Single-agent therapy with bicalutamide: a comparison with medical or surgical castration in the treatment of advanced prostate carcinoma

Enzalutamide-Induced Acute Maculopapular Rash in Treatment of Metastatic Prostate Cancer: First Case Report from a Tertiary Cancer Care Center of North India

Enzalutamide is a new potent inhibitor of the signaling pathway for the androgen receptor with a half-life of 5.8 days. It has been on the market for the treatment of metastatic castration-resistant prostate cancer since November 2013. We report a case of acute generalized exanthematous maculopapular rash induced by enzalutamide. In summary, newer androgen receptor blockers have a propensity to cause skin related adverse effects. Most common among these are apalutamide. Enzalumatamide, per se, is a safe drug and has not been associated frequently in causing maculopapular rash. Few cases has been reported. In all these cases, the drug was discontinued and 2nd line therapy was instituted. In this report, Enzalutamide was withheld for 10 days and anti-histaminics was instituted. After a full recovery, Enzalutamide was reinstituted in treatment. A 62-year-old male patient with no significant medical history, was diagnosed in March 2020 with metastatic prostatic adenocarcinoma. Baseline PSA was 456 ng/ml. PSMA PET scan showed evidence of multiple bony metastasis. He was started on Degarelix subcutaneous injection with oral abiraterone initially. PSA level showed initial decreasing trend till September 2021 followed by sudden increase. Intramuscular Injection leuprolide was started and initial responses were good followed by later rise of PSA from January. Tab Xtandi (Enzalutamide) was added to the regimen from 31.1.22. Three days after starting enzalutamide treatment, the patient experienced an acute skin reaction. It is about of the plaques covered with widespread millimetric non-follicular papules. Enzalutamide was stopped after appearance of rashes to avoid further serious adverse effects. Anti-histaminics were started. Complete resolution of skin lesions occurred within 10 days. Tab Enzalutamide was reinstituted on 11th day after stoppage and on complete resolution of skin resolutions. According to the CTCAE 5.0 criteria, these skin rash was graded as grade 2. In view of evidence in literature and clinical improvement after stoppage, the acute drug reaction was attributed to enzalutamide. Uro oncologist can be confronted with adverse skin drug reactions attributable to new therapeutic molecules. The slow resolution of symptoms seems be due to the long half-life of enzalutamide. It should not be withdrawn from therapy owing to these effects. Rather, it should be with stopped for 10-14 days. Basic treatment with anti-histaminics or topical steroids may be enough to warranty the resolution of symptoms, and the drug (Enzalutamide) can be continued thereafter.

Skin rash following Administration of Apalutamide in Japanese patients with Advanced Prostate Cancer: an integrated analysis of the phase 3 SPARTAN and TITAN studies and a phase 1 open-label study

BACKGROUND

A higher incidence of apalutamide-related skin rash has been observed in Japanese patients with prostate cancer (PC).

METHODS

This integrated analysis of data of Japanese patients from 2 global Phase 3 studies, SPARTAN ( NCT01946204 ; patients with non-metastatic castration-resistant PC [nmCRPC]) and TITAN ( NCT02489318 ; patients with metastatic castration-sensitive PC [mCSPC]), and the Phase 1 study 56021927PCR1008 ( NCT02162836 ; patients with metastatic CRPC [mCRPC]), assessed clinical risk factors of apalutamide-related skin rash as well as the potential correlation with plasma exposure to apalutamide. Kaplan-Meier method was used for time-to-event analyses. Clinical risk factors for skin rash were assessed using odds ratio.

RESULTS

Data from 68 patients (SPARTAN: n = 34, TITAN: n = 28, 56021927PCR1008: n = 6) receiving apalutamide 240 mg orally once-daily were analyzed. Rash (13 [19.1%]) and maculo-papular rash (11 [16.2%]) were the most frequently reported skin rash. All Grade and Grade 3 skin rash occurred in 35 (51.5%) and 10 (14.7%) patients, respectively. Most (85.7%) skin rash occurred within 4 months of apalutamide initiation and resolved in a median time of 1 month following the use of antihistamines, topical or systemic corticosteroids, with/without apalutamide dose interruptions/reductions. Median time-to-remission of first incidence of rash and maximum grade incidence of rash were 1.0 month (IQR: 0.36-1.81) and 1.0 month (IQR: 0.30-2.43), respectively. No significant clinical risk factors for the incidence of skin rash were observed. Areas under the curve (0-24 h) (AUC0-24, ss) at steady-state of plasma apalutamide concentration were numerically slightly higher in patients with skin rash than those without.

CONCLUSIONS

No clinical risk factors for rash could be detected. There is a potential correlation between incidence of skin rash and plasma exposure to apalutamide. In general, apalutamide-related skin rash is easily managed, with appropriate treatment with or without dose adjustment.

TRIAL REGISTRATION

Retrospective pooled analysis of NCT01946204 , NCT02489318 , and NCT02162836 .

Efficacy and Safety of Non-Steroidal Anti-Androgens in Patients with Metastatic Prostate Cancer: Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Prostate cancer (PCa) is the sixth primary cause of cancer death. However, conflicts are present about the efficacy and safety of Non-steroidal anti-androgens (NSAA) for its treatment. The aim of this study was to assess the efficacy and safety of NSAAs versus any comparator for the treatment of advanced or metastatic PCa (mPCa).

METHODS

MEDLINE and the Cochrane Library were searched. References of included studies and clinicaltrials.gov were also searched for relevant studies. Only English language studies after 1990 were considered for review. Randomized controlled trials (RCTs) examining the efficacy and safety of NSAAs as compared with any other comparator including surgery or chemotherapy in mPCa patients were included. The outcomes include efficacy, safety and the tolerability of the treatment. The Cochrane Risk of Bias Assessment Tool was used for quality assessment. Two authors were independently involved in the selection, extraction and quality assessment of included studies and disagreements were resolved by discussion or by consulting a third reviewer.

RESULTS

Fifty-eight out of 1307 non-duplicate RCTs with 29154 patients were considered for the review. NSAA showed significantly better progression-free survival [PFS] (Hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.46-0.78; P=0.0001), time to distant metastasis or death [TTD] (HR, 0.80; 95% CI 0.73-0.91; P<0.0001), objective response (Odds ratio [OR], 1.64; 95% CI 1.06-2.54; P=0.03) and clinical benefits (OR, 1.33; 95% CI 1.08-1.63; P=0.006) as compared to the control group. There was no significant difference observed between the groups in terms of overall survival (HR, 0.95; 95%CI, 0.87-1.03; P=0.18) and time to progression (HR, 0.93; 95% CI 0.77-1.11; P=0.43). Treatment-related adverse events were more with the NSAA group, but the discontinuation due to lack of efficacy reason was 43% significantly lesser than the control group in patients with mPCa. Rest of the outcomes were appeared to be non-significant.

CONCLUSION

Treatment with NSAA was appeared to be better efficacious with respect to PFS, TTD, and response rate with considerable adverse events when compared to the control group in patients with metastatic PCa.

Key design and analysis principles for quality of life and patient-reported outcomes in clinical trials

Advances in early detection and therapy have increased the number of prostate cancer survivors, leading to a greater emphasis on examining patient-reported outcomes (PROs). PROs augment clinical outcomes, providing a more comprehensive assessment of the patient experience, including symptoms and quality of life, that may impact the overall evaluation of new therapies. The successful incorporation of PROs into clinical trials requires adherence to key design and analysis principles. We present these principles and argue that adherence to these principles is vital to ensure valid interpretation of clinical trial findings, identify meaningful differences among investigational strategies, and better translate clinical trial results to diverse stakeholders.

