A research team at Bundang CHA Hospital has developed a new treatment method that overcomes the resistance of Ibrance, a treatment for metastatic breast cancer, for the first time in the world.
Ibrance is a targeted anticancer drug developed by Pfizer and treats hormone receptor (HR)-positive subtype cases, accounting for about 70 percent of breast cancers. While HR-positive breast cancer is mild, treatment options are limited if it recurs, metastasizes, and develops drug resistance.
Recently, targeted therapies that inhibit the cyclin-dependent kinase (CDK) 4/6 gene that regulates cell division and growth, such as Ibrance, have increased cancer survival rates in the treatment of metastatic breast cancer. However, most patients develop resistance within two to three years, making treatment difficult.
The team, led by Professor Moon Yong-wha of the Department of Hemato-oncology, developed an animal model of breast cancer resistant to Ibrance and administered a combination of existing breast cancer treatments Halaven and Verzenio. As a result, the team confirmed that the combination treatment more than doubled the apoptosis of breast cancer cells that were resistant to Ibrance.
When the team administered the two drugs in combination, the tumor size decreased by 88.8 percent compared to 78.1 percent using Verzenio as monotherapy and 78.1 percent using Halaven.
The treatment showed a complete remission rate of 33.3 percent when administered in combination, confirming that it effectively suppressed Ibrance-resistant breast cancer.
“This study provided the basis for confirming the treatment of metastatic breast cancer that has developed resistance to CDK inhibitor Ibrance in a situation where there have been no methods developed to overcome CDK 4/6 inhibitor resistance worldwide,” Professor Moon said. ”Since it is a method of combining the two drugs already used for breast cancer treatment, we expect to conduct clinical trials as soon as possible so that metastatic breast cancer patients can receive more effective treatment.”
Moon stressed that the research team plans to conduct further studies related to CDK 4/6 inhibitors in cooperation with the University of Texas Southwestern Medical Center.
The study results were published in the latest issue of Cancers.