Megestrol acetate therapy for advanced breast cancer

A review of FDA approved drugs and their formulations for the treatment of breast cancer

Breast cancer is one of the most diagnosed solid cancers globally. Extensive research has been going on for decades to meet the challenges of treating solid tumors with selective compounds. This article aims to summarize the therapeutic agents which are either being used or are currently under approval for use in the treatment or mitigation of breast cancer by the US FDA, to date. A structured search of bibliographic databases for previously published peer-reviewed research papers on registered molecules was explored and data was sorted in terms of various categories of drugs used in first line/adjuvant therapy for different stages of breast cancer. We included more than 300 peer-reviewed papers, including both research and reviews articles, in order to provide readers an useful comprehensive information. A list of 39 drugs are discussed along with their current status, dose protocols, mechanism of action, pharmacokinetics, possible side effects, and marketed formulations. Another interesting aspect of the article included focusing on novel formulations of these drugs which are currently in clinical trials or in the process of approval. This exhaustive review thus shall be a one-stop solution for researchers who are working in the areas of formulation development for these drugs.

Ribosome-Directed Therapies in Cancer

The human ribosomes are the cellular machines that participate in protein synthesis, which is deeply affected during cancer transformation by different oncoproteins and is shown to provide cancer cell proliferation and therefore biomass. Cancer diseases are associated with an increase in ribosome biogenesis and mutation of ribosomal proteins. The ribosome represents an attractive anti-cancer therapy target and several strategies are used to identify specific drugs. Here we review the role of different drugs that may decrease ribosome biogenesis and cancer cell proliferation.

Understanding Breast cancer: from conventional therapies to repurposed drugs

Breast cancer is the most common cancer among women and is considered a developed country disease. Moreover, is a heterogenous disease, existing different types and stages of breast cancer development, therefore, better understanding of cancer biology, helps to improve the development of therapies. The conventional treatments accessible after diagnosis, have the main goal of controlling the disease, by improving survival. In more advance stages the aim is to prolong life and symptom palliation care. Surgery, radiation therapy and chemotherapy are the main options available, which must be adapted to each person individually. However, patients are developing resistance to the conventional therapies. This resistance is due to alterations in important regulatory pathways such as PI3K/AKt/mTOR, this pathway contributes to trastuzumab resistance, a reference drug to treat breast cancer. Therefore, is proposed the repurposing of drugs, instead of developing drugs de novo, for example, to seek new medical treatments within the drugs available, to be used in breast cancer treatment. Providing safe and tolerable treatments to patients, and new insights to efficacy and efficiency of breast cancer treatments. The economic and social burden of cancer is enormous so it must be taken measures to relieve this burden and to ensure continued access to therapies to all patients. In this review we focus on how conventional therapies against breast cancer are leading to resistance, by reviewing those mechanisms and discussing the efficacy of repurposed drugs to fight breast cancer.

Inhibiting eukaryotic ribosome biogenesis

BACKGROUND

Ribosome biogenesis is a central process in every growing cell. In eukaryotes, it requires more than 250 non-ribosomal assembly factors, most of which are essential. Despite this large repertoire of potential targets, only very few chemical inhibitors of ribosome biogenesis are known so far. Such inhibitors are valuable tools to study this highly dynamic process and elucidate mechanistic details of individual maturation steps. Moreover, ribosome biogenesis is of particular importance for fast proliferating cells, suggesting its inhibition could be a valid strategy for treatment of tumors or infections.

RESULTS

We systematically screened ~ 1000 substances for inhibitory effects on ribosome biogenesis using a microscopy-based screen scoring ribosomal subunit export defects. We identified 128 compounds inhibiting maturation of either the small or the large ribosomal subunit or both. Northern blot analysis demonstrates that these inhibitors cause a broad spectrum of different rRNA processing defects.

CONCLUSIONS

Our findings show that the individual inhibitors affect a wide range of different maturation steps within the ribosome biogenesis pathway. Our results provide for the first time a comprehensive set of inhibitors to study ribosome biogenesis by chemical inhibition of individual maturation steps and establish the process as promising druggable pathway for chemical intervention.