A unifying biology of sex steroid-induced apoptosis in prostate and breast cancers

Prostate and breast cancer are the two cancers with the highest incidence in men and women, respectively. Here, we focus on the known biology of acquired resistance to antihormone therapy of prostate and breast cancer and compare laboratory and clinical similarities in the evolution of the disease. Laboratory studies and clinical observations in prostate and breast cancer demonstrate that cell selection pathways occur during acquired resistance to antihormonal therapy. Following sex steroid deprivation, both prostate and breast cancer models show an initial increased acquired sensitivity to the growth potential of sex steroids. Subsequently, prostate and breast cancer cells either become dependent upon the antihormone treatment or grow spontaneously in the absence of hormones. Paradoxically, the physiologic sex steroids now kill a proportion of selected, but vulnerable, resistant tumor cells. The sex steroid receptor complex triggers apoptosis. We draw parallels between acquired resistance in prostate and breast cancer to sex steroid deprivation. Clinical observations and patient trials confirm the veracity of the laboratory studies. We consider therapeutic strategies to increase response rates in clinical trials of metastatic disease that can subsequently be applied as a preemptive salvage adjuvant therapy. The goal of future advances is to enhance response rates and deploy a safe strategy earlier in the treatment plan to save lives. The introduction of a simple evidence-based enhanced adjuvant therapy as a global healthcare strategy has the potential to control recurrence, reduce hospitalization, reduce healthcare costs and maintain a healthier population that contributes to society.

Systemic therapy for the treatment of hormone-sensitive metastatic prostate cancer: from intermittent androgen deprivation therapy to chemotherapy

Treatment of advanced prostate cancer has changed considerably in recent years, but the vast majority of advances have been made in patients with metastatic castration-resistant disease. There have been relatively fewer advances in the earlier, hormonally responsive stage of metastatic disease. Since the empiric establishment of androgen deprivation therapy as first-line therapy for metastatic prostate cancer decades ago, there have been multiple studies looking at variations of suppressing testosterone, but the overall paradigm has not been strongly challenged until more recently. In particular, the dramatic results reported by the CHAARTED trial not only bring chemotherapy to an arena historically dominated solely by hormonal therapy but also stimulate renewed efforts into improving upon our management of metastatic hormone-sensitive prostate cancer.

Non-steroidal antiandrogen monotherapy compared with luteinising hormone-releasing hormone agonists or surgical castration monotherapy for advanced prostate cancer

BACKGROUND

Non-steroidal antiandrogens and castration are the main therapy options for advanced stages of prostate cancer. However, debate regarding the value of these treatment options continues.

OBJECTIVES

To assess the effects of non-steroidal antiandrogen monotherapy compared with luteinising hormone-releasing hormone agonists or surgical castration monotherapy for treating advanced stages of prostate cancer.

SEARCH METHODS

We searched the Cochrane Prostatic Diseases and Urologic Cancers Group Specialized Register (PROSTATE), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science with Conference Proceedings, three trial registries and abstracts from three major conferences to 23 December 2013, together with reference lists, and contacted selected experts in the field and manufacturers.

SELECTION CRITERIA

We included randomised controlled trials comparing non-steroidal antiandrogen monotherapy with medical or surgical castration monotherapy for men in advanced stages of prostate cancer.

DATA COLLECTION AND ANALYSIS

One review author screened all titles and abstracts; only citations that were clearly irrelevant were excluded at this stage. Then, two review authors independently examined full-text reports, identified relevant studies, assessed the eligibility of studies for inclusion, assessed trial quality and extracted data. We contacted the study authors to request additional information. We used Review Manager 5 for data synthesis and used the fixed-effect model for heterogeneity less than 50%; we used the random-effects model for substantial or considerable heterogeneity.

MAIN RESULTS

Eleven studies involving 3060 randomly assigned participants were included in this review. The quality of evidence is hampered by risk of bias. Use of non-steroidal antiandrogens decreased overall survival (hazard ratio (HR) 1.24, 95% confidence interval (CI) 1.05 to 1.48, six studies, 2712 participants) and increased clinical progression (one year: risk ratio (RR) 1.25, 95% CI 1.08 to 1.45, five studies, 2067 participants; 70 weeks: RR 1.26, 95% CI 1.08 to 1.45, six studies, 2373 participants; two years: RR 1.14, 95% CI 1.04 to 1.25, three studies, 1336 participants), as well as treatment failure (one year: RR 1.19, 95% CI 1.02 to 1.38, four studies, 1539 participants; 70 weeks: RR 1.27, 95% CI 1.05 to 1.52, five studies, 1845 participants; two years: RR 1.14, 95% CI 1.05 to 1.24, two studies, 808 participants), compared with medical or surgical castration. The quality of evidence for overall survival, clinical progression and treatment failure was rated as moderate according to GRADE. Predefined subgroup analyses showed that use of non-steroidal antiandrogens, compared with castration, was less favourable for overall survival, clinical progression (at one year, 70 weeks, two years) and treatment failure (at one year, 70 weeks, two years) in men with metastatic disease. Use of non-steroidal antiandrogens also increased the risk for treatment discontinuation due to adverse events (RR 1.82, 95% CI 1.13 to 2.94, eight studies, 1559 participants), including events such as breast pain (RR 22.97, 95% CI 14.79 to 35.67, eight studies, 2670 participants), gynaecomastia (RR 8.43, 95% CI 3.19 to 22.28, nine studies, 2774 participants) and asthenia (RR 1.77, 95% CI 1.36 to 2.31, five studies, 2073 participants). The risk of other adverse events, such as hot flashes (RR 0.23, 95% CI 0.19 to 0.27, nine studies, 2774 participants), haemorrhage (RR 0.07, 95% CI 0.01 to 0.54, two studies, 546 participants), nocturia (RR 0.38, 95% CI 0.20 to 0.69, one study, 480 participants), fatigue (RR 0.52, 95% CI 0.31 to 0.88, one study, 51 participants), loss of sexual interest (RR 0.50, 95% CI 0.30 to 0.83, one study, 51 participants) and urinary frequency (RR 0.22, 95% CI 0.11 to 0.47, one study, 480 participants) was decreased when non-steroidal antiandrogens were used. The quality of evidence for breast pain, gynaecomastia and hot flashes was rated as moderate according to GRADE. The effects of non-steroidal antiandrogens on cancer-specific survival and biochemical progression remained unclear.

AUTHORS' CONCLUSIONS

Currently available evidence suggests that use of non-steroidal antiandrogen monotherapy compared with medical or surgical castration monotherapy for advanced prostate cancer is less effective in terms of overall survival, clinical progression, treatment failure and treatment discontinuation due to adverse events. Evidence quality was rated as moderate according to GRADE. Further research is likely to have an important impact on results for patients with advanced but non-metastatic prostate cancer treated with non-steroidal antiandrogen monotherapy. However, we believe that research is likely not necessary on non-steroidal antiandrogen monotherapy for men with metastatic prostate cancer. Only high-quality, randomised controlled trials with long-term follow-up should be conducted. If further research is planned to investigate biochemical progression, studies with standardised follow-up schedules using measurements of prostate-specific antigen based on current guidelines should be conducted.

Efficacy of peripheral androgen blockade in prostate cancer patients with biochemical failure after definitive local therapy: results of Cancer and Leukemia Group B (CALGB) 9782

BACKGROUND

The treatment for prostate cancer patients with biochemical failure after local therapy remains controversial. Peripheral androgen blockade using a combination of a 5-alpha reductase inhibitor and an antiandrogen may allow control of the prostate-specific antigen (PSA). Because testosterone levels are not suppressed, this approach may be associated with less morbidity than conventional gonadal androgen suppression.

METHODS

All patients had undergone previous definitive local therapy and had evidence of a rising PSA >1ng/mL, with no evidence of recurrent disease. Patients received both finasteride, 5 mg orally per day, and flutamide, 250 mg orally 3× a day. Patients were followed for a PSA response and quality of life assessment.

