Irving M. Spitz

Long-Term Administration of Mifepristone (RU486): Clinical Tolerance During Extended Treatment of Meningioma

Background: Mifepristone (RU486) is an oral antiprogestational and, to a lesser extent, antiglucocorticoid agent commonly used for short-term (single-day) therapy. However, treatment of neoplasms or chronic conditions will require long-term administration. Meningioma is a benign central nervous system tumor that is often progesterone-but not estrogen-receptor positive, making long-term antiprogestational therapy a logical treatment strategy. Methods: Patients with unresectable meningioma were treated with oral mifepristone 200 mg/day. This dose was selected to provide significant antiprogestational but not antiglucocorticoid activity. Patients also received oral dexamethasone 1 mg/day for the first 14 days. Serial follow-up allowed evaluation for tolerability and side effects of long-term therapy as well as observation for efficacy (tumor shrinkage or improvement in visual fields). Results: Twenty-eight patients received daily oral mifepristone for a total of 1,626 patient-months of treatment. The median duration of therapy was 35 months (range 2–157 months). Repeated oral administration was well tolerated with mild fatigue (22 patients), hot flashes (13 patients), and gynecomastia/breast tenderness (6 patients) being the most common side effects. However, endometrial hyperplasia or polyps were documented in 3 patients and one patient developed peritoneal adenocarcinoma after 9 years of therapy. Minor responses (improved automated visual field examination or improved CT or MRI scan) were noted in 8 patients, 7 of whom were male or premenopausal female. Conclusions: Long-term administration of mifepristone is feasible and clinically well tolerated, with generally mild toxicity. However, endometrial hyperplasia was noted in several patients. In view of the association between long-term treatment with tamoxifen (another agent that can induce an unopposed estrogen effect) and endometrial cancer, this observation will require further investigation and screening. Minor regression of meningioma that can result in significant clinical benefit is suggested in the male and premenopausal female subgroups of patients.

Long-term mifepristone (RU486) therapy resulting in massive benign endometrial hyperplasia.

Mifepristone (RU486) is a potent antiprogestagen, and at high doses it also acts as an antiglucocorticoid drug. Mifepristone, administered as a single 600u2003mg dose, is commonly employed to induce medical abortion in conjunction with prostaglandins. The long‐term safety profile of mifepristone, especially at high doses, is less well‐established. Long‐term mifepristone is considered efficacious in treating uterine myomas, endometriosis (25–100u2003mg/day), and possibly in inoperable meningiomas (200u2003mg/day), as well as inoperable Cushings syndrome. Many animal studies document an antiproliferative effect (antioestrogenic), as do some reports in humans. However, there are also data to suggest that, as an antiprogestagen, mifepristone may promote an unopposed oestrogen milieu, and thus have a proliferative effect upon the endometrium.

Tandem CAG repeats of the androgen receptor gene and prostate cancer risk in black and white men

The most common malignancy in men worldwide is cancer of the prostate. Androgens play a direct role in normal and malignant growth of prostate cells via the androgen receptor (AR). This study analyzed the polymorphic CAG repeat sequence in exon 1 of the AR gene to determine if the number of repeats might be an indicator of prostate cancer risk or aggressive disease. DNA was extracted from blood samples of 20 black and 20 white men with well-documented prostate cancer and 40 healthy, controls (20 blacks and 20 whites). PCR amplifications was followed by gel electrophoresis and DNA sequencing. This region normally contains between 9 and 29 repeats. Patients and controls both had minor variations in the number of repeats, which ranged from 13 to 27 with 21 being the most frequent allele. Black controls and patients both had a mean of 20±3, repeats; in whites the mean was significantly lower in patients than controls (21±2 versus 23±2; p=0.004). Combined black and white patients also had a lower number than the combined group of controls (20±3 versus 22±3; p=0.02). Similarly, black and white patients with aggressive disease has a lower number than patients whose disease was more slowly progressive (19±2 versus 22±3; p=0.02). We conclude that the small differences in the number of CAG repeats in both black and white patients do not appear to be a strong indicator of risk or aggressive disease but that this size polymorphism may be one of many genetic and environmental risk factors involved in prostate cancer.

An implant releasing the gonadotropin hormone-releasing hormone agonist histrelin maintains medical castration for up to 30 months in metastatic prostate cancer.

PURPOSEnThe administration of gonadotropin hormone-releasing hormone agonists is well established for treating metastatic prostate cancer. In an ongoing study we evaluated the effect of a long acting implant that releases the gonadotropin hormone-releasing hormone agonist histrelin ([ImBzl]D-His6,Pro9-Net) in 15 patients with disseminated prostate cancer.nnnMATERIALS AND METHODSnThe 2.6 cm. implant releasing 60 microg. histrelin daily is inserted subcutaneously into the upper arm using local anesthesia. Of the patients 8 received 1 and the remainder received 2 implants. Treatment with the antiandrogen flutamide or cyproterone acetate began 2 weeks before implant insertion and continued for up to 12 weeks. Testosterone, luteinizing hormone (LH) and prostate specific antigen were determined monthly, and a metastatic evaluation was performed every 6 months.nnnRESULTSnLH and testosterone increased after flutamide administration and decreased after implant insertion. By day 28 LH and testosterone were completely suppressed. LH and testosterone decreased immediately after cyproterone acetate administration. Prostate specific antigen began to decrease during antiandrogen therapy and decreased further after implant insertion. One patient requested implant removal after 1 year for personal reasons and 1 died of an unrelated cause 18 months after insertion. Escape was demonstrated in 4 cases at 5, 10, 12 and 19 months, although LH and testosterone remained suppressed. Duration of treatment in the remaining 9 patients was between 21 and 30 months. LH and testosterone remained completely suppressed and prostate specific antigen levels were in the normal range. The clinical and biochemical response was identical in those who received 1 or 2 implants. At 12 months 8 patients were challenged at intermittent intervals for up to 24 months with a bolus of 100 microg. gonadotropin hormone-releasing hormone followed by 2 weeks of flutamide. The response was compared with that in untreated controls recently diagnosed with prostate cancer. Unlike controls there was complete LH suppression in the 8 challenged patients.nnnCONCLUSIONSnA histrelin implant suppresses LH and testosterone in prostate cancer for up to 30 months. This finding represents a significant improvement over existing preparations, which must be administered at 1 to 3-month intervals.

