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Background: We evaluated patient-reported outcomes (PRO) during neoadjuvant androgen deprivation therapy (ADT) plus external beam radiation therapy (EBRT) followed by either adjuvant continuous ADT (CADT) or intermittent ADT (IADT) for patients with locally advanced prostate cancer (Pca)., Methods: A multicenter, randomized phase III trial enrolled 303 patients with locally advanced Pca. The patients were treated with 6 months (M) of ADT followed by 72 Gy of EBRT, and were randomly assigned to CADT or IADT after 14 M. The PROs were evaluated at sic points: baseline, 6 M, 8 M, 14 M, 20 M, and 38 M using FACT-P questionnaires and EPIC urinary, bowel, and sexual bother subscales., Results: The FACT-P total scores were significantly better (p < 0.05) in IADT versus CADT at 20 M (121.6 vs.115.4) and at 38 M (119.9 vs. 115.2). The physical well-being scores (PWB) were significantly better (p < 0.05) in IADT versus CADT at 38 M (25.4 vs. 24.0). The functional scores were significantly better in IADT than those in CADT at 14 M (20.2 vs18.7, p < 0.05) and at 20 M (21.0 vs.18.9, p < 0.05)., Conclusion: The PRO was significantly favorable in IADT on FACT-P total score at 20 M and 38 M, PWB and functional scores at 38 M., (© 2021 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Background: To date, research has not determined the optimal procedure for adjuvant androgen deprivation therapy (ADT) in patients with locally advanced prostate cancer (PCa) treated for 6 months with neoadjuvant ADT and external-beam radiation therapy (EBRT)., Methods: A multicenter, randomized, phase 3 trial enrolled 303 patients with locally advanced PCa between 2001 and 2006. Participants were treated with neoadjuvant ADT for 6 months. Then, 280 patients whose prostate-specific antigen levels were less than pretreatment levels and less than 10 ng/mL were randomized. All 280 participants were treated with 72 Gy of EBRT in combination with adjuvant ADT for 8 months. Thereafter, participants were assigned to long-term ADT (5 years in all; arm 1) or intermittent ADT (arm 2). The primary endpoint was modified biochemical relapse-free survival (bRFS) with respect to nonmetastatic castration-resistant prostate cancer (nmCRPC) progression, clinical relapse, or any cause of death., Results: The median follow-up time after randomization was 8.2 years. Among the 136 and 144 men assigned to trial arms 1 and 2, respectively, 24 and 30 progressed to nmCRPC or clinical relapse, and 5 and 6 died of PCa. The 5-year modified bRFS rates were 84.8% and 82.8% in trial arms 1 and 2, respectively (hazard ratio, 1.132; 95% confidence interval, 0.744-1.722)., Conclusions: Although modified bRFS data did not demonstrate noninferiority for arm 2, intermittent adjuvant ADT after EBRT with 14 months of neoadjuvant and short-term adjuvant ADT is a promising treatment strategy, especially in a population of responders after 6 months of ADT for locally advanced PCa., (© 2020 American Cancer Society.)

