New drug combination boosts survival for some breast cancer patients

Two drugs used together — ribociclib and letrozole, improve progression-free survival of post-menopausal women diagnosed with hormone receptor-positive metastatic breast cancer by 44%, compared to hormone therapy alone, researchers found.More than two-thirds of all breast cancers are hormone dependent, says Gabriel Hortobagyi, M.D., professor of Breast Medical Oncology, the study’s principal investigator.

“These findings have the potential to impact tens of thousands of women each year,” Hortobagyi says. “At some point, all breast cancers become resistant to endocrine therapy, so reversing, preventing or delaying that resistance is a major unmet need in this population.

“Women with metastatic disease will be on some therapy for the rest of their lives, and it’s paramount that we delay the progression of their disease for as long as possible,” Hortobagyi says.

The results of this trial, named MONALEESA-2, could represent a paradigm shift in the future medical management of this patient population, Hortobagyi said.

“When I started my career at MD Anderson in the 1970s, the median survival for women with metastatic breast cancer was just under two years. Now, with this discovery and other advances in the field, we can increasingly treat this as a chronic disease,” says Hortobagyi. “Also, because we are able to delay or avoid chemotherapy, the quality of these women’s lives has improved dramatically.”

As follow-up, adjuvant trials with ribociclib are now being designed, says Hortobagyi. Ribociclib will also be studied in younger, pre-menopausal women with breast cancer.

Read more about the MONALEESA-2 study in MD Anderson's Newsroom.