Emerging medical treatments for endometriosis

Current state of medical therapy research for the treatment of endometriosis

Key Points

Highlights:

• Several hormonal and non-hormonal medical therapies are being investigated for their anti-estrogenic, anti-inflammatory, and selective toxicity against endometriotic cells.

Key Results:

• Current treatment options for endometriosis are mainly drugs acting against the estrogenic environment needed for the progression of endometriosis.
• Gonadotropin-releasing hormone (GnRH) antagonists suppress the hormonal cascade needed for estrogen production, thereby decreasing the synthesis of estrogen in the body.
• Aromatase inhibitors (AIs) such as anastrozole inhibit the enzyme Aromatase, thereby decreasing estradiol and estrone production and has been seen to produce promising results in the reduction of the progression and inflammatory environment associated with endometriosis.
• Bazedoxifene (BZA) is a third-generation SERM and has shown promising results in animal studies.
• Non-hormonal drugs such as immunomodulatory drugs and histone deacetylase inhibitors are being investigated for their efficacy in the treatment of endometriotic lesions.

What’s done here? 

• This article discusses the current treatment options available for individuals with endometriosis and the current hormonal and non-hormonal medications currently being investigated and their initial clinical efficacy.

Limitations:

• Double-blind, randomized control clinical studies are needed to confirm the initial results of the medical therapies discussed in this article.

Lay Summary

Endometriosis is a disease whereby uterine tissue grows outside the walls of the uterus to the surfaces of other tissues in the body. It is a chronic disease and relies upon estrogen to grow and survive. Current medical therapies take advantage of this weakness by creating a hypoestrogenic environment either by blocking ovarian estrogen secretion (GnRH-agonist, GnRH-a) or by inhibiting estrogenic stimulation of the ectopic endometrium (progestins and androgenic progestins).

Clemenza and authors at the University of Florence, Italy have recently published an article titled, “From pathogenesis to clinical practice: Emerging medical treatments for endometriosis” in the Journal of Best Practice & Research Clinical Obstetrics and Gynaecology detailing new medical treatments being investigated for endometriosis.

GnRH antagonists currently being developed include Abarelix and Elagolix. Elagolix, in particular, is a short-acting oral GnRH antagonist that suppresses LH and FSH production, thereby decreasing the synthesis of estrogen. Recent clinical trials detailed in the article have shown that Elagolix significantly reduces menstrual pain. However, side effects due to decreased estrogen in the body such as hot flashes, headaches, and a decrease in bone mineral density are important side effects.

Aromatase inhibitors (AIs) inhibit the enzyme Aromatase, which catalyzes the conversion of testosterone and androstenedione to estradiol and estrone, respectively. Aromatase is found in the endometriotic lesions and in the eutopic endometrium of women with endometriosis but not in the eutopic endometrium of women without the disease. Thus, for women who have endometriosis and are postmenopausal, AIs such as anastrozole and letrozole can be used to prevent the growth and invasion of endometriotic lesions and decrease pain and prostaglandin-mediated inflammation.

Selective estrogen receptor modulators (SERMs) bind to estrogen receptors in endometriosis and exert estrogen or antiestrogen-like actions depending on tissue type. These molecules are predominantly antagonistic in the breast and uterus and agonistic in the bone on serum lipid metabolism and on coagulation factors. A SERM currently being developed named bazedoxifene (BZA), is a third-generation SERM and has promising results in animal studies. BZA has the greatest antagonistic and the least agonistic effect compared to other SERMs. It antagonizes estrogen-induced uterine endometrial stimulation without countering estrogenic effects in the bone or central nervous system and has shown to reduce the size of endometriotic lesions and decrease proliferating cell nuclear antigen and estrogen receptor expression in the endometrium of treated animals compared with controls.

The non-hormonal treatment options currently being investigated include Immunomodulatory drugs, Antiangiogenic drugs, Histone deacetylase inhibitors, Icon, and Peroxisome proliferator receptor gamma (PPAR). Immunomodulatory drugs have been made to antagonist proinflammatory molecules such as TNF-alpha for the management of pelvic pain symptoms. Other agents such as trichostatin A and valproic acid suppress proliferation of endometrial stromal cells by fixing epigenetic aberrations and reactivating previously suppressed genes. Icon is a cameral antibody-like molecule that activates immune cells (NK cells) to destroy endometriotic implants. Partial PPARy activators such as telmisartan have been speculated to inhibit vascularization and growth of endometriotic lesions.

The drugs discussed above and their application to the treatment of endometriosis are still in their infancy and requires additional clinical trials to fully assess their efficacy in the clinical setting.

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/29559388