RESULTS

Ninety-nine of 101 accrued patients were eligible. A ≥80% PSA decline was seen in 96 (96%) patients. The median time to PSA progression was 85 months. With a median follow-up of 10 years, the median survival time had not been reached, and the 5-year overall survival rate was 87%. Toxicity was mild, with 18 patients stopping for toxicity; 15 had diarrhea, 4 had gynecomastia, and 3 had transaminase elevation. Baseline Functional Assessment of Cancer Therapy Prostate Module and Treatment Outcome Index scores decreased by 5 points each at 6 months after enrollment.

CONCLUSIONS

The use of the finasteride/flutamide combination is feasible, and results in PSA declines of ≥80% in 96% of patients with serologic progression after definitive local therapy. There were no unexpected toxicities, and the change in quality of life was mild. Further evaluation of this or a similar regimen in a controlled clinical trial is warranted.

Hormonal approaches in prostate cancer: application in the contemporary prostate cancer patient

Early studies beginning in the 1940s confirmed the importance of the androgen receptor and benefits of androgen depletion in metastatic prostate cancer. These studies helped to establish management strategies with an excellent response rate. Despite this, there remains some controversy as to the optimal approach for patients. Fueling this controversy is the fact that routine PSA testing did not come into practice until the early 1990s, while the majority of the large trials evaluating the use of hormonal therapy were conducted in the pre-PSA era and in patients who had metastatic disease identifiable with radiographic imaging. With the onset of routine PSA testing and the subsequent stage migration that has occurred in men presenting with prostate cancer, the question of when to initiate hormonal therapy has become ever more controversial.

The quality of life of men with locally advanced prostate cancer during neoadjuvant hormone therapy: data from the Medical Research Council RT01 trial (ISRCTN 47772397)

OBJECTIVE

To explore patients' quality of life (QoL) during neoadjuvant hormone therapy (HT) using data from the Medical Research Council RT01 trial of standard- (64 Gy/32-fraction) and high- (74 Gy/37-fraction) dose radiotherapy (RT, both given conformally).

PATIENTS AND METHODS

Of the 843 patients randomized to the RT01 trial, 316 completed the Functional Assessment Of Cancer Therapy core questionnaire with its additional prostate subscale, and the Short Form-36 Health Survey questionnaire with the University of California-Los Angeles Prostate Cancer Index before HT and again before starting RT. Three predefined QoL hypotheses were generated to focus the analyses.

RESULTS

For the three primary QoL analyses there was evidence that sexual functioning deteriorated, urinary function did not change, and there was a slight decline in physical well-being after > or = 3 months of HT. Sensitivity analyses confirmed these findings. Exploratory analyses also suggested that role functioning deteriorated, sleep was more disturbed, and there was an increase in fatigue. However, overall QoL was not reported to be affected and patients indicated an improvement in attitude and satisfaction with treatment.

CONCLUSIONS

In this group of men, many of whom reported reduced sexual functioning before treatment, the additional decline during HT seemed to be generally accepted as the price to pay for an appropriate cancer treatment. Nevertheless, these changes need to be discussed with patients before HT is commenced.

Health-related quality of life measurement in randomized clinical trials in surgical oncology

PURPOSE

There is debate about the value of measuring health-related quality of life (HRQL) in clinical trials in oncology because of evidence suggesting that HRQL does not influence clinical decisions. Analysis of HRQL in surgical trials, however, may inform decision making because it provides detailed assessment of the immediate detrimental short-term impact of surgery on HRQL that needs to be considered against the long-term survival benefits and functional outcomes of surgery. This study evaluated whether HRQL in randomized trials in surgical oncology contributes to clinical decision making.

METHODS

A systematic review identified randomized trials in surgical oncology with HRQL. Trials were evaluated independently by two reviewers and the value of HRQL in clinical decision making was categorized in three ways: whether trial investigators reported that HRQL influenced final treatment recommendations, whether trial investigators reported that HRQL would be useful for informed consent, and whether HRQL was assessed robustly according to predefined criteria.

RESULTS

Thirty-three randomized trials with valid HRQL questionnaires were identified; 22 (67%) concluded that HRQL outcomes influenced treatment decisions or provided valuable data for informed consent, and seven of these trials had robust HRQL design. Another five trials had robust HRQL design but investigators reported that HRQL outcomes were not clinically important enough to influence treatment recommendations.

CONCLUSION

In surgical trials in oncology, HRQL informed clinical decision making. It is recommended that HRQL be included in relevant surgical trials, and that information be used to inform clinicians and patients about the impact of surgery on short- and long-term HRQL.

INCIDENCE AND MANAGEMENT OF GYNECOMASTIA IN MEN TREATED FOR PROSTATE CANCER

PURPOSE

Gynecomastia is a potentially treatment limiting adverse event in men receiving hormone therapy for prostate cancer.

MATERIALS AND METHODS

In large, randomized, placebo controlled studies approximately 50% or more of patients with prostate cancer experienced gynecomastia due to multiple mechanisms. Although its severity was mostly reported as mild to moderate, gynecomastia was cited as the reason for most premature withdrawals from therapy. In patients with advanced forms of prostate cancer bilateral orchiectomy was associated with the lowest incidence of gynecomastia, followed by nonsteroidal antiandrogen therapy, diethylstilbestrol and estrogen in rank order.

RESULTS

It is important that gynecomastia is well managed in patients with prostate cancer who want to proceed with hormone therapy. Patients should be assessed for the likely etiology of gynecomastia and preventive therapy or treatment for established gynecomastia should be instituted. Prophylactic radiotherapy has been shown to decrease the incidence of hormone induced gynecomastia by more than 50%. An alternative course of action, which may be more convenient for the patient, is the prophylactic use of tamoxifen. Tamoxifen may also mitigate or resolve gynecomastia during its early or proliferative phase. In severe long-standing gynecomastia surgery is warranted since medical therapies are less likely to succeed. Aromatase inhibitors and 4-hydroxytamoxifen are investigational.

CONCLUSIONS

Gynecomastia is a significant problem in men undergoing hormonal therapy for prostate cancer. It requires prompt recognition, evaluation and management.

Clinical strategies in the management of biochemical recurrence after radical prostatectomy

Prostate cancer is the most frequently diagnosed cancer and the second leading cause of cancer death in men, following lung cancer. Although radical prostatectomy continues to be a curative treatment for most patients diagnosed with prostate cancer, nearly 25% of patients undergoing radical prostatectomy will have biochemical recurrence as defined by an increase in serum prostate-specific antigen (PSA) level to >0.4 ng/mL after prostatectomy or a rapid doubling of the PSA over a 10-year follow-up period. The clinical challenges, an overview of available data, and a framework for the integration of this information for clinical management of biochemical recurrence postprostatectomy for prostate carcinoma are presented in this article. Therapeutic options, in addition to conservative management and watchful waiting, include radiation therapy and androgen deprivation. These options are discussed herein along with expected outcomes.

