FDA approves Enhertu for gastric cancer subset
The FDA approved fam-trastuzumab deruxtecan-nxki for treatment of certain patients with gastric or gastroesophageal adenocarcinoma.
The approval applies to use of the agent by adults with locally advanced or metastatic HER2-positive disease who received a prior trastuzumab (Herceptin, Genentech)-based regimen.
Fam-trastuzumab deruxtecan-nxki (Enhertu; AstraZeneca, Daiichi Sankyo) is a novel antibody-drug conjugate with three components: a humanized anti-HER2 immunoglobulin G1 monoclonal antibody with the same amino acid sequence as trastuzumab; a topoisomerase 1 inhibitor payload; and a tetrapeptide-based cleavable linker.
The FDA based the approval on results of the randomized, open-label DESTINY-Gastric01 trial, which included 188 patients with HER2-positive locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma who progressed on at least two prior regimens, including trastuzumab and chemotherapy.
Researchers randomly assigned patients 2:1 to fam-trastuzumab deruxtecan-nxki dosed at 6.4 mg/kg via IV every 3 weeks or physician’s choice of either irinotecan or paclitaxel monotherapy.
OS and objective response rate in the intent-to-treat population as assessed by independent central review served as the main efficacy outcome measures. PFS and duration of response served as additional efficacy outcome measures.
Researchers reported longer median OS (12.5 months vs. 8.4 months; HR = 0.59; 95% CI, 0.39-0.88) and a higher confirmed ORR (40.5% vs. 11.3%) in the fam-trastuzumab deruxtecan-nxki group. Results for PFS (median, 5.6 months vs. 3.5 months) and duration of response (median, 11.3 months vs. 3.9 months) also favored the experimental treatment group.
The most common adverse events included anemia, leukopenia, neutropenia, lymphocytopenia, thrombocytopenia, nausea, decreased appetite, increased aspartate aminotransferase, fatigue, increased blood alkaline phosphatase, increased alanine aminotransferase, diarrhea, hypokalemia, vomiting, constipation, increased blood bilirubin, pyrexia and alopecia.
A boxed warning advises clinicians about the risks for interstitial lung disease and embryo-fetal toxicity with fam-trastuzumab deruxtecan-nxki.
The FDA previously granted priority review to fam-trastuzumab deruxtecan-nxki for this indication. The agent also is approved for treatment of adults with unresectable or metastatic HER2-positive breast cancer who received at least two prior anti-HER2-based regimens in the metastatic setting.