The estradiol vaginal ring--a study of existing clinical data

Eleven reports on clinical trials with the estradiol vaginal ring have been completed to date. In five of these, the ring was compared with other vaginally-applied estrogen preparations while in the other six trials there were no parallel controls. Three trials with no parallel controls were carried out on patients who had participated in previously controlled studies. In the controlled studies, reference therapy included an estriol pessary in two, conjugated estrogen cream in two and an estriol vaginal cream in one. After 3 and 12 weeks of treatment in the non-controlled studies, vaginal maturation by cytologic as well as physician assessment was documented. These urogenital maturation changes were associated with improvement or elimination of patient symptoms in 67%-100% of the subjects. Average plasma levels of estradiol, with first and second ring, indicated a transient Cmax of 232 and 162 pmol/l, respectively, but with steady-state concentrations at 28 and 21 pmol/l, respectively. In the five controlled studies, patients were randomized to the agents mentioned above or to the ring, and the dependent variables were vaginal and urinary symptoms reported by subjects and physician and cytopathologic evaluation of the urogenital tissue. These variables were vaginal dryness, pruritus, dyspareunia, dysuria, urinary urgency and stress incontinence. Physician assessment of overall improvement in vaginal and urinary status and cytologic maturation value and vaginal pH were also recorded. Statistical analysis of each trial revealed no significant difference between treatments, and good patient acceptance of the ring. The longer term studies (over 1 year) indicated good to excellent patient acceptance of this low dose estradiol-releasing vaginal ring in the treatment of symptoms associated with urogenital ageing. In summary, clinical experience from 946 postmenopausal women treated with the ring for up to 96 weeks indicates a good response with respect to patient complaints and physical and cytologic examination, without serious adverse reactions.