ASCO: Combo Hormone Tx Promising in Prostate Cancer

“A combination attack on androgens in metastatic prostate cancer resistant to initial hormone therapy drove down testosterone levels and appeared safe, according to a proof of concept study.

“Enzalutamide (Xtandi) plus abiraterone (Zytiga) dropped blood and bone marrow androgens down to undetectable levels for 80% of such patients, reported Eleni Efstathiou, MD, PhD, of the MD Anderson Cancer Center in Houston.

Editor’s note: This article discusses a treatment that may benefit men with metastatic prostate cancer that has become resistant to hormonal therapy (a condition known as castration-resistant prostate cancer or CRPC). The treatment, which combines the drugs enzalutamide (Xtandi) and abiraterone (Zytiga), was tested in a study with volunteer patients. The treatment appeared safe and also lowered testosterone levels—a promising sign that indicates potential cancer-fighting power. More studies will have to be done to determine just how well the treatment might work.

Prostate Cancer Drug Delivers Benefits Before Chemotherapy

“A drug used to treat men with late-stage prostate cancer proved effective in stemming progression of the disease in research participants who had not yet received chemotherapy and extended their survival, according to results from a multi-national Phase III clinical trial led by the Knight Cancer Institute .

“A comprehensive analysis of the study’s results ― published in June 1 online edition of the New England Journal of Medicine and to be presented at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago ― found participants treated with enzalutamide saw an 81 percent reduction in the risk the cancer would progress and a 29 percent reduction in the risk of death. The oral medication, which is marketed under the brand name Xtandi®, also helped prevent the spread of the disease to the bones, delayed the need for chemotherapy, and reduced evidence of prostate cancer in the bloodstream.

” ‘Based on the study results, this drug could fill an important gap in prostate cancer treatment today. The strong response to this new use of enzalutamide shows that it can provide a viable, less toxic alternative to chemotherapy in staving off the disease in men who aren’t responding to standard first line hormonal treatments,’ said Tomasz Beer, M.D., the lead author on the study and deputy director of the Knight Cancer Institute at OHSU.”

Editor’s note: Learn more about clinical trials.

FDA Grants Priority Review to Xtandi for Advanced Prostate Cancer

“The FDA today granted priority review to enzalutamide for the treatment of chemotherapy-naive patients with metastatic castration-resistant prostate cancer, according to a press release issued by the drug’s manufacturers.

“The FDA based its decision in part on results of the phase 3 PREVAIL trial, which included more than 1,700 patients with chemotherapy-naive disease who progressed during treatment with a luteinizing hormone-releasing hormone analogue or after bilateral orchiectomy.”

Editor’s note: Enzalutamide (Xtandi) is a promising treatment for prostate cancer that has been shown to benefit patients in clinical trials. Based on this promise, the U.S. Food and Drug Administration (FDA) will review the drug and decide whether to allow oncologists across the U.S. prescribe it to people with metastatic castration-resistant prostate cancer who have not been treated with chemotherapy. The FDA is expected to make a decision by September 18.

Clinical Trials to Investigate Prostate Cancer Treatment

“The way prostate cancer is treated could have a radical re-think as two international clinical trials go ahead.

“The Australian and New Zealand Urogenital and Prostate (ANZUP) Cancer Trials Group will involve more than 1,900 sufferers from Australia, New Zealand, Ireland, UK and Canada.

“ANZUP is an active and emerging cancer cooperative clinical trials group established to bring together all the professional disciplines and groups involved in researching and treating urogenital and prostate cancers.”

Thematic Session 10: Update on treatment options for patients with CRPC

“There are new treatment options for castration resistant prostate cancer (CRPC) but finding the optimal strategy and selecting the right patient is still fraught with challenges and difficulties, according to uro-oncology experts during a thematic session at the 29th Annual EAU Congress in Stockholm, Sweden.

“ ‘With many prostate cancer patients hoping for a better life without symptoms of the disease, the aim is to identify which new drugs, or a combination of these drugs, can offer prolong survival or effectively palliate bone disease,’ said Prof. Maria De Santis who chaired Thematic Session 10.