The Emerging Roles of Steroid Hormone Receptors in Ductal Carcinoma in Situ (DCIS) of the Breast

Ductal carcinoma in situ (DCIS) is a non-obligate precursor to most types of invasive breast cancer (IBC). Although it is estimated only one third of untreated patients with DCIS will progress to IBC, standard of care for treatment is surgery and radiation. This therapeutic approach combined with a lack of reliable biomarker panels to predict DCIS progression is a major clinical problem. DCIS shares the same molecular subtypes as IBC including estrogen receptor (ER) and progesterone receptor (PR) positive luminal subtypes, which encompass the majority (60-70%) of DCIS. Compared to the established roles of ER and PR in luminal IBC, much less is known about the roles and mechanism of action of estrogen (E2) and progesterone (P4) and their cognate receptors in the development and progression of DCIS. This is an underexplored area of research due in part to a paucity of suitable experimental models of ER+/PR + DCIS. This review summarizes information from clinical and observational studies on steroid hormones as breast cancer risk factors and ER and PR as biomarkers in DCIS. Lastly, we discuss emerging experimental models of ER+/PR+ DCIS.

Megestrol acetate and mirtazapine for the treatment of unplanned weight loss in the elderly

A rising concern among clinicians is treatment of unplanned weight loss in the elderly, especially given the predicted growth of this population over the next few decades. Unexpected weight loss in the geriatric patient worsens overall health outcomes. A variety of pharmacotherapeutic options are available for treatment; however, evidence underlying their use is limited, and none has gained approval from the United States Food and Drug Administration for this indication. At present, no guidelines support the choice of one agent over another. Although several drug interventions have been employed for this problem, megestrol acetate and mirtazapine are becoming increasingly used for appetite stimulation. These drugs represent two feasible options for geriatric patients because of their generally favorable adverse-effect profiles and few drug interactions, but they are often misused. In a comprehensive search of the MEDLINE and International Pharmaceutical Abstracts databases, we identified all published reports on the use of megestrol acetate or mirtazapine for the treatment of weight loss and on any adverse events associated with these drugs. Special emphasis was placed on trials performed in an elderly population. Results were conflicting, most likely because of differing study designs and small numbers of patients. Megestrol acetate and mirtazapine appear to be effective for appetite stimulation and weight gain in some settings. However, applicability of the data to elderly individuals is unclear, and adverse events reported in a few of the trials and in case reports were not benign. Therefore, the use of megestrol acetate or mirtazapine for weight loss should be thoroughly evaluated on an individual basis. Pharmacotherapy should be used only after all underlying causes of weight loss are assessed and treated.

Hormonal therapy for advanced breast cancer

Hormonal therapy for advanced breast cancer has evolved significantly in the more than 100 years since the first publications documenting the effect of ovarian ablation on advanced breast cancer in premenopausal women. Since that time, not only have we developed the methods to measure estrogen and progesterone receptors in cancer cells, but more recently we have understood that expression of these receptors determines response to hormone therapy. The availability of more selective antiestrogen therapies has changed and significantly improved the treatment options for women who have advanced hormone-responsive breast cancer. Current research is focusing on reversing resistance to hormone therapy with the addition of targeted biologic agents to standard hormonal treatment.

Oesophageal cancer and cachexia: the effect of short-term treatment with thalidomide on weight loss and lean body mass

BACKGROUND

Cachexia is common in patients with advanced cancer and has a direct impact on well-being and mortality.

AIM

To test the hypothesis that thalidomide can promote weight gain and lean body mass in patients with advanced oesophageal cancer.

METHODS

In an open-label study, 11 patients with non-obstructing and inoperable oesophageal cancer were established on an isocaloric diet for 2 weeks, followed by 2 weeks on thalidomide, 200 mg daily. The primary end-points were weight change and lean body mass. Secondary end-points were quality of life and changes in resting energy expenditure.

RESULTS

Ten patients completed the study protocol. The average caloric intake remained the same throughout the study period in all patients. Nine of 10 patients (95% confidence interval, 0.60, 0.98) lost weight on diet alone. The mean weight gain on thalidomide in the following 2 weeks was 1.29 kg (median, 1.25 kg). A similar trend was shown in the lean body mass. Eight of nine patients (95% confidence interval, 0.57, 0.98) initially lost lean body mass on diet alone (missing data in one patient). The mean gain in lean body mass on thalidomide in the following 2 weeks was 1.75 kg (median, 1.33 kg).

