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Immunological evaluation of individualized peptide vaccination with a low dose of estramustine for HLA-A24+ HRPC patients.

BACKGROUND: The safety, toxicity, and immunological response of individualized peptide vaccination or human leukocyte antigen (HLA)-A24+ hormone refractory prostate cancer (HRPC) patients in combination with a low dose of estramustine were evaluated. METHODS: Sixteen patients with HLA-A24+ HRPC were enrolled in the phase I/II study. Conducted immune monitorings for those patients were peptide-specific cytotoxic T lymphocyte (CTL) precursor analysis by interferon-gamma production and peptide-reactive immunoglobulin G (IgG) by an enzyme-linked immunosorbent assay. Clinical responses and quality of life (QOL) outcomes using a self-reported patient questionnaire were also evaluated. RESULTS: Vaccinations were well tolerated, but all patients developed grade 1 or 2 local redness and swelling at the injection site. There was no significant immunosuppression in most cases when the peptide and a half dose (280 mg/day) of estramustine were administrated. Augmentation of peptide-specific CTL precursors or peptide-specific IgG was observed in 10 of 14 or 7 of 14 patients at 12 weeks (peptide vaccination alone), and in 6 of 8 or 10 of 12 patients at 24 weeks (during the combination therapy), respectively. All 13 patients treated, with the combination therapy, showed a decrease of serum prostate-specific antigen (PSA) level from the baseline, including six patients with a serum PSA level decrease of >or=50%. QOL outcomes were not deteriorated during the treatment. CONCLUSION: These results might encourage the further evaluation of the combination of peptide vaccination and a low dose of estramustine phosphate for HLA-A24+ HRPC patients.

Aged↗

Effect of treatment on the expression of estramustine-binding protein (EMBP) in prostatic cancer patients: an immunohistochemical study.

Estramustine-binding protein (EMBP) was determined immunohistochemically in prostatic cancer (PC) specimens taken from patients before and after therapy. The EMBP staining intensity was correlated with the tumor malignancy grade in untreated PCs. The effect of various treatments (i.e., androgen-withdrawal therapy, treatment with estramustine phosphate or radiation) on the expression of EMBP was also investigated. Although a rabbit polyclonal antiserum raised against rat EMBP was used all through the study, all untreated PCs (n = 53) examined so far displayed a positive immunoreaction. The staining intensity was higher in moderately and poorly differentiated than in well-differentiated tumors. Furthermore, two types of staining patterns were observed, that is, a diffuse type in about 70% and a focal in the remaining cases, which might reflect the multifocal appearance of PCs. The prognostic significance of these staining patterns is discussed. Irrespective of the treatment used, EMBP staining was reduced to lower or undetectable levels in PCs where cytological as well as clinical regression were indicated after 6-30 months of therapy. In nonresponders or patients with refractory disease, however, EMBP expression reappeared and returned to pretreatment levels. In a short-term follow-up, the diminuation of EMBP was evident as early as 10 days after androgen-withdrawal therapy and persisted as long as the patient responded to therapy. When estramustine phosphate was given as secondary treatment to hormone refractory PCs, EMBP decreased to undetectable levels in 3/4 of the specimens, suggesting response to therapy. In conclusion, a decreased EMBP staining was well correlated with favorable cytological regression as well as with clinical regression, whereas unchanged staining intensity was indicative of clinical progression and a poor cytological regression grade. The high levels of EMBP in moderately and poorly differentiated tumors as well as in relapsing PCs, despite continued androgen withdrawal, strongly support a regulation of EMBP that is not under androgenic control. Based on the present findings, we suggest the use of EMBP as a therapy marker. Provided that immunohistochemical measurements can be performed on fine-needle aspirates, EMBP analysis may be a direct and early means to distinguish between responding patients and nonresponders.

Carrier Proteins↗

Inhibition of prostate cancer growth by estramustine and colchicine.

