Nomegestrol, a related compound, was patented in 1975, and NOMAC was described in 1983.[15][16] NOMAC was first introduced for medical use, for the treatment of gynecological disorders and in menopausal hormone therapy, in Europe in 1986.[1][17][18] It was subsequently approved in Europe in 2011 as a component of birth control pills.[1][17][18] NOMAC is available widely throughout the world.[8][19] It is not available in the United States or Canada.[8][1][17][18]
There have been no reports of serious adverse effects due to overdose of NOMAC.[7] NOMAC has been administered alone at a dosage of up to 40 times the recommended dosage, and the combination of NOMAC and estradiol has been administered in multiple doses of up to 5 times the recommended dosage to women in clinical trials, and no safety concerns or harmful effects were observed in either case.[28][7] Symptoms of NOMAC and estradiol overdose might include nausea, vomiting, and, in young girls, slight vaginal bleeding.[7] There is no antidote for NOMAC overdose and treatment of overdose should be based on symptoms.[7]
Like many other progestogens,[34][35] NOMAC has been assessed and found in vitro to inhibit the conversion of estrone sulfate to estrone (via inhibition of steroid sulfatase) and estrone to estradiol (via inhibition of 17β-HSD) at high concentrations (0.5–50 μM) and to stimulate the conversion of estrone into estrone sulfate (via activation of estrogen sulfotransferase activity) at low concentrations (0.05–0.5 μM), whilst not affecting aromatase activity at any tested concentration (up to 10 μM).[1][5] These activities appear to be PR-dependent, as NOMAC is more potent in producing them in PR-rich cell lines (e.g., T47-D vs. MCF-7) and they can be blocked by the PR antagonist mifepristone (RU-486).[5] Although the clinical implications of these actions are unclear and they have yet to be confirmed in vivo or assessed in clinical studies, it has been suggested that NOMAC and certain other progestins may be useful in the treatment of ER-positive breast cancer by decreasing levels of estrogens in breast tissue.[34][35] In accordance with this notion, in vitro, NOMAC does not have proliferative effects on breast tissue, does not stimulate breast cell proliferation via PGRMC1 (similarly to progesterone), and reduces the breast proliferative effects of estradiol when added to it in medium.[36]
The ovulation-inhibiting dosage of NOMAC is 1.5 to 5 mg/day.[1][3][37] Due to its high antigonadotropic activity and its long elimination half-life, the contraceptive effectiveness of NOMAC is maintained even when a dose is missed; clinical studies found no increased incidence of pregnancy with one missed pill of Zoely or even with two missed pills during days 8 to 17 of the menstrual cycle.[2]
Nomegestrol was patented in 1975, and NOMAC, under the developmental code name TX-066, was first described in the literature in 1983.[15][16] It was developed by Theramex Laboratories, a pharmaceutical company in Monaco (a satellite country of France).[1] The medication was first introduced in Europe alone or in combination with estradiol under the respective brand names Lutenyl and Naemis[5] for the treatment of gynecological disorders and menopausal symptoms in 1986, and was subsequently developed and approved in 2011 in Europe as a birth control pill in combination with estradiol under the brand name Zoely.[1][17][18] As Zoely, NOMAC has been studied in over 4,000 women as a method of birth control.[2]
NOMAC is marketed in combination with estradiol as a birth control pill primarily under the brand name Zoely, in combination with estradiol for use in menopausal hormone therapy primarily under the brand name Naemis, and as a standalone medication for use in menopausal hormone therapy and the treatment of gynecological disorders primarily under the brand name Lutenyl.[8] NOMAC is also marketed alone or in combination with estradiol under a variety of other less common brand names throughout the world.[8]
Known availability of NOMAC in countries throughout the world (as of August 2018). Alone is NOMAC as a standalone medication. With E2 is in combination with estradiol. Discontinued is no longer available.