Bicalutamide

Bicalutamide is a nonsteroidal pure antiandrogen given at a dosage of 150 mg once daily as monotherapy for the treatment of early (localised or locally advanced) nonmetastatic prostate cancer. It is used at a dosage of 50 mg once daily in combination with a luteinising hormone-releasing hormone analogue or surgical castration for the treatment of advanced prostate cancer. Bicalutamide is a racemate and its antiandrogenic activity resides almost exclusively in the (R)-enantiomer, with little, if any, activity in the (S)-enantiomer. (R)-Bicalutamide is slowly and saturably absorbed, but absorption is unaffected by food. It has a long plasma elimination half-life (1 week) and accumulates about 10-fold in plasma during daily administration. (S)-Bicalutamide is much more rapidly absorbed and cleared from plasma; steady-state concentrations (Css) of (R)-bicalutamide are 100-fold higher than those of (S)-bicalutamide. Css increases linearly with doses up to 50 mg, but nonlinearly at higher doses, reaching a plateau above 300 mg. Css is higher in Japanese than in Caucasians, but no relationship with degree of renal impairment, bodyweight or age exists. Although mild-to-moderate hepatic impairment does not affect pharmacokinetics, there is evidence for slower elimination of (R)-bicalutamide in subjects with severe hepatic impairment. Bicalutamide metabolites are excreted almost equally in urine and faeces with little or no unchanged drug excreted in urine; conversely, unchanged drug predominates in plasma. Bicalutamide in faeces is thought to arise from hydrolysis of bicalutamide glucuronide and from unabsorbed drug. Bicalutamide appears to be cleared almost exclusively by metabolism; this is largely mediated by cytochrome P450 (CYP) for (R)-bicalutamide, but glucuronidation is the predominant metabolic route for (S)-bicalutamide. (S)-Bicalutamide is metabolised in vitro by CYP3A4, and it is probable that this isoenzyme is also responsible for the metabolism of (R)-bicalutamide. In vitro data suggest that (R)-bicalutamide has the potential to inhibit CYP3A4 and, to a lesser extent, CYP2C9, 2C19 and 2D6. However, using midazolam as a specific CYP3A4 marker, no clinically relevant inhibition is observed in vivo with bicalutamide 150mg. Although bicalutamide is a CYP inducer in laboratory animals, dosages < or = 150 mg/day have shown no evidence of enzyme induction in humans. Daily administration of bicalutamide increases circulating levels of gonadotrophins and sex hormones; although testosterone increases by up to 80%, concentrations in most patients remain within the normal range. Bicalutamide produces a dose-related decrease in prostate-specific antigen (PSA) at dosages < or = 150 mg/day. However, little relationship is observed between median PSA reduction and (R)-bicalutamide Css.

Combination of low-dose flutamide and finasteride for PSA-only recurrent prostate cancer after primary therapy

OBJECTIVES

To evaluate the efficacy and tolerability of combined finasteride and low-dose flutamide for prostate-specific antigen (PSA)-only recurrence after definitive therapy and to determine the predictors of recurrence-free survival.

METHODS

Seventy-one men with biochemical recurrence after primary therapy for prostate cancer were prospectively enrolled from 1996 to 1998. Forty-two patients had undergone radical retropubic prostatectomy and 29 had undergone external beam radiotherapy. Radionuclide bone scans and computed tomography of the abdomen and pelvis showed no metastasis. The initial treatment with finasteride (5 mg twice daily) and flutamide (125 mg twice daily) was continued unless participants were unable to tolerate the agents or experienced PSA progression.

RESULTS

At a mean of 44.4 months (range 12 to 92) of follow-up, 54 (76%) of 71 patients were available for measurement of disease status and response to therapy. Three patients had died of unrelated causes; 5 men withdrew from the study because of side effects and 1 patient for protocol violation. Eight patients were lost to follow-up. Twenty-seven patients (38%) continued receiving therapy with no evidence of PSA progression (PSA level less than 0.4 ng/mL), 6 patients maintained a more than 50% reduction in their baseline PSA level at the time of analysis, and 21 (29%) had PSA progression (ie, elevated PSA level on three consecutive tests more than 4 weeks apart). Major side effects were breast tenderness (90%), gynecomastia (72%), gastrointestinal disturbances (22%), fatigue (10%), and decreased libido (4%). The side effects were mild and well tolerated by most patients.

CONCLUSIONS

The combination of finasteride and flutamide showed a moderate efficacy in patients with PSA-only recurrence after definitive therapy. The efficacy appears to be greater in patients who can achieve a PSA nadir of 0.1 ng/mL or less after the start of treatment.

The use of flutamide as a single antiandrogen treatment for hormone-refractory prostate cancer

OBJECTIVE

To investigate the efficacy of low-dose flutamide (125 mg twice daily) in the treatment of prostate-specific antigen (PSA) recurrence after definitive treatment with radical retropubic prostatectomy (RRP), external-beam radiation therapy (RT), or cryotherapy.

PATIENTS AND METHODS

In this phase II prospective trial, patients who had a PSA recurrence after definitive treatment for prostate cancer were treated with flutamide. Endpoints for assessing treatment efficacy were PSA progression, treatment toxicity and clinical symptoms. Results were stratified into complete response (PSA < 0.2 ng/mL on two consecutive assessments), partial response (PSA decrease of half that at baseline on two consecutive assessments) and progressive disease. Seventeen patients were enrolled in who definitive treatment for primary prostate cancer had failed.

RESULTS

Low-dose flutamide was clinically effective (i.e. complete or partial response) in 13 patients. Four had a complete response (mean duration 28 months), nine a partial response (mean duration 19 months), and two progressive disease, but were in the study for a mean of 1 year before progression. Two patients discontinued the study at 3 months, secondary to drug-related toxicity; one had grade 3 toxicity and five grade 1 toxicity.

CONCLUSIONS

The administration of low-dose flutamide (125 mg) was clinically effective in treating PSA recurrence after definitive treatments for prostate cancer, and was well tolerated. Further investigation in a phase III trial is warranted.

Beyond the development of health-related quality-of-life (HRQOL) measures: a checklist for evaluating HRQOL outcomes in cancer clinical trials--does HRQOL evaluation in prostate cancer research inform clinical decision making?

PURPOSE

The aim of this study was to evaluate whether the inclusion of health-related quality of life (HRQOL), as a part of the trial design in a randomized controlled trial (RCT) setting, has supported clinical decision making for the planning of future medical treatments in prostate cancer.

MATERIALS AND METHODS

A minimum standard checklist for evaluating HRQOL outcomes in cancer clinical trials was devised to assess the quality of the HRQOL reporting and to classify the studies on the grounds of their robustness. It comprises 11 key HRQOL issues grouped into four broader sections: conceptual, measurement, methodology, and interpretation. Relevant studies were identified in a number of databases, including MEDLINE and the Cochrane Controlled Trials Register. Both their HRQOL and traditional clinical reported outcomes were systematically analyzed to evaluate their consistency and their relevance for supporting clinical decision making.

RESULTS

Although 54% of the identified studies did not show any differences in traditional clinical end points between treatment arms and 17% showed a difference in overall survival, 74% of the studies showed some difference in terms of HRQOL outcomes. One third of the RCTs provided a comprehensive picture of the whole treatment including HRQOL outcomes to support their conclusions.

CONCLUSION

A minimum set of criteria for assessing the reported outcomes in cancer clinical trials is necessary to make informed decisions in clinical practice. Using a checklist developed for this study, it was found that HRQOL is a valuable source of information in RCTs of treatment in metastatic prostate cancer.

The truth is out there: an overall perspective on androgen deprivation

Androgen deprivation therapy (ADT) is a mainstay in the treatment of prostate cancer. The ideal timing, duration and composition of ADT remains undefined. At the present time, first-line therapy consists of orchiectomy, LHRH agonists, or combined androgen blockade (CAB). However, new combinations and treatment settings show promise for improving outcomes and decreasing toxicity.

