The purpose of this study is to evaluate the efficacy of two doses of 4-hydroxy tamoxifen (4-OHT) compared with placebo on the intensity of cyclic mastalgia in pre-menopausal women with regular menstrual cycles who are not taking oral contraceptives.

This study is a Phase II, randomised, double-blind, placebo-controlled, two-dose, multicentre trial of 4-OHT gel in approximately 130 otherwise healthy pre-menopausal women with a history of cyclical mastalgia, peaking during the second half of the menstrual cycle and decreasing significantly with the onset of menstruation, during the four months prior to study entry.

The primary efficacy endpoint in this study is change in change in average pain Visual Analog Scale (VAS) scores for the seven worst pain scores within a cycle, from baseline to the fourth cycle after start of treatment.

Inclusion Criteria:

• A woman is eligible for this study if she:

  • is pre-menopausal and at least 18 years of age.
  • has a history of cyclical mastalgia for each of the four months prior to study entry.
  • moderate or severe mastalgia as determined by >40 mm on the VAS for ≥7 days per cycle in the second part of the cycle, i.e. 13 days prior to menses and the first two days of the next cycle with a substantial decrease during the two weeks following the onset of menses, assessed during the two month run-in period.
  • has a history of regular menstrual cycles of 28 plus/minus 3 days.

Exclusion Criteria:

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