Background: Patients with high Gleason score, elevated prostate specific antigen (PSA) level, and advanced clinical stage are at increased risk for both local and systemic relapse. Recent data suggests higher radiation doses decrease local recurrence and may ultimately benefit biochemical, metastasis-free and disease-specific survival. No randomized data is available on the benefits of long-term hormonal therapy (HT) in these patients. A prospective study on the efficacy and safety of trimodality treatment consisting of HT, external beam radiation therapy (EBRT), and brachytherapy (BT) for high-risk prostate cancer (PCa) is strongly required., Methods/design: This is a phase III, multicenter, randomized controlled trial (RCT) of trimodality with BT, EBRT, and HT for high-risk PCa (TRIP) that will investigate the impact of adjuvant HT following BT using iodine-125 ((125)I-BT) and supplemental EBRT with neoadjuvant and concurrent HT. Prior to the end of September 2012, a total of 340 patients with high-risk PCa will be enrolled and randomized to one of two treatment arms. These patients will be recruited from more than 41 institutions, all of which have broad experience with (125)I-BT. Pathological slides will be centrally reviewed to confirm patient eligibility. The patients will commonly undergo 6-month HT with combined androgen blockade (CAB) before and during (125)I-BT and supplemental EBRT. Those randomly assigned to the long-term HT group will subsequently undergo 2 years of adjuvant HT with luteinizing hormone-releasing hormone agonist. All participants will be assessed at baseline and every 3 months for the first 30 months, then every 6 months until 84 months from the beginning of CAB.The primary endpoint is biochemical progression-free survival. Secondary endpoints are overall survival, clinical progression-free survival, disease-specific survival, salvage therapy non-adaptive interval, and adverse events., Discussion: To our knowledge, there have been no prospective studies documenting the efficacy and safety of trimodality therapy for high-risk PCa. The present RCT is expected to provide additional insight regarding the potency and limitations of the addition of 2 years of adjuvant HT to this trimodality approach, and to establish an appropriate treatment strategy for high-risk PCa., Trial Registration: UMIN000003992.

Purpose: We analyzed the outcome of primary androgen depletion therapy, which has gained more attention as a potential therapeutic option in patients with localized or locally advanced prostate cancer as it has been increasingly implemented despite limited data on its therapeutic impact in Japan and the United States., Materials and Methods: We analyzed data from CaPSURE and the Japanese Prostate Cancer study., Results: In Japan primary androgen depletion therapy has long been the treatment of choice for localized and locally advanced prostate cancer. Based on CaPSURE data the frequency of primary androgen depletion therapy being chosen to treat localized and locally advanced disease is also increasing in clinical practice in the United States. A study of the outcomes of endocrine therapy is currently being performed in Japan by the Japanese Prostate Cancer Study Group., Conclusions: It is important to obtain such information about the role of primary androgen depletion therapy for localized and locally advanced prostate cancer from studies of natural history and clinical trials. It is also important to update practical treatment guidelines.

Objective: Hormone therapy for prostate cancer has empirically prevailed in Japan. We planned to evaluate the trends and outcome of hormone therapy for establishing an adequate guideline., Methods: Patients with prostate cancer who were initially treated by hormone therapy were registered through the J-CaP registration system. This report summarizes the background factors., Results: From January 2001 to October 2003, 17,872 patients were registered from 395 institutes throughout Japan. The background factors of 17,312 patients were analyzed. The 17,872 patients were estimated as composing more than half of newly diagnosed prostate cancer patients in Japan. Of these, 22.9, 35.1, 32.9 and 8.6% belonged to T1, T2, T3 and T4, respectively. For the purposes of hormone therapy, 77.5% was primary hormone therapy. Neoadjuvant setting and adjuvant setting were 18.1 and 4.3%, respectively. About 60% of the hormone therapy was combined hormone therapy with LH-RHa plus anti-androgens., Conclusion: Irrespective of patients' age, TNM, stage of illness, or histological background, the majority of prostate cancer patients in Japan are receiving hormone therapy. It is necessary to evaluate whether this trend is merely a continuation of past experience of Japanese urologists or if there is a difference in the profile of effect and side-effect in the case of Japanese patients compared to therapy given in Westerners.

Objectives: To clarify the basic aspects of the regulation of the prostatic blood supply by antiandrogens, their effect on the prostatic blood supply was studied for both androgen content and morphology of true capillaries in the rat ventral prostate. The effectiveness of antiandrogens on the control of hemorrhagic status in prostatic diseases has been previously reported., Methods: Androgen concentrations in the prostate were quantified after administration of chlormadinone acetate (CMA), finasteride, or flutamide. The prostatic blood supplies were measured after administration of CMA, finasteride, flutamide, or bicalutamide. The alpha-blockers, terazosin and tamsulosin, were included in the study as negative controls. The histologic changes in the capillaries of the ventral prostate were observed, and the luminal area was measured., Results: The prostate dihydrotestosterone concentrations were decreased by the administration of all antiandrogens. Treatment with CMA, finasteride, flutamide, or bicalutamide reduced the prostatic blood supply by 50% to 65%. The parallel reduction in luminal areas of the true capillaries was observed in rats treated with CMA. Treatment with alpha-blockers did not affect the prostate androgen content, prostatic blood supply, or capillary luminal area., Conclusions: The reduction of the prostatic blood supply was suggested to be the result of a decrease in dihydrotestosterone content and the reduction in the luminal area of capillaries. The early reductive effect of antiandrogens on the prostatic blood supply suggests an alternative use for antiandrogens independent of their typical use for prostate volume regression. The results support the basic aspects of the advantage of preoperative treatment with CMA, flutamide, and bicalutamide, similar to finasteride, in reducing perioperative hemorrhage.

