Xtandi Shows Significant Benefit in Chemotherapy-Naïve, Metastatic, Hormone-Refractory Prostate Cancer

Xtandi® (enzalutamide) showed significant survival benefit in men with chemotherapy-naïve, metastatic, hormone-refractory prostate cancer, according to the results of a study presented at the 2014 European Association of Urology (EAU) Congress in Stockholm, Sweden. The targeted agent delayed the progression of metastatic disease, reduced the risk of death, and delayed the start of chemotherapy.

The prostate is a male sex gland responsible for producing fluid that forms semen. It is located below the bladder, in front of the rectum, and surrounds the urethra. Prostate cancer occurs when the cells in the prostate gland grow out of control.

Prostate cancer is a hormonally sensitive disease that can often be controlled for long periods with androgen deprivation therapy (ADT). When prostate cancer stops responding to this treatment, it is referred to as hormone-refractory prostate cancer. Metastatic hormone-refractory prostate cancer is a challenging form of the disease to treat because the cancer has spread to distant sites in the body and does not respond to treatment with hormonal therapy.

Xtandi targets multiple steps in the androgen-receptor–signaling pathway, interfering with molecular pathways that help the cancer grow. What’s more, the drug does not cause side effects commonly associated with chemotherapy, such as nausea and hair loss.

The PREVAIL trial was a randomized, double-blind, placebo-controlled, multicenter phase III study that included 1,717 patients with asymptomatic or mildly symptomatic metastatic hormone-refractory prostate cancer who had not received previous chemotherapy. Patients were randomly assigned to Xtandi or placebo plus standard hormone therapy. The two primary endpoints were overall survival and radiographic progression-free survival. The study was conducted at more than 200 centers in 22 countries and was stopped at the interim phase when results showed significant benefit.

At the time of interim analysis and after a median follow-up of 20 months, the results indicated that Xtandi significantly reduced the risk of death by 29 percent and reduced the risk of radiographic progression by 81 percent. The most common adverse events associated with the agent were fatigue, back pain, constipation, arthralgia and hypertension.

The researchers concluded that Xtandi significantly delayed the progression of metastatic disease, reduced the risk of death, and delayed the initiation of chemotherapy. As a result, the drug provides meaningful clinical benefit, significantly prolonging survival in this population.

Reference:

Tombal B, Iversen P, Miller K, et al: Enzalutamide in men with chemotherapy-naïve metastatic castration resistant prostate cancer (MCRPC): Primary and European regional results of the phase 3 prevail study. Presented at the 2014 EAU Congress in Stockholm Sweden. Abstract LBA3.

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