Clinical experience with Systen, a new transdermal form of hormone replacement therapy

Transdermal therapeutic systems (TTSs) represent an important advance in the evolution of hormonal replacement therapy. Not only do these formulations offer an advantage over oral dosing forms with respect to various pharmacokinetic characteristics, but also their lack of first-pass hepatic metabolism results in a highly favorable safety profile. Two multicenter studies have recently evaluated the efficacy, safety and patient acceptability of a new estradiol-containing TTX, Systen. Systen is a thin, transparent patch that contains 3.2 mg micronized 17 beta-estradiol within a novel drug delivery system. In Study 1, 196 postmenopausal women were treated continuously or cyclically for 5 months with Systen. About half of the study participants had been switched from another form of ERT. The results showed that Systen was effective and well tolerated, independent of whether it was used continuously or cyclically by "starters" or "switchers." Eighty-seven percent of the subjects rated Systen as very comfortable to wear. In Study 2, 549 postmenopausal women were randomized to six cycles of treatment with either Systen or an older TTS, Estraderm. Once again, both patches were effective and well tolerated. However, Systen was associated with fewer adverse skin reactions and was significantly superior to Estraderm with respect to patch adhesiveness and patient assessment of treatment convenience. These differences between the two patches reflect progressive refinements in TTS technology.