The FDA ( Food and Drug Administration ) has approved Enhertu ( fam-Trastuzumab Deruxtecan-nxki; fam-Trastuzumab Deruxtecan ) for adult patients with locally advanced or metastatic HER2-positive gastric or gastroesophageal junction ( GEJ ) adenocarcinoma who have received a prior Trastuzumab-based regimen.
Efficacy was evaluated in a multicenter, open-label, randomized trial ( DESTINY-Gastric01 ) in patients with HER2-positive locally advanced or metastatic gastric or GEJ adenocarcinoma who had progressed on at least two prior regimens, including Trastuzumab, a fluoropyrimidine- and a Platinum-containing chemotherapy.
A total of 188 patients were randomized ( 2:1 ) to receive fam-Trastuzumab deruxtecan-nxki 6.4 mg/kg intravenously every 3 weeks or physician’s choice of either Irinotecan or Paclitaxel monotherapy.
The main efficacy outcome measures were overall survival ( OS ) and objective response rate ( ORR ) assessed by independent central review ( RECIST 1.1 ) in the intent-to-treat population.
Additional efficacy outcome measures were progression-free survival ( PFS ) and duration of response ( DOR ).
Overall survival was 12.5 months ( 95% CI: 9.6, 14.3 ) in the fam-Trastuzumab deruxtecan-nxki arm compared with 8.4 months ( 95% CI: 6.9, 10.7 ) in the Irinotecan or Paclitaxel arm ( hazard ratio, HR=0.59; 95% CI: 0.39, 0.88, p=0.0097 ).
Confirmed objective response rate was 40.5% ( 95% CI: 31.8, 49.6 ) in the fam-Trastuzumab deruxtecan-nxki arm compared with 11.3% ( 95% CI: 4.7, 21.9 ) for those receiving Irinotecan or Paclitaxel.
Median progression-free survival was 5.6 months ( 95% CI: 4.3, 6.9 ) in the fam-Trastuzumab deruxtecan-nxki arm compared to median PFS of 3.5 months ( 95% CI: 2.0, 4.3 ) in the Irinotecan or Paclitaxel arm.
Median duration of response was 11.3 months ( 95% CI: 5.6, NR ) vs 3.9 months ( 95% CI: 3.0, 4.9 ), respectively.
The most common ( 20% or more ) adverse reactions including laboratory abnormalities were: 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.
The Prescribing Information includes a Boxed Warning to advise health professionals of the risks of interstitial lung disease and embryo-fetal toxicity.
The recommended fam-Trastuzumab deruxtecan-nxki dose for gastric cancer is 6.4 mg/kg administered as an intravenous infusion once every 3 weeks ( 21-day cycle ) until disease progression or unacceptable toxicity. ( Xagena )
Source: FDA, 2021