It was already used against recurrences of ovarian cancer. Olaparib, a molecule known under the trade name of Lynparza also appears to be effective against recurrences of certain breast cancers.

This is what the results of the OlympiA clinical trial, published in the New England Journal of Medicine (NEJM) on June 3 and presented at the famous annual congress of oncology, theASCO, June 6.

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BRCA1 and BRAC2 breast cancers

This treatment does not target all breast cancers, but only cancers in women with the BRCA1 and BRCA2 genetic mutations. These mutations, which predispose to an increased risk of breast cancer, exist in 5 to 10% of these cancers.

And when the disease is associated with these mutations, it is often more aggressive, and at a higher risk of recurrence and metastasis.

This is why these breast cancers generally require other treatments than the so-called “standard” treatments such as chemotherapy, surgery and radiotherapy.

Prevent cancer cells from repairing themselves

Among these other treatments, therefore, there is olaparib, which is called a “PARP inhibitor”. It prevents cancer cells from repairing their DNA. When they make these repairs, they stay alive.

But if we prevent them, with olaparib for example, they end up dying.

86% three-year survival

To verify the effectiveness of this treatment against these particular breast cancers, the international clinical trial OlympiA recruited 1,836 patients, distributed in 420 centers across 23 countries, between June 2014 and May 2019. These women received randomly either olaparib or a placebo.

Result: After three years of treatment, 86% of patients who received olaparib were alive, without breast cancer recurrence or metastasis. This was the case for only 77% of the patients who received the placebo.

Track mutations to choose treatment

Olaparib was also associated with 27 fewer deaths than placebo. But the researchers believe that longer follow-up is still necessary to assess the impact of the drug on the overall survival of patients.

In the meantime, what is certain for researchers is that olaparib significantly improves survival when given for one year as an “adjuvant” treatment, after the end of standard treatments such as chemotherapy, surgery and radiotherapy.

Provided that the patients are tested for these two genes. Thus, for the signatories of the study, the sequencing of the BRCA1 and BRCA2 mutations is becoming an important marker for selecting the right treatment for breast cancer.