Under the tentative brand name Uniplant, NOMAC was under development by Theramex as a 38 mg or 55 mg 4 cm Silastic (silicone-plastic) subcutaneousbirth control implant of one-year duration (75 ug/day or 100 μg/day release rate) in Brazil from the 1990s and was extensively studied for this purpose in clinical trials.[10][11][12][13] The clinical studies included 19,900 women-months of use and demonstrated a one-year failure rate of 0.94%. Uniplant was regarded as showing high effectiveness, and was well tolerated.[13] In spite of this however, "[f]urther plans to make it available have been deferred by decision of the company holding the progestin patent",[51] and, although it continued to be investigated as late as 2006,[52] the implant ultimately never became commercially available.[53][54]
Oral NOMAC was under development for the treatment of breast cancer and for use as a progestogen-only pill for birth control but did not complete development for these indications.[55] An estradiol and NOMAC vaginal ring was under development for use in birth control and to treat dysmenorrhea but did not complete development and was not marketed.[56] A continuous oral formulation of estradiol and NOMAC was under development for the treatment of menopausal symptoms and the treatment or prevention of postmenopausal osteoporosis but did not complete development.[57]
^ abcdefShields-Botella, J.; Chetrite, G.; Meschi, S.; Pasqualini, J.R. (2005). "Effect of nomegestrol acetate on estrogen biosynthesis and transformation in MCF-7 and T47-D breast cancer cells". The Journal of Steroid Biochemistry and Molecular Biology. 93 (1): 1–13. doi:10.1016/j.jsbmb.2004.11.004. ISSN0960-0760. PMID15748827. S2CID25273633.
^ abBrache, V.; Faundes, A.; Alvarez, F.; Cochon, L. (2002). "Nonmenstrual adverse events during use of implantable contraceptives for women: data from clinical trials". Contraception. 65 (1): 63–74. doi:10.1016/S0010-7824(01)00289-X. ISSN0010-7824. PMID11861056.
^Gourdy P, Bachelot A, Catteau-Jonard S, Chabbert-Buffet N, Christin-Maître S, Conard J, Fredenrich A, Gompel A, Lamiche-Lorenzini F, Moreau C, Plu-Bureau G, Vambergue A, Vergès B, Kerlan V (November 2012). "Hormonal contraception in women at risk of vascular and metabolic disorders: guidelines of the French Society of Endocrinology". Ann. Endocrinol. (Paris). 73 (5): 469–87. doi:10.1016/j.ando.2012.09.001. PMID23078975.
^Lyseng-Williamson, Katherine A.; Yang, Lily P. H.; Plosker, Greg L. (2012). "Nomegestrol acetate/estradiol: a guide to its use in oral contraception". Drugs & Therapy Perspectives. 29 (1): 1–6. doi:10.1007/s40267-012-0005-9. ISSN1172-0360. S2CID71591520.
^Passeri T, Champagne PO, Bernat AL, Hanakita S, Salle H, Mandonnet E, Froelich S (April 2019). "Spontaneous regression of meningiomas after interruption of nomegestrol acetate: a series of three patients". Acta Neurochir (Wien). 161 (4): 761–765. doi:10.1007/s00701-019-03848-x. PMID30783806. S2CID67750259.
^Champagne PO, Passeri T, Froelich S (March 2019). "Combined hormonal influence of cyproterone acetate and nomegestrol acetate on meningioma: a case report". Acta Neurochir (Wien). 161 (3): 589–592. doi:10.1007/s00701-018-03782-4. PMID30666456. S2CID58573065.
^ abNeubauer H, Ma Q, Zhou J, Yu Q, Ruan X, Seeger H, Fehm T, Mueck AO (October 2013). "Possible role of PGRMC1 in breast cancer development". Climacteric. 16 (5): 509–13. doi:10.3109/13697137.2013.800038. PMID23758160. S2CID29808177.
^ abSweetman, Sean C., ed. (2009). "Sex hormones and their modulators". Martindale: The Complete Drug Reference (36th ed.). London: Pharmaceutical Press. p. 2119. ISBN978-0-85369-840-1.