Purpose: Chlormadinone acetate and finasteride are androgen suppressive agents clinically used for benign prostatic hyperplasia but their mechanism for inducing prostatic atrophy differs. We investigated the effect of these androgen suppressive agents on prostatic histology and apoptosis using the spontaneous canine benign prostatic hyperplasia model., Materials and Methods: Animals were treated with oral chlormadinone acetate or finasteride for 25 weeks. The prostatic volumes were analyzed every 5 weeks. Prostatic androgen and estrogen concentrations, histological composition and apoptosis were determined at the end of treatment. Apoptosis was measured by in situ labeling of 3' hydroxy ends of the DNA breaks using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling method., Results: There was a similar volume reduction effect with 0.3 mg./kg. chlormadinone acetate daily and 1 mg./kg. finasteride daily. Chlormadinone acetate decreased testosterone and dihydrotestosterone but finasteride decreased only dihydrotestosterone in the prostate gland. The concentration ratio of estradiol-to-total androgen in the prostate was significantly increased in finasteride treated canines. Chlormadinone acetate and finasteride decreased the epithelial and stromal components. The extent of apoptosis observed in the prostate was significantly higher in the chlormadinone acetate group compared to that of the control and finasteride groups., Conclusions: Although a similar effect of chlormadinone acetate and finasteride was observed in the induction of prostatic regression and composition of the histological components, the sustained increase in apoptosis was observed only in chlormadinone acetate treated canines. We suggest that different intraprostatic endocrine environments created by chlormadinone acetate or finasteride, which have different intraprostatic testosterone levels and estradiol-to-androgen ratios, may be responsible for the different outcomes in the extent of apoptosis.

A 62-year-old man was admitted to our hospital because of urinary retention. A digital rectal examination revealed an enlarged, elastic, and hard prostate with an irregular surface. Prostatic biopsy was done and the pathological diagnosis was moderately differentiated adenocarcinoma. He was diagnosed as stage D2 by bone scan and MRI. We gave him 250 mg of fosfestrol intravenously for 13 days. Afterward, he underwent orchiectomy castrate and was given flutamide for two years. His condition has improved and he has experienced no relapse.

It is generally accepted that early human prostate cancers reveal higher androgen dependency than do advanced ones. In the present study, we examined whether the animal model of prostate cancer has already lost androgen dependency at the early stages of carcinogenesis. At experimental week 46, androgen deprivation was induced in rats and the incidences of atypical hyperplasia and cancer were examined in the ventral, dorsolateral prostate, coagulating glands, and seminal vesicles. Androgen deprivation significantly lowered the incidence of atypical hyperplasia in all four organs. As for the incidence of cancer, no significant differences were observed in the coagulating glands and seminal vesicles. Regarding atypical hyperplasia, androgen deprivation significantly decreased the proliferative cell nuclear antigen labeling index in the coagulating gland and seminal vesicles. The presence of cancer was also decreased in the coagulating gland but not in the seminal vesicles. With control group specimens, more intense staining of androgen receptor was observed in atypical hyperplasias than in cancers. Compared with the atypical hyperplasias, the cancers revealed low androgen dependency at the early stages of carcinogenesis. The cancers in the seminal vesicles also revealed higher androgen independency than did those in the coagulating gland.

