Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Cyclopentanohydrophenanthrene ring system doai
Reexamination Certificate
1997-07-02
2002-11-12
Webman, Edward J. (Department: 1617)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Cyclopentanohydrophenanthrene ring system doai
C514S843000, C514S181000, C514S182000
Reexamination Certificate
active
06479475
ABSTRACT:
BACKGROUND OF THE INVENTION
The vast majority of oral contraceptives consist of a combination of a progestin and estrogen that are administered concurrently for 21 days followed either by a 7 day pill free interval or by the administration of a placebo for 7 days in each 28 day cycle. The most important aspects of a successful oral contraceptive product are effective contraception, good cycle control (absence of spotting and breakthrough bleeding and occurrence of withdrawal bleeding), and minimal side effects. Combination oral contraceptives have traditionally acted by suppression of gonadotropins. In addition, it appears that the progestin component is primarily responsible for contraceptive efficacy through inhibition of ovulation, and other peripheral effects which include changes in the cervical mucus (which increase the difficulty of sperm entry into the uterus) and the endometrium (which reduce the likelihood of implantation). The estrogenic component intensifies the anovulatory effect of the progestin, and is also important for maintaining cycle control.
Since the introduction of oral contraceptives (OCs) over a quarter-century ago, research has been directed toward developing preparations that minimize the potential for side effects while maintaining efficacy and normal menstrual patterns. The first-generation OCs contained more progestin and estrogen than was necessary to prevent conception. Adverse hemostatic and metabolic changes, clinical problems, and side effects were associated with these high-dose preparations. In 1978, the World Health Organization (WHO) recommended that the focus of OC research should be the development of products containing the lowest possible dose levels of estrogen and progestin.
The first reductions in steroid content in a combination pill were focused on estrogen because it, rather than progestin, was thought to be related to the most serious side effects. Reduction in progestin content followed, as evidence mounted that lowering progestin intake might lower the risk of cardiovascular complications such as stroke and ischemic heart disease. [Kay CR, Am J Obstet Gynecol 142:762 (1982)]. However, this evidence was not as clear as that implicating estrogen in thromboembolic disorders. [Inman WHW, Br Med J 2:203 (1970); Stolley PD, Am J Epidemiol 102:197 (1975)]. The need for a balance between estrogens and progestins to minimize adverse effects on carbohydrate metabolism and on lipid and lipoprotein levels was also recognized. [Bradley DD, N Engl J Med 299:17 (1978); Wynn V, Lancet 1:1045 (1979)]. Researchers then found that the synergistic action between progestin and estrogen in a balanced ratio successfully inhibited ovulation at low levels of both components.
Research into low-dose progestins was advanced significantly by the development of norgestrel (Ng) and levonorgestrel (LNg). Levonorgestrel is the biologically active moiety of racemic norgestrel. It is strongly progestational, has no inherent estrogenic activity, is antiestrogenic, and possesses good biologic activity. The contraceptive effects of levonorgestrel are manifested throughout the hypothalamic-pituitary-gonadal-target organ axis.
Ethinyl estradiol (EE) is the estrogen most frequently used in combination OCs. In attempts to fulfill the WHO objective, the dosage of EE in marketed OC formulations has been steadily reduced from that found in earlier OCs. Thromboembolic mortality decreased when the amount of synthetic estrogen in OC formulations was reduced from 100 &mgr;g to 50 &mgr;g. Subsequently, a significant reduction in fatal myocardial infarctions was reported for women using OCs with 30 &mgr;g of EE rather than 50 &mgr;g of EE. [Meade TW,Br Med J 280:1157 (1980)].
