January 19, 2021
The U.S. FDA has approved a new indication for Enhertu® (fam-trastuzumab deruxtecan-nxki), manufactured by Daiichi Sankyo. Enhertu is now indicated to treat adults who have locally advanced or metastatic HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma and have received prior treatment with a trastuzumab-based regimen.
Approximately one-fifth of all cases of gastric cancer are HER2-positive, which is associated with more aggressive tumor development. While treatable, gastric cancer is often not diagnosed until it has reached an advanced stage. At this stage, the five-year survival rate is only 5%.
In a clinical trial, patients treated with Enhertu had a 41% reduced risk of death compared to patients who received standard chemotherapy. Patients who received Enhertu also had a longer median overall survival, at 12.5 months versus 8.4 months with chemotherapy. The overall response rate with Enhertu was 40.5%, and 11.3% with chemotherapy. In addition, median progression-free survival with Enhertu was 5.6 months compared to 3.5 months with chemotherapy and the median duration of response was
11.3 months versus 3.9 months with chemotherapy.
Recommended dosing under the new indication is s 6.4mg/kg of the patient’s body weight administered via intravenous infusion once every three weeks until disease progression or unacceptable toxicity occur. A black box warning cautions that there is a risk of interstitial lung disease and embryo-fetal toxicity associated with the use of Enhertu.
First FDA approved in 2019, Enhertu is also indicated to treat adults who have unresectable or metastatic HER2-positive breast cancer and have received treatment with at least two prior anti-HER2-based regimens in the metastatic setting.