To elucidate the autoregulation of androgen receptor (AR) by androgen and antiandrogen, Western blot analysis and immunohistochemical study were performed. Castration reduced the immunodetected AR content, and nuclear staining was lost without cytoplasmic staining. Testosterone (T) supplement restored AR content. Quick response of AR content restoring following single administration of T was observed 48 hours after castration. The recovery of AR content detected by Western blot under each condition was accompanied by recovery of the reduced unclear staining intensities in the epithelia. Neither steroidal nor non-steroidal antiandrogens, chlormadinone acetate and flutamide, altered the AR content in normal rat ventral prostate 5, 12, 24 or 48 hours after single administration. Furthermore, neither of the drugs at various doses altered AR levels 12 hours after single administration. In summary, the rat AR is upregulated by androgen. Single administration of antiandrogens have no effect on immunodetected AR content.

The effects of the new steroidal antiandrogen, TZP-4238 on spontaneously-developed canine prostatic hyperplasia (BPH) were studied in comparison with those of chlormadinone acetate (CMA), a steroidal antiandrogen used for the treatment of BPH and prostatic cancer in Japan. Aged beagle dogs (5-9 years old) with spontaneously developed BPH (mean prostate volume, 17.7ml) were treated orally with a placebo, TZP-4238 (0.1 mg/kg/day, 0.01 mg/kg/day), or CMA (3 mg/kg/day), for 25 weeks. Prostate volume was measured by transrectal ultrasonography before treatment and every 5 weeks during treatment. TZP-4238 produced a regression in spontaneously developed canine BPH, its effects being more potent than those of CMA. TZP-4238 reduced the content of testosterone, dihydrotestosterone (DHT) and androgen receptor in the prostates of these animals, suggesting antiandrogenic mechanisms of the agent. TZP-4238 also appeared to reduce 5 alpha-reductase activity by prevention of the androgen action in prostate as described above.

TZP-4238 suppresses plasma testosterone in humans, but its action on the androgen biosynthesis pathway has not been established. Therefore, we researched the testicular testosterone level and the testosterone biosynthesis pathway in vitro in rats before and after receiving a single or continuous oral dose of TZP-4238. The total testosterone fell to 60% of the basal level within 3-8 hr (p < 0.05) and then returned to the control concentration by 24 hr after a single administration of 32 mg/kg. The alteration of the plasma testosterone level correlated well with that of the intratesticular level, which was decreased to 50% at 3-8 hr and recovered to the control level by 24 hr. However, the decrement of the plasma LH level at 3-8 hr after a single oral administration was slight and it then returned to the original level at 12 hr. During the 8 weeks of daily administration of 0.5 mg/kg of TZP-4238 or chlormadinone acetate to dogs, the plasma testosterone levels were slightly lower than the basal extent. In vitro experiments were conducted on the rat testis using the exogenous precursor steroids 20 alpha-hydroxycholesterol, pregnenolone and progesterone, in various steps leading to the biosynthesis of testosterone. Trilostane acted at 3 beta-hydroxysteroid dehydrogenase (50% inhibition concentration, IC50 was 1 microM), ketoconazole inhibited the 17 alpha-hydroxylase, and C20, 22- and C17, 20-lyase activities, with an IC50 of 1-50 microM. Cyproterone acetate inhibited both the 3 beta-hydroxysteroid dehydrogenase (IC50;50 microM) and C17, 20-lyase. On the other hand, TZP-4238 exhibited a weaker inhibition of 3 beta-hydroxysteroid dehydrogenase (IC50; 100 microM) than cyproterone acetate, but not of hydroxylase and lyase. Though TZP-4238 did not inhibit the increased testosterone level induced by hCG, trilostane markedly inhibited the effect induced by hCG.(ABSTRACT TRUNCATED AT 250 WORDS)