In keeping with the goal of reducing the total steroidal dosage, while maintaining contraceptive efficacy, good cycle control, and minimizing side effects, numerous regimens have been developed in which the progestin/estrogen combination is administered either as a fixed dosage combination (monophasic) or as biphasic or triphasic regimens in which the dosage of the combination is varied either once or twice throughout the menstrual cycle. In these regimens, the progestin/estrogen combination is typically administered for 21 days followed by either a 7-day pill free period or the administration of a non-contraceptive placebo (or iron supplement) for 7 days. In these regimens, 3-ketodesogestrel (3-KDSG), desogestrel (DSG), levonorgestrel (LNg), gestodene (GTD), norgestrel (NG), and norethindrone (NE) are typically used as the progestin while ethinyl estradiol (EE); 17&bgr;-estradiol, and mestranol are typically the estrogenic components. Other progestins less frequently used include drospirenone (DRSP) and dienogest (DGST).
An oral contraceptive product containing a combination of 3 mg DGST and 30 &mgr;g EE for 21-day administration per cycle is marketed in Germany.
Several examples of attempts at reducing the total steroidal dosage are provided below.
Spona (PCT Publication WO 95/17194) discloses contraceptive regimens which consist of the administration of a combination of a progestin (50-75 &mgr;g GTD, 75-125 &mgr;g LNg, 60-150 &mgr;g DSG, 60-150 &mgr;g 3-KDSG, 100-300 &mgr;g DRSP, 100-200 &mgr;g cyproterone acetate, 200-300 &mgr;g norgestimate, or >350-750 &mgr;g norethisterone) and anestrogen (15-20 &mgr;g EE or 2-6 mg 17&bgr;-estradiol) for 23-24 days per cycle.
Oettel (EP 628,312 A1) discloses combination contraceptive combinations containing the combination of three components: a biogenic estrogen (estradiol, estrone, or estriol), a synthetic estrogen (EE or mestranol), and a progestin (LNg, desogestrel, progesterone, norethisterone acetate, DGST, chlormadinone acetate, gestodene, or cyproterone actate). In one embodiment, the combination is administered for 21 days followed by the administration of placebo (or pill free) or an estrogen on days 22-28 of the cycle.
Bergink (U.S. Pat. No. 5,262,408) discloses a 24 day triphasic combination regimen in which the first 7-9 day phase consists of the administration of a progestin at a daily dosage equivalent to 100 &mgr;g DSG and an estrogen at a daily dosage equivalent to 25 &mgr;g EE, the second 7-9 day phase consists of the administration of a progestin at a daily dosage equivalent to 125 &mgr;g DSG and an estrogen at a daily dosage equivalent to 20 &mgr;g EE and the third 7-9 day phase consists of the administration of a progestin at a daily dosage equivalent to 50 &mgr;g DSG and an estrogen at a daily dosage equivalent to 20 &mgr;g EE. It is preferred that the three phases be 8 days each. Following the 24 day contraceptive steroid administration, a placebo may be administered for 4 days, the 4 day interval may be pill free, or a progestin at a dosage equivalent to 25-35 &mgr;g DSG may be administered.
Lachnit-Fixson (U.S. Pat. No. 3,957,982) discloses triphasic 21-day progestin/estrogen regimens in which a combination of 40-90 &mgr;g LNg and 20-50 &mgr;g EE is administered for 4-6 days in the first phase, 50-125 &mgr;g LNg and 30-50 &mgr;g EE is administered for 4-6 days in the second phase, and 100-250 &mgr;g LNg and 25-50 &mgr;g EE is administered for 9-11 days in the third phase. It is preferred that the first, second, and third phases are 6, 5, and 10 days, respectively.
Bennick (U.S. Pat. No. 5,418,228) discloses triphasic regimens which consist of the administration of a combination progestin/estrogen in a 6-8 day phase, a second 6-8 day phase, and a third 6-8 day phase, with it being preferred that the three contraceptive steroid phases be 7 days each. Bennick discloses that the first contraceptive steroid phase consists of a progestin at a daily dosage equivalent to 75-150 &mgr;g DSG and an estrogen at a daily dosage equivalent to 20-25 &mgr;g EE; the second contraceptive steroid phase consists of a progestin at a daily dosage equivalent to 75-125 &mgr;g DSG and an estrogen at a daily dosage equivalent to 20 &mgr;g EE; and the third contraceptive steroid phase consists of a progestin at a daily dosa
Milowsky Arnold S
Wyeth
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