Stockholm, Sweden—An investigational alpha-pharmaceutical not only prevented skeletal-related events (SREs) in patients with prostate cancer with bone metastases in a phase 3 study presented at the 2011 European Multidisciplinary Cancer Congress, but it also improved overall survival.
“This is the first drug targeted to bone metastases in prostate cancer to improve survival,” said lead investigator Chris Parker, MD, Royal Marsden Hospital, London. “There are other bone drugs used in prostate cancer, but they help to minimize symptoms; they don’t improve survival. In my opinion, radium-223 is likely to become a new standard of treatment for advanced prostate cancer,” Dr Parker told journalists at a press briefing.
Jean-Charles Soria, MD, Institut Gustave Roussy, Villejuif, France, who cochaired the meeting’s scientific program, agreed. “This is really practice changing, and after regulatory approval, I think this is going to be a major player in advanced prostate cancer.”
A US coinvestigator of the trial, Oliver Sartor, MD, Tulane University, New Orleans, LA, said the radiopharmaceutical is far superior to prior compounds of the sort, and the study results were highly impressive.
Radium-223 chloride (Alpharadin) was recently granted a fast-track designation by the US Food and Drug Administration. The company plans to file a new drug application in mid-2012.
The Alpharadin in Symptomatic Prostate Cancer (ALSYMPCA) trial was a phase 3, randomized, doubleblind, placebo-controlled international study that compared radium-223 chloride plus current standard of care with placebo plus current standard of care in 922 men with symptomatic castration- resistant prostate cancer that had spread to the bone. Patients had multiple skeletal metastases on bone scan and were taking regular analgesics for bone pain.
At a planned interim analysis, the patients who received radium-223 had the following positive outcomes:
- Median overall survival: 14 months compared with 11.2 months for the placebo group, a 30% reduction in mortality (P = .00185)
- Time to first SREs: 13.6 months versus 8.4 months, a 64% improvement (P = .00046)
- Total alkaline phosphatase (bone marker) normalization: 33% versus 1% (P <.001)
- Time to prostate-specific antigen progression: 49% improvement (P = .00015).
Nonhematologic adverse events were not significantly worse with radium-223 versus placebo; the most common grade 3-4 adverse events were bone pain (18% vs 23%, respectively). Other serious toxicities were uncommon.
Based on the interim analysis, the data monitoring committee recommended the study be stopped and patients in the placebo arm be offered radium-223.