Comparison of two estradiol transdermal systems (Oesclim 50 and Estraderm TTS 50). II. Local skin tolerability.

Objectives: The objectives were to compare the local skin tolerability of a matrix-type estradiol transdermal system, Oesclim 50, with that of the reservoir-type system, Estraderm TTS 50.
Methods: Two randomised studies were performed. In the first study, the modified Draize-Shelanski-Jordan method of sensitization was used in an open, parallel-group trial to compare the cutaneous tolerability of repeated applications of Oesclim 50 with that of Estraderm TTS 50 in 24 healthy postmenopausal women. The second study was an open, randomised, parallel-group, multi-centre clinical trial involving 283 healthy menopausal women. A total of 143 women were allocated to treatment with Oesclim 50 and 140 to Estraderm TTS 50. The treatment duration was four months.
Results: The first study showed that the treatments, Oesclim 50 and Estraderm TTS 50, had no sensitizing potential and did not induce allergic reactions. In the second study, 4.2% of applications in the Oesclim group provoked reactions compared with 9.5% in the Estraderm group (P < 0.001). Thirty-seven patients (25.9%) treated with Oesclim and 55 patients (39.9%) receiving Estraderm experienced one or more reactions (P < 0.05). Redness and itching were the most frequent types of application site reaction in both treatment groups. The durations of the reactions were significantly shorter in the Oesclim group (P < 0.01), with a higher percentage of durations of less than 1 h and a lower percentage of durations of over 48 h than in the Estraderm TTS 50 group. None of the reactions in the Oesclim group led to premature removal of the patch, compared with 11 (3.4%) in the Estraderm group (P < 0.05). The number of patients who discontinued treatment due to application site reactions was one (0.7%) in the Oesclim group and seven (5.1%) in the Estraderm group (P < 0.05). Efficacy and general safety were comparable in the two treatment groups.
Conclusions: In the first study, neither Oesclim nor Estraderm induced allergic reactions. In the second study, the local skin tolerability of Oesclim was significantly better than that of Estraderm, in terms of the number, duration and severity of the application site reactions.