THE DECREASED BASAL AND STIMULATED PROLACTIN LEVELS IN ISOLATED GONADOTROPHIN DEFICIENCY: A CONSEQUENCE OF THE LOW OESTROGEN STATE

Prolactin secretion has been evaluated in seven male and six female patients with isolated gonadotrophin deficiency (IGD). The subjects were challenged with the dopaminergic antagonist, metoclopramide (10 mg) and TRH (200 μg) before, during and after cessation of hormonal treatment. Five females received three consecutive 21‐day courses of ethinyl oestradiol (0·1 mg daily) at monthly intervals and the remaining subject conjugated oestrogens (Premarin 0·625 mg daily) according to a similar protocol. Treatment of the males with hCG (pregnyl) 5000 iu twice weekly led to a rise in oestradiol and testosterone levels. Two males were receiving pergonal (human menopausal gonadotrophin) in addition. In the untreated state in both males and females, basal oestradiol and PRL levels were decreased as were the PRL responses to metoclopramide and TRH as compared with normal controls. During treatment in both groups, there was an increase in basal PRL levels as well as PRL response to the two stimuli, which became indistinguishable from the controls. Cessation of treatment was associated with a rapid decrease in basal PRL levels and PRL elevation following metoclopramide and TRH. In contrast to the effect of hCG, the administration of two non‐aromatizable androgens (mesterolone and fluoxymesterone) had no effect on basal and TRH‐induced PRL secretion. The administration of clomiphene citrate during hCG treatment in one male IGD patient produced a decrease in the basal and stimulated PRL response.

Alterations in sex steroids and gonadotropins in post-menopausal women subsequent to long-term mifepristone administration.

Long-term administration of progesterone antagonists (PAs) and progesterone receptor modulators (PRMs) has been proposed as a novel hormonal therapy for various hormone dependent maladies. We studied the long-term endocrine effects of mifepristone on the kinetics of estradiol (E(2)) and its precursors, and on gonadotropin levels in five postmenopausal women treated for unresectable meningioma with mifepristone [200 mg/day] for at least 15 months. Serum samples were analyzed for LH, FSH and SHBG with fluoroimmunoassay; androstenedione (A), testosterone (T), estrone (E(1)) and E(2) were measured with radioimmunoassay (RIA). Serum levels of mifepristone were measured using both RIA and high performance-liquid chromatography (HPLC). Serum levels (mean +/- SD) of LH and FSH were suppressed from pretreatment values of 32 +/- 16 and 65 +/- 30 IU/l to 13 +/- 7 and 33 +/- 16 IU/l at 6 months (P < 0.05), respectively. Serum (mean +/- SD) A, T, E(1), and E(2) were increased from initial values of 6.9 +/- 0.9 nmol/l, 1.2 +/- 0.3 nmol/l, 77 +/- 25 pmol/l, and 29 +/- 14 pmol/l to 6 month values of 13.1 +/- 5.6 nmol/l, 1.8 +/- 0.6 nmol/l, 178 +/- 60 pmol/l, and 45 +/- 22 pmol/l (n.s.). The correlation coefficients between the levels of A, T, E(1), and E(2) were statistically significant, whereas the ratios of T/A, E(1)/A, E(2)/E(1), and E(2)/T remained unchanged. The levels of SHBG remained stable, and ranged from 48 +/- 10 to 65 +/- 9 nmol/l (mean +/- SD). Thus, prolonged mifepristone treatment marginally increased the serum levels of A, T, E(1) and E(2). These effects of mifepristone are likely due to its antiglucocorticoid effect and thus increased secretion of adrenal A. Serum levels of LH and FSH declined. The serum levels of gonadotropins and those of T, E(1) and E(2) were inversely, yet significantly, correlated. Therefore the decrease in LH and FSH might reflect the slightly increased levels of T, E(1) and E(2). However, the lack of change in SHBG and the low E(2) levels suggest that enhanced systemic estrogen effects are unlikely during long-term mifepristone treatment.

CLOMIPHENE CITRATE DOES NOT MODIFY THE EXAGGERATED THYROTROPHIN RESPONSE TO THYROTROPHIN-RELEASING HORMONE OCCURRING IN PRIMARY TESTICULAR FAILURE

Patients with primary testicular failure have increased basal TSH levels and an exaggerated TSH response to TRH in the presence of normal circulating levels of thyroid hormones. In order to evaluate if this TSH profile is an oestrogenrelated phenomenon, sixteen patients with primary testicular failure were challenged with 200 μg TRH prior to and after the administration of clomiphene citrate. The latter was given in a dose of 100 mg/day for 4 weeks to ten patients; 200 mg/day for 4 weeks to three patients and 100 mg/day for 2 months to the final three patients.