TZP-4238, a new steroidal antiandrogen, is an orally active drug in rats and dogs. The effects of TZP-4238 on the androgen receptor and androgen content were examined in comparison with other antiandrogens in rats. The prostate DHT levels decreased markedly within 4-8 hr after a single oral administration of TZP-4238 8mg/kg. The prostatic testosterone concentrations fell below the detection limit (5pg/g of tissue) at 4-12 hr after the initiation of treatment. The plasma testosterone level also fell to 60% of the control level after 4-8 hr and then returned to the normal range. Eight percent of DHT present in normal prostatic tissue was located in the nuclear fraction. TZP-4238 reduced the concentration of DHT in nuclei to 50% of the normal level. The concentration of the plasma drug which induced a 50% decrease in the prostatic DHT, the IC50, was about 10ng/ml, while the IC50 value for plasma testosterone was 30-50ng/ml. After oral administration of 15-OH TZP-4238, the main metabolite, the level of plasma testosterone was significantly elevated above the control level. The androgen receptor level was markedly reduced at 24 hr following castration and returned to the normal range within 5 hr of a single injection of testosterone. TZP-4238 reduced the nuclear androgen receptor level to 60% at 24 hr after a single oral dose and then, the receptor content returned to its original level. Both 15-OH TZP-4238 and cyproterone acetate also reduced the androgen receptor and DHT contents to 50%. A series of in vivo studies demonstrated that TZP-4238 inhibited the uptake of testosterone and the decrease of DHT and testosterone, and decreased the nuclear androgen receptor in the rat prostate.

The effects of sodium-4-[2-(2,3-dimethyl-4-[1-(4-isobutylphenyl) ethoxy]benzolamino)phenoxy]butyrate (ONO-3805), newly developed as a non-steroidal 5 alpha-reductase inhibitor, on rat accessory sex organs was compared with chlormadinone acetate (CMA) and non-steroidal antiandrogen, flutamide (FLU). ONO-3805 demonstrated excellent antiandrogenic activity which was similar to that of CMA in reducing the accessory sex organ weight. Moreover this agent did not show any significant effects on the serum testosterone level, but CMA and FLU changed it significantly. We previously reported the androgenic activity of antiandrogen (CMA, FLU, AA560, cyproterone acetate, medroxy progesterone, estrogen), but ONO-3805 is free of androgenic activity.

It is well known that some adrenal androgens are converted into testosterone and dihydrotestosterone which are more powerful androgens than the adrenal androgens. However, most of the experiments to investigate the antiprostatic agents have been done on rats which secrete only a marginal amount of adrenal androgen. A study was performed to investigate the effects of antiprostatic agents on the action of the adrenals in rats. Non-sterodidal antiandrogens flutamide and 1-chloro-2-hydroxy-2-methyl-N-(3,4,5-trichlorophenyl)propanamide (AA560), steroidal anti-androgens, chlormadinone acetate (CMA) and 17 alpha-acetoxy-6-chloro-2-oxapregna-4,6-diene-3,20-dione (TZP-4238) and 5 alpha-reductase inhibitor, sodium (-)-4[2-[2,3-dimethyl-4-[1-(4-isobutylphenyl)ethoxy]benzolamino ] phenoxy]butyrate (ONO-3805) and N-(2-methyl-2-propyl)-3-oxo-4-aza-5 alpha-androst-l-ene-17 beta-carboxamide (MK-906) were tested in rats treated with dehydroepiandrosterone sulfate (DHEA-S) and androstenendione (A). In the noncastrated rats not treated with DHEA-S and A, all of these agents decreased the accessory organ weights in a dose dependent manner. In the rats treated with LHRH agonist and DHEA-S and A, all agents (3.3 mg/day) showed similar effects in intact rats. However nonsteroidal antiandrogens and TZP-4238 were stronger than the others. It was not clear whether this effect was mediated through the suppression of adrenal androgen action or the inhibition of physiological increase in testosterone caused by an LHRH agonist. The effects of Flu, ONO-3805, CMA and TZP-4238 on the accessory sex organs were investigated in castrated rats receiving DHEA-S and A.(ABSTRACT TRUNCATED AT 250 WORDS)

It was reported that a new steroidal anti-androgen, TZP4238 (17 alpha-acetoxy-6-chloro-2-oxapregna-4,6-diene-3,20-dione), was 10 times stronger than chlormadinone acetate (CMA) as the in vivo anti-androgenic potential. To confirm this result, the effect of TZP4238 and CMA on ventral prostates of intact rats, or castrated ones treated by testosterone, was investigated. Our experiments demonstrated that TZP4238 was 3-5 times stronger than CMA. The effects of this compound on the androgen-receptor complex formation in the human and rat prostates were investigated and compared to the other anti-androgen and related compounds. An aliquot of cytosol or KCl extract from rat or human prostate was incubated with [3H]R1881 in the presence of various tested compounds. By means of dextran coated charcoal assay and sucrose density gradient centrifugation analysis, TZP4238 and TZP4239 showed a stronger inhibitory effect than other compounds except dihydrotestosterone. Judging from all these results, it was estimated that TZP4238 was 2-3 times stronger than CMA. The Scatchard plot analysis revealed that the inhibitory effect of TZP4238 was a competitive type. Between CMA and TZP4238, the difference of in vivo anti-androgenic potential was not identical with that of the inhibitory effect on the androgen-receptor complex formation.

To investigate the efficacy and the safety of RU23908 for the treatment of prostatic cancer, an early phase 2 study with the oral administration of 150 or 300 mg daily was performed in 47 patients with stage C or D prostatic cancer at 15 institutions from April 1987 to June 1988. Forty patients were evaluable for efficacy. Concerning the effect on the object lesion, the results of the overall evaluation revealed that complete or partial response (CR + PR) was obtained in 34 of the 40 cases (85.0%). As to the effect classified by site, CR + PR were observed in 35 out of the 40 cases with primary lesion (87.5%), in 10 of the 22 cases with bone metastasis (45.5%), in 5 of the 6 cases with lymph node metastasis (83.3%) and CR was observed in one case with lung metastasis. In the PAP evaluation, 33 out of the 34 cases were judged to be CR + PR (97.1%). The improvement rate of clinical symptoms was 88.9% for bone pain, 83.3% for dysuria and 45.5% for performance status. Adverse reactions were observed in 29 of the 47 cases (61.7%) investigated and 7 cases (14.9%) were withdrawn. During the study period of 12 weeks and the subsequent period of continued administration, 6 cases (12.8%) and 2 possible cases of interstitial pneumonia were diagnosed. From the above results, the treatment of prostatic cancer with RU23908 150 mg/day or 300 mg/day in combination with surgical castration showed an excellent clinical effect compared to conventional endocrine therapy, but has a problem of safety. Therefore, this drug may be expected to be a highly useful therapeutic drug, if safely is improved in the future by reviewing the dose.

The effect of a synthetic steroidal anti-androgen, TZP-4238, on steroid-induced canine prostatic hyperplasia was studied by light and electron microscopy. Male beagle dogs (1-2 years old) were divided into four experimental groups. Group 1 consisted of intact controls. The other animals were castrated. The castrated animals were treated for 25 weeks with 1) 5 alpha-androstane-3 alpha, 17 beta-diol (A-diol) plus 17 beta-estradiol (E2) (Group 2), 2) A-diol plus E2 + TZP-4238 0.5 mg/kg (Group 3) and 3) A-diol plus E2 + chlormadinone acetate (CMA) 2.5 mg/kg (Group 4). TZP-4238 and CMA were administered orally for 21 weeks after 4 weeks treatment with A-diol plus E2. In group 2, glandular hyperplasia of the prostate was clearly noted. In contrast, combined treatment with TZP-4238 (Group 3) or CMA (Group 4) produced marked atrophy of the glandular epithelium. Loss of secretory and metabolic activities was confirmed by ultrastructural investigations. Our data indicate that TZP-4238 is a potent anti-androgen for the prevention of canine prostatic hyperplasia in the steroid-induced benign prostatic hyperplasia (BPH) model.

