Comparison of two estradiol transdermal systems (Oesclim 50 and Estraderm TTS 50). I. Tolerability, adhesion and efficacy.

Objectives: The objectives were to compare the tolerability, adhesion and efficacy of a new matrix-type estradiol transdermal system, Oesclim 50, with those of Estraderm TTS 50, a reservoir-type system.

Methods: This was an open, randomised, parallel-group, multi-centre clinical trial, performed in six European countries. A total of 143 healthy menopausal women were allocated to treatment with Oesclim 50 and 140 to Estraderm TTS 50. The transdermal systems were applied twice weekly for 24 days out of each 28-day cycle, over a period of four cycles. Oral progestogen treatment was taken by non-hysterectomised patients for the last 12 days of estrogen therapy in each cycle.

Results: The local skin tolerability of the Oesclim 50 transdermal system was significantly better than that of Estraderm TTS 50. In the Oesclim 50 group, 4.2% of applications caused a reaction, compared with 9.5% in the Estraderm TTS 50 group (P < 0.001). Safety assessments showed both treatments to be well tolerated. Seven patients in the Oesclim 50 group, and 12 in the Estraderm TTS 50 group, discontinued due to adverse events. Of these discontinuations, one (0.7% of patients) in the Oesclim 50 group and seven (5.1% of patients) in the Estraderm TTS 50 group were due to application site reactions (P < 0.05). There was no statistically significant difference between the two groups in the percentage of patients with signs of hyperestrogenism (29 patients (20.3%) in the Oesclim group and 28 patients (20.0%) in the Estraderm TTS 50 group). Adhesion was significantly better for the Oesclim 50 transdermal system, with 6.0% of Oesclim 50 applications becoming detached compared with 11.3% of Estraderm TTS 50 applications (P < 0.001). The greater adhesion of Oesclim 50 was particularly apparent when the systems were exposed to water, with three times fewer Oesclim 50 systems becoming detached during a shower or bath (P < 0.001 in each case). Both treatments produced significant and comparable improvements in vasomotor symptoms, other menopausal symptoms and gynaecological assessments. A near-maximal effect on vasomotor symptoms was observed after approximately 1 month of treatment, and was maintained for the entire treatment period.

Conclusion: Overall, Oesclim 50 provided statistically significantly better local skin tolerability and adhesion than Estraderm TTS 50, together with comparable efficacy and safety.