Effect of low-dose transdermal E2/NETA on the reduction of postmenopausal bone loss in women

Abstract

To assess the efficacy of a continuous-combined transdermal patch (estradiol/ norethisterone acetate [E2/NETA] 25/125; Estragest TTS, Novartis, Basel, Switzerland) in the reduction of bone loss in postmenopausal women. In a 96-week, double-blind, randomized, multicenter, parallel study, 124 healthy women with an intact uterus more than 4 years after menopause received either transdermal continuous-combined E2/NETA (0.025/0.125 mg/day) or placebo patch for 24 treatment cycles; diet was normalized for calcium intake. Lumbar spine bone mineral density (BMD) ranged from 0.969 to 0.805 g/cm2 with a mean annual BMD decrement ranging from 3% to 8% within the last 24 months. BMD at lumbar spine L2-L4 (postero-anterior) and femur were assessed by dual energy x-ray absorptiometry after 6, 12, and 24 cycles. Efficacy variables included measurement of biochemical markers of bone turnover (3, 6, 12, and 24 months). BMD at lumbar spine was significantly higher at all time points in the E2/NETA group than in the placebo group (P P E2/NETA 25/125 Estragest TTS was more effective than placebo in reducing the activation frequency of bone remodeling and in preventing bone loss at the spine and hip. Effects on the hip were similar to those observed for higher doses of estrogen.