coactivator is a type of transcriptional coregulator that binds to an activator (a transcription factor) to increase the rate of transcription of a gene or set of genes. The activator contains a DNA binding domain that binds either to a DNA p ...

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s. As such, it has been described as an AR signaling inhibitor in addition to antagonist. The drug is described as a "second-generation" NSAA because it has greatly increased efficacy as an antiandrogen relative to so-called "first-generation" NSAAs like

flutamide Flutamide, sold under the brand name Eulexin among others, is a nonsteroidal antiandrogen (NSAA) which is used primarily to treat prostate cancer. It is also used in the treatment of androgen-dependent conditions like acne, excessive hair grow ...

and bicalutamide. The drug has only 2-fold lower affinity for the AR than DHT, the endogenous ligand of the AR in the prostate gland. When

LNCaP LNCaP cells are a cell line of human cells commonly used in the field of oncology. LNCaP cells are androgen-sensitive human prostate adenocarcinoma cells derived from the left supraclavicular lymph node metastasis from a 50-year-old caucasian ma ...

cells (a prostate cancer cell line) engineered to express elevated levels of AR (as found in patients with advanced prostate cancer) were treated with enzalutamide, the expression of androgen-dependent genes PSA and

TMPRSS2 Transmembrane protease, serine 2 is an enzyme that in humans is encoded by the ''TMPRSS2'' gene. It belongs to the TMPRSS family of proteins, whose members are transmembrane proteins which have a serine protease activity. The TMPRSS2 protein is f ...

was down regulated in contrast to bicalutamide where the expression was upregulated. In VCaP cells which over-express the AR, enzalutamide induced

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

whereas bicalutamide did not. Furthermore, enzalutamide behaves as an antagonist of the W741C mutant AR in contrast to bicalutamide which behaves as a pure

agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...

when bound to the W741C mutant. Dose-ranging studies of enzalutamide in men with prostate cancer have been performed.

Changes in hormone levels

Enzalutamide monotherapy at a dosage of 160 mg/day has been found to increase circulating levels of

by 114.3%,

(DHT) by 51.7%,

estradiol Estradiol (E2), also spelled oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Estradiol is responsible for the development of f ...

by 71.7%,

sex hormone-binding globulin Sex hormone-binding globulin (SHBG) or sex steroid-binding globulin (SSBG) is a glycoprotein that binds to androgens and estrogens. When produced by the Sertoli cells in the seminiferous tubules of the testis, it has also been called androgen-bi ...

(SHBG) by 100.6%,

dehydroepiandrosterone Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It functio ...

(DHEA) by 9.6%,

androstenedione Androstenedione, or 4-androstenedione (abbreviated as A4 or Δ4-dione), also known as androst-4-ene-3,17-dione, is an endogenous weak androgen steroid hormone and intermediate in the biosynthesis of estrone and of testosterone from dehydroepia ...

by 51.1%,

luteinizing hormone Luteinizing hormone (LH, also known as luteinising hormone, lutropin and sometimes lutrophin) is a hormone produced by gonadotropic cells in the anterior pituitary gland. The production of LH is regulated by gonadotropin-releasing hormone (GnRH) ...

(LH) by 184.7%,

follicle-stimulating hormone Follicle-stimulating hormone (FSH) is a gonadotropin, a glycoprotein polypeptide hormone. FSH is synthesized and secreted by the gonadotropic cells of the anterior pituitary gland and regulates the development, growth, pubertal maturation, an ...

(FSH) by 47.0%, and

prolactin Prolactin (PRL), also known as lactotropin, is a protein best known for its role in enabling mammals to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans. Prolactin is secreted from the pit ...

by 16.8%. These changes in hormone levels are similar to those with high-dose bicalutamide monotherapy. The median maximum decrease in levels of

prostate-specific antigen Prostate-specific antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KLK3), P-30 antigen, is a glycoprotein enzyme encoded in humans by the ''KLK3'' gene. PSA is a member of the kallikrein-related peptidase family and is secreted b ...

(PSA) levels was 99.6%.