Hormone-refractory prostate cancer continues to be associated with a very poor prognosis. Agents that inhibit microtubule function have been found to be cytotoxic to prostate cancer cells in preclinical and clinical settings. It was the aim of this study to assess the activity of estramustine and colchicine, two microtubule inhibitors, in hormone-refractory prostate cancer. In clinically achievable concentrations, the combination of estramustine and colchicine was cytotoxic to both the Dunning rat prostate adenocarcinoma cell line MAT-LyLu (MLL) and human prostate cancer cells (PC-3). Microtubule function was assessed in vitro to evaluate possible mechanisms of action. In motility and cell cycle analysis assays, estramustine and colchicine inhibited cellular motility but not cell cycle transit. In vivo, these two agents both inhibited the growth of implanted Dunning rat prostate adenocarcinoma MLL cells but did not appear to have additive effects. The use of oral colchicine in the treatment of hormone-refractory prostate cancer requires further investigation.

Adenocarcinoma↗

Purification of estramustine-binding protein and production of monoclonal antibodies to its different components.

Estramustine-binding protein (EMBP) is a heterodimeric 46-kDa glycoprotein that is secreted from the prostate. Upon reductive cleavage it decomposes into two closely related components, C1 and C2, and the shared glycosylated peptide C3. EMBP binds estramustine and estromustine, the active metabolites of estramustine phosphate (Estracyt), which is a drug with antimitotic properties used in the treatment of prostatic carcinoma. In the present study, a two-step procedure (i.e., anion-exchange and Con A-Sepharose chromatography) is described for the isolation of EMBP in high yield from rat prostate tissue. Mouse monoclonal antibodies (mAbs) were produced using the major DEAE-Sepharose fraction of EMBP as an immunogen. Eleven mAbs were selected by screening in a solid-phase ELISA. One displayed high-affinity binding with soluble EMBP (Ka approximately 3 x 10(10) M-1) and crossreacted with a human prostate tumor extract in a radioimmunoassay. The epitopes defined by these mAbs were analyzed by Western immunoblotting. All constituents of EMBP, except component C1, were identified by at least one antibody. Nine visualized either one or both of the two EMBP subunits under denaturing conditions, two of which retained their reactivity after reduction of disulfide bridges. One epitope was exposed to its mAb only when the antigen was in its reduced state. The immunoreactivity was eliminated by protease treatment, whereas deglycosylation with glycopeptidase F had a minimal effect. EMBP has been detected in tissues other than the prostate as well as in prostate neoplastic specimens and in several other human malignancies. Hence, these mAbs will be a useful tool in the characterization of EMBP in different tissues and in evaluating existing and in defining new indications for Estracyt therapy.

Animals↗

Impairment of estramustine phosphate absorption by concurrent intake of milk and food.

The effect of milk and food on the pharmacokinetics of estramustine phosphate was investigated in six patients with prostatic cancer. In a randomized three-way cross-over study, the patients were given single doses of the drug together with low calcium water, low calcium food and milk. The evaluation was based upon the plasma concentration of two metabolites, estromustine and estrone, as parent drug could not be detected in plasma. The tmax and lag time of estromustine were significantly increased by milk and food intake and Cmax and AUC were significantly decreased. In comparison with water, the AUC of estromustine was 41% when the drug was taken with milk and 67% after simultaneous intake of standardized food. Corresponding figures for the peak values were 32 and 57%, respectively. The effect of milk and food intake on the pharmacokinetics of estrone was similar. Studies in vitro demonstrated that the dissolution of estramustine phosphate disodium was markedly impaired in the presence of calcium. It was concluded that the rate and extent of absorption of estramustine phosphate were decreased when the drug was taken with milk or food due to the formation of a poorly absorbable calcium complex. To obtain high and reproducible absorption of Estracyt, the drug should not be taken together with milk, milk products or other calcium-rich food or drugs.

Aged↗

Pharmacokinetics of estramustine phosphate (Estracyt) in prostatic cancer patients.

