The FDA has accepted and granted priority review to a supplemental Biologics License Application for trastuzumab deruxtecan for the treatment of patients with HER2-positive metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma, according to a press release from the manufacturer.

The priority review designation was based on results from the DESTINY-Gastric01 trial, a phase 2, open-label, randomized controlled study.

The study included 188 patients from Japan and South Korea with HER2-positive, advanced gastric or GEJ adenocarcinoma who have progressed on two or more prior treatment regimens including fluoropyrimidine and platinum chemotherapy, and trastuzumab.

Patients were randomly assigned 2:1 to receive trastuzumab deruxtecan 6.4mg/kg once every three weeks or investigator’s choice of chemotherapy (paclitaxel or irinotecan monotherapy).

Treatment with trastuzumab deruxtecan resulted in statistically significant and clinically meaningful improvements in objective response rate and overall survival.

“Once patients with HER2-positive metastatic gastric cancer progress following initial treatment with an anti-HER2 regimen, there are no approved HER2-directed medicines. The prognosis for these patients is poor, as available treatment options offer only limited clinical benefit. This milestone brings us one step closer to delivering a potentially practice-changing medicine to patients with gastric cancer in the US," José Baselga, Executive Vice President, Oncology R&D at AstraZeneca, said in the release.

The safety profile was consistent with previous trials of trastuzumab deruxtecan. The most common grade 3 or higher treatment-emergent adverse events included decreased neutrophil count, anemia, decreased white blood cell count and decreased appetite.

“The results of the DESTINY-Gastric01 trial are unprecedented as they represent the first time a HER2-directed medicine has demonstrated an improvement in survival following chemotherapy and HER2 treatment in the metastatic setting. Building on the recent Breakthrough Therapy Designation, the filing of the application and Priority Review by the FDA for this potential new indication for [trastuzumab deruxtecan] reflects the importance of the data and the significant unmet need for patients with previously treated HER2-positive metastatic gastric cancer," Antoine Yver, Executive Vice President and Global Head, Oncology Research and Development, Daiichi Sankyo, said in the release.

The FDA set a Prescription Drug User Fee Act date of first quarter 2021.