CONCLUSIONS

Thalidomide treatment appeared to reverse the loss of weight and lean body mass over the 2-week trial period.

Improvement in quality-of-life measures and stimulation of weight gain after treatment with megestrol acetate oral suspension in geriatric cachexia: results of a double-blind, placebo-controlled study

BACKGROUND

Weight loss among older patients is a severe problem, associated with an increased incidence of infections, decubiti, and death. Megestrol acetate (MA) causes weight gain in cachectic cancer and AIDS patients, but its effects in older cachectic patients are unknown.

OBJECTIVE

To compare the effects of MA oral suspension (O.S.), 800 mg/day, versus placebo on weight in geriatric nursing home patients with weight loss or low body weight.

DESIGN

Twelve-week, randomized, double-blind, placebo-controlled trial with a 13-week follow-up period.

SETTING

Veterans Administration Medical Center (VMAC) nursing home.

PATIENTS

Nursing home patients with weight loss of > or =5% of usual body weight over the past 3 months, or body weight 20% below their ideal body weight.

INTERVENTIONS

Patients were randomly assigned to receive placebo or MA 800 mg/day for 12 weeks and were then followed for 13 weeks off treatment.

MEASUREMENTS

Primary outcome was measured by weight and appetite change. Secondary outcome measures included sense of well-being, enjoyment of life, change in depression scale, laboratory nutrition parameters, energy intake counts, body composition, and adverse events.

RESULTS

At 12 weeks there were no significant differences in weight gain between treatment groups, whereas MA-treated patients reported significantly greater improvement in appetite, enjoyment of life, and well-being. Body composition was not statistically different between the two groups. At Week 25 (3 months after treatment), 61.9% of MA-treated patients had gained > or =1.82 kg (4 lbs) compared to 21.7% of placebo patients.

CONCLUSIONS

In geriatric patients with weight loss or low body weight MA improves appetite and well-being after 12 weeks of treatment. During the 3 months of MA treatment, there was no statistically significant weight gain (> or =4 lbs). Three months after treatment, weight gain (> or =4 lbs) was significantly increased in MA-treated patients.

Open comparative trial of formestane versus megestrol acetate in postmenopausal patients with advanced breast cancer previously treated with tamoxifen

The aim of the trial was to compare efficacy and safety of the aromatase inhibitor formestane (250 mg i.m. given every 2 weeks) with the progestin megestrol acetate (160 mg administered orally once daily), as second-line therapy in postmenopausal patients with advanced breast cancer previously treated with tamoxifen. A total of 547 patients were enrolled. Analyses revealed no statistically significant or clinically relevant difference between treatments with respect to time endpoints. In the intent-to-treat analysis, the median values for time to failure and overall survival for formestane were 169 and 561 days, respectively. The corresponding values for megestrol acetate were 169 days and 597 days, respectively. Overall response rates were comparable for formestane and megestrol acetate (16.3% vs 20.3%). Formestane was better tolerated than megestrol acetate. In the megestrol acetate group, cardiovascular events, weight increase, and vaginal haemorrhage were significantly more frequent than in the formestane group. Thus, formestane is a suitable alternative to progestins in patients previously treated with tamoxifen.

Geriatric cachexia: the role of cytokines

Weight loss in elderly patients is a common clinical problem. Wasting and cachexia are associated with severe physiologic, psychologic, and immunologic consequences, regardless of the underlying causes. Cachexia has been associated with infections, decubitus ulcers, and even death. Multivariate analyses of risk and prognostic factors in community-acquired pneumonia in the elderly have found that age by itself is not a significant factor related to prognosis. Among the significant risk factors, only nutritional status is amenable to medical intervention. Cachexia in the elderly may have profound consequences: medical, cognitive, and psychiatric disorders may diminish self-reliance in activities of daily living, thus reducing quality of life and increasing the frequency of secondary procedures, hospitalizations, and the need for skilled care. Cachexia is associated with higher-than-normal concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin (IL) 1, IL-6, serotonin, and interferon gamma. The role of these proinflammatory cytokines has been established in the cachexia seen in cancer and AIDS patients. Reduction in the concentrations of these cytokines is associated with weight gain. Drugs that promote appetite stimulation and weight gain, such as progestational agents, cyproheptadines, pentoxifylline, and thalidomide may work by down-regulating these proinflammatory cytokines. An understanding of the relation between cachexia and negative regulatory cytokines may point to effective treatment of geriatric cachexia as well.

