The Food & Drug Administration has approved a new treatment for American patients with a common form of breast cancer that has spread to other parts of the body or cannot be surgically removed.
In December, it was approved in Japan to treat patients with a type of breast cancer who had previously received chemotherapy.
The drug, known as datopotamab deruxtecan but marketed under the brand name Datroway, is intended to treat hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative tumours that have already been treated with hormone therapy and chemotherapy.
WebMD reports that while early-stage cases often respond well to treatment, only about one in three people with metastatic breast cancer survive more than five years, highlighting the urgent need for improved tumour-targeted therapies.
Datroway belongs to a class of medicines called antibody-drug conjugates and is designed to target cancer cells while sparing the healthy ones. It combines a monoclonal antibody, datopotamab, that targets trophoblast cell surface antigen 2 (TROP2), a protein commonly found in high levels on breast cancer cells, with the chemotherapy drug deruxtecan.
Once attached to cancer cells, it releases the drug directly inside, disrupting the cells’ DNA and stopping their growth.
Developed by AstraZeneca and Daiichi Sankyo, Datroway is given as an IV every three weeks. AstraZeneca and Daiichi’s first co-developed ADC, Enhertu, was first approved by the FDA in 2019 for a type of breast cancer and later expanded for use in multiple conditions. Gilead’s Trodelvy also belongs to the same class of drugs.
The effectiveness of the new drug was evaluated in a clinical trial involving 732 patients whose disease had worsened, were unsuitable to receive more hormonal therapy, and had already received one or two rounds of chemotherapy for advanced or metastatic cancer.
Patients were randomly assigned to receive either Datroway or standard chemotherapy. Results showed that patients treated with Datroway lived for about 6.9 months on average without their cancer worsening, compared with 4.9 months for the standard chemotherapy group.
Cancer improved in 36% of patients in the Datroway group, compared with 23% in the standard chemotherapy group, with responses lasting for an average of 6.7 months versus 5.7 months seen in the group receiving standard chemotherapy.
The most common side effects included mouth sores, nausea, vomiting, constipation, tiredness, hair loss, dry eyes, eye inflammation (keratitis), and certain abnormalities in blood cell counts, haemoglobin levels, and liver enzymes.
Reuters reports that the two companies are also seeking approval for the drug in patients with a type of lung cancer with a mutated form of a gene called EGFR, who have previously received treatment.
Reuters article – US FDA approves AstraZeneca’s drug for breast cancer (Open access)
WebMD article – FDA Approves New Treatment for Advanced Breast Cancer (Open access)
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