Scientists say they have made a breakthrough in the treatment of breast cancer by using the drug olaparib after chemotherapy.
After two-and-a-half years, women given the drug during the trial saw a 42% decrease in the risk of their cancer returning and a 43% decrease in the risk of it having spread.
A major trial in the use of olaparib at an early stage, which was conducted by a series of international partners, including London’s Institute of Cancer Research, has shown that giving women the drug following chemotherapy significantly reduces the risk of inherited breast cancer returning or spreading.
The study, named the OlympiA trial, showed that after a two-and-a-half year follow up appointment, 85.9% of patients were free of their cancer, compared with 77.1% who had received a placebo. This represented a 42% overall drop in the risk of cancer returning.
Similarly, 87.5% of olaparib patients were alive and free of disease which had spread to other parts of their body, compared with 80.4% who were given a placebo, a 43% drop in the risk of cancer spreading via distant metastases.
What is olaparib?
Olaparib is a PARB inhibiter.
PARB are enzymes that repair cancerous cells.
Until now, olaparib has been used for advanced cancers. But the study has now demonstrated its effectives at the early or “curative” stage, researchers say.
The ICR said the trial suggested olaparib, which exploits a genetic weakness in cancer cells, “could become a new treatment option to reduce the risk of recurrence or metastasis in women with inherited forms of high-risk early breast cancer and could lead to more patients being cured”.
OlympiA steering committee chair Professor Andrew Tutt, professor of oncology at the ICR, said in a statement: “We are thrilled that our global academic and industry partnership in OlympiA has been able to help identify a possible new treatment option for women with early-stage breast cancer who have inherited mutations in their BRCA1 or BRCA2 genes.
“Women with early-stage breast cancer who have inherited BRCA1 or BRCA2 mutations are typically diagnosed at a younger age.
"Up to now, there has been no treatment that specifically targets the unique biology of these cancers to reduce the rate of recurrence, beyond initial treatment such as surgery, hormone treatment, radiotherapy and chemotherapy.
“This major international study coordinated by the Breast International Group shows that giving olaparib for a year to patients with inherited BRCA mutations after they have completed initial treatment increases the chances that they will remain free of invasive or metastatic breast cancer.”
Prof Tutt said olaparib had the potential to be used “as a follow-on to all the standard initial breast cancer treatments to reduce the rate of life-threatening recurrence and cancer spread for many patients identified through genetic testing to have mutations in these genes”.
He added the frequency of significant side effects from the drug in the study was relatively low.
The ICR’s chief executive, Professor Paul Workman, said: “Olaparib was the first cancer drug in the world to target inherited genetic faults.
"It is also now the first targeted drug to have been shown to effectively treat patients with inherited mutations and early-stage breast cancer, potentially curing some women of their disease.
"This is a major breakthrough.
“It’s fantastic that decades of ICR science into identifying cancer’s weaknesses – alongside academic, charity and industry partners in the UK and worldwide – has led to global trials which are now changing the outlook for patients. I am now keen to see this new treatment be approved and made available to patients in the UK and worldwide as fast as possible."