New Hormonal Therapies for Breast Cancer

BACKGROUND: There has been an explosion in the development of hormonal therapies for the treatment of breast cancer. Several new agents have been approved for the treatment of breast cancer in the metastatic setting, and trials are ongoing in the adjuvant and prevention setting to improve hormonal therapy for the prevention and treatment of breast cancer. METHODS: The literature on new hormonal therapies for the treatment of breast cancer is reviewed, with an emphasis on newer agents. RESULTS: Two antiestrogens are now approved in the United States for the treatment of metastatic breast cancer. Other antiestrogens have activity in metastatic breast cancer as well as in osteoporosis. Newer pure antiestrogens may overcome resistance to tamoxifen. Several aromatase inhibitors are available for the treatment of metastatic breast cancer. CONCLUSIONS: Many hormonal agents are now available for both adjuvant and advanced disease settings. Developments will depend on clarifying mechanisms of resistance to antiestrogens and identifying new classes of agents that lack cross-resistance to standard therapy.

HIV wasting syndrome: treatment update

OBJECTIVE

To review the pathophysiology and treatment of HIV wasting syndrome.

DATA SOURCES AND STUDY SELECTION

MEDLINE searches (January 1987-September 1997) of the English-language medical literature were conducted. Bibliographies were also selected during a manual review.

DATA SYNTHESIS

HIV-related weight loss, often referred to as HIV wasting syndrome, is a common manifestation of advanced HIV infection. Wasting in HIV involves the preferential loss of lean body mass with a paradoxical preservation of body fat. The etiology of wasting appears to be the result of many factors, which may include decreased caloric intake, malabsorption, alterations in energy expenditure and metabolism, cytokine effects, and endocrine dysfunction. Pharmacologic treatment options include appetite stimulants (e.g., dronabinol, megestrol acetate), cytokine inhibitors (e.g., thalidomide, cyproheptadine, ketotifen, pentoxifylline, fish oil, N-acetylcysteine), and anabolic agents (e.g., testosterone, nandrolone, oxandrolone, recombinant human growth hormone).

CONCLUSIONS

Wasting associated with HIV has a high morbidity and mortality rate if not adequately managed. Therapeutic strategies include appetite stimulants, cytokine inhibitors, and growth-promoting agents. Selection of the appropriate agent(s) depends on the underlying cause for weight loss, adverse effects, and cost of therapy.

Effect of megestrol acetate and prepulsid on nutritional improvement in patients with head and neck cancers undergoing radiotherapy

BACKGROUND AND PURPOSE

Anorexia is a common problem in cancer patients who receive radiotherapy. In this current study, we attempt to determine the effect of megestrol acetate and prepulsid on appetite and nutritional improvement in patients with head and neck cancers undergoing radiotherapy.

MATERIALS AND METHODS

One hundred twenty-nine consecutive patients with head and neck cancers treated between July 1993 and June 1994 were prospectively randomized to receive either megestrol acetate, 40 mg qid (megace group), prepulsid, 5 mg tid (cisapride group), or a placebo treatment (control group) during radiotherapy. Before radiotherapy, body weight (kg), appetite score, performance status, biochemical parameters and hematological parameters were evaluated, and the above-noted clinical and biochemical parameters were assessed and recorded every other week. All patients received 6- 10 MV X-rays or Co-60 gamma-ray to head and neck region for a full course of radiotherapy, 61.2-75.6 Gy/7-9 weeks.

RESULTS

Forty-eight patients were enrolled in the megace group, 41 patients in the cisapride group, and 40 patients in the control group. At the 2nd, 4th, 6th and 8th week, as the radiation dose escalated, the megace group had significantly less body weight loss than did the cisapride and control groups (P = 0.045, 0.024, 0.006, 0.003, respectively). The appetite scores of the megace group were significantly higher than those of the cisapride and control groups (P = 0.0001). However, there were no statistically significant differences in the change of albumin level among these three groups at the 2nd, 4th, 6th and 8th week (P > 0.05, respectively).