The pharmacokinetics of estramustine phosphate (EMP) was studied in five prostatic cancer patients given single i.v. and oral doses of EMP in a cross-over study. Plasma and urinary concentrations of parent drug, estramustine, estromustine (the estrone analogue), estradiol and estrone were followed by 32 h. The elimination of intravenous EMP from plasma was biphasic. The mean volumes of distribution were small, being 43 and 108 ml/kg for the central and peripheral compartments, respectively. The plasma clearance was 64 ml/kg/h, and the half-lives of the two phases were 0.16 and 1.27 h. Metabolism was the major route of elimination of EMP. It was readily dephosphorylated and oxidized to yield the cytotoxic metabolites estramustine and estromustine. Estromustine was the main metabolite in plasma. When given orally EMP underwent extensive presystemic dephosphorylation, which started in the gastrointestinal tract. The relative bioavailability of estromustine after administration of EMP-capsules was 44%, which reflects incomplete absorption of EMP rather than first-pass metabolism of estromustine. The terminal half-life of estromustine was 10-20 h, which suggests that EMP might be given once or twice a day.

Administration, Oral↗

Metabolism of estramustine phosphate (Estracyt) in patients with prostatic carcinoma.

Plasma samples from patients with prostatic cancer under oral treatment with estramustine phosphate (Estracyt) were quantitatively analyzed for the presence of the parent drug and some of its possible metabolites. Specific methods based on radioimmunoassay and gas chromatography-mass fragmentography were used. Dephosphorylation and oxidation at the 17-position of estradiol were shown to be the major metabolic routes. The estrone analogue of estramustine was found to be the main metabolite in plasma. Elevated levels of estradiol and estrone showed that hydrolysis of the carbamic ester also occurred in these patients. Their estrogen levels were compared with those of another group of prostatic cancer patients receiving conventional hormonal therapy, polyestradiol phosphate (Estradurin). Similar concentrations of estradiol were found in the two groups but the concentrations of estrone were higher in patients given estramustine phosphate.

Aged↗

Estramustine phosphate--hormone, chemotherapeutic agent, or both?

Estramustine phosphate, a combination steroid and alkylating agent, has been used for treatment of cancer of the prostate since 1969. We treated 32 patients with Stages C and D prostate cancer with this compound. Using the National Prostatic Cancer Project criteria of response, no patient achieved complete or partial objective response. Sixty-two per cent of the patients without prior hormonal manipulation and 12 per cent of those who were progressing following hormonal therapy met the criteria for a stable response. Both Stage C patients, 50 per cent of D1 and 28 per cent of D2 patients achieved disease stabilization for a mean duration of 14.8 months. There was no correlation between tumor grade and response to treatment. Fifty per cent of the patients whose elevated acid phosphatase declined remain stable, whereas 80 per cent in whom the acid phosphatase did not decline have progressed. Estramustine is effective in patients without prior hormonal manipulation. In those refractory to hormones, the prognosis is poor yet data exist to support the superiority of estramustine phosphate over conventional therapy.

Aged↗

Estramustine binding site in human breast cancer biopsy samples. Its relation to estrogen and progesterone receptor levels, age and menopausal status.

Estramustine is a cytotoxic metabolite of estramustine phosphate (Estracyt), which is used in the treatment of prostatic carcinoma. An estramustine binding site (EMBS) at pH 4.8-4.9 was demonstrated in 74 of 306 (24%) breast cancer biopsy samples using isoelectric focusing in polyacrylamide gels. The presence of EMBS was significantly (P less than 0.001) correlated with negative or low estrogen and progesterone receptor values. EMBS positivity was found in 31% of the samples from pre- and perimenopausal patients and in 22% of the samples from postmenopausals. If patients were instead divided into different age groups, EMBS positivity was most frequent in samples from patients between 50 and 59 years of age (42%). With increasing age the percentage of EMBS positivity fell successively. For patients under 50 years, no difference with respect to EMBS positivity between age groups could be demonstrated. The possible value of EMBS determinations in breast cancer tissue specimens for the selection of those patients that will respond to Estracyt therapy should be evaluated.

Adult↗

Amiloride but not bumetanide protects against the cytotoxic effects of estramustine and bleomycin in cultured fibroblasts.

