Targeted Chemotherapy, Genetic Testing Could Change How BRCA-Mutated Breast Cancer Is Treated

Researchers found that women with advanced triple-negative breast cancer who had inherited a BRCA mutation benefited more from the chemotherapy carboplatin than standard treatment.

A major clinical trial reported increased benefits for women with advance triple-negative breast cancer who had BRCA gene faults treated with carboplatin versus the standard treatment, docetaxel.

Rather than providing the same standard of care to all patients, targeted chemotherapy with genetic testing may be able to improve response to treatment, according to the study’s findings.

The study, led by a team of researchers from The Institute of Cancer Research, London, and King’s College London, compared the efficacy of docetaxel with carboplatin in women with breast cancer.

Both drugs worked similarly well across all 376 women observed in the trial, regardless of BRCA gene status. However, among the 43 women who also had BRCA gene fault, those who received carboplatin were twice as likely to respond to therapy, compared with those given docetaxel.

According to the results, 68% of patients who received carboplatin demonstrated tumor shrinkage compared with only 33% of those treated with docetaxel.

The findings support testing women with triple-negative breast cancer for faults in BRCA genes to guide treatment.

“This is a great example of using personalized genetics to repurpose a chemotherapy drug into a targeted treatment, by understanding that its DNA-damaging effects might be particularly effective against cancer cells with deficiencies in DNA repair in appropriately selected patients,” Andrew Tutt, PhD, professor of breast oncology at The Institute of Cancer Research, London, said in a press release.

Carboplatin also had fewer adverse effects and delayed tumor progression for longer in women with BRCA gene faults. Tumor growth was stalled for approximately 7 months compared with 4 months with docetaxel, according to the study.

The findings exemplify repurposing existing, often less costly, treatments to enable a more targeted approach to therapy, rather than developing new drugs.

“While a cornerstone treatment, chemotherapy can be a blunt tool for many, with side effects that can be difficult to cope with,” Baroness Delyth Morgan, chief executive officer at Breast Cancer Now, which co-funded the trial, said in the press release.

“It is fantastic news that carboplatin will now offer a more effective, kinder, and targeted treatment to a group of patients who have long been in need of new hope.”

Reference

Tutt A, Tovey H, Bliss JM. Carboplatin in BRCA1/2-mutated and triple-negative breast cancer BRCAness subgroups: the TNT trial. Nature Medicine. 2018. Doi:10.1038/s41591-018-0009-7

Targeting chemotherapy with genetic testing provides effective treatment for women with aggressive breast cancer [news release]. https://www.icr.ac.uk/news-archive/targeting-chemotherapy-with-genetic-testing-provides-effective-treatment-for-women-with-aggressive-breast-cancer. Accessed May 4, 2018.