CONCLUSIONS

Megestrol acetate can significantly decrease the degree of body weight loss, and can prevent the deterioration of appetite in patients with head and neck cancers receiving radiotherapy. However, prepulsid lacks the above-mentioned clinical benefits.

Supportive use of megestrol acetate in patients with head and neck cancer during radio(chemo)therapy

To study the supportive effect of megestrol acetate during intensive combined modality treatment, a randomised, double-blind, placebo-controlled study was performed in patients with head and neck cancer. The patients received either 160 mg of megestrol acetate daily or placebo during radio(chemo)therapy and for up to 6 weeks thereafter. The nutritional status as measured by anthropometric and biochemical parameters and the subjective quality of life were assessed prior to therapy, at weeks 1, 4 and 6 of radiotherapy and 12 and 18 weeks from the start of therapy. 61 of 64 patients were evaluable. In the control group (n = 30), the nutritional parameters deteriorated during therapy and were fully restored during follow-up. By contrast, the patients treated with megestrol acetate (n = 31) could maintain their baseline values. The difference between the groups was most pronounced in patients taking food per mouth (weight loss during treatment: control group: 4.1 kg; megestrol acetate group: 0.8 kg, P = 0.0004), but was not significant in patients fed via percutaneous endoscopically guided gastrostomy (PEG). Subjective quality of life remained constant in the megestrol acetate group while it decreased in the control group. However, differences were not statistically significant. Megestrol acetate prevents further deterioration of nutritional status during radio(chemo)therapy and may have an impact on subjective quality of life.

A randomised phase III cross-over study of tamoxifen versus megestrol acetate in advanced and recurrent breast cancer

139 peri- and postmenopausal women with advanced or recurrent breast cancer who had not received prior hormonal therapy were randomised in an open, cross-over study comparing the synthetic progestogen megestrol acetate with tamoxifen. The response rate (CR/PR) to megestrol acetate (25%; 95% confidence interval (CI) 15-35%) was not significantly different from that produced by tamoxifen (33%, CI 22-44%). Time-to-treatment failure was also similar in the two groups. Cross-over treatment was given on progression in 76 cases. Cross-over response (CR/PR) was seen in 3 of 35 patients (9%) receiving megestrol acetate as second-line therapy and in 6 of 41 patients (15%) receiving tamoxifen second-line. There was no significant difference in survival between the groups (P = 0.17) with median survival times of 24 and 32 months for the megestrol acetate and tamoxifen groups, respectively. The toxicity profile of the two drugs was different, although significant toxicity was rare with either agent. Megestrol acetate is an effective treatment for advanced breast cancer in older women when used either as first- or second-line treatment. Cross-over response is seen following both treatments. Given that most patients now receive tamoxifen as adjuvant treatment, megestrol acetate would appear to be one of the logical choices for patients who find the side-effects of tamoxifen unacceptable and for those who relapse on tamoxifen with further hormone therapy being clinically indicated.

Residual Ca2+ channel current modulation by megestrol acetate via a G-protein alpha s-subunit in rat hypothalamic neurones

1. The inhibition of voltage-activated Ca2+ channel currents by the orally active progesterone derivative, megestrol acetate (MA), was examined in freshly dissociated rat ventromedial hypothalamic nucleus (VMN) neurones using the whole-cell voltage-clamp technique with 10 mM Ba2+ as the charge carrier. 2. The steady-state inhibition of the peak high-threshold Ca2+ channel current evoked by depolarization from -80 to -10 mV by MA increased in a concentration-dependent fashion. MA inhibited a fraction of the whole-cell Ca2+ channel current while progesterone had no effect on the peak Ca2+ channel current (7% at 10 microM). The low-threshold Ca2+ (T-type) current, evoked from -100 to -30 mV, was unaffected by MA. 3. Intracellular dialysis with MA had no effect on the Ca2+ channel current. Concomitant extracellular perfusion of MA showed normal inhibitory activity, suggesting that the MA binding site can only be accessed extracellularly. 4. The high-threshold Ca2+ channel current in VMN neurones was found to consist of four pharmacologically distinguishable components: an N-type current, an L-type current, a P-type current, and a residual current. MA had no effect on the N-, L- and P-type Ca2+ channel currents, but inhibited the residual current. 5. In neurones isolated from cholera toxin-treated animals, the MA-induced inhibition of the Ca2+ channel current was significantly diminished, suggesting a G-protein alpha S-subunit involvement. 6. Treatment with antisense phosphothio-oligodeoxynucleotides to the G alpha S-subunit (antisense-G alpha S) significantly reduced the MA-induced inhibition of the Ca2+ channel current. Treatment with either sense-G alpha S or antisense-G alpha 11 had no effect, confirming a G alpha S-subunit involvement. 7. These results suggest that appetite enhancement induced by MA in cachectic patients may in part be due to a novel central nervous system action, that is, inhibition of a fraction of the whole-cell Ca2+ channel current to attenuate the firing of VMN neurones that may be involved in satiety mechanisms.

