An experimental drug from Germany's Bayer and Norwegian biotech Algeta that prolongs the lives of patients with advanced prostate cancer is a major step forward in treatment of the disease, cancer experts said on Saturday.
A late stage trial of Alpharadin, a new type of drug that delivers minute, highly-charged doses of radiation to secondary tumors in the bone, was halted early after researchers saw patients on the new treatment living almost three months longer on average than those on standard treatment plus placebo.
"It would have been unethical not to offer the active treatment to those taking placebo," Chris Parker, who led the trial at Britain's Royal Marsden Hospital, told delegates at the European Multidisciplinary Cancer Congress (EMCC) in Stockholm.
Alpharadin is based on the active ingredient radium 223 and is designed to treat patients with advanced disease whose cancer has spread to their bones.
Parker said he expected the drug to become a new standard treatment for these patients. Both Jean Charles Soria, a co-chair of the EMCC congress, and Michael Baumann, president of the European Cancer Organization, said Alpharadin was "a major new player" and likely to be "practice changing."
Kemal Malik, Bayer's head of global development, has described the success of Alpharadin, which first showed promise in headline data released in June, as a "transforming moment" for the company.
Sales of Alpharadin are expected to reach $662 million by 2015, according to consensus forecasts from Thomson Reuters Pharma. The drug's performance is also particularly important for Algeta, whose fortunes are tied closely its success.
Parker said the two firms now intend to use the data to submit the drug for regulatory approval.
Alpharadin is from a class of drugs called alpha-pharmaceuticals which work by sending tiny, charged, targeted doses of damaging radiation to a secondary tumor, known as a metastasis, in the bone.
Because it is so targeted, side effects are minimal in comparison with more conventional treatments, a factor that is likely to boost its popularity with patients and doctors.
"Compared to chemotherapy, which affects all the tissues of the body, radium-223 is highly targeted to the bone metastases, and it has a completely different safety profile," Parker explained. In the trial, he said, the drug was "extremely well tolerated."
Radium is similar to calcium in that it sticks to bone, particularly to where new bone is being formed, so it is a highly effective way of delivering radiation to a target.
"It takes only a single alpha particle to kill a cell," Parker said. "And collateral damage is minimized because the particles have such a tiny range, a few millionths of a meter, so we can be sure that the damage is being done where it should be, to the metastasis."
Parker's team studied the drug in patients with prostate cancer because it has a high tendency to spread to the bones. Around 90 percent of all men with prostate cancer will develop bone metastases in the advanced stages of the disease.
Prostate cancer is also the second most common cancer in men after lung cancer, killing an estimated 255,000 men each year.
Complete data from the trial showed that the median overall survival period for patients on the new drug was 14 months compared with 11.2 months for the placebo. The hazard ratio was 0.695, meaning that patients taking Alpharadin had a 30 percent lower rate of death compared to patients taking placebo.