By Dennis Thompson
HealthDay reporter
FRIDAY, June 4, 2021 (HealthDay News) – A twice-daily pill can dramatically reduce the risk of breast cancer recurring in women who are genetically prone to the disease, researchers report.
The pill – olaparib (Lynparza) – works by blocking a natural enzyme called PARP that normally fixes DNA damage in healthy cells, but actually promotes cancer cell growth in these women.
High-risk early breast cancer patients who took olaparib for a year had a 42% lower risk of cancer recurrence or death compared to those who received a placebo, said lead researcher Dr. Andrew Tutt, Director of the Breast Cancer Now Toby Robins Research Center at the Institute for Cancer Research in London.
“Patients who received olaparib after surgery and chemotherapy were more likely to be alive without cancer and avoid metastasis than those who received a placebo,” he said.
These results were presented on Thursday at an online meeting of the American Society of Clinical Oncology. The results presented at the meetings should be considered preliminary until published in a peer-reviewed journal.
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Olaparib is already approved for the treatment of metastatic breast cancer patients who have mutations in the BRCA1 or BRCA2 genes. These genes usually suppress cancer, but mutations increase the risk of cancer for some people.
About 5% of breast cancers are linked to BRCA1 or BRCA2 mutations, Tutt found.
Breast cancer resulting from BRCA1 or BRCA2 mutations relies on the PARP enzyme to stay alive, grow, and divide. Medicines called PARP inhibitors take advantage of this fact to block the enzyme and prevent the cancer from recurring.
In this clinical trial, more than 1,800 patients with stage 2 to 3 breast cancer treated with surgery and chemotherapy were randomized to receive either 300 milligrams of olaparib or placebo twice daily for one year.
Patients who received olaparib had a three-year invasive disease-free survival rate – no recurring breast cancer or other new cancers – of about 86%, compared with 77% for those who took a placebo, the results showed.
Dr. Amy Tiersten is Professor of Hematology and Medical Oncology at the Icahn School of Medicine on Mount Sinai in New York City. She said, “We have known for some time that PARP inhibitors are effective in patients with metastatic breast cancer, but this is the first time we have seen early-stage effectiveness. This study showed a significant reduction in the risk of recurrence in this population and therefore the potential to cure more patients with early-stage BRCA-associated breast cancer. “
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Side effects were consistent with previous studies of olaparib, Tutt said. The most serious common side effects included anemia, low white blood cell counts, and fatigue.
Tutt said the study shows the importance of genetic testing in cancer patients to look for traits and mutations that could be exploited to improve treatment and survival.
“There is certainly a reason for a change in the mindset in the community where we do germline genetic testing,” Tutt said. “We traditionally viewed it as something to help assess someone’s risk of disease and maybe let other family members know if they already had it.”
Instead of just estimating the risk, this genetic information could be used to save lives, Tutt noted.
Dr. Lori Pierce, president of the American Society of Clinical Oncology, agreed.
“This underscores the importance of genetic testing in appropriate patients so we know which patients will benefit from this therapy,” said Pierce. “I think it could even open the door to further studies with adjuvant PARP inhibitors for other BRCA1 and 2-associated cancers.”
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Olaparib can be an expensive drug. The cost to ship sixty 100-milligram tablets is just over $ 7,500, according to Drugs.com.
More information
The Dana-Farber Cancer Institute has more about PARP inhibitors.
SOURCES: Andrew Tutt, MBChB, PhD, Director, Breast Cancer Now Toby Robins Research Center, Institute of Cancer Research, London; Lori Pierce, MD, President, American Society of Clinical Oncology, Alexandria, Virginia; Amy Tiersten, MD, Professor of Hematology and Medical Oncology, Icahn School of Medicine at Mount Sinai, New York City; Presentation, American Society of Clinical Oncology, June 3, 2021, online
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