Background to and management of treatment-related bone loss in prostate cancer

Prostate cancer is a common disease among older men. Androgen suppression by either orchiectomy or administration of luteinising hormone-releasing hormone (LHRH) analogues is the mainstay of treatment. Since the use of prostate-specific antigen (PSA) serum testing has become widespread, however, the timing of endocrine therapy has expanded considerably to include patients with limited involvement of extraprostatic sites and patients presenting an isolated elevation of PSA after radical treatments. These patients are expected to be treated for a long time, since they have a rather low risk of disease progression and there is no recommended time limit for LHRH analogue therapy. The long-term adverse effects of androgen deprivation therapy, therefore, deserve more attention than they have received in the past. Osteoporosis represents a special concern for men with prostate cancer receiving androgen deprivation therapy. The rate of bone loss in these men seems to markedly exceed that associated with menopause in women, and fractures occur more frequently than in the healthy elderly male population. Serial bone mineral density (BMD) evaluation could allow the detection of patients with prostate cancer who are at greater risk of osteoporosis and adverse skeletal events after androgen deprivation therapy, such as patients already osteopenic or osteoporotic at baseline and men with rapid bone loss during treatment. BMD evaluated during treatment could also be a potential surrogate parameter of antiosteoporotic therapeutic efficacy. Treatment of bone loss induced by androgen deprivation comprises general prevention measures, antiosteoporotic drugs and the use of alternative endocrine therapies. Optimising lifestyle and diet is important, although it cannot completely prevent bone loss. Patients with nonsevere bone disease may benefit from calcium and vitamin D supplements. Men who are osteoporotic before androgen deprivation or men becoming osteoporotic during treatment and/or experiencing adverse skeletal events may also require bisphosphonates. The effectiveness of these drugs in preventing fractures has been shown in a single randomised study involving patients with osteoporosis, but it has not yet been established in a prostatic cancer population without bone metastases given androgen deprivation therapy. Different forms of endocrine therapy such as low-dose estrogens, antiandrogens and intermittent androgen ablation are under investigation. They could offer the advantage of avoiding (or limiting) treatment-related bone loss. In our opinion, however, the data available so far are not robust enough to recommend these alternative endocrine therapies instead of standard androgen deprivation in routine clinical practice.

The physical burden of prostate cancer

The physical burden of prostate cancer is considerable and affects quality of life in men with both localized and metastatic disease. This physical impact results as much from treatment for prostate cancer as from the disease itself. In advanced disease, although patients can experience considerable pain and discomfort from bony lesions, they also can experience bothersome fatigue and sleep disturbances from institution of hormone ablation therapy. In localized disease, although patients can have lower urinary tract symptoms from untreated prostate cancer, all aggressive treatments can result in urinary, sexual, and bowel dysfunction that can bother the patient and affect quality of life. Patients and providers must be vigilantly aware of the physical burden of prostate cancer when initiating treatment for this disease and during follow up after treatment. By being cognizant of the physical impact of prostate cancer on quality of life, providers can address patients' problems early in their course of treatment and maximize patients' HRQOL and overall satisfaction with care.

Health related quality of life in men with prostate cancer

PURPOSE

Quality of life is of great concern to patients considering treatment options for prostate cancer. In the absence of clinical trial data clearly demonstrating that a particular treatment is superior to another for localized prostate cancer, in terms of cause specific survival, patients may value quality of life as much as quantity of life. The goal of this review is to familiarize the reader with the methodology of quality of life research and to review the recent literature on quality of life outcomes in prostate cancer.

MATERIALS AND METHODS

A structured MEDLINE review of literature on health related quality of life in prostate cancer for the years 1995 to 2001 was performed, and was augmented with highly relevant articles from additional selected journals.

RESULTS

In the case of advanced or metastatic disease, where the goal of treatment is palliation and symptom-free survival, quality of life often becomes the primary desired outcome. In localized disease all treatments affect health related quality of life, although the impact of each therapy on sexual, urinary and bowel function is unique.

CONCLUSIONS

Although a highly personal and subjective entity, health related quality of life can be assessed using rigorous and scientifically stringent methods from the field of psychometric test theory. A substantial amount of literature exists regarding the use of established and validated instruments for assessing the impact of prostate cancer and its treatment on health related quality of life. This information is of critical importance when counseling men with newly diagnosed prostate cancer regarding treatment choices and is also helpful in setting appropriate expectations for men with metastatic disease.

Hormonal therapy: historical perspective to future directions

Prostate cancer is second only to lung and bronchial cancer as the leading cause of cancer death in men. Local treatment, surgery, and radiation remain the mainstay of treatment for early-stage disease. However, in locally advanced and advanced disease, there has been considerable evolution in the hormonal therapies. Suppression of testosterone production, the primary goal of hormonal therapy, may be accomplished with the use of estrogens, antiandrogens, and agonists and antagonists of luteinizing hormone-releasing hormone (LHRH). This article provides an overview of the primary hormonal therapies currently used in prostate cancer. Estrogen therapy was initially the predominant medical form of hormone manipulation and an alternative to orchiectomy. However, serious thrombogenic side effects were associated with its use, which decreased after the introduction of LHRH agonists in the 1980s. Many of the side effects occurring with oral estrogen therapy may be modulated by parenteral administration, and thus estrogen use is being revisited. LHRH agonists effectively reduce testosterone levels to castration levels (<50 ng/mL) within 2 to 4 weeks, although their use is associated with tumor flare. Antiandrogen monotherapy may offer quality-of-life benefits over treatment with androgen deprivation. The additive benefit of combined androgen blockade is yet to be determined. Recent evidence suggests that hormonal therapy may offer a survival benefit when initiated in earlier stages of prostate cancer. Future investigations will be directed to determining the most efficacious regimens.

Health related quality of life in prostate carcinoma patients: a systematic review of randomized controlled trials

BACKGROUND

Health related quality of life (HRQOL) is increasingly reported as an important endpoint in cancer clinical trials. However, evidence suggests that HRQOL reporting is often inadequate. Given this, the authors undertook a systematic review to evaluate HRQOL assessment methodology and reported outcomes of randomized controlled clinical trials (RCTs) with prostate carcinoma patients.

METHODS

A comprehensive search of the literature from 1980 to 2001, mainly on the following databases, was undertaken: MedLine, Cancerlit, and the Cochrane Controlled Trials Register. Studies were identified according to a predefined coding scheme, including HRQOL measure, cultural validity, compliance data reported and the clinical significance of the results.

RESULTS

Twenty-five RCTs were identified, involving 8015 patients primarily with metastatic cancer. Bicalutamide was the medical treatment against which most treatment comparisons were made. Limitations identified included the fact that only 44% of the studies gave a rationale for selecting a specific HRQOL measure, 64% of the studies failed to report information about the administration of the HRQOL measure, and 56% failed to report compliance at baseline. The measure most often used was the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Care 30 (EORTC QLQ-C30), although some studies used non-validated HRQOL tools.

CONCLUSIONS

The current study revealed a lack of a uniform approach to HRQOL assessment and several methodologic limitations. It is possible that such methodologic limitations have influenced trial findings for HRQOL outcomes.

Health-related quality-of-life assessments in patients with advanced cancer of the prostate

Health-related quality of life (HR-QOL) research, in general, is developing. It is becoming increasingly recognised as being important and knowledge on how to assess HR-QOL is spreading. Modern HR-QOL research should assess prevalence and severity of symptoms or functions, as well as the bother that symptoms or changes in functions inflict and whether this bother affects the overall well-being of the patient. In the prostate cancer field, HR-QOL assessments have evolved rapidly during the last decade. The importance of HR-QOL and associated research in prostate cancer is being more and more appreciated. Most published studies concern patients with early prostate cancer; studies in patients with late advanced stages are less frequent. In early stages, patients often have no or few symptoms from the disease. HR-QOL aspects for these patients are thus often associated with anxiety and treatment adverse effects such as changes in sexual, urinary and bowel functions. Changes in these functions also often affect HR-QOL in patients with more advanced local stages of prostate cancer or metastatic disease. Moreover, HR-QOL in these patients is also affected by endocrine treatment aiming to castrate the patient. Monotherapy with antiandrogens as endocrine treatment may be the treatment alternative that affects HR-QOL the least. This alternative may, however, not be as effective as castration. In the palliative phase, patients with prostate cancer have problems common to patients dying of other cancers. HR-QOL research should be encouraged and the knowledge on how HR-QOL can be assessed needs to be disseminated. HR-QOL assessments should be as natural in outcomes research as survival assessments. The technology of assessing HR-QOL needs to be further investigated and improved particularly with respect to the understanding of differences in performance between instruments using summary scores and item-specific assessments. Also, we need an increased understanding of the mechanisms behind patients' trade-offs and of how information should be communicated to patients in order to give the best possibilities for making informed treatment decisions.

