The Food and Drug Administration has approved the use of Enhertu, developed by AstraZeneca plc (NASDAQ: AZN) and Daiichi Sankyo (OTCMKTS: DSNKY) for treating metastatic or unpredictable HER2-Low breast cancer. The patients receiving the drug should have received chemotherapy or had recurrent disease after about six months of adjuvant chemotherapy.

The authorisation came after the company released the results of a Phase II trial which showed a 50% reduction in the risk of breast cancer progression or death.

The drug is the first to target Her2-low

According to Dr Shanu Modi, a medical oncologist at the Memorial Sloan Lettering Cancer Centre in the U.S, about 50% of breast cancer patients have HER2-low tumours. These tumours are previously diagnosed as HER2-negative, and the treatment that targets HER2 is interactive for them.

Dr Modi points out that the study could allow medical professionals to find better ways of detecting HER2-low breast cancer and find patients that qualify for the appropriate treatment. As a result, this could lower disease progression or mortality among these patients.

The Executive Vice President of the Oncology Business Unit at AstraZeneca, Dave Fredrickson, said the drug had received fast approval from the FDA as there is a sizeable unmet need for patients with breast cancer. Patients with HER2-low disease will now receive adequate treatment.

The CEO, President and Global Head of the Oncology Business Unit at Daiichi Sankyo, Ken Keller, adds that this is the first approved treatment for patients with HER2-low breast cancer, thus a significant step for the company.

The drug gained Breakthrough Therapy Designation and Priority Review from the FDA, thus allowing the companies to accelerate research and development. The companies presented their finding at the American Society of Clinical Oncology’s Annual Meeting. They also published the results in The New England  Journal of Medicine.

The companies hope to gain approval in other countries 

 The drug’s safety profile showed similar results to previous clinical trials. Moreover, researchers found no safety concerns after administering it to trial participants. Regulars from other regions are also looking into authorising the drug. This includes Seissmedic in Switzerland, Health Canada, the Brazilian Health Regulatory Agency and the Australian Therapeutic Goods Administration. It is also under review in Japan and several European countries.