Translucent image of a woman's torso showing triple negative breast cancer in one breast
Credit: Science Photo Library - ROGER HARRIS/Getty Images

A genetic test developed at the University of California San Francisco (UCSF) can identify triple negative breast cancer patients who will and won’t respond to commonly used immunotherapies.

Triple negative breast cancer accounts for up to 15% of all breast cancers and affects around 13 in 100,000 women in the U.S. Immunotherapy treatment for this type of cancer is now considered “standard of care” but does not work for everyone and can cause significant adverse events such as thyroid dysfunction and adrenal insufficiency.

“Immunotherapy drugs can have very severe, irreversible adverse side effects, as observed in the I-SPY2 trial. The findings I’m presenting today should provoke a discussion about whether giving immunotherapy drugs to all patients with triple negative disease, which has recently become the standard of care in most countries, is the right strategy,” said Laura van ‘t Veer, professor of laboratory medicine, co-leader of the breast oncology program and director of applied genomics at the Helen Diller Family Comprehensive Cancer Center, UCSF, in a press statement.

“Our research shows that it should be adapted so as to select only those patients who are very likely to benefit from this treatment. Patients who are unlikely to respond could then receive alternative therapies.”

Speaking at the 14th European Breast Cancer Conference in Milan, van ‘t Veer presented study results showing the ImPrint test, including 53 genes, can accurately predict immunotherapy response in people with triple negative breast cancer.

ImPrint was developed based on results from the I-SPY2 trial, which was set up to test new cancer drugs in a way that also matched them with relevant biomarkers. The researchers previously tested ImPrint in a mixed group of high risk, early breast cancer patients to predict response to pembrolizumab. While the results were generally good, they felt the test could be more accurate in triple negative breast cancer patients so went on to develop a modified version of the test ImPrintTN.

In this study, van ‘t Veer and team showed that ImPrintTN predicted a 74% responder and a 16% non-responder rate across five different test groups of patients with a sensitivity of 90% and a negative predictive value of 84%. The researchers now plan to validate their test further.

“This new work now presents an update of the ImPrint classifier specifically for triple negative breast cancers, ImPrintTN. We found that it can predict patients who are unlikely to respond to immunotherapy, so that the harms from the treatment are greater than the benefit. This means it would be acceptable for them to forgo an immunotherapy drug in order to avoid the risk of these sometimes life-long irreversible adverse effects.”

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