NEW YORK – Japanese regulators have approved Daiichi Sankyo's trastuzumab deruxtecan (Enhertu), a HER2-targeted antibody drug conjugate, for chemotherapy-treated, unresectable or recurrent breast cancer patients.
Japan's Ministry of Health, Labor, and Welfare (MHLW) approved the drug after reviewing data from the Phase II DESTINY-Breast01 study, in which nearly 200 HER2-positive metastatic breast cancer patients received trastuzumab deruxtecan. In the single-arm study, 64 percent of 167 evaluable patients saw their tumors shrink. The median duration of response was more than 14 months. As of the data cutoff in March last year, 26 Japanese women were included in the analysis.
The US Food and Drug Administration also approved trastuzumab deruxtecan in December, based on results from the same study, for the treatment of unresectable or metastatic HER2-positive breast cancer patients who had previously received another anti-HER2 regimen.
In Japan, the approval also limits the drug's use to advanced HER2-positive breast cancer patients who are refractory or intolerant to standard-of-care treatments.
Most patients in the trial experienced adverse events on the drug, but those events were not serious. However, in Japan the drug is approved with a warning about the risk for interstitial lung disease, which occurred in 8 percent of patients. There were fatal cases of ILD, though none of the seven Japanese patients who had it died. The drug must be used with the involvement of a respiratory disease expert.
This is Daiichi Sankyo's second precision oncology drug approved in Japan. In June 2019, the MHLW approved quizartinib (Vanflyta), a FLT3 inhibitor for adult patients with relapsed or refractory acute myeloid leukemia with FLT3 internal tandem duplications.