The effects of the clinically used diuretics amiloride (an inhibitor of Na+/H+ exchange) and bumetanide (an inhibitor of Na+, K+, Cl- co-transport) were tested on the cytotoxicity of estramustine and bleomycin in cultured fibroblasts. Both estramustine (50 micrograms/ml) and bleomycin (10 micrograms/ml) reduced the number of surviving clones. Amiloride (100 microM) but not bumetanide (100 microM) partly protected against the cytotoxic effect of both estramustine and bleomycin. The protective effect of the combination of amiloride and bumetanide was not stronger than the effect of amiloride alone. Amiloride or bumetanide alone did not affect the clonal survival. It is suggested that the protective effect of amiloride is not mediated by an effect of the molecular mechanism of cytotoxicity but may rather be due to changes in cellular metabolism and/or drug handling.

Amiloride↗

Identification of potassium flux pathways and their role in the cytotoxicity of estramustine in human malignant glioma, prostatic carcinoma and pulmonary carcinoma cell lines.

Clinically-used drugs such as furosemide, bumetanide and cardiac glycosides, are modulators of transmembrane fluxes of cations. Recently, it has been suggested that the regulation of intracellular cation concentrations could be a primary target for anti-neoplastic drugs, and that the cytotoxic activity may be altered by inhibitors of cation fluxes at the level of the plasma membrane. Therefore, we investigated the mechanisms by which cations are translocated across the plasma membrane of malignant glioma (U251 MG), prostatic carcinoma (PC3) and pulmonary carcinoma (P31) cell lines. The interactions between cation flux inhibitors and the cytotoxicity of estramustine were also evaluated. Ouabain, the classical inhibitor of Na+, K+ATPase, markedly reduced 86Rb (K+) influx in all three lines, indicating that this ion transport system is present in the cells. Furosemide and especially bumetanide inhibited the 86Rb influx, indicating the presence of the Na+, K+, Cl- co-transport system. The potassium channel blocker, tetraethylammonium, but not apamin reduced the influx of 86Rb showing that high conductance K+ channels are present, but that channels of low conductance probably do not exist in these cell lines. The Na+, K+, Cl- co-transport inhibitors furosemide and bumetanide significantly reduced cytotoxicity of estramustine in P31 cells, whereas no interaction between other K+ flux inhibitors and the anti-neoplastic drugs were detected in any of the cell lines investigated. Thus, the data show that Na+, K+, ATPase and NA+, K+, Cl- co-transport systems and K+ channels of high conductance are present in malignant glioma (U251 MG), prostatic carcinoma (PC3) and pulmonary carcinoma (P31) cell lines, and that inhibition of the Na+, K+, Cl- co-transport system in P31 is associated with reduced cytotoxicity of estramustine. The results justify further studies evaluating the role of these cation flux pathways in terms of targets for anti-neoplastic therapy.

Bumetanide↗

The combination of estramustine, vinorelbine, and mitoxantrone in hormone-refractory prostate cancer: a Phase II feasibility study conducted by the Hellenic Cooperative Oncology Group.

OBJECTIVES: To evaluate the safety profile and therapeutic value of the combination of estramustine, mitoxantrone, and vinorelbine in the treatment of hormone-refractory prostate cancer. METHODS: Fifty-two patients with hormone-refractory prostate cancer were included in the study. Median age was 70 years (range, 49 to 100 years), World Health Organization performance status ranged from 0 to 2. The treatment schedule consisted of estramustine capsules (140 mg 3 times daily on days 1 to 3 and days 8 to 10 per os), intravenous mitoxantrone (12 mg/m2 on day 2), and intravenous vinorelbine (25 mg/m2 on day 2 and day 9), given in a 3-week cycle. RESULTS: Thirty-one percent of patients with measurable soft-tissue disease demonstrated an objective response, which included six complete and ten partial responses in all involved organs (bone responses not included). Twenty-nine patients (56%) had a greater than 50% reduction in serum prostate-specific antigen level. The median duration of response was 6.9 months, and the median survival for all patients was 14.5 months. CONCLUSIONS: The combination of estramustine, vinorelbine, and mitoxantrone is safe, well tolerated, and relatively active in patients with hormone-refractory prostate cancer.

