Detailed results from the positive DESTINY-Gastric02 phase 2 trial showed that ENHERTU® (trastuzumab deruxtecan), the Daiichi Sankyo Company, Limited (hereafter, Daiichi Sankyo) and AstraZeneca HER2 directed antibody drug conjugate (ADC), provided a clinically meaningful and durable tumor response in patients with HER2 positive metastatic and/or unresectable gastric or gastroesophageal junction (GEJ) adenocarcinoma previously treated with a trastuzumab-containing regimen. Results were presented during a late-breaking Mini Oral presentation at the European Society for Medical Oncology (#ESMO21) 2021 Virtual Congress (#LBA55). In the primary analysis of DESTINY-Gastric02, the first trial of ENHERTU specifically in Western patients with HER2 positive metastatic gastric cancer or GEJ adenocarcinoma, ENHERTU (6.4 mg/kg) demonstrated a confirmed overall response rate (ORR) of 38.0% (n=30; CI: 27.3-49.6) as assessed by independent central review (ICR). Out of a total of 79 patients treated with ENHERTU, three (3.8%) complete responses (CR) and 27 (34.2%) partial responses (PR) were observed. These results were consistent with those from the pivotal DESTINY-Gastric01 phase 2 trial, previously published in The New England Journal of Medicine, which evaluated ENHERTU in patients from Japan and South Korea with HER2 positive advanced gastric or GEJ adenocarcinoma who had progressed on two or more prior treatment regimens, including trastuzumab, a fluoropyrimