Women with hereditary breast cancer, triggered by the BRCA1 or BRCA2 genes, stand a better chance of survival following successful trials of a drug that cuts the likelihood of the disease reoccurring after treatment, a new study shows.
Academic researchers undertook a major 30-month trial to see whether the drug, known as Lynparza (olaparib) and produced by AstraZeneca, can prevent recurrence of breast cancer.
The results, published in the New England Journal of Medicine and presented online at the American Society of Clinical Oncology conference, showed that it reduced the relative risk of invasive recurrence, second cancers, or death by over 40 percent.
In absolute terms, 85.9 percent of women given olaparib in pill form for a year after their treatment remained alive with no return of their cancer for three years. This is in comparison to 77.1 percent on a placebo.
The difference was similar when it came to metastatic disease, which is cancer occurring in other places in the body – 87.5 percent on olaparib and 80.4 percent on a placebo.
Out of 921 patients on olaparib, 106 had a recurrence of invasive cancer or died by three years, compared with 178 (of 915) patients on a placebo.
Speaking on the findings, Andrew Tutt, a professor from the Institute of Cancer Research in London, who led the international trial, said: “In curative therapy trial terms, this is a really major result.”
For every 100 women treated, it meant, he explained, “an extra nine women – let’s say eight or nine women – who are alive and well, without evidence of a recurrence of breast cancer, or the development of any other cancer.”
Before this trial, there was nothing to help women with the inherited breast cancer genes (BRCA1 or BRCA2) – who are often young and suffer from the most severe forms of cancer – who feared their cancer would return.
Olaparib stops cancer cells from repairing their DNA by inhibiting the molecule PARP, causing the cells to die.
It works well for patients with faulty versions of the BRCA1 or BRCA2 genes, which are normally involved in another system for repairing DNA. In the trial, significant side-effects were reported to be relatively infrequent.
Olaparib is already licensed for use in treating genetic forms of breast, ovarian, prostate, and pancreatic cancers.
While the drug is expensive, the researchers said they hope their study will speed up a license for olaparib that will enable all women who have recovered from hereditary breast cancer to take it.