Aged↗

Association of estramustine resistance in human prostatic carcinoma cells with modified patterns of tubulin expression.

Estramustine (EM) is an antimicrotubule drug used in the treatment of hormone refractory advanced prostate cancer. To investigate the mechanism of resistance to EM, we compared its effects on human prostate cancer cells (DU145) and an estramustine-resistant derived cell line (E4). Immunofluorescence demonstrated that EM caused depolymerization of microtubules and blocked cells in mitosis in DU145 cells, with less effect in E4 cells. Using tubulin isotype-specific antibodies, a threefold increase in betaIII and approximately twofold increase in betaI + II isotype in E4 cells compared to DU145 cells were observed. A most interesting observation concerned an increase in the posttranslational modification of alpha-tubulin of both polyglutamylation and acetylation in the E4 cells. Significant to this observation, using direct EM photoaffinity labeling of tubulin, drug binding to the most acidic posttranslationally modified forms of alpha-tubulin was shown to be minimal. Taken together, these results indicate that the modification of the tubulin expression pattern may be responsible for estramustine resistance by both lowering the amount of drug bound to microtubules and inducing more stable microtubules.

Animals↗

Combined therapy of advanced prostatic carcinoma with estramustine and prednimustine.

We treated 21 patients with stage D prostatic adenocarcinoma who had had unsuccessful hormonal therapy with a combination of 600 mg. per M.2 per day estramustine phosphate (Estracyt) and 15 mg. per M.2 per day prednimustine (Stereocyt, Leo 1031) in daily oral doses. Estramustine is a combination of estradiol and nitrogen mustard, and alone has shown objective responses in advanced prostatic cancer. Prednimustine is an ester of chlorambucil and prednisone. The preliminary results (after 2 to 9 months of therapy) show 5 patients (24 per cent) did not benefit from the drug and 7 patients (33 per cent) are stable. These preliminary results indicate the possible advantage of adding an alkylating agent (prednimustine) to estramustine in advanced prostatic carcinoma. Currently, a national randomized trial by the National Prostatic Cancer Project is evaluating this therapeutic innovation.

Aged↗

Fatal respiratory failure associated with treatment of prostate cancer using docetaxel and estramustine.

Chemotherapy that targets microtubular trafficking induces responses in most patients with prostate cancer. One regimen under investigation is the combination of docetaxel and estramustine. We report on 2 patients with androgen-independent disease who received continuous weekly docetaxel and estramustine and who died of irreversible respiratory failure. The clinical, pathologic, and radiographic data support drug toxicity as the likely etiology. Inclusive of these patients, only 17 cases (10 fatal) of acute pulmonary toxicity using docetaxel have been reported, despite its wide use. We recommend that patients receiving weekly docetaxel, with or without estramustine, have frequent treatment breaks and be evaluated with computed tomography of the chest every 8 weeks.

Aged↗

Neoadjuvant docetaxel and estramustine chemotherapy in high-risk/locallyadvanced prostate cancer.