Progestins in breast cancer treatment. A review

The two most widely used synthetic progestins in breast cancer treatment, medroxyprogesterone acetate (MPA) and megestrol acetate (MA), are reviewed with regard to pharmacological, endocrinological and clinical aspects. In high oral doses as second- or first-line endocrine therapy in advanced breast cancer, they give a similar response rate as tamoxifen (TAM) and aminoglutethimide (AG). The mechanism of action is probably complex. Considerable changes in serum levels of different hormones are induced by progestin treatment. The decrease of serum estrone sulfate (E1S) may be part of the therapeutic mechanism. Some studies suggest that the two drugs, MPA and MA, have a different mode of action, and possibly a low cross resistance. Randomized studies using the two progestins with a cross-over design may answer these questions. Further studies on the influence of progestin on different receptors and growth factors are warranted. To determine the most effective clinical dose of the two progestins, studies with increasing therapeutic doses are needed.

A phase I/II study of high-dose megestrol acetate in the treatment of metastatic breast cancer

A dose-response relationship has been suggested for medroxyprogesterone acetate in the treatment of advanced breast cancer. To determine the tolerability and efficacy of increasing doses of megestrol acetate in the treatment of metastatic breast cancer, we conducted a phase I/II study among 57 patients. Three patients each received 480, 800, and 1280 mg/d; 48 patients received 1600 mg/d. Of the 57 patients, 56 patients had had disease progression on prior hormone therapy, chemotherapy, or both. Twenty-seven patients had previously received standard-dose MA (160 mg/d). Among the 37 patients with measurable disease, high-dose megestrol acetate (HDMA) produced 6 (16%) complete responses (CRs) and 6 (16%) partial responses (PRs); 11 patients achieved stable disease (SD). HDMA resulted in improvement or stabilization in 12 of the 20 patients with evaluable, non-measurable disease. There were no responses among the 6 patients with liver metastases. Among the 27 patients who were previously treated with standard-dose MA, including 9 patients with primary treatment failure, HDMA resulted in 1 CR, 3 PRs, and 10 SD. Toxicities, which were mild and reversible, included fluid retention, hypertension, hyperglycemia, and mild congestive heart failure. Two patients had superficial phlebitis. The most profound side effect was weight gain which occurred in 43 patients (75%). This study suggests a dose-response relationship for MA in the treatment of advanced breast cancer. A randomized trial to determine the optimal dose is ongoing.

Megestrol acetate: phase II study of a single daily administration in advanced breast cancer

A new formulation of megestrol acetate, a semisynthetic oral progestin used in the hormonal treatment of breast cancer, allows the administration of 160 mg of the drug in a single daily dose. Sixty-nine postmenopausal patients with advanced breast cancer have been treated with this regimen: five patients received megestrol acetate as first-line treatment of their metastatic disease, while all the others had been previously treated with one or more regimens of chemotherapy and/or hormone therapy. The median duration of the treatment for evaluable patients was 3 months (range 1-13+). Among 65 evaluable patients 2 complete responses and 12 partial responses (objective response rate 21.5%; 95% confidence limits 12.31%-33.49%) were observed. Median duration of response was 7 months (range 2-12+). Responses were observed both in visceral and in non-visceral sites of disease. Twenty-nine patients obtained a stabilization of disease (44.7%), and twenty-two progressed (33.8%). Median duration of stabilization was 4 months (range 3-13+). Median survival for all patients from the start of megestrol acetate was 9 months (range 1-22+). The most common side effect of therapy was weight gain, occurring in 36% of patients. Megestrol acetate on a single-daily-dose schedule can be considered as an interesting hormonal treatment for advanced breast cancer, especially in the clinical instance of patients who, after having obtained a remission or stabilization of disease with tamoxifen, need further palliative treatment.

