Trastuzumab deruxtecan ups PFS in HER2+ metastatic breast cancer

For patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer previously treated with trastuzumab and a taxane, the risk of progression or death from any cause is lower with trastuzumab deruxtecan versus trastuzumab emtansine, according to a study published in the March 24 issue of the New England Journal of Medicine.

Javier Cortés, M.D., Ph.D., from the International Breast Cancer Center in Barcelona, Spain, and colleagues conducted a phase 3, open-label trial to compare the efficacy and safety of trastuzumab deruxtecan (a HER2 antibody-drug conjugate) with trastuzumab emtansine in 524 patients with HER2-positive metastatic breast cancer who had previously been treated with trastuzumab and a taxane.

The researchers found that the percentage of patients who were alive without disease progression at 12 months was 75.8 and 34.1 percent with trastuzumab deruxtecan and trastuzumab emtansine, respectively (hazard ratio for progression or death from any cause, 0.28). The corresponding percentage of patients who were alive at 12 months was 94.1 and 85.9 percent (hazard ratio for death, 0.55; prespecified significance boundary not reached). An overall response occurred in 79.7 and 34.2 percent of the patients, respectively. The incidence of grade 3 or 4 drug-related adverse events was 45.1 and 39.8 percent, respectively; adjudicated drug-related interstitial lung disease or pneumonitis occurred in 10.5 and 1.9 percent of patients in the trastuzumab deruxtecan and trastuzumab emtansine groups, respectively.

"Trastuzumab deruxtecan is an effective new treatment for patients with HER2-positive metastatic breast cancer who have been previously treated with trastuzumab and a taxane, as well as with pertuzumab when available," the authors write.

The study was funded by Daiichi Sankyo and AstraZeneca, the manufacturers of trastuzumab deruxtecan.

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