A new drug has helped reduce the risk of death by 33 per cent in men with prostate cancer that has spread, according to the results of an international trial led by the B.C. Cancer Agency’s Dr. Kim Chi.
The double-blind study on the androgen receptor inhibitor drug called apalutamide was conducted in 23 countries at 260 cancer centres. It involved 1,052 men whose median age was 68. The study was sponsored by Janssen, the drug company who makes apalutamide.
At two years, those taking the treatment drug in addition to their standard treatment had a 52 per cent lower risk of cancer spread or death.
The findings of the TITAN (Targeted Investigational Treatment Analysis of Novel Anti-androgen) trial which began in 2015 are published in the New England Journal of Medicine (NEJM). Results were also recently presented by Chi at the annual meeting of the American Society of Clinical Oncology.
Chi, an oncologist, said overall survival rate is only about five years once prostate cancer has spread beyond the prostate so new treatments are desperately needed. The percentage of patients who took the drug whose cancer did not spread was 68.2 per cent, but in the placebo group the proportion was 47.5 per cent. There was a 33 per cent reduction in the risk of death for those who took the drug.
After about two years, 82 per cent of men in the investigational drug group were alive compared to 74 per cent on placebo. Men in both groups also took standard male hormone deprivation therapy showing that combination therapy helps to improve survival. Male hormones (androgens) like testosterone feed prostate tumours and currently, men with metastatic cancer are put on hormone deprivation treatment that has been the standard of care for many decades. Apalutamide, also called Erleada, is said to more completely block male hormones.
Chi said the drug is “not toxic” and there were no significant differences in the proportion of study participants in the intervention or placebo groups who experienced side effects, but skin rashes were just over three times more common in the drug group.
The drug has already been approved in Canada for certain patients with hormone-resistant, non-metastatic cancer but Chi said now that it is showing benefit for patients whose cancer has spread, he expects the drug will be approved by Health Canada for those patients as well, perhaps later this year. After that approval, provinces will have to decide on whether to expand funding for the drug, which costs about $3,000 a month. Chi said he expects more Canadian patients will have access to it next year.
“This is a next generation, better-designed androgen inhibitor and we really need better drugs for those with metastatic prostate cancer,” Chi said.
“There’s a critical need to improve outcomes for these patients and this study suggests this treatment can prolong survival and delay the spread of the disease.”
Chi was also a co-author on another drug trial, the results of which were published in the same issue of the NEJM medical journal. The ENZAMET trial, as it was called, is on a drug called enzalutamide (Xtandi). The results of that trial were similarly favourable.
About 2,700 men will be newly diagnosed with prostate cancer in B.C. this year. More than 600 men will die from it.