A randomized comparison of megestrol acetate (MA) and medroxyprogesterone acetate (MPA) in patients with advanced breast cancer

The efficacy and side-effects of megestrol acetate and medroxyprogesterone acetate in postmenopausal patients with advanced breast cancer were compared in a prospectively randomized study. The dosage of MA was 2 X 80 mg p.o. or MPA 2 X 500 mg p.o. daily, given as a secondary hormonal treatment, mostly after previous treatment with tamoxifen. Ninety-eight patients entered the study and 92 were evaluable for effect, 48 patients on MA and 44 on MPA. Age, main tumor site and prior treatment were not different, but there was a preponderance of ER-negative tumors in the MA group. Responses appeared to be more frequent in the MPA-treated group (25% vs. 43%), predominantly in bone lesions, 12% for MA and 45% for MPA. Median progression-free survival was comparable, 15 vs. 10 months, and overall survival was not different (20 vs. 16 months). Toxicity was frequent, occurring in 83% vs. 74% of patients: increased appetite, nausea and dizziness in more than 20%, and a preponderance of pyrosis and breathlessness on MA and hot flashes, sweating and tremors on MPA. Cushingoid symptoms were present in about a quarter of the patients treated for more than 3 months. The occurrence of thrombo-embolic episodes and cardiovascular events was evenly distributed. Patients on MPA had more often increase in body weight, systolic blood pressure and serum creatinine than those treated with MA. It is concluded that MPA may be more effective for treatment of bone metastases, at the expense of more progestational side-effects. The occurrence of Cushingoid effects is frequent but similar in both arms, while the incidence of cardiovascular or thrombo-embolic events cannot be related to the use of either compound.

Factors predicting the response of patients with advanced breast cancer to endocrine (Megace) therapy

We have treated 238 patients with advanced breast cancer with megestrol acetate (Megace, Bristol-Myers): 221 were assessable for response at 6 months by UICC criteria. Thirty-six (16%) patients responded, 54 (25%) were static and 131 (59%) progressed. Survival from the time of starting Megace calculated by log-rank analysis showed no significant difference in survival between patients showing response and static disease at 6 months. Patients with progression of disease within 6 months survived significantly shorter than patients who showed response or static disease at 6 months. Categorizing response at 6 months appeared to identify patients who had static disease of worthwhile duration. ER status of the primary tumour correlated significantly with survival from the time of commencing Megace. However, when Megace was used as a second-line hormone therapy the assessment of response or static disease on prior hormone therapy was a better predictor of the effect of Megace than ER status of the primary tumour.

The definition of the 'no change' category in patients treated with endocrine therapy and chemotherapy for advanced carcinoma of the breast

In the criteria used for assessment of response to treatment for advanced breast cancer the definition of no change (NC) is clear; however, there is no indication of the duration of stabilization required for patients to qualify for this category of response. We have made the assumption that NC is a worthwhile category of response if the overall time to progression (TTP) and survival of this group is not significantly different from patients with partial remissions (PR). Two hundred and sixty-three evaluable patients treated with endocrine therapy and 302 evaluable chemotherapy-treated patients were studied and the TTP and survival curves for PR and periods of NC from 1 to 6 months compared. For the endocrine-treated patients the TTP and survival curves for NC became non-significantly different from the PR curves after 4 and 5 months respectively. For chemotherapy-treated patients the TTP curves became non-significantly different from PR at 4 months and for survival the period was 3 months. In order to define NC as a useful category of response and to eliminate the possibility that NC taken for a shorter period could simply represent a slowly progressive tumour, we suggest that the minimum period of disease stabilization be taken as 5 months for both endocrine- and chemotherapy-treated patients.

Clinical trial of high-dose oral medroxyprogesterone acetate in the treatment of metastatic breast cancer and review of the literature

Recent studies have suggested that there are benefits from the use of high-dose parenteral medroxyprogesterone acetate (MPA) in the treatment of metastatic breast cancer. The present study was designed to assess the efficacy and toxicity of high-dose oral MPA in women with clinical parameters suggesting potentially hormonally sensitive metastatic breast cancer. The first 28 patients received 800 mg/day, and 11 of them had received no previous hormone (NPH) therapy. The response rate (complete plus partial) was 63% for those receiving NPH and 12% for those receiving previous hormone (PH) therapy. Toxicity was significant at these doses, especially for women treated for more than 5 weeks. Toxic effects included excessive weight gain, Cushingoid facies, worsening of diabetes mellitus, and other stigmata suggestive of hypercorticism. Nineteen other patients were treated at 400 mg/day with a 60% response rate for 10 NPH patients and 44% for patients with PH treatment. Toxicity was less severe in these patients. The median time to treatment failure was 23 weeks, and to survival, 119 weeks for all treated patients. Moderately high (400 mg/d) and higher dose (800 mg/d) oral MPA are capable of inducing reasonable response rates in patients with NPH treatment. The toxicity of these regimens was significant--profound weight gain was dose limiting in some patients. While effective, high-dose oral MPA is unlikely to supplant tamoxifen as first-line therapy in metastatic breast cancer.

Combination hormone therapy for metastatic breast cancer. An ECOG study of megestrol and aminoglutethimide

This study was performed to determine the toxicity and effectiveness of megestrol acetate used with aminoglutethimide-hydrocortisone in the treatment of patients with metastatic breast cancer. Forty-five patients were treated, 29 of whom were fully eligible. Twelve of the 45 who had diabetes and/or hypertension were also analyzed. All had measurable sites of disease. The median age was 63 years, and the median time from first recurrence to on-study was 19 months. Approximately half the patients already had chemotherapy, and about 90% had hormone therapy for advanced disease. The most common side effects were skin rash, weight gain, hyperglycemia, and renal and neurologic problems. No life-threatening or lethal toxicities were reported. The overall response rate (complete or partial) among the fully eligible patients was 34% (90% confidence intervals from 20% to 51%), with a 5-month median duration of response. Patients with soft tissue, visceral, and osseous disease responded. Seventy-two percent of fully eligible patients have progressed or relapsed. The median time to failure of treatment was 6 months, and the median survival time was 15 months.

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.

Fundamental research leading to improved endocrine therapy for breast cancer

Whilst endocrine therapy has a long-established role in the management of patients with advanced breast cancer, current therapies produce remission in, at best, only between 30 and 40% of cases. The most efficient use of hormonal measures therefore requires the accurate identification of individuals with hormone-responsive tumours. Oestrogen receptor measurements are useful but not fully discriminatory and additional predictive factors are required. Markers, such as specific hormonally induced proteins and mRNA, and antagonistic systems, such as epidermal growth factor receptors and cyclic AMP binding proteins are currently being evaluated. In terms of therapy, surgical manoeuvres such as adrenalectomy and hypophysectomy have already been replaced by the medical administration of anti-oestrogens, progestogens and drug regimes such as aminoglutethimide-hydrocortisone. Although castration by surgery or radiation remains the first-line treatment in premenopausal women with advanced disease, the advent of depot preparations of LHRH agonists offers the opportunity of performing medical ovariectomies which have the added advantage of being reversible. As a result of laboratory studies, more potent anti-oestrogens and more specific "suicide" aromatase inhibitors are entering into clinical practice. These can be expected to increase efficacy of treatment whilst reducing its side-effects. Research using cell-lines of human breast cancer also suggests that anti-progestins and agents capable of antagonizing steroid-induced growth factors will inhibit tumour growth. Such novel therapies potentially could make a major impact in the endocrine management of breast cancer. Lastly, although the primary management of early breast cancer predominantly involves non-hormonal modalities, clinical trials are now providing evidence of survival benefit from adjuvant endocrine therapy. The knowledge accrued from the use of newer endocrine agents in advanced cancer could therefore ultimately be relevant to the treatment of earlier stages of the disease.

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.