A history of prostate cancer treatment

The increased incidence of prostate cancer has led to remarkable changes in diagnosis and treatment over the past century. What were the first ways in which prostate cancer was treated, and how did these evolve into the variety of therapeutic strategies from which patients have to choose today?

Prostate cancer and health-related quality of life: a review of the literature

With the established effectiveness of diverse treatments for prostate cancer, identification of the physical and psychosocial consequences of the disease and various treatments becomes critical. We review the literature on the effects of prostate cancer and its treatment on health-related quality of life (HRQoL). Studies show that prostate cancer and its treatment affect both disease-specific HRQoL (i.e. urinary, sexual, and bowel function) as well as general HRQoL (i.e. energy/vitality, performance in physical and social roles). Yet, these effects appear to differ across stage of disease and type of treatment. We outline evidence from three sources: (1) studies that compare men with the disease with an age-matched sample of men without the disease, (2) studies that assess men with the disease across time, and (3) cross-sectional studies that highlight predictors of HRQoL. Future research directions are discussed.

Androgen deprivation therapy for patients with clinically localized (stages T1 to T3) prostate cancer and for patients with biochemical recurrence after radical prostatectomy

Recently published studies suggest a benefit for androgen deprivation therapy (ADT) delivered early in the course of prostate cancer. However, the use of ADT specifically in patients with clinically localized disease or biochemical-disease recurrence after local therapy is not well defined. Potential candidates for primary ADT include patients who are poor candidates for definitive local therapy because of advanced age or comorbid conditions, as well as patients with significant local disease who refuse standard therapy. Treatment strategies designed to minimize the side effects of prolonged therapy, such as intermittent ADT or antiandrogen monotherapy, show promise as alternatives to continuous ADT in some patients. The role of ADT in patients with clinically localized and recurrent prostate cancer, whether it is delivered in a continuous or intermittent fashion, must be determined in randomized, prospective trials.

Androgen antagonists: Potential role in prostate cancer prevention

This article summarizes discussions of the importance of androgens and androgen antagonists in the genesis of prostate cancer. These discussions occurred at a recent symposium on prostate cancer chemoprevention sponsored by the National Cancer Institute. Considerable information exists indicating the importance of androgens in the development of prostate cancer. Trials in breast cancer indicate that estrogen antagonists prevent breast cancer-suggesting, by analogy, that the blockade of androgen action might prevent the emergence of prostate cancer. The 5alpha-reductase inhibitors block the intracellular metabolism of testosterone and inhibit the growth of the prostate. Limited data suggest that 5alpha-reductase inhibitors reduces prostate-specific antigen in men with localized and advanced, primary or recurrent prostate cancer. An ongoing national trial of 18,000 men over 50 years of age has completed accrual and will evaluate whether a standard dose of finasteride will prevent the development of prostate cancer. The toxicity profile of finasteride (Proscar, Merck & Co., West Point, PA), the only approved 5alpha-reductase inhibitor, is favorable leading to its evaluation as a potential chemopreventive agent for prostate cancer. Anti-androgens such as bicalutamide (Casodex, AstraZeneca, Wilmington, DE) are active in the treatment of prostate cancer and comparable, in some trials, to testicular androgen suppression. These data suggest that antiandrogens may be active in the prevention of prostate cancer; however, the toxicity of antiandrogens (gynecomastia, gastrointestinal toxicity) poses concerns for application in prevention studies. Opportunities for study of factors predictive or associated with the development of prostate cancer and new agents that may interrupt this process offer numerous leads that may reduce the incidence of prostate cancer.

Hormonal treatment for prostate cancer

For nearly six decades the preferred primary treatment for advanced prostate cancer has been continuous suppression of testicular androgen production by medical or surgical castration. While androgen deprivation is effective in inducing tumour regression in the large majority of cases, essentially all patients will develop progressive disease. In addition androgen deprivation may be associated with a variety of side effects. Thus, strategies that minimise the use of these agents could potentially lower the morbidity and cost associated with the treatment of advanced prostate cancer. In the era of prostate-specific antigen (PSA) testing, hormonal therapy is being used earlier in the course of the disease when the only evidence of recurrent disease is an elevated PSA. These men may survive for many years and thus have the potential for long periods of exposure to hormonal therapy and its side effects. It has been hoped that the development of alternative hormonal interventions might lead to both enhanced antitumour efficacy as well as improvements in side effect profile.

Patient-Clinician choice in palliation of metastatic prostate cancer

Palliation of patients with metastatic prostate cancer is based primarily on offering a form of androgen ablation. Each therapeutic modality has advantages and disadvantages. The decision with regards to the chosen option relies on thorough and open discussion between the treating urologist and the patient. Quality of life issues are increasingly an integral part of the treatment choice opted for. Thus, quality of life questionnaires should be incorporated into future clinical trial assessments and end-points.

Hormone therapy of prostate cancer: is there a role for antiandrogen monotherapy?

Androgen suppressive maneuvers still represent the gold standard for prostate cancer patients. However, they are associated with side effects (fatigue, sexual impotence, hot flushes, anemia, anxiety, depression and osteoporosis) all of which have a negative impact on quality of life. Nonsteroidal antiandrogens compete with dihydrotestosterone for the linkage of its own receptors. These compounds are commonly used in combination with suppressive maneuvers. However, there is a growing experience with them as monotherapy, based on the possibility to spare gonadal function and therefore prevent the effects related to its suppression. Many studies have demonstrated the feasibility and safety of this approach, which can represent a valuable alternative to suppressive maneuvers for patients wishing to retain sexual function, especially for those without distant metastases. Unfortunately, none of the comparative studies performed so far had the power to detect the equivalence between monotherapy and castration.

Single-therapy androgen suppression in men with advanced prostate cancer: a systematic review and meta-analysis

PURPOSE

To compare luteinizing hormone-releasing hormone (LHRH) agonists with orchiectomy or diethylstilbestrol, and to compare antiandrogens with any of these three alternatives.

DATA SOURCES

A search of the MEDLINE, Cancerlit, EMBASE, and Cochrane Library databases from 1966 to March 1998 and Current Contents to 24 August 1998 for articles comparing the outcomes of the specified treatments. The search was limited to studies on prostatic neoplasms in humans. Total yield was 1477 studies.

STUDY SELECTION

Reports of efficacy outcomes were limited to randomized, controlled trials. Twenty-four trials involving more than 6600 patients, phase II studies that reported on withdrawals from therapy (the most reliable indicator of adverse effects), and all studies reporting on quality of life were abstracted.

DATA EXTRACTION

Two independent reviewers abstracted each article by following a prospectively designed protocol. The meta-analysis combined data on 2-year overall survival by using a random-effects model and; reported results as a hazard ratio relative to orchiectomy.

DATA SYNTHESIS

Ten trials of LHRH agonists involving 1908 patients reported no significant difference in overall survival. The hazard ratio showed LHRH agonists to be essentially equivalent to orchiectomy (hazard ratio, 1.1262 [corrected] [95% CI, 0.915 to 1.386]). There was no evidence of difference in overall survival among the LHRH agonists, although CIs were wider for leuprolide (hazard ratio, 1.0994 [CI, 0.207 to 5.835]) and buserelin (hazard ratio, 1.1315 [CI, 0.533 to 2.404]) than for goserelin (hazard ratio, 1.1172 [CI, 0.898 to 1.390]). Evidence from 8 trials involving 2717 patients suggests that nonsteroidal antiandrogens were associated with lower overall survival. The CI for the hazard ratio approached statistical significance (hazard ratio, 1.2158 [CI, 0.988 to 1.496]). Treatment withdrawals were less frequent with LHRH agonists (0% to 4%) than with nonsteroidal antiandrogens (4% to 10%).

