Disease flare induced by luteinising hormone releasing hormone analogues in cancer patients

Long term follow-up of patients with advanced prostatic cancer treated with nasal buserelin

Sixty one men, with advanced prostatic cancer, were entered on a trial using a nasally administered gonadotropin-releasing hormone analogue agonist, buserelin, as first line treatment. This is the first trial to use intranasal buserelin without primary injections and without antiandrogens. No 'flare' phenomenon was observed. The only side effects were hot flashes (69%) and decreased libido (25%). The response rate of 82%, with a median response duration of 16 months, compares favourably to responses reported with orchidectomy or estrogens. Serum testosterone, FSH and LH were monitored at regular intervals. Mean serum testosterone baseline values of 15 nmol/L decreased to castrate levels, and remained low while patients were on study. It is concluded that intranasal buserelin is an effective, simple and safe method to achieve androgen deprivation and is an alternative to orchidectomy in the treatment of advanced prostatic cancer.

Effect of adrenalectomy, flutamide, and leuprolide on the growth of the Dunning rat R-3327 prostatic carcinoma

The R-3327 prostatic tumor implanted in the male Copenhagen x Fischer F1 rat continues to grow because androgen is being supplied from an endogenous source. It follows that regimens which decrease the availability of androgen will retard the growth rate of the tumor. These experiments showed that castration, the antiandrogen flutamide, and the luteinizing hormone-releasing hormone (LHRH) agonist leuprolide inhibited tumor growth. Adrenalectomy alone had no significant effect on tumor size and did not further retard the growth of the tumor in castrated rats. Further, under the conditions of this study, there was no significant difference in tumor growth rates between the groups of rats treated with either flutamide alone or flutamide combined with leuprolide. Total ablation of androgen may not be needed for maximal inhibition of tumor growth.

Zoladex (ICI 118,630): clinical trial of new luteinizing hormone-releasing hormone analog in metastatic prostatic carcinoma

Twenty-seven patients with metastatic adenocarcinoma of the prostate were treated with the new luteinizing hormone-releasing hormone analog, Zoladex (ICI 118,630) for up to ninety-eight weeks. Initially, treatment was randomized between Zoladex 250 micrograms and 500 micrograms self-injected subcutaneously every day for a minimum period of twelve weeks following which a sustained-release, once-monthly depot formulation of Zoladex 3.6 mg s.c. was used. Acute rises in serum gonadotropins and testosterone during the first two days were followed by declines in hormone levels over the following three weeks. Median time to castration with 500 micrograms/day was twenty-two days compared with forty-three days with 250 micrograms/day (p = 0.06). No significant endocrinologic changes occurred during the transfer to the depot, and serum testosterone remained 95 per cent suppressed throughout the duration of the study. After three months the median daily serum Zoladex concentrations ranged between 0.47 and 0.53 ng/ml and were not significantly different among the three dosage forms. No specific correlation among serum Zoladex concentrations, endocrinologic parameters, and tumor response rates were found. Hot flashes initially, and decreased libido were the only common complaints. Zoladex was well tolerated, and no side effects required dose-modification or removal from the study. Tumor response rates up to one year appeared to be comparable to the conventional endocrine therapies. This analog in monthly depot formulation is recommended for further clinical evaluation.

Long-term results with a long-acting formulation of D-TRP-6 LH-RH in patients with prostate cancer: an Italian prostatic cancer project (P.O.N.CA.P.) study

Ninety-five patients with stage C (C1 + C2) or D (D1 + D2) prostatic carcinoma were treated with the depot formulation of D-TRP-6 LH-RH ("Decapeptyl") for up to 33 months. Serum testosterone (T) levels were significantly reduced to castration levels within 4 weeks and maintained persistently low. Similarly, LH levels were decreased, although they remained in the normal range. Stimulation tests with either Gn-RH or HCG in course of treatment showed the achievement of a complete pituitary desensitization and almost a complete down-regulation of testicular LH receptors. Of 88 patients evaluable for response, about one-half showed an objective response. In most cases, subjective improvement with relief of bone pain and/or urinary symptoms was obtained without major side effects. These results indicate that the depot formulation of D-TRP-6 LH-RH offers an effective therapeutic alternative for patients with advanced prostatic cancer.

