Authors: Jeanette Torres
(SAN ANTONIO) -- Two trials presented Wednesday at the San Antonio Breast Cancer Symposium may offer some relief for breast cancer patients undergoing treatments and surgeries. Both were shown to improve "progression-free survival," a term experts use to measure the length of time during and after medication that the cancer does not get worse.
In the BOLERO-2 trial (Breast Cancer Trials of Oral Everolimus), lead study author Dr. Gabriel Hortobagyi, professor and chairman of MD Anderson's Department of Breast Medical Oncology, said the findings demonstrated for the first time that the combination therapies are more effective than a single hormonal treatment in patients who have already tried hormonal therapy.
"Over the years, our treatment approach for such women with metastatic breast cancer has been sequential use of as many hormone therapies as possible, keeping metastatic disease under control for as long as possible," Hortobagyi said. "These findings may allow us to change our approach. In this group of heavily pre-treated patients, all of whom progressed on prior endocrine therapy, the addition of this mTOR inhibitor resulted in significant prolongation of progression-free survival and an improved response rate, with only a modest addition of toxicity."
Researchers enrolled 724 metastatic breast cancer patients into the international phase 3 trial. Study participants were post-menopausal and most had been treated with extensive hormone therapy treatments. Patients were randomized, then 485 received a combination of everolimus (a medication that stops cancer cells from reproducing by decreasing blood supply to the cancer cells) and exemestane (a medication that decreases estrogen in the body). Those patients were then compared to the 239 participants who received exemestane and a placebo.
Participants who received the combination therapy experienced 7.4 months of progression-free survival, compared to the 3.2 months that patients experienced on the placebo.
The trial was partially funded by pharmaceutical giant, Novartis. Hortobagyi acts as a consultant and receives research fund from the company, as well.
In a similar, second study presented at the symposium, researchers of the CLEOPATRA (CLinical Evaluation Of Pertuzumab And TRAstuzumab) trial found that adding pertuzumab (a medication that is believed to slow tumor growth) and certain chemotherapies lengthened progression-free survival by an average 6.1 months in patients with metastatic breast cancer patients.
"This is huge," Dr. Jose Baselga, lead author of the study and professor of medicine at Harvard Medical School," said in a statement. "It is very uncommon to have a clinical trial show this level of improvement in PFS. ...The fact that we now have an agent that can be added to current treatment to delay progression is very exciting."
While Dr. Vered Stearns, co-director of the Breast Cancer Program at Johns Hopkins, said the results of both trials could be game changers for treatment of metastatic breast cancer patients, progression free survival is a complicated point of treatment.
"The breast cancer community, government agencies and stakeholders should be evaluating what endpoints are most relevant and set proper guidelines," said Stearns.
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