To investigate the androgenic activity of steroidal and nonsteroidal anti-androgens, the effect of several compounds on some parameters as an androgenic activity was measured in the ventral prostate (VP) and seminal vesicle gland (SV) of castrated male rats. Ornithine decarboxylase (ODC) activity, arginase activity, androgen receptor (AR) in cytosol and nucleus, histological examination and weight of accessory sex organs were used as parameters for androgenic activity. The ventral prostate weight was increased by the administration of not only steroidal anti-androgen, medroxyprogesterone (MPA), chlormadinone acetate (CMA) and cyproterone acetate (CPA), but also estradiol-17 beta(E2) and nonsteroidal anti-androgen, AA 560. However flutamide (Flu) failed to increase VP weight. In SV, the tendency to increase weight by the administration of these compounds was also observed. However, it was not obvious as in VP. It was proven by the measurement of the parameters that all tested compounds except Flu had an androgenic activity. It seems that the androgenic activity was caused by a different mechanism because the parameter response to the administrated compounds was not identical.

Transrectal ultrasonotomography is useful in following patients with benign prostatic hypertrophy, because prostatic shape and weight are precisely assumed. We studied the effect of chlormadinone acetate (CMA) on benign prostatic hypertrophy. CMA (50 mg/day) was administered to 30 patients with benign prostatic hypertrophy. Weight reduction over 10% of the gland was noticed in 24 cases (80%). Mictional conditions were improved in 70% subjectively and in 71.4% objectively. However, the number of nocturia decreased in only 18.9%. Reduction rate of the weight was unrelated with the weight of prostate before administration of CMA. Duration of administration of CMA and the reduction rate were estimated. There was no definite difference in reduction rate for the first 15 months, but there was a slightly high reduction rate after administration of CMA for more than 24 months. In 3 cases, the shape and weight of prostate were studied after discontinuation of CMA. The size of prostate showed a tendency to increase gradually.

The antiandrogenic properties of a new nonsteroidal antiandrogens, AA560 (N-2-chloromethyl-2-hydroxypropionyl)-3, 4, 5-trichloroaniline) were investigated. The ventral prostate, dorselateral prostate and coagulating gland weights in rats given AA560 at 1-9 mg/head were significantly less than those in the intact rats. The seminal vesicle weights in rats given 3-9 mg/head were significantly less than those of the intact group. In intact animals given daily 3 or 9 mg of AA560 there were significantly increases of serum FSH, LH and testosterone concentrations. In the in vivo experiment, the pretreatment with AA560 decreased the uptake of 3H-androgens in the nuclear fraction of the ventral prostate. On the other hand, a significant increase in the uptake of 3H-radioactivity in the cytosol fraction was observed. It was proved by the in vitro displacement study that AA560 inhibited the binding of 5 alpha-dihydrotestosterone with a receptor protein in the prostatic cytosol.

A radiation polymerized drug-vinyl copolymer delivery composite (0.8 mm in diameter, 3 mm long) was inserted into the right-lobe ventral prostate (I), into the right testis (II), and subcutaneously (III) into the back of male Wistar rats. The implantation was carried out over a period of 12 weeks maximum. From the relationship between the site of surgical insertion of the implant and the physiologic response (as measured by the decrease in the weight of the prostatic organs, e.g., ventral prostates, dorsolateral prostates, and seminal vesicles), it was found that in an AA560-containing composite (36 micrograms daily), the physiologic response is increased in order of (III) greater than (II) greater than (I). The same tendency was observed in the Estracyt-containing composite system (15 micrograms daily). The difference in the physiologic response owing to the site of surgical insertion of the implant was not observed in an E2-17 beta-containing composite (6 micrograms daily), although this composite showed the strongest physiologic response. No physiologic response in rats with CMA-containing composite (28 micrograms daily) was noted.

The anti-androgen activity of allylestrenol was studied in the rat, and it was found to have an activity which was equivalent to that of chlormadinone acetate. The direct anti-prostatic activity is the result of the following mechanism: inhibition of serum testosterone uptake into the prostate, inhibition of testosterone-5 alpha-reductase activity and inhibition of 5 alpha-DHT . receptor complex formation. Large doses of allylestrenol administered to normal mature rats, inhibit the hypothalamus-pituitary-gonadal axis, and atrophy of the prostate will be more marked due to an indirect effect as a result of the reduction in the serum testosterone level. Based on this finding, we performed a clinical trial with allylestrenol in patients with hypertrophy of the prostate and cancer of the prostate. We administered 45 mg a day allylestrenol to 19 patients with prostatic hypertrophy and obtained satisfactory clinical results in so far as improvement of micturition and reduction in prostate mass was concerned. We also administered 90 mg a day of allylestrenol to 4 patients with cancer of the prostate and obtained a cytostatic effect.