Phase II trial with D-Trp-6-LH-RH in prostatic carcinoma: comparison with other hormonal agents

Various approaches to hormonal treatment of prostate carcinoma are discussed. Eighty-one patients with prostatic carcinoma, eight with stage B, nine with stage C, and 64 with stage D disease, were treated subcutaneously daily for 3 months with the LH-RH agonist D-Trp-6-LH-RH (Decapeptyl) in order to evaluate the incidence of remissions according to WHO recommendations for oncologic trials. The findings were compared to those obtained with other hormonal therapies of prostatic carcinoma according to the statistical method of "expected response rate" as adapted by Lee and Wesley for phase II trials. Treatment with D-Trp-6-LH-RH greatly reduced serum LH and testosterone levels without raising serum prolactin. After 1-2 weeks of therapy, there was relief of subjective symptoms and a reversal of the signs of prostatism as well as a marked decrease in bone pain. At 90 days 52 patients had complete relief of prostatism and 21 had only mild signs and symptoms. Seventy patients were experiencing no bone pain and an additional six had only mild pain. Prostatic size, evaluated by rectal examination and transabdominal ultrasonography, reverted to normal in 26.4% of patients (complete remission) and was reduced by more than 50% in an additional 17.6% (partial remission), the overall rate of complete plus partial regression of prostatic enlargement being 44%. Scans showed a major improvement of bone lesions in 14.8% of cases. This response increased to 37% after more than 6 months of follow-up. Prostatic acid phosphatase levels were decreased by more than 50% in 61% of the patients, but this test appears to be a less valid marker than the lipid-associated sialic acid (LASA). The increase in LASA before treatment and a reduction after treatment can frequently be correlated with the objective volume of the neoplasms. No flare-up of the disease was encountered, and there were no side effects except for impotence. Statistical analyses of results by the method of Lee and Wesley indicated that the incidence of complete and partial regression (CR and PR) observed with D-Trp-6-LH-RH was not significantly different from that recorded in previous studies for another LH-RH analog, Buserelin. However, CR and PR obtained with D-Trp-6-LH-RH (44%) were significantly higher than with subcapsular orchiectomy (22%). Hormonal effects and some other actions of D-Trp-6-LH-RH were compared and contrasted with those produced by castration, estrogens, antiandrogens, and progestogens.(ABSTRACT TRUNCATED AT 400 WORDS)

Investigation of the combination of the agonist D-Trp-6-LH-RH and the antiandrogen flutamide in the treatment of Dunning R-3327H prostate cancer model

The therapy for the treatment of prostate cancer and other sex-steroid-dependent tumors based on agonists of LH-RH has been made more practical and efficacious by the development of a long-acting formulation of microcapsules of D-Trp-6-LH-RH for controlled release. Antiandrogens, which neutralize the effect of endogenous androgens, have been used also in the management of prostate cancer in man. The effects of a simultaneous administration of the antiandrogen flutamide and microcapsules of the agonist D-Trp-6-LH-RH were studied in the Dunning R-3327H rat prostate adenocarcinoma model to determine whether the combination of these two drugs might inhibit tumor growth more effectively than single agents. Microcapsules of D-Trp-6-LH-RH, calculated to release a controlled dose of 25 micrograms/day for a period of 30 days were injected intramuscularly once a month. Flutamide was administered SC at a daily dose of 25 mg/kg. The therapy was started 100 days after the tumor transplantation and continued for 60 days. Tumor weights and volumes were significantly reduced in rats treated with microcapsules or flutamide alone, but the former drug inhibited tumor growth more than the latter. The combined treatment of flutamide and microcapsules significantly decreased tumor weight and volume, but did not exert a synergistic effect on tumor growth, the reduction being smaller for the combination than for the microcapsules alone. There was a significant elevation of serum testosterone, LH, and prolactin in rats treated with flutamide. On the other hand, in rats given microcapsules of D-Trp-6-LH-RH, testosterone fell to castration levels within 7 days and remained at nondetectable values, serum LH and prolactin levels being also suppressed in this group. The combined administration of microcapsules and flutamide also significantly decreased serum testosterone to nondetectable levels by day 7 and suppressed serum LH and prolactin. Our findings raise doubts of whether the daily administration of the combination of LH-RH agonist with an antiandrogen offers an advantage over the use of microcapsules of an agonist like D-Trp-6-LH-RH alone in the treatment of prostatic carcinoma.