CONCLUSIONS

Survival after therapy with an LHRH agonist was equivalent to that after orchiectomy. No evidence shows a difference in effectiveness among the LHRH agonists. Survival rates may be somewhat lower if a nonsteroidal antiandrogen is used as monotherapy.

Bicalutamide monotherapy versus flutamide plus goserelin in prostate cancer patients: results of an Italian Prostate Cancer Project study

PURPOSE

To compare the efficacy of bicalutamide monotherapy to maximal androgen blockade (MAB) in the treatment of advanced prostatic cancer.

PATIENTS AND METHODS

Previously untreated patients with histologically proven stage C or D disease (American Urological Association Staging System) were randomly allocated to receive either bicalutamide or MAB. After disease progression, patients treated with bicalutamide were assigned to castration. The primary end point for this trial was overall survival. Secondary end points included response to treatment, disease progression, treatment safety, quality-of-life (QOL), and sexual function.

RESULTS

A total of 108 patients received bicalutamide and 112 received MAB. There was no difference in the percentage of patients whose prostate-specific antigen returned to normal levels. At the time of the present analysis (median follow-up time, 38 months; range, 1 to 60 months), 129 patients progressed and 89 died. There was no difference in the duration of either progression-free survival or overall survival. However, a survival trend favored bicalutamide in stage C disease but MAB in stage D disease. Overall and subgroup trends were confirmed by multivariate analysis. Serious adverse events and treatment discontinuations were more common in patients receiving MAB (P =.08 and P =.04, respectively). Fewer patients in the bicalutamide group complained of loss of libido (P =. 01) and of erectile dysfunction (P =.002). Significant trends favored bicalutamide-treated patients also with respect to their QOL, namely relative to social functioning, vitality, emotional well-being, and physical capacity.

CONCLUSION

Bicalutamide monotherapy yielded comparable results relative to standard treatment with MAB, induced fewer side effects, and produced a better QOL.

Bicalutamide dosages used in the treatment of prostate cancer

BACKGROUND

Androgen deprivation is often used for the treatment of patients with prostate cancer. Androgen deprivation can be achieved by surgical castration or medical castration, with or without using an antiandrogen. Each of these treatments may be used alone, or an antiandrogen may be used alongside castration to produce combined androgen blockade therapy.

METHODS

The nonsteroidal antiandrogen, bicalutamide (Casodex), has been evaluated as a component in combined androgen blockade and as monotherapy. We review the arguments that indicate why a 50-mg once-daily dose of bicalutamide is appropriate in combined androgen blockade, while ongoing clinical trials evaluate 150-mg once-daily as monotherapy in the treatment of prostate cancer.

RESULTS

The choice of the 50-mg dose of bicalutamide when used in combined androgen blockade is supported by four main arguments. First, bicalutamide 50 mg is at least equivalent to, if not better than, flutamide 750 mg in terms of receptor affinity, potency, and favorable plasma concentration profile. Second, the reduction in testosterone concentrations produced by medical or surgical castration decreases the potential competition between bicalutamide and testosterone for androgen receptors in prostate cells, allowing the use of a lower dose of antiandrogen in combined androgen blockade than is necessary in monotherapy. Third, bicalutamide 50 mg has an excellent tolerability profile. Fourth, at the 50-mg dose, bicalutamide plus luteinizing hormone-releasing hormone analogue was equivalent to flutamide plus luteinizing hormone-releasing hormone analogue, although there was a trend towards longer survival with bicalutamide. Furthermore, investigations of higher doses of bicalutamide have justified evaluation of bicalutamide 150 mg as monotherapy. First, pharmacodynamic studies reveal an increasing prostate-specific antigen response with increasing dose, which appears to plateau at a dose of around 150-200 mg. Second, in an analysis with 31% mortality, bicalutamide 150 mg appeared to have equivalent efficacy compared with castration in terms of survival in patients with nonmetastatic prostate cancer.

CONCLUSIONS

On the basis of available data, bicalutamide 50 mg is an appropriate dose to use in combined androgen blockade, while 150 mg is being evaluated in ongoing clinical trials as a suitable dose for monotherapy.

Clinical pharmacokinetics of the antiandrogens and their efficacy in prostate cancer

Prostatic cancer is the second most common cause of cancer death in males. Treatment by radical prostatectomy and radiotherapy is useful in the early stages of the disease. Whenever metastases occur, patients are usually treated by surgical (orchidectomy) or medical [gonadotropin releasing hormone (GnRH) analogue] castration. This form of treatment is, however, associated with unwanted adverse effects, such as flushing, loss of libido and potency and all patients ultimately escape therapy after a delay of 1 to 2 years. For this reason antiandrogens have been developed as another means of endocrine ablation therapy. Antiandrogens fall in 2 groups of which the first group, the steroidal antiandrogens such as cyproterone acetate (CPA), have a direct blocking effect at the cellular level but also inhibit testosterone production by their additional gestagenic properties blocking gonadotropin secretion. Except in preventing the flare-up associated with the start of GnRH analogue therapy and in reducing flushing, no evidence exist of any superiority for CPA over classical therapy in terms of adverse effects and survival. The second group, the nonsteroidal or 'pure' antiandrogens, only block androgens at the cellular level without any central effects. In contrast with other forms of castration, patients on pure antiandrogens as monotherapy preserve their sexual function and potency, at the expense of a slightly inferior androgen blockade and gynecomastia. These latter effects are explained by a compensatory rise in androgens as a result of the blockade at the central level, which weakens the androgen blockade, and by peripheral aromatisation of the increased androgens to oestrogens. In addition, some evidence exist that pure antiandrogens improve survival if combined with other forms of castration as they also inhibit the adrenal androgens, the so-called maximal androgen blockade (MAB). If patients escape control under MAB, a trial of stopping the antiandrogen must always be considered, as some tumours have 'learned' to be activated by these drugs. At the moment it is not yet clear if antiandrogens are of any benefit in downstaging the extent of disease before prostatectomy and/or radiotherapy. Of the currently known pure antiandrogens, bicalutamide offers some advantages over flutamide as it possesses a much longer half-life, allowing a once daily regimen, and has advantages over nilutamide in terms of fewer adverse effects.

Bicalutamide in advanced prostate cancer. A review

Bicalutamide is a nonsteroidal antiandrogen with a long elimination half-life (t1/2) that permits once-daily administration. When combined with a gonadorelin (gonadotrophin releasing hormone; GnRH) agonist in maximum androgen blockade (MAB) regimens, bicalutamide 50 mg once daily is at least as effective as flutamide 250 mg 3 times daily, as shown in a large randomised trial. Rate of treatment failure, the primary end-point, was significantly lower at 49 weeks with bicalutamide in this study, mainly because of a lower rate of withdrawal due to adverse events. Final results at a median follow-up of 160 weeks revealed longer median times to progression and death with bicalutamide than flutamide, but between-group differences were not significant overall. Although early trials demonstrated clinical benefits with bicalutamide 50 mg/day as monotherapy, the drug in this dosage is less effective than castration. Increasing the dosage to 150 mg/day has improved its efficacy in patients with non-metastatic disease: combined data from 2 trials demonstrate similar survival with bicalutamide in this dosage compared with castration. Accumulating evidence from these and other studies indicates that sexual interest appears to be better preserved with bicalutamide than with castration. The tolerability profile of bicalutamide is characteristic of antiandrogens, with breast pain and gynaecomastia occurring most often. Bicalutamide has not been causally associated with problems such as interstitial pneumonitis and difficulty with light/dark adaptation seen with nilutamide, and in a 50 mg/day dosage causes a lower incidence of diarrhoea than flutamide 750 mg/day. Changes in hepatic function are generally transient and resolve or improve during therapy or after bicalutamide treatment is withdrawn.

