High dose medroxyprogesterone-acetate treatment in advanced mammary carcinoma. A phase II investigation

Alternating sequential endocrine therapy: tamoxifen and medroxyprogesterone acetate versus tamoxifen in postmenopausal advanced breast cancer patients

The effects of tamoxifen (TAM) versus the alternating sequential combination of TAM plus medroxy-progesterone acetate (MPA) has been evaluated in 20 postmenopausal patients with advanced breast cancer in a randomized controlled trial. In the TAM arm, patients received 20 mg b.i.d. of TAM. In the TAM-MPA arm, patients received only 20 mg b.i.d. of TAM for 7 days and, on the following 7 days. TAM plus an oral daily dose of 500 mg of MPA, in alternating sequence. Objective tumor reduction was achieved in 22 (41%) of the 54 patients in the TAM arm and in 25 (43%) of the 58 patients in the TAM-MPA arm. With regard to the stabilization of disease, a significant difference was observed between patients treated with the TAM-MPA combination and those treated with TAM alone (47% vs 22%). The percentage of nonresponders was also significantly higher in the TAM group (37%) than in the TAM-MPA group (10%). The time to progression was significantly shorter for the TAM arm than for the TAM-MPA arm (median, 7 vs 15 months), but the duration of remission was not significantly different for either treatment.

Determination of megestrol acetate and cyproterone acetate in serum of patients with advanced breast cancer by high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method with ultraviolet detection of megestrol acetate and cyproterone acetate in human sera is described. The proposed assay is linear up to 1400 ng/ml (r = 0.999) and has a detection limit of 5 ng/ml. Recoveries of both compounds in spiked sera were ca. 95%; inter-assay coefficients of variation were 4.0 and 3.1% and intra-assay values were 1.3 and 1.4%, respectively. For validation of the method we also developed a gas chromatographic-mass spectrometric method for both steroids. The results obtained by the two methods showed good correlation: for megestrol acetate r = 0.98, n = 31, p less than 0.0001, and for cyproterone acetate r = 0.94, n = 0, p less than 0.0001. Large inter-individual differences in the serum concentrations of both substances were found in groups of patients with metastatic breast cancer receiving the same oral load of either steroid.

The structure and function of progesterone receptors in breast cancer

This paper is a review of the clinical role of progesterone receptors (PR) in the management of breast cancer, and the use of synthetic progestins in treatment of the metastatic disease. Also reviewed are our basic molecular studies dealing with the structure of human breast cancer PR, focusing on the two hormone binding proteins (the A- and B-receptors) and the role of phosphorylation. A model for the structure of PR and their subcellular compartmentalization following hormone treatment is presented.

Oral high-dose medroxyprogesterone acetate versus tamoxifen. A randomized crossover trial in postmenopausal patients with advanced breast cancer

In a prospective randomized multicenter study in previously untreated postmenopausal patients with advanced breast cancer, the response to treatment with oral medroxyprogesterone acetate (MPA) 300 mg three times daily was compared with tamoxifen (TAM) 20 mg twice daily. Of 61 patients treated with MPA, 27 (44%) had a partial or complete remission, 6 showed no change, and 28 had progressive disease. Of 68 patients treated with TAM, 24 (35%) showed a remission, 15 no change, and 29 progression. The difference in response rate is not significant. However, 11 of 25 patients with osseous metastases as predominant site, responded to MPA and 7 of 31 to TAM (P = 0.05). Moreover, in patients older than age 70 years, 13 of 26 responded to MPA and 6 of 31 to TAM (P less than 0.05). Median duration of remission of all patients in the MPA arm was 17 months and in the TAM arm, 23 months (not significant). Median survival was 20 months for MPA and 26 months for TAM (not significant). After cross-over from TAM to MPA 8 of 31 patients responded and after cross-over from MPA to TAM, no response was seen in 27 patients. These data indicate that the response rate and duration to MPA and TAM are comparable, except in patients with osseous metastases and in patients older than age 70 years. MPA has more side effects, but seems to be more effective after cross-over, and may thus be reserved for second-line treatment.

A phase III trial of oral high-dose medroxyprogesterone acetate (MPA) versus mepitiostane in advanced postmenopausal breast cancer

A randomized controlled trial was performed to compare the therapeutic results of oral high-dose medroxyprogesterone acetate (HD-MPA) versus mepitiostane (MS) in the treatment of postmenopausal breast cancer. MPA was given at three doses of 400 mg orally daily to 47 patients and produced objective responses in 19 cases (40.4%). An objective response was seen in 14 of the 40 control patients given MS at two doses of 10 mg orally daily (35.0%). Among patients with bone metastases, 6 of 19 (31.6%) for HD-MPA and 2 of 13 (15.4%) for MS showed objective responses. The other merits of HD-MPA suggested in the study were improvement in performance status, increase in appetite, and myeloprotective effect.

Advanced breast cancer: response to high dose oral medroxyprogesterone acetate

We treated 105 patients with advanced breast cancer, using the progestational agent medroxyprogesterone acetate (MPA), 200 mg orally tds in a non-randomised trial. In general they were a poor risk population, since 78 had received prior endocrine therapy (21 more than one type) and 58 prior chemotherapy. Treatment was well tolerated. Side effects included weight gain, muscle cramps, fine tremor and fluid retention, but these were usually mild, resolved if the dose of drug was reduced, and only one patient stopped treatment because of toxicity. Seventeen patients died within six weeks of starting MPA, and disease progression occurred in a further 58. Nine have had stable disease for periods ranging from two to 11 months, and there were 21 who showed disease regression. Response to treatment continues in 13 of these patients, and at the time of writing the median duration of response is 10 months. Response rates were similar in pre- and post-menopausal patients. The dose of MPA was double to 400 mg tds in 16 patients whose disease had progressed on 200 mg tds, but no additional responses were seen in this group. Seven out of 24 (29%) patients who had not received prior endocrine therapy responded to high dose oral MPA, a response rate similar to that seen following other hormonal manipulations, but because the drug also has activity against hormone-resistant tumours and is well tolerated, it should have role in the treatment of advanced breast cancer.

