Patients with hormone-refractory prostate cancer and bone metastases had significant improvement in skeletal- and pain-related outcomes when treated with Xofigo® (radium-223), according to the results of a study presented at the annual meeting of the American Society of Radiation Oncology.
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 (or castration-resistant) prostate cancer. The majority of patients with hormone-refractory prostate cancer develop bone metastases, which can cause significant pain and other skeletal events. Some of the options for treating bone pain include opioids (pain medication), radiation therapy, and surgery, but many patients do not experience pain relief with these interventions.
Xofigo is a radiopharmaceutical agent that binds with minerals in the bone to deliver radiation directly to bone tumors, thereby limiting the damage to the surrounding normal tissues. The U.S. Food and Drug Administration (FDA) approved the drug in May 2013 after a trial known as Alpharadin in Symptomatic Prostate Cancer Patients (ALSYMPCA) was stopped early after an interim analysis showed that treatment with Xofigo significantly improved survival, compared with placebo. Now, a secondary analysis of the trial results indicates that Xofigo significantly improved skeletal and pain-related outcomes.
The trial was designed to evaluate overall survival, but also included several secondary endpoints, including skeletal events, bone pain, and quality of life. The 921 patients in the study were randomly assigned to receive Xofigo or placebo. Patients treated with Xofigo had a 34 percent reduction in the relative risk of any skeletal even compared with those in the placebo group. Patients in the Xofigo group experienced less overall bone pain than those in the placebo group. What’s more, Xofigo appeared to improve pain-related quality of life and delay time to the use of radiation and/or opioids for bone pain as well as delay time to the first skeletal event.
The results of the secondary analysis indicated that all bone- and pain-related outcomes favored the Xofigo group:
- Time to first skeletal event was 15.6 months in the Xofigo group, compared with 9.8 months in the placebo group
- Xofigo delayed the time to first radiation of the bone; 30 percent of patients receiving Xofigo underwent radiation, compared to 34 percent of those receiving placebo
- Fewer patients in the Xofigo group (36%) needed opioids for pain compared with those in the placebo group (50%)
- Despite longer survival time, fewer Xofigo patients (50%) reported bone pain as an adverse event compared with placebo patients (62%).
- Fewer patients in the Xofigo group experienced symptomatic pathologic fractures or spinal cord compression, compared with the placebo group.
The researchers concluded that Xofigo improves pain-related quality of life in patients with metastatic hormone-refractory prostate cancer and delays the time to the first skeletal-related event and the first use of radiation and opioids.
Michalski J, Sartor O, Parker C, et al. Radium-223 dichloride (Ra-223) impact on skeletal-related events, external-beam radiotherapy (EBRT), and pain in patients with castration-resistant prostate cancer (CRPC) with bone metastases: Updated results from the phase III ALSYMPCA trial. Proceedings of the 55th Annual Meeting of the American Society of Radiation Oncology. International Journal of Radiation Oncology Biology Physics. 2013; 87(2): S108-S109. Abstract 265.
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