19 January 2021 - - British-Swedish pharmaceutical and biopharmaceutical company AstraZeneca (OTC: AZNCF) and Japan-based pharmaceutical company Daiichi Sankyo Company, Ltd's (OTC: DSKYF) Enhertu (fam-trastuzumab deruxtecan-nxki) has been approved in the US for the treatment of adult patients with locally advanced or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma who have received a prior trastuzumab-based regimen, the company said.

In the US, gastric cancer is more frequently diagnosed in the advanced stage with only approximately 5% of patients surviving beyond five years.

Approximately one in five gastric cancers are HER2 positive.

The approval by the Food and Drug Administration was based on the positive results from the randomized DESTINY-Gastric01 Phase II trial conducted in Japan and South Korea.

In the trial, Enhertu demonstrated a statistically significant and clinically meaningful improvement in overall survival and objective response rate versus chemotherapy (irinotecan or paclitaxel) in patients with advanced gastric cancer or GEJ adenocarcinoma who had progressed on at least two or more prior regimens including trastuzumab plus a fluoropyrimidine- and a platinum-containing chemotherapy combination.

In a pre-specified interim analysis from the DESTINY-Gastric01 trial, patients treated with Enhertu had a 41% reduction in the risk of death versus patients treated with chemotherapy (based on a hazard ratio [HR] of 0.59; 95% confidence interval [CI] 0.39-0.88; p=0.0097) with a median OS of 12.5 months versus 8.4 months.

Confirmed ORR, assessed by independent central review was a major efficacy outcome. Results showed a confirmed ORR of 40.5% in patients treated with Enhertu (n=126) compared to 11.3% in patients treated with chemotherapy.

Patients treated with Enhertu had a 7.9% complete response rate and a 32.5% partial response rate compared to a complete response rate of 0% and a partial response rate of 11.3% for patients treated with chemotherapy.

Enhertu demonstrated a median progression-free survival of 5.6 months compared to 3.5 months with chemotherapy (HR=0.47; 95% CI 0.31-0.71). 

Additionally, Enhertu showed a median duration of response of 11.3 months versus 3.9 months with chemotherapy.

Results from the DESTINY-Gastric01 trial were published in The New England Journal of Medicine in June 2020.