The possible mechanisms for the antiprostatic effects of a nonsteroidal antiandrogen, SCH 13521 (4'-nitro-3'-trifluoromethylisobutyranilide), were investigated in rats and dogs. The influence of administered SCH 13521 on the deposition of the radioactivity associated with labeled testosterone, dihydrotestosterone, and estriol (E-3) in the prostate and other tissues of the dog, and rat was determined in short term experiments. SCH 13521 definitely interfered with the localization of the radioactivity of these steroids in the prostate and indicated a competitive situation between SCH 13521 and the steroids. Even though in vitro binding data were generally in accord with in vivo results, he descrepancies regarding E-3 and the more intense effects of SCH 13521 observed in vivo, as compared to those in vitro, lead us to suggest that a metabolite of the compound may also play an important competitive role in vivo. Of particular interest was the competition between SCH 13521 and estrogens in vitro (estradiol-17-beta) and in vivo (E-3). Sch 13521 greatly decreased the volume of prostatic secretion whereas id minor effects on prostatic 5-alpha-reductase and arginase activities. The latter is surprising, since both enzymes are very highly androgen-dependent. Thus, even though the mechanisms of action of SCH 13521 on the prostate may involve competition with androgens at the cellular level, we think that its competition with some estrogens points to a more complicated action than observed with other antiandrogens.

The efficacy of cytotoxic agents in the treatment of prostatic cancer is difficult to evaluate because objective, measurable lesions, such as lung, liver, skin, subcutaneous and nodal metastasis are often not found. However, most of the patients with advanced prostatic cancer have bone involvement and elevated serum acid-phosphatase in addition to the primary tumor. Exact clinical trials on such cases, especially phase II studies can not be performed without appropriate evaluations of these three parameters. The criteria of these three parameters offered by various study groups are reviewed and the relevant response criteria are proposed. A stable category was thought to be useful to evaluate the efficacy on the patients with progressing disease. In our proposal, overall assessment of response involves all objective parameters including these three parameters as well as both measurable and unmeasurable disease described in the WHO handbook for reporting results of cancer treatment.

We studied the progressive factors for incidental carcinoma of the prostate of 38 patients. Effects of anti-androgen drugs for the development of incidental carcinoma were examined. There were no statistical differences with age, tumor size, histopathological grade, or invasion of BPH capsule. However, the tumor progression rate was high for a tumor size of more than 10 mm or poorly differentiated adenocarcinoma. Therefore, tumor progression was related with tumor size and histopathological grade. Of 15 patients with stage A1 disease, two patients had tumor progression. Patients with stage A1 disease are being followed with no treatment, but radical treatment may be necessary for young men. Patients with stage A2 disease must be treated with radical prostatectomy, radiation therapy or hormone therapy case by case. None of the patients who were treated with anti-androgen drugs had stage A1 disease. Patients not treated had stage A1 and A2 diseases. Anti-androgen drugs may have inhibited the development of stage A1 disease.

The binding of 5alpha-dihydrotestosterone to the hypophyseal and hypothalamic cytosol macromolecules prepared from castrated male rats was observed. The effects of antiprostatic agents on 5alpha-dihydrotestosterone binding to both hypophyseal and hypothalamic cytosol macromolecules was examined. Cyproterone acetate and chlormadionone acetate showed the significant inhibiting effects on 5alpha-dihydrotestosterone binding to 7-8 S macromolecules of cytosol from both hypophysis and hypothalamus. SCH 13521 and AA 560 did also affect 5alpha-dihydrotestosterone binding to 7-8 S macromolecules of cytosol from both tissues.