Additive hormonal therapy in women with advanced breast cancer

A great deal of work has been done over the last decade in the assessment of additive hormonal treatment approaches in women with advanced breast cancer. This work has been prompted by a number of factors which include: (1) the introduction of new hormonal agents, (2) increased knowledge of the physiologic actions of several hormonal agents, (3) the development of hormonal receptor assays to better predict the probability of hormonal responsiveness in a given patient, and (4) the apparent plateau in efficacy of cytotoxic chemotherapeutic approaches. The hormonal agents that have been studied most extensively in the recent past include tamoxifen (an antiestrogen), aminoglutethimide (an aromatase inhibitor), and medroxyprogesterone acetate (a progestin). In postmenopausal women, several agents exist that appear about equal in efficacy; but, currently, tamoxifen appears to be preferred as the initial hormonal treatment, primarily because of its low incidence of side effects. Studies involving combination hormonal therapy have produced interesting results, but further work is needed to establish superiority over tamoxifen alone. In premenopausal women, tamoxifen does have antitumor activity in some patients but has not been established as a replacement for oophorectomy. Properly conducted comparative trials will remain essential for the determination of the proper place of newer hormonal therapy approaches in clinical practice.

[High dose medroxyprogesteroneacetate in metastasizing breast cancer: correlations between course of the disease and hormone profiles]

Based upon preliminary observations that tumor response to MPA was correlated to cortisol suppression 42 patients were treated with MPA at different dose levels. 1500 mg MPA p.o. almost completely suppressed endogenous cortisol production in 23 out of 23 patients. Consequently, 51 patients with advanced stage metastatic breast cancer were treated with Medroxyprogesteroneacetate (HD-MAP) at a dosage of 1500 mg p.o. daily or 500 mg i.m. on 5 days per week. There were 5 complete and 7 partical remissions, 23 patients with no change and 10 with progressive disease. 7 patients were not evaluable. Clinical results correlated to plasma cortisol and prolactin blood levels bot not to LH, FSH, TSH, TBI, T3, T4, ACTH and aldosterone measurements. There was no patient with relapse and suppressed cortisol or normal prolactin measurements. The development of pituituary resistance to MPA is suggested. HD-MPA was equally effective in estrogen and/or progesterone receptor positive as in receptor negative patients. It is proposed that cortisol and prolactin determinations are useful to monitor for effective MPA treatment and the early detection of MPA resistance.

Pharmacokinetic approach to the selection of dose schedules for medroxyprogesterone acetate in clinical oncology

The pharmacokinetic and bioavailability properties of medroxyprogesterone acetate (MPA) after single PO and IM doses in man were used as a basis to predict, on a theoretical pharmacokinetic basis, the blood level profile of the drug during repeated dose administration with various dosage schedules. Because of the unusually long-lasting depot effect of IM MPA, a different build-up process of blood levels is expected during repeated IM or PO administration, and this should be taken into account when dose schedules for use in clinical oncology are selected. As regards the IM route, dose schedules based on 4 weeks' treatment with daily injections of 500-1,000 mg followed by a maintenance therapy with 1,000 mg/week are suggested, since they permit rapid achievement and maintenance of relatively high plasma levels. A similar plasma level profile can be obtained with oral MPA provided that daily doses twice as large as the IM doses are given during the first month of treatment and continued during the maintenance period. The serum levels observed in 25 patients with advanced breast cancer treated with MPA given IM or PO according to various dose schedules and recent literature data are very close to the serum level profiles predicted on a theoretical pharmacokinetic basis.

Studies on ovarian and adrenal steroids at different phases of the menstrual cycle. III. Steroid and lutropin levels before and after the administration of a single contraceptive dose of depot-medroxyprogesterone acetate (DMPA)

Ovarian and adrenal steroids and biologically active lutropin were measured in peripheral plasma samples obtained from 5 normally menstruating women. Plasma samples were collected every 3 h for a period of 39 hours in the periovulatory period of a pretreatment (control) cycle and then 16 and 54 days after a single i.m. injection of 150 mg of depot-medroxyprogesterone acetate (DMPA). Sixteen days after DMA administration, the levels of estradiol, progesterone, 17-hydroxyprogesterone, and lutropin were reduced to early follicular phase levels. No further decrease was found in 17-hydroxyprogesterone and lutropin levels; however an additional decrease occurred in the levels of estradiol and in the "morning" levels of progesterone 54 days after the administration of DMPA. Furthermore, the levels of pregnenolone, androstenedione, testosterone and dihydrotestosterone were significantly diminished in all samples collected after the administration of DMPA. Fifty-four days following the administration of DMPA, the levels of cortisol and 17-hydroxypregnenolone were significantly reduced. The administration of DMPA did not interfere with the circadian rhythm of cortisol, pregnenolone, 17-hydroxypregnenolone, dehydroepiandrosterone, 17-hydroxyprogesterone, and androstenedione levels. A significant circadian rhythm was also found in testosterone (after 16 days) and lutropin (after 54 days) levels. No circadian variation was found in estradiol, progesterone and dihydrotestosterone levels.