“The session focussed on castration-resistant prostate cancer (CRPC) which is often considered one of the toughest challenges in uro-oncology since despite repeated treatments the disease accelerates or progresses with severe impact on quality of life (QoL).”

Editor’s note: This article is about an event at a urology conference in Sweden. During the event, participants discussed the latest in prostate cancer treatment, with a focus on castration-resistant prostate cancer (CRPC).

Blood-Based Biomarker May Identify Prostate Cancers That Will be Resistant to Enzalutamide

“Men with metastatic, castration-resistant prostate cancer who started treatment with the drug enzalutamide (Xtandi) and had a molecule called AR-V7 present in circulating tumor cells (CTCs) obtained prior to treatment had a worse response to enzalutamide compared with those who had no detectable AR-V7, according to results presented here at the AACR Annual Meeting 2014, April 5-9.”

Editor’s note: Biomarkers and molecular testing to find them can help guide treatment decisions for people with many different types of cancer. In this story, patients who had a biomarker called AR-V7 did not benefit from the drug enzalutamide as much as patients who did not have AR-V7. So, for patients who are considering enzalutamide, a molecular test for AR-V7 could help guide the decision by indicating whether the drug is likely to help. Learn more.

PREVAIL Trial Shows Enzalutamide to Be a Promising Option for Metastatic Castration-Resistant Prostate Cancer

“Encouraging results of the large phase III PREVAIL trial represent another positive milestone for men with metastatic castration-resistant prostate cancer. Enzalutamide (Xtandi) improved overall survival by 29% and reduced the risk of radiographic progression of disease by 81% in men who had not received chemotherapy.

“An interim analysis of the trial data in 2013 was so favorable that the Independent Data Monitoring Committee halted the trial prematurely and offered all placebo recipients enzalutamide. Complete trial results were reported at the 2014 Genitourinary Cancers Symposium in San Francisco.

“ ‘In my view, enzalutamide provides clinically meaningful benefit for men with [metastatic castration-resistant prostate cancer]. It is approved by the FDA in men previously treated with docetaxel, but not yet approved for use prior to docetaxel. If it does get expanded approval for this indication, it is likely to become an important standard option for use in patients with asymptomatic or minimally symptomatic advanced prostate cancer,’ said lead author Tomasz M. Beer, MD, Professor of Medicine and Deputy Director of the Knight Cancer Institute at Oregon Health Science University, Portland.”

Astellas and Medivation Submit Supplemental New Drug Application for XTANDI (Enzalutamide) for Chemotherapy-Naive Advanced Prostate Cancer

“Astellas Pharma Inc. (TSE: 4503) and Medivation Inc. (NASDAQ: MDVN) today announced the submission of a supplemental New Drug Application (sNDA) to the U.S. Food and Drug Administration (FDA) seeking approval of XTANDI® (enzalutamide) capsules for the treatment of men with metastatic castration-resistant prostate cancer (mCRPC) who have not received chemotherapy. XTANDI is currently approved for the treatment of patients with mCRPC who have previously received docetaxel chemotherapy.

“The sNDA application is based on the results from the Phase 3 PREVAIL trial evaluating XTANDI as compared to placebo in more than 1,700 chemotherapy-naïve mCRPC patients. The marketing authorization application is expected to be submitted to the European Medicines Agency later this year.”

Editor’s Note: This is a corporate press release. The takeaway for patients is that, if the application is successful, doctors will be able to start giving XTANDI (enzalutamide) to patients who have not previously had chemotherapy. The FDA has already approved the use of XTANDI for men with mCRPC who have had chemotherapy with the drug docetaxel.

Enzalutamide Improved Outcomes in Prostate Cancer Regardless of Age

“Enzalutamide significantly prolonged OS, radiographic PFS and time to PSA progression in both younger and older patients with metastatic castration-resistant prostate cancer, according to a post-hoc analysis of the phase 3 AFFIRM trial.

“The original analysis of the randomized, double blind trial indicated that patients with prostate cancer who previously received docetaxel chemotherapy demonstrated improved median OS when treated with enzalutamide (Xtandi, Astellas Pharma) — an oral androgen receptor inhibitor — compared with patients assigned placebo (18.4 months vs. 13.6 months; HR=0.63; 95% CI, 0.53-0.75).”