The U.S. Food and Drug Administration (FDA) approved Xofigo® (radium Ra 223 dichloride) to treat men with metastatic, hormone-refractory prostate cancer that has spread to bones but not to other organs in May 2013. Xofigo is being evaluated in other cancers that are metastatic to bone.
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.1-5
The U.S. FDA approved the drug based on results from a clinical 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. The trial included 921 men with symptomatic hormone-refractory prostate cancer that had spread to bones, but not other organs. Patients were randomly assigned to receive Xofigo or a placebo plus standard treatment. The results indicated that men who received Xofigo lived an average of 15 months, compared to 11 months for the men in the placebo group.
The most common side effects associated with Xofigo were nausea, diarrhea, vomiting and swelling of the leg, ankle or foot. The most common abnormalities detected during blood testing included low levels of red blood cells (anemia), lymphocytes (lymphocytopenia), white blood cells (leukopenia), platelets (thrombocytopenia) and infection-fighting white blood cells (neutropenia).
What Do Other Clinical Studies of Xofigo Show?
Xofigo Combined with Enzamet
The combination of Xofigo and Enzamet (enzalutamide), and androgen receptor blocking agent appears to produce long-term clinical benefit compared with Enzamet alone in patients with progressive metastatic castration-resistant prostate cancer (mCRPC), according to the final results of a clinical trial presented at the February 2021 Genitourinary Cancers Symposium.
The small trial evaluated 35 patients with progressive mCRPC, 23 received the combination and 12 were treated with Enzamet therapy alone. At a median follow-up of 22 months patients treated with the combination survived on average 8.9 months without cancer progression compared to 3.4 months with Enzemet alone. Median survival was also improved from 20.6 to 30.8 months with the combination.
Xofigo Improves Bone Pain in Prostate Cancer
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.
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.
Xofigo Extends Survival in Hormone-Refractory Prostate Cancer
For patients with advanced hormone-refractory prostate cancer, the agent Xofigo® (radium-223) appears similarly effective in patients who have and have not received Taxotere® (docetaxel), a chemotherapy drug that can be used in the treatment of advanced prostate cancer. These findings were published in The Lancet Oncology.
To evaluate the effect of Xofigo in patients who had and had not received Taxotere, researchers divided participants in the ALYSYMPCA trial in two treatment groups:
- One group received six injections with Xofigo (one injection given every four weeks).
- The other group received the same injection schedule with a placebo (inactive substitute).
All participants had advanced hormone-refractory prostate cancer and at least two bone metastases. The researchers noted whether or not the patients had received Taxotere. Of the 921 patients in the trial, 526 had received Taxotere; 352 of these patients received Xofigo during the trial, and 174 received placebo. The remaining patients had not previously received Taxotere (262 in the Xofigo group and 133 in the placebo group).
Xofigo appeared active in patients with advanced hormone-refractory prostate cancer, whether or not they had received previous treatment with Taxotere. Both patients who had and had not been treated with Taxotere had longer median survival than patients who received placebo. As well, patients who had previously been treated with Taxotere had a significantly longer median time before their first symptomatic skeletal event (pathological fracture, radiation therapy to bone, surgery to bone, or spinal cord compression) compared with those who had not received Taxotere: about 15 months versus about eight months.
Side effects for Xofigo were similar between patients who had and hadn’t received Taxotere. They occurred in 62% of those who had received Taxotere and in 54% of those who had not. Side effects included thrombocytopenia (low platelet counts), anemia, and neutropenia (low neutrophil counts, a type of blood cell that fights infection).
Based on these trial results, the researchers concluded that Xofigo appears effective in patients with advanced hormone-refractory prostate cancer, whether or not they’ve had previous treatment with Taxotere. Xofigo also appears well tolerated in these patients.1
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- Hoskin P, Sartor O, O’Sullivan JM, et al. Efficacy and Safety of Radium-223 Dichloride in Patients with Castration-Resistant Prostate Cancer and Symptomatic Bone Metastases, with or without Previous Docetaxel Use: a Prespecified Subgroup Analysis from the Randomised, Double-Blind, Phase 3 ALSYMPCA Trial. The Lancet Oncology. doi:10.1016/S1470-2045(14)70474-7.
- Parker C, Nilsson S, Heinrich D, et al. Alpha emitter radium-223 and survival in metastatic prostate cancer. New England Journal of Medicine. 2013; 369:213-223.
- 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.
- FDA approves new drug for advanced prostate cancer. [FDA News Release]. U.S. Food and Drug Administration website. Available at: fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm352363.htm
- Kessel A, McFarland TR, Sayegh N, et al. Randomized phase II trial of radium-223 (RA) plus enzalutamide (EZ) versus EZ alone in metastatic castration-refractory prostate cancer (mCRPC): final efficacy and safety results. Presented at: 2021 Genitourinary Cancers Symposium; February 11-13, 2021. Abstract 135.