Endoxifen for local transdermal therapy to the breast
Disclosed are methods and topical formulations for treating and/or preventing cell proliferative diseases and disorders including breast cancer and ductal carcinoma is situ (DCIS) using local transdermal therapy (LTT). The disclosed methods typically include administering topically to the breast or breasts of the patient a topical formulation comprising an effective dose of the tamoxifen metabolite, N-desmethyl-4-hydroxytamoxifen (i.e., endoxifen or ENX) for treating breast cancer. The topical formulation may be described as a transdermal formulation and the topical formulation may comprise, consist essentially of, or consist of endoxifen as an active ingredient.
1. A method for treating breast cancer and ductal cancer in situ (DCIS) in a patient in need thereof, the method comprising administering topically to the breast or breasts of the patient a topical formulation for treating breast cancer and ductal cancer in situ (DCIS) in a patient in need thereof, the topical formulation comprising an effective dose of endoxifen for treating breast cancer, wherein after the topical formulation is administered topically to the breast or breasts of the patient, an effective concentration of endoxifen for treating breast cancer and ductal cancer in situ (DCIS) is delivered to the breast or breasts of the patient, and wherein:
(i) the endoxifen is present in the topical formulation at a concentration of 0.5 mg/ml-2 mg/ml;
(ii) the topical formulation comprises oleic acid at a concentration of 0.1%-1% (w/w);
(iii) the topical formulation comprises ethanol at a concentration of 50%-70% (w/w);
(iv) the topical formulation is a gel comprising hydroxypropylcellulose at a concentration of 1%-2% (w/w);
(v) the topical formulation is formulated to deliver a dose of endoxifen per bodyweight of the patient of about 1.0-20 mg/kg/day; and
wherein:
the endoxifen is administered at a dose per bodyweight of the patient of about 1.0-20 mg/kg/day;
the dose of endoxifen delivered to the breast of the patient is at least about 1.0-20 ng/g and the dose delivered to the plasma of the patient is no more than about 5 ng/ml; and
the ratio (R) of the dose of endoxifen delivered to the breast of the patient (D Breast in ng/g) to the dose delivered to the plasma of the patient (D Plasma in ng/ml) is greater than about 5.