Comparison with other antiandrogens

Enzalutamide has approximately 8-fold higher

binding affinity In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a mol ...

for the

(AR) compared to

. One study found an of 21 nM for enzalutamide and 160 nM for bicalutamide at the AR in the

cell line (7.6-fold difference), while another found respective IC₅₀ values of 36 nM and 159 nM (4.4-fold difference). In accordance, clinical findings suggest that enzalutamide is a significantly more potent and effective antiandrogen in comparison to first-generation NSAAs such as bicalutamide, flutamide, and nilutamide. Also, unlike with the first-generation NSAAs, there has been no evidence of

hepatotoxicity Hepatotoxicity (from ''hepatic toxicity'') implies chemical-driven liver damage. Drug-induced liver injury is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdrawn fro ...

elevated liver enzymes In medicine, the presence of elevated transaminases, commonly the transaminases alanine transaminase (ALT) and aspartate transaminase (AST), may be an indicator of liver dysfunction. Other terms include transaminasemia, transaminitis, and elevated ...

in association with enzalutamide treatment in clinical trials.

Resistance mechanisms in prostate cancer

Enzalutamide is only effective for a certain period of time, after that the growth of the cancer is not inhibited by this antiandrogen. The mechanisms of resistance to Enzalutamide are being intensively studied. Currently, several mechanisms have been found: * AR mutations * AR

splice variant Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be in ...

s *

Glucocorticoid receptor The glucocorticoid receptor (GR, or GCR) also known as NR3C1 (nuclear receptor subfamily 3, group C, member 1) is the receptor to which cortisol and other glucocorticoids bind. The GR is expressed in almost every cell in the body and regulates ...

bypass * Increase in

flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport ph ...

glycolysis Glycolysis is the metabolic pathway that converts glucose () into pyruvate (). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH ...

Autophagy Autophagy (or autophagocytosis; from the Ancient Greek , , meaning "self-devouring" and , , meaning "hollow") is the natural, conserved degradation of the cell that removes unnecessary or dysfunctional components through a lysosome-dependent re ...

mediated resistance *

Wnt signaling The Wnt signaling pathways are a group of signal transduction pathways which begin with proteins that pass signals into a cell through cell surface receptors. The name Wnt is a portmanteau created from the names Wingless and Int-1. Wnt signaling ...

activation * Increase in intra-tumoral androgen biosynthesis mediated by

AKR1C3 Aldo-keto reductase family 1 member C3 (AKR1C3), also known as 17β-hydroxysteroid dehydrogenase type 5 (17β-HSD5, HSD17B5) is a key steroidogenic enzyme that in humans is encoded by the ''AKR1C3'' gene. Function This gene encodes a member of t ...

enzyme *

Interleukin 6 Interleukin 6 (IL-6) is an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine. In humans, it is encoded by the ''IL6'' gene. In addition, osteoblasts secrete IL-6 to stimulate osteoclast formation. Smooth ...

signaling mediated resistance

Cytochrome P450 modulation

Enzalutamide is reported to be a strong

of the

and a moderate inducer of

and

, and can affect the circulating concentrations of drugs that are metabolized by these enzymes.

Pharmacokinetics

The

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

of enzalutamide in humans is unknown, but is at least 84.6% based on the amount recovered from

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra. Cel ...

and

bile Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile ...

excretion Excretion is a process in which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after lea ...

studies. Similarly, the bioavailability of enzalutamide in rats is 89.7%.

Steady-state In systems theory, a system or a process is in a steady state if the variables (called state variables) which define the behavior of the system or the process are unchanging in time. In continuous time, this means that for those properties ''p'' ...

concentrations of enzalutamide are achieved within 28 days of treatment initiation. The

plasma protein binding Plasma protein binding refers to the degree to which medications attach to proteins within the blood. A drug's efficiency may be affected by the degree to which it binds. The less bound a drug is, the more efficiently it can traverse or diffuse th ...

of enzalutamide is 97 to 98%, while that of ''N''-desmethylenzalutamide (NDME), its major

metabolite In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...

, is 95%. Enzalutamide is primarily bound to

albumin Albumin is a family of globular proteins, the most common of which are the serum albumins. All the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins ...

. The medication is

metabolized Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

in the

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

, mainly by the

and

. CYP2C8 is primarily responsible for the formation of NDME. Enzalutamide has a long

elimination half-life Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the bl ...

of 5.8 days on average, with a range of 2.8 to 10.2 days. The elimination half-life of NDME is even longer, at about 7.8 to 8.6 days. Enzalutamide is eliminated 71.0% in

, 13.6% in

, and 0.39% in

feces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

Chemistry

Enzalutamide is a synthetic di

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

thiohydantoin

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. F ...

and is structurally related to the earlier first-generation NSAAs such as

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 ...