OBJECTIVES: To evaluate the efficacy and safety of neoadjuvant docetaxel and estramustine in patients with high-risk, newly diagnosed, prostate cancer. METHODS: Eligible patients had prostate cancer with one or more of the following criteria: clinical Stage T2b or greater, prostate-specific antigen (PSA) of 15 ng/mL or greater, and/or Gleason score of 8 to 10. Chemotherapy consisted of docetaxel (70 mg/m(2)) on day 1 and estramustine (280 mg three times daily) on days 1 to 3 every 21 days for three to six courses. This was followed by local therapy, as deemed appropriate. RESULTS: Twenty-one patients with a median age of 60 years, median PSA level of 16.1 ng/mL (range 2.4 to 175), and median baseline testosterone of 3.4 ng/mL were enrolled. Seven patients met one of the inclusion criteria, 10 met two, and 4 met three. The Gleason score was 8 or greater in 14 patients. A median of five cycles of chemotherapy was delivered. The most frequent high-grade toxicities were grade 3 (8 patients) and 4 (1 patient) neutropenia and deep venous thrombosis (grade 3 in 2 patients) before institution of low-dose warfarin. All patients responded as determined by protocol-defined criteria. Ten patients underwent radical prostatectomy, with negative surgical margins in 7 patients, and 11 received radiotherapy with negative preradiotherapy biopsies in 2. CONCLUSIONS: Induction docetaxel and estramustine is well tolerated and feasible in patients with newly diagnosed, high-risk prostate cancer. This combination is active; however, its efficacy relative to hormonal therapy will require a controlled randomized trial.

Aged↗

The combination of estramustine and mitoxantrone in hormone-refractory prostate cancer: a phase II feasibility study conducted by the Hellenic Cooperative Oncology Group.

OBJECTIVES: To consider the safety profile and therapeutic value of the combination of estramustine and mitoxantrone in a bimonthly schedule to treat hormone-refractory prostate cancer. The survival of patients with prostate cancer who relapse after androgen ablation is limited and the therapeutic options are restricted. METHODS: Twenty-nine patients with relapse after previous treatment were included in the study; however, 3 patients who refused to start treatment were not included in the analysis, leaving 26 eligible patients. The median age was 64 years (range 44 to 82), the World Health Organization performance status ranged from 1 to 3, and the mean prostate-specific antigen level was 103 ng/mL (range 1 to 620). The Gleason score ranged from 2 to 9. The patients received a total of 208 therapeutic cycles (mean 8, range 3 to 24). Every cycle consisted of oral estramustine 140 mg, 3 times a day continuously, and intravenous mitoxantrone 20 mg (total dose). The regimen was repeated every 2 weeks. RESULTS: Twenty-seven percent of patients with measurable soft-tissue disease demonstrated an objective response, which included one complete and six partial responses. Thirteen patients (50%) had a greater than 50% reduction in serum prostate-specific antigen level. The median duration of response was 9.2 months, and the median survival for all patients was 15 months. The most common side effects were neutropenia and thrombocytopenia. CONCLUSIONS: The combination of estramustine and mitoxantrone is safe, well tolerated, and relatively active in patients with hormone-refractory prostate cancer. More patients are needed to partake in Phase III studies to establish the survival benefit that this combination may offer.

Administration, Oral↗

Oral estramustine and oral etoposide for hormone-refractory prostate cancer.

OBJECTIVES: Estramustine and etoposide have been shown to inhibit the growth of prostate cancer cells in experimental models. An in vivo synergism of the two agents, when administered to patients with metastatic prostate cancer refractory to hormone therapy, has been reported. To confirm these results, we administered this combination to a large number of patients with hormone-refractory prostate cancer (HRPC). METHODS: Fifty-six patients with metastatic HRPC were treated with oral estramustine 140 mg three times a day and oral etoposide 50 mg/m2/day for 21 days. Therapy was discontinued for 7 days and the cycle was then repeated. Therapy was continued until evidence of disease progression or unacceptable toxicity occurred. To control for the possible interference of an antiandrogen withdrawal effect, all patients discontinued antiandrogen therapy and were not enrolled in the study unless there was evidence of disease progression. RESULTS: Forty-five percent of 33 patients with measurable soft tissue disease demonstrated an objective response, which included five complete and ten partial responses. Among 52 patients with osseous disease 17% showed improvement and 50% showed stability of bone scan. Thirty patients (58%) demonstrated a decrease of more than 50% in pretreatment prostate-specific antigen (PSA) levels. The median survival of all patients was 13 months. Good pretreatment performance status, measurable disease response, improvement or stability of bone scan, and PSA response were important predictors of longer survival. CONCLUSIONS: We conclude that the combination of estramustine and etoposide is an active and well-tolerated oral regimen in HRPC.

Adenocarcinoma↗