It May Be Time for Standard Breast Cancer Treatment to Change
Results from a clinical trial show that adding ribociclib, a targeted therapy drug, to the standard treatment plan for women with advanced hormone-receptor positive/HER2- breast cancer helps patients live longer and better quality lives. The researchers involved now believe the drug should be the first line of treatment for patients with this very common form of breast cancer.
Results from the Phase III clinical trial were presented at the 2019 European Society for Medical Oncology (ESMO) Congress 2019 last weekend. The trial involved 726 postmenopausal women with advanced hormone-receptor positive HER2-breast cancer who had not received endocrine therapy in the past, and aimed to see if the treatment could effectively increase lifespan.
Results showed that women who received the drug experienced significant improvement in survival. For example, there was a 28 percent reduction in risk of death in women who received ribociclib in combination with their standard therapy, when compared to those who were only treated with the standard hormone therapy.
The most commonly reported side effects experienced with this drug included low blood count, nausea and vomiting, fatigue, diarrhea and hair loss.
“Increasing overall survival is the hardest endpoint to move,” said lead researcher Dr. Dennis Slamon, chair of hematology/oncology and director of Clinical/Translational Research at UCLA’s Jonsson Comprehensive Cancer Center. “We’re also seeing that the time of progression-free survival is the longest yet reported for any of the drugs in this class. And even when patients are off the drug, the effect seems to be long-lasting in terms of the benefit. It’s important because this means we are helping women live longer and have a better quality of life.”
"It’s important because this means we are helping women live longer and have a better quality of life.”
The majority of breast cancer is hormone receptive, meaning that the tumors will grow in response to estrogen. In the case of advanced hormone-receptor positive HER2-breast cancer, the cancer cells have too much of a growth-promoting protein. This causes the tumors to grow and in turn, spread the cancer throughout the body.
Hormone therapy is the standard treatment for most women with such forms of breast cancer. However, research into targeted therapy suggests that hormonal therapy alone may not be best to achieve the desired results in patients.
Targeted therapy, such as ribociclib, are sometimes used alongside hormone therapy to increase the chance of successful outcomes. Ribociclib is part of a class of CDK4/6 inhibitors. These work by blocking certain hormones in breast cancer cells, which in turn slow down the cancer’s growth and spread. Doctors often prescribe the standard treatment first and then add a targeted therapy later, based on how a patient is responding. However, Slamon argues that these results show there is no need to wait.
“We found there’s a significant difference when you use the combination of ribociclib with hormone therapy as the first line of therapy,” said Slamon. “There is absolutely no reason to wait to give women this treatment. This should be the new standard.”
The most recent study on ribociclib was sponsored by Novartis. The drug will next be involved in an international clinical trial titled NATALEE which will aim to test how effective ribociclib is in treatment women with early-stage breast cancer.