CONCLUSIONS

Bicalutamide, with its once-daily regimen and good tolerability, is an attractive option when combined with a GnRH agonist in patients with advanced prostate cancer who are suitable to receive MAB regimens. The role of bicalutamide as monotherapy in the management of this common malignancy is currently being assessed.

Casodex (bicalutamide) 150-mg monotherapy compared with castration in patients with previously untreated nonmetastatic prostate cancer: results from two multicenter randomized trials at a median follow-up of 4 years

OBJECTIVES

To compare the efficacy, tolerability, and quality of life benefits of bicalutamide (Casodex) 150-mg/day monotherapy and castration in previously untreated nonmetastatic (M0) advanced prostate cancer.

METHODS

A total of 480 patients with Stage T3/T4 nonmetastatic disease randomly received oral bicalutamide 150 mg/day or castration (either bilateral orchiectomy or goserelin acetate [Zoladex] 3.6 mg every 28 days) in a 2:1 ratio in two open multicenter studies (studies 306 and 307). The design of these studies was similar to allow a pooled analysis.

RESULTS

In the combined survival analysis, at median follow-up of 202 and 205 weeks in studies 306 and 307, respectively, with 31% of the cases resulting in death, bicalutamide 150-mg monotherapy was statistically equivalent to castration; the risk of death from any cause was 7% less with bicalutamide than with castration (hazard ratio [HR] = 0.93). Data on time to treatment failure and objective progression could not be pooled, as results for these end points differed between the trials. In study 306, bicalutamide 150-mg monotherapy increased time to objective progression (HR = 0.58; P = 0.033) and treatment failure (HR = 0.66; P = 0.074), whereas in study 307, time to progression (HR = 1.35; P = 0.0471) and treatment failure (HR = 1.24; P = 0.097) favored castration. Bicalutamide therapy showed significant advantages over castration for both sexual interest (P = 0.029) and physical capacity (P = 0.046). Bicalutamide 150-mg monotherapy was well tolerated.

CONCLUSIONS

Bicalutamide 150-mg monotherapy provides a similar survival outcome to castration in previously untreated patients with nonmetastatic advanced prostate cancer and confers statistically significant benefits over castration with respect to sexual interest and physical capacity.

Bicalutamide (Casodex) in the treatment of prostate cancer: history of clinical development

BACKGROUND

Bicalutamide (Casodex) is a new nonsteroidal antiandrogen developed for use in patients with prostate cancer. The efficacy and tolerability of bicalutamide as monotherapy and as combination therapy for patients with advanced prostate cancer have been evaluated in randomized clinical trials. Clinical trials are currently in progress to further evaluate bicalutamide as monotherapy in patients with advanced stages of disease and as adjuvant or first-line therapy in patients with early-stage disease.

METHODS

A review of published trials of bicalutamide focusing on dose-ranging investigations, phase II and phase III monotherapy trials, a phase III trial of combined androgen blockade, and a safety overview.

RESULTS

In dose-ranging trials, bicalutamide doses of 10-200 elicited biochemical, objective, and subjective responses; higher bicalutamide doses (up to 600 mg) have also been evaluated. A 50-mg daily dose of bicalutamide was initially evaluated as monotherapy in phase II and phase III trials; in subsequent trials, a 150-mg daily dose was investigated. A 150-mg daily dose is considered to provide equivalent survival outcome compared with castration in patients with locally advanced prostate cancer, whereas the benefits of a better quality of life and better palliation with the 150-mg daily bicalutamide dose relative to castration in patients with metastatic disease needs to be balanced against the small shortfall (median difference, 42 days) in survival. In combination with a luteinizing hormone-releasing hormone agonist analogue (LHRH-A), a 50-mg daily dose of bicalutamide has equivalent efficacy to a corresponding flutamide (250 mg three times daily) combination regimen. Treatment with the bicalutamide combination regimen resulted in a longer median survival than with the flutamide combination regimen. Bicalutamide is well tolerated when used as monotherapy or in combination with a LHRH-A. The benefits of bicalutamide as monotherapy include retention of libido and sexual potency and as combination therapy a lower incidence of diarrhea relative to flutamide.

CONCLUSIONS

A 50-mg daily dose of bicalutamide is sufficient when given in combination with an agent, such as a LHRH-A, that lowers serum testosterone, but higher doses of bicalutamide may be needed when the drug is given as monotherapy. Bicalutamide, 50-mg daily, is a logical first choice for antiandrogen therapy when used in combination with an LHRH-A for the treatment of patients with advanced prostate cancer. Bicalutamide 150-mg daily is considered an effective monotherapy for use in patients with locally advanced disease. Additional clinical trials are currently in progress to further evaluate bicalutamide as a monotherapy for advanced prostate cancer and to assess its value as adjuvant or first-line therapy for early-stage prostate cancer.

Finasteride and flutamide as potency-sparing androgen-ablative therapy for advanced adenocarcinoma of the prostate

OBJECTIVES

Androgen ablation with luteinizing hormone-releasing hormone (LHRH) agonists, orchiectomy, or oral estrogens has significant untoward sexual side effects. We evaluated a combination of finasteride and flutamide as potency-sparing androgen ablative therapy (AAT) for advanced adenocarcinoma of the prostate. In addition, we evaluated whether finasteride provided additional intraprostatic androgen blockade to flutamide.

METHODS

Twenty men with advanced prostate cancer were given flutamide, 250 mg orally three times daily. Serum prostate-specific antigen (PSA) values were measured weekly. At a nadir PSA value, finasteride, 5 mg orally every day, was added. PSA values were then measured weekly until a second nadir PSA value was achieved. Sexual function was evaluated at baseline, at the second nadir PSA value, and every 3 months thereafter. Testosterone, dihydrotestosterone (DHT), and dehydroepiandrostenedione (DHEA) levels were measured at baseline and at the first and second nadir PSA values.

RESULTS

The median follow-up period was 16.9 months. Therapy failed in 1 patient with Stage D2 disease at 12 months, but an additional response to subsequent LHRH agonist therapy was observed. One patient developed National Cancer Institute grade 3 diarrhea and was withdrawn from the study. Seven of 20 men developed mild gynecomastia, and 3 of 20 developed mild transient liver function test elevations. Mean PSA levels were 94.6 +/- 38.2 ng/mL at baseline and 7.8 +/- 2.7 and 4.7 +/- 2.2 ng/mL at the first and second PSA nadir values, respectively (P = 0.034). Mean percent decline in PSA value from baseline was 87.0 +/- 3.1% with flutamide alone and 94.0 +/- 1.9% with both flutamide and finasteride (P = 0.001). Eleven of 20 men were potent at baseline. At the second nadir PSA value, 9 (82%) of 11 were potent, whereas 2 (18%) of 11 were impotent. With longer follow-up (median 16.4 months), 6 (55%) of 11 men were potent, 2 (18%) of 11 were partially potent, and 3 (27%) of 11 were impotent. With flutamide alone, testosterone rose a mean of 77 +/- 14.7% of baseline (P = 0.0001), DHEA fell a mean of 32.4 +/- 4.6% (P = 0.0001), and DHT was unchanged. With the addition of finasteride, testosterone rose another 14 +/- 6% (P = 0.06, not significant), DHEA was unchanged, and DHT fell a mean of 34.8 +/- 4.7% (P = 0.0009).

CONCLUSIONS

Finasteride and flutamide were safe and well tolerated as AAT for advanced prostate cancer. Finasteride provided additional intraprostatic androgen blockade to flutamide, as measured by additional PSA suppression. Sexual potency was preserved initially in most patients, although there was a reduction in potency and libido in some patients on longer follow-up. Further evaluation of this therapy is needed.