Maximum androgen blockade

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Maximum or maximal androgen blockade (MAB) or complete or combined androgen blockade (CAB) is a medical treatment involving the combination of both androgen receptor (AR) antagonism and inhibition or suppression of androgen production to attain maximal effectiveness in androgen deprivation therapy (ADT). [1] An example of MAB is the combination of bicalutamide, an AR antagonist, with a gonadotropin-releasing hormone (GnRH) analogue such as leuprorelin or cetrorelix. [1] MAB was developed for and is employed in the treatment of prostate cancer. [1]

Triple androgen blockade (TrAB) is a method of ADT in which a 5α-reductase inhibitor such as finasteride or dutasteride is added to CAB. [2] [3]

MAB has been found to produce higher rates of gynecomastia (7 to 28%) than orchiectomy and GnRH analogues alone (1 to 16%), but lower rates than nonsteroidal antiandrogen monotherapy such as with bicalutamide (30 to 85%). [4]

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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 androgen receptor (AR) and/or inhibiting or suppressing androgen production. They can be thought of as the functional opposites of AR agonists, for instance androgens and anabolic steroids (AAS) like testosterone, DHT, and nandrolone and selective androgen receptor modulators (SARMs) like enobosarm. Antiandrogens are one of three types of sex hormone antagonists, the others being antiestrogens and antiprogestogens.

<span class="mw-page-title-main">Goserelin</span> Chemical compound

Goserelin, sold under the brand name Zoladex among others, is a medication which is used to suppress production of the sex hormones, particularly in the treatment of breast and prostate cancer. It is an injectable gonadotropin releasing hormone agonist.

<span class="mw-page-title-main">Bicalutamide</span> Prostate cancer treatment

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 removal of the testicles to treat metastatic prostate cancer (mPC). To a lesser extent, it is used at high doses for locally advanced prostate cancer (LAPC) as a monotherapy without castration. Bicalutamide was also previously used as monotherapy to treat localized prostate cancer (LPC), but authorization for this use was withdrawn following unfavorable trial findings. Besides prostate cancer, bicalutamide is limitedly used in the treatment of excessive hair growth and scalp hair loss in women, as a puberty blocker and component of feminizing hormone therapy for transgender girls and women, to treat gonadotropin-independent early puberty in boys, and to prevent overly long-lasting erections in men. It is taken by mouth.

<span class="mw-page-title-main">Nafarelin</span> Pharmaceutical drug

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<span class="mw-page-title-main">Polyestradiol phosphate</span> Chemical compound

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<span class="mw-page-title-main">Flutamide</span> Chemical compound

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 growth, and high androgen levels in women. It is taken by mouth, usually three times per day.

<span class="mw-page-title-main">Nilutamide</span> Chemical compound

Nilutamide, sold under the brand names Nilandron and Anandron, is a nonsteroidal antiandrogen (NSAA) which is used in the treatment of prostate cancer. It has also been studied as a component of feminizing hormone therapy for transgender women and to treat acne and seborrhea in women. It is taken by mouth.

<span class="mw-page-title-main">Gonadotropin-releasing hormone agonist</span> Drug class affecting sex hormones

A gonadotropin-releasing hormone agonist is a type of medication which affects gonadotropins and sex hormones. They are used for a variety of indications including in fertility medicine and to lower sex hormone levels in the treatment of hormone-sensitive cancers such as prostate cancer and breast cancer, certain gynecological disorders like heavy periods and endometriosis, high testosterone levels in women, early puberty in children, as a part of transgender hormone therapy, and to delay puberty in transgender youth among other uses. GnRH agonists are given by injections into fat, as implants placed into fat, and as nasal sprays.

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<span class="mw-page-title-main">Enzalutamide</span> Antiandrogen medication used in treatment of prostate cancer

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 castration-resistant prostate cancer (mCRPC), nonmetastatic castration-resistant prostate cancer, and metastatic castration-sensitive prostate cancer (mCSPC). It is taken by mouth.

<span class="mw-page-title-main">Androgen deprivation therapy</span>

Androgen deprivation therapy (ADT), also called androgen suppression therapy, is an antihormone therapy whose main use is in treating prostate cancer. Prostate cancer cells usually require androgen hormones, such as testosterone, to grow. ADT reduces the levels of androgen hormones, with drugs or surgery, to prevent the prostate cancer cells from growing. The pharmaceutical approaches include antiandrogens and chemical castration.

<span class="mw-page-title-main">Cyproterone acetate</span> Chemical compound

Cyproterone acetate (CPA), sold alone under the brand name Androcur or with ethinylestradiol under the brand names Diane or Diane-35 among others, is an antiandrogen and progestin medication used in the treatment of androgen-dependent conditions such as acne, excessive body hair growth, early puberty, and prostate cancer, as a component of feminizing hormone therapy for transgender women, and in birth control pills. It is formulated and used both alone and in combination with an estrogen. CPA is taken by mouth one to three times per day.

