Daiichi Sankyo Company, Limited (Daiichi Sankyo) announced that the US Food and Drug Administration (FDA) has granted Fast Track designation to its investigational HER2-targeting antibody drug conjugate DS-8201 for the treatment of HER2-positive unresectable and/or metastatic breast cancer in patients who have progressed after prior treatment with HER2-targeted therapies including ado-trastuzumab emtansine (T-DM1).
Fast Track designation is designed to facilitate the development and expedite the review of drugs that treat serious conditions and address an unmet medical need. The designation enables early and frequent communication with the FDA and is intended to accelerate drug approval and patient access to novel treatment options.
“This is an important milestone for DS-8201 that underscores the critical need to develop new and effective therapeutic options for patients with metastatic breast cancer whose tumors are no longer controlled by currently approved targeted HER2 treatments,” said Antoine Yver, MD, MSc, executive vice president and global head, Oncology Research and Development, Daiichi Sankyo. “It’s our obligation to drive science forward to help bring innovative treatment options to cancer patients with the greatest unmet needs and we look forward to working closely with the FDA to optimize development of DS-8201.”
Fast Track designation was granted based on results from the dose escalation part of a two-part phase 1 study that assessed the safety, tolerability and preliminary efficacy of DS-8201. These results were recently presented during a late-breaking poster discussion at the European Society for Medical Oncology (ESMO) 2016 Congress and further highlighted in the concluding summary session.
The second part (dose expansion) of the ongoing phase 1 study is enrolling patients in Japan and the United States to evaluate the safety and efficacy of DS-8201 in four different cohorts of HER2 expressing cancers: patients with HER2+ metastatic breast cancer previously treated with T-DM1; patients with HER2+ gastric or gastroesophageal junction adenocarcinoma previously treated with trastuzumab; patients with HER2 low expressing breast cancer; and patients with other solid cancers that express HER2.
DS-8201 is an investigational HER2-targeting antibody drug conjugate (ADC) currently in phase 1 clinical development for HER2+ advanced or metastatic breast cancer or gastric cancer, HER2 low expressing breast cancer and other HER2 expressing solid cancers.
DS-8201 is comprised of a humanized anti-HER2 antibody attached by a peptide linker to a novel topoisomerase I inhibitor that utilizes Daiichi Sankyo’s proprietary linker-payload technology, offering a unique mechanism of action. This linker-payload combination of DS-8201 allows for a higher drug-to-antibody ratio (DAR) of about 8, which may help target low expressing HER2 tumors by supplying more payload per antibody to a tumor.
Human epidermal growth factor receptor 2 (known as HER2) is a tyrosine kinase receptor growth-promoting protein found on the surface of some cancer cells. About one in five breast cancers overexpress the HER2/neu gene, which causes these cancers to grow more aggressively. Several unmet needs remain today in HER2+ metastatic breast cancer. Many tumors advance to the point where no currently approved HER2-targeted treatment continues to control the disease. Additionally, there are no existing options indicated for HER2 low expressing tumors (IHC2+/FISH- or IHC1+), which generally have poor prognosis.