New Drugs for Hard-to-Treat Breast Cancer
Study Shows PARP Inhibitors Fight Triple-Negative Breast Cancer
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How PARP Inhibitors Work continued...
The first study involved 116 women with triple-negative breast cancer whose disease had spread to other parts of the body. These women, who account for 15% to 20% of breast cancer patients, have a very aggressive form of the disease for which chemotherapy is the only available therapy, says researcher Joyce O'Shaughnessy, MD, co-director of the Breast Cancer Research Program at Baylor-Charles A. Sammons Cancer Center in Dallas.
The women were randomly assigned to receive standard chemotherapy plus BSI-201, or standard chemo alone.
Women who received BSI-201 lived a median of 9.2 months, compared with 5.7 months for the chemotherapy-only group. Tumors shrank in 48% of patients treated with the PARP inhibitor, compared with 16% of patients on chemotherapy alone.
The new drug was well tolerated, with minimal side effects.
BiPar Sciences Inc., which makes the drug and funded the work, plans to launch a larger study this summer.
In the second study, 54 women with breast cancer that was deficient in BRCA1 or BRCA2 and that persisted despite several rounds of standard chemotherapy were given one of two doses of olaparib. Olaparib is given in pill form, while BSI-201 is injected.
Tumors shrank in 41% of those given the higher dose. The most common side effects were low-grade fatigue and nausea.
Drugmaker AstraZeneca, which funded the work, is in the process of designing a larger study, according to a company spokesperson.
More research is needed, all agree. But if the positive results hold up in future studies, PARP inhibitors will "be a real advance" for women with aggressive, hard-to-treat breast tumors, Winer says.