7000 ORAL Final Overall Survival (OS) Analysis of COU-AA-301, a Phase 3 Study of Abiraterone Acetate Plus Prednisone in Patients With Metastatic Castration-Resistant Prostate Cancer (mCRPC) Pretreated With Docetaxel

Systemic therapy in men with metastatic castration-resistant prostate cancer: a systematic review

AIMS

Since 2004, docetaxel-based chemotherapy has been the standard of care for men with metastatic castration-resistant prostate cancer (mCRPC), but recently randomised controlled trials (RCTs) of novel agents have shown promise in extending overall survival. These trials have evaluated agents delivered before chemotherapy, to replace or supplement docetaxel, or addressed treatment options for men who have progressed on docetaxel therapy. This review was undertaken to determine which systemic therapies improve cancer- or patient-related outcomes in men with mCRPC.

MATERIALS AND METHODS

Searches were carried out in MEDLINE, EMBASE, the Cochrane Library and relevant conference proceedings. Eligible articles included RCTs comparing systemic therapy or combination (excluding primary or secondary androgen deprivation therapy, bone protective agents or radionuclides) with placebo or other agents in men with mCRPC.

RESULTS

Twenty-five RCTs met the selection criteria. In chemotherapy-naive patients, targeted therapy with tasquinimod conferred a benefit in progression-free survival. Immunotherapy with sipuleucel-T extended overall survival and was well tolerated, but had no effect on the time to disease progression. Hypercastration with abiraterone extended progression-free survival, whereas overall survival was improved but not statistically proven. In the chemotherapy setting, updated and new trials of docetaxel alone confirmed the survival benefit seen in previous studies. A survival benefit with the addition of estramustine to docetaxel shown in a previous study did not lead to an improvement in pain palliation or quality of life. Trials of combining targeted therapies with docetaxel generally did not extend survival. The addition of bevacizumab improved progression-free survival, but not overall survival. The addition of GVAX immunotherapy or calcitriol was harmful. In the post-chemotherapy setting, progression-free and overall survival benefits were detected with cabazitaxel, abiraterone and enzalutamide. Cabazitaxel was associated with greater toxicity, whereas abiraterone and enzalutamide had less severe adverse effects. Satraplatin and sunitinib both extended progression-free survival, but did not improve overall survival.

CONCLUSION

Docetaxel-based chemotherapy remains the standard of care in men with mCRPC who are candidates for palliative systemic therapy. Promising results are emerging with sipuleucel-T and abiraterone in the pre-docetaxel setting and cabazitaxel, abiraterone and enzalutamide in patients who progress on or after docetaxel. Further research to determine the optimal choice, sequence or even the combination of these agents is necessary.

Effect of abiraterone acetate on fatigue in patients with metastatic castration-resistant prostate cancer after docetaxel chemotherapy

BACKGROUND

Fatigue is a common, debilitating side-effect of prostate cancer and its treatment. Patient-reported fatigue was evaluated as part of COU-AA-301, a randomized, placebo-controlled, phase III trial of abiraterone acetate and prednisone versus placebo and prednisone in metastatic castration-resistant prostate cancer (mCRPC) patients after docetaxel chemotherapy. This is the first phase III study in advanced prostate cancer to evaluate fatigue outcomes using a validated fatigue-specific instrument.

PATIENTS AND METHODS

The Brief Fatigue Inventory (BFI) questionnaire was used to measure patient-reported fatigue intensity and fatigue interference with activities of daily life. All analyses were conducted using prespecified responder definitions of clinically meaningful changes.

RESULTS

A total of 797 patients were randomized to abiraterone acetate and prednisone, and 398 were randomized to placebo and prednisone. Compared with prednisone alone, in patients with clinically significant fatigue at baseline, abiraterone acetate and prednisone significantly increased the proportion of patients reporting improvement in fatigue intensity (58.1% versus 40.3%, P = 0.0001), improved fatigue interference (55.0% versus 38.0%, P = 0.0075), and accelerated improvement in fatigue intensity (median 59 days versus 194 days, P = 0.0155).

CONCLUSIONS

In patients with mCRPC progressing after docetaxel chemotherapy, abiraterone acetate and prednisone yielded clinically meaningful improvements in patient-reported fatigue compared with prednisone alone.

Progress in emerging therapies for advanced prostate cancer

The landscape of prostate cancer treatment is rapidly changing as extensive research into potential therapies yields new options. In this article, the literature is reviewed to identify emerging therapies for advanced prostate cancer. Emphasis is placed on agents that have been approved in the United States of America (USA) and the European Union, or that have reached phase III clinical studies. Several new therapies have been approved in recent years across different stages of the natural history of the disease. Degarelix, a luteinizing hormone-releasing hormone antagonist, has been approved for reducing testosterone to castrate levels in hormone-sensitive disease. No new agents have been approved for use in combination with docetaxel chemotherapy, the current standard of care for metastatic castration-resistant prostate cancer. One immunotherapy, sipuleucel-T, has been approved (USA only) in the pre-docetaxel setting. Cabazitaxel, a next-generation taxane, and abiraterone acetate, an inhibitor of androgen biosynthesis, have both been approved as second-line agents following chemotherapy. Enzalutamide (MDV3100), an androgen receptor antagonist, has been shown to increase overall survival in the post-chemotherapy setting in metastatic disease. Denosumab, an antibody-based bone-targeted agent, has been approved for the prevention of skeletal-related events in patients with bone metastases. Radium-223 chloride, an α-emitting radiopharmaceutical, is likely to gain approval soon following promising results in a phase III trial. Clinical studies involving other promising agents are ongoing. The emergence of these therapies adds to the growing armamentarium against prostate cancer.

[Urological cancers: ECCO/ESMO congress 2011]

In the Congress of European Cancer Organisation (ECCO)/European Society for Medical Oncology (ESMO), which took place in Stockholm between 23 and 27 September 2011, urological cancers were the subject of various oral presentations and posters. A selection of the more innovative researches, likely to change the patients' management was performed. In prostate cancer, abiraterone acetate should be indicated in patients previously treated with docetaxel and sipuleucel-T in patients with asymptomatic or minimally symptomatic castrate-resistant prostate cancer. Alpharadine should be indicated in patients with symptomatic bone metastases and denosumab in non-metastatic prostate cancer patients with a high risk of developing bone metastases. In metastatic renal clear cell carcinoma, the genetic polymorphisms are predictive for efficacy of anti-angiogenic agents. Targeting both vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) pathways is a very promising strategy. In urothelial cancer, two molecules are promising, the belinostat and the bortezomib. Other news on penile cancer and testicular seminoma are discussed.