Breast cancer is the most common cancer in women worldwide, especially in Taiwan. In 2018, Taiwan recorded 14,127 new cases of breast cancer and 2,418 deaths related to breast cancer.
Currently, estrogen-receptor-positive breast cancer accounts for about 70% of all breast cancers, with hormone therapy (or endocrine therapy) being the main treatment. However, patients with recurrent or progressive disease often exhibit resistance to hormone therapy, calling for better alternative therapies.
GNT Biotech & Medicals Corporation (GNTbm), a Taiwan-based biotechnology company, decided to focus on other treatment options against breast cancer. Dr. Chia-Nan Chen, President of GNTbm, explains, "Fortunately, endocrine therapy combined with other target drugs can overcome endocrine resistance and significantly prolong the progression-free survival of patients."
In treatment-resistant cancer, "epigenetic" abnormalities (changes unrelated to our genetic sequences) are common. These abnormalities can often be found in enzymes that act on "histones"—proteins that support the DNA structure. Thus, these enzymes can be targeted to suppress tumor growth in breast cancer. An example is "chidamide/tucidinostat," a benzamide-based selective inhibitor of "histone deacetylase" (HDAC; a histone-modifying enzyme that is seen to be overexpressed in certain cancers). This motivated GNTbm to collaborate with Shenzhen Chipscreen Biosciences (a drug development company in China) and conduct a phase III clinical trial in Taiwan and China. Dr. Chen says, "In a clinical study in China, Chipscreen Biosciences showed that chidamide, in combination with exemestane, effectively reduced tumor growth in hormone-receptor (HR)-positive patients, inspiring the final outcome of this cross-strait clinical trial. And thereafter, chidamide was approved and launched in China."
In this new randomized, double-blind, placebo-controlled trial, GNTbm used chidamide (brand name Kepida® in Taiwan) in combination with exemestane (a standard endocrine drug against breast cancer) in 55 patients from Taiwan and 365 patients from China. These patients had HR-positive and HER-2-negative advanced breast cancer, resistant to endocrine therapy. And, the results were promising!
According to the data for Taiwan and China combined, the median progression-free survival was 7.4 months for the chidamide group and 3.7 months for the placebo group, whereas according to Taiwan's separate data on 55 patients, the median progression-free survival was 8.6 months for the chidamide group and 3.7 months for the placebo group. These findings firmly establish the efficacy of the medication.
"The current clinical study is the first to explore the effects of an HDAC inhibitor combined with exemestane. The findings show progression-free survival benefit in HR-positive endocrine treatment-resistant patients with breast cancer, hopefully, leading to better survival rates for patients in the future," concludes Dr. Chen.
These findings from GNTbm's new clinical trial generate some much-needed hope for patients fighting against breast cancer!
