December 08, 2020
A targeted therapy approved for the treatment of metastatic triple-negative breast cancer may also be effective in the treatment of hormone receptor-positive, HER2-negative breast cancer that has metastasized. Priyanka Sharma, MD, breast medical oncologist, and Shane Stecklein, MD, PhD, radiation oncologist, recently gave their thoughts on these findings in an editorial accompanying the study results.
Roughly 80% of all breast cancers are hormone-positive, and up to 30% of these will metastasize, or spread, to other parts of the body. Many patients with metastatic hormone receptor-positive breast cancer respond well to first-line therapy, but most patients eventually develop resistant disease. According to Dr. Sharma, more treatment options are needed for those whose cancer has become resistant to currently available treatments.
“Metastatic cancer is difficult to treat, and it accounts for most cancer deaths,” Dr. Sharma said. “The nature of metastatic cancer means that it can become resistant to the anticancer drugs being used to treat it. Once this happens, a different therapy is needed.”
In a study published in Annals of Oncology, researchers found sacituzumab govitecan may be an effective treatment option for patients with metastatic hormone receptor-positive, HER2-negative breast cancer that has become resistant to endocrine therapy. Sacituzumab govitecan is an antibody-drug conjugate that targets breast cancer cells and was approved for the treatment of metastatic triple-negative breast cancer in 2020.
About one-third of participants in the study who received the therapy had a clinically significant reduction in their tumors and an additional one-third had their tumors well-controlled. Of those who experienced a positive outcome from the study, about one in four were able to sustain the benefit for more than 12 months. These results are favorable compared to available standard-of-care chemotherapy options. Sacituzumab govitecan was overall well-tolerated by patients, with low white blood cell count and diarrhea being the most common side effects.
“The findings are promising but will need to be confirmed in a larger, randomized clinical trial, which is already underway,” Dr. Stecklein said. “We will also need to further explore the combination of this agent with other targeted drugs in future studies.”