Using both extended the time before the cancers spread in patients whose tumours lacked a gene known as PTEN. Researchers assessed the effectiveness of the standard hormone drug abiraterone plus new treatment ipatasertib in men with advanced prostate cancer who had received no prior treatment. The phase three trial took place in 26 countries and involved 1,101 men, of whom 521 had tumours that lacked a fully functioning PTEN gene.
Funded by pharma giant Roche, the trial found that giving ipatasertib plus abiraterone as a first-line treatment reduced the risk of death or cancer progression in patients by 23 percent compared with abiraterone alone.
Around half of men with advanced prostate cancer have tumours with faulty PTEN genes – more than 10,000 men per year in the UK. They could potentially benefit from the combination treatment if it wins approval.
Researchers say men with tumours lacking the gene tend to have a poor prognosis, but the latest findings could open up the combination treatment to keep patients healthy for longer.
Among patients with tumours that lacked PTEN, 61 percent of those who received the combination saw their tumour shrink, compared with 39 percent for those who took just abiraterone.
While 19 percent of those on the combination had full remission, it was six percent for those taking abiraterone only, the study published in The Lancet found.
The drug combination works by simultaneously switching off two powerful growth signals that fuel prostate cancer.
Researchers, headed by The Institute of Cancer Research, London (ICR) and The Royal Marsden NHS Foundation Trust, say follow-up work will be needed before the dual approach achieves regulatory approval or can be made available through the NHS.
Study leader Johann de Bono, ICR professor of experimental cancer medicine and consultant medical oncologist at The Royal Marsden, said: “The findings offer a promising new treatment option for patients with a common and aggressive type of prostate cancer.
“PTEN is one of the most commonly deleted genes in prostate cancer, so this study offers hope to many patients.”