, and

as well as to newer second-generation NSAAs like

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 ...

and

proxalutamide Proxalutamide (developmental code name GT-0918) is a nonsteroidal antiandrogen (NSAA) – specifically, a selective high-affinity silent antagonist of the androgen receptor (AR) – which is under development by Suzhou Kintor Pharmaceuticals, ...

History

Enzalutamide was discovered by

Charles Sawyers Charles L. Sawyers (born 1959) is a Howard Hughes Medical Institute (HHMI) investigator who holds the Marie-Josée and Henry R. Kravis Chair of the Human Oncology and Pathogenesis Program (HOPP) at Memorial Sloan Kettering Cancer Center (MSK) ...

, now at the

Memorial Sloan–Kettering Cancer Center Memorial Sloan Kettering Cancer Center (MSK or MSKCC) is a cancer treatment and research institution in the borough of Manhattan in New York City, founded in 1884 as the New York Cancer Hospital. MSKCC is one of 52 National Cancer Institute– ...

, and Michael Jung at the

University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...

. They and their colleagues synthesized and evaluated nearly 200 thiohydantoin

s of

RU-59063 RU-59063 is a nonsteroidal androgen or selective androgen receptor modulator (SARM) which was first described in 1994 and was never marketed. It was originally thought to be a potent antiandrogen, but subsequent research found that it actually p ...

, an analogue of

, for AR antagonism in human prostate cancer cells, and identified enzalutamide and

RD-162 RD-162 is a second-generation nonsteroidal antiandrogen (NSAA) which was developed for the treatment of prostate cancer but was never marketed. It acts as a potent and selective silent antagonist of the androgen receptor (AR). The drug is a ...

as lead compounds. These compounds were

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...

ed in 2006 and described in 2007.Sawyers, C., Jung, M., Chen, C., Ouk, S., Welsbie, D., Tran, C., ... & Yoo, D. (2006). U.S. Patent Application No. 11/433,829. https://www.google.com/patents/US20070004753 Enzalutamide was developed and marketed by

Medivation Medivation was an American biopharmaceutical company focused on development of novel therapies to treat serious diseases for which there are limited treatment options. Medivation was headquartered in San Francisco, California, beginning operations ...

for the treatment of prostate cancer. It was approved by the U.S.

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(FDA) for the treatment of mCRPC in the United States in August 2012, and for the treatment of nonmetastatic castration-resistant prostate cancer in July 2018. Enzalutamide was the first new AR antagonist to be approved for the treatment of prostate cancer in over 15 years, following the introduction of the first-generation NSAA

in 1995. It was the first second-generation NSAA to be introduced.

Research

Breast cancer

Research suggests that enzalutamide may be effective in the treatment of certain types of

in women. It has been tested for the treatment of triple-negative, AR-positive breast cancer in a phase II

Hirsutism

Enzalutamide has been suggested as a potential treatment for

hirsutism Hirsutism is excessive body hair on parts of the body where hair is normally absent or minimal. The word is from early 17th century: from Latin ''hirsutus'' meaning "hairy". It usually refers to a "male" pattern of hair growth in a female that ...

and

hyperandrogenism Hyperandrogenism is a medical condition characterized by high levels of androgens. It is more common in women than men. Symptoms of hyperandrogenism may include acne, seborrhea (inflamed skin), hair loss on the scalp, increased body or facial ...

in women with

polycystic ovary syndrome Polycystic ovary syndrome, or PCOS, is the most common endocrine disorder in women of reproductive age. The syndrome is named after the characteristic cysts which may form on the ovaries, though it is important to note that this is a sign and no ...

References

External links

* {{Portal bar , Medicine Astellas Pharma Pfizer brands Benzamides CYP3A4 inducers Fluoroarenes GABAA receptor negative allosteric modulators Hormonal antineoplastic drugs Imidazolidines Lactams Nitriles Nonsteroidal antiandrogens Progonadotropins Prostate cancer Thioureas Trifluoromethyl compounds