<span class="mw-page-title-main">Apalutamide</span> Chemical compound

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 treatment of non-metastatic castration-resistant prostate cancer (NM-CRPC). It is taken by mouth.

<span class="mw-page-title-main">Progonadotropin</span> Drug class

A progonadotropin, or hypergonadotropin, also known as a gonad stimulant, is a type of drug which increases the secretion of one or both of the major gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This, in turn, results in increased function and maintenance of the gonads and increased gonadal steroidogenesis of sex hormones such as androgens, estrogens, and progestogens. Progonadotropins are the functional opposites of antigonadotropins. They have clinical applications in the treatment of hypogonadism and infertility. Conversely, hypergonadotropic effects can occur as a side effect of some drugs. Examples of progonadotropic drugs include gonadotropin-releasing hormone (GnRH) agonists when administered in a pulsatile manner, antiestrogens such as tamoxifen, clomifene, fulvestrant, and aromatase inhibitors like anastrozole, and, only in men, pure antiandrogens such as flutamide, bicalutamide, enzalutamide, and apalutamide.

The medical uses of bicalutamide, a nonsteroidal antiandrogen (NSAA), include the treatment of androgen-dependent conditions and hormone therapy to block the effects of androgens. Indications for bicalutamide include the treatment of prostate cancer in men, skin and hair conditions such as acne, seborrhea, hirsutism, and pattern hair loss in women, high testosterone levels in women, hormone therapy in transgender women, as a puberty blocker to prevent puberty in transgender girls and to treat early puberty in boys, and the treatment of long-lasting erections in men. It may also have some value in the treatment of paraphilias and hypersexuality in men.

The side effects of bicalutamide, a nonsteroidal antiandrogen (NSAA), including its frequent and rare side effects, have been well-studied and characterized. The most common side effects of bicalutamide monotherapy in men include breast tenderness, breast growth, feminization, demasculinization, and hot flashes. Less common side effects of bicalutamide monotherapy in men include sexual dysfunction, depression, fatigue, weakness, and anemia. Bicalutamide is well tolerated and has few side effects in women. General side effects of bicalutamide that may occur in either sex include diarrhea, constipation, abdominal pain, nausea, dry skin, itching, and rash.

Comparison of the nonsteroidal antiandrogen (NSAA) bicalutamide with other antiandrogens reveals differences between the medications in terms of efficacy, tolerability, safety, and other parameters. Relative to the other first-generation NSAAs, flutamide and nilutamide, bicalutamide shows improved potency, efficacy, tolerability, and safety, and has largely replaced these medications in clinical practice. Compared to the second-generation NSAAs, enzalutamide and apalutamide, bicalutamide has inferior potency and efficacy but similar tolerability and safety and a lower propensity for drug interactions.

<span class="mw-page-title-main">Pharmacology of bicalutamide</span>

The pharmacology of bicalutamide, a nonsteroidal antiandrogen (NSAA), has been well-characterized. In terms of pharmacodynamics, bicalutamide acts as a selective antagonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT). It has no capacity to activate the AR. It does not decrease androgen levels and has no other important hormonal activity. The medication has progonadotropic effects due to its AR antagonist activity and can increase androgen, estrogen, and neurosteroid production and levels. This results in a variety of differences of bicalutamide monotherapy compared to surgical and medical castration, such as indirect estrogenic effects and associated benefits like preservation of sexual function and drawbacks like gynecomastia. Bicalutamide can paradoxically stimulate late-stage prostate cancer due to accumulated mutations in the cancer. When used as a monotherapy, bicalutamide can induce breast development in males due to its estrogenic effects. Unlike other kinds of antiandrogens, it may have less adverse effect on the testes and fertility.

The Scandinavian Prostate Cancer Group (SPCG) is a group of scientific researchers who have conducted a series of clinical trials of treatments for prostate cancer. The group was founded in 1981 and the first study, SPCG-1, began in 1984.

References

  1. 1 2 3 "Maximum androgen blockade in advanced prostate cancer: an overview of the randomised trials". The Lancet. 355 (9214): 1491–1498. 2000. doi:10.1016/S0140-6736(00)02163-2. ISSN   0140-6736. S2CID   25366526.
  2. Hellerstedt, Beth A; Pienta, Kenneth J (2003). "The truth is out there: an overall perspective on androgen deprivation". Urologic Oncology: Seminars and Original Investigations. 21 (4): 272–281. doi:10.1016/S1078-1439(03)00046-2. ISSN   1078-1439. PMID   12954498.
  3. Leibowitz RL, Tucker SJ (2001). "Treatment of localized prostate cancer with intermittent triple androgen blockade: preliminary results in 110 consecutive patients". The Oncologist. 6 (2): 177–82. doi: 10.1634/theoncologist.6-2-177 . PMID   11306729.
  4. Di Lorenzo G, Autorino R, Perdonà S, De Placido S (December 2005). "Management of gynaecomastia in patients with prostate cancer: a systematic review". Lancet Oncol. 6 (12): 972–9. doi:10.1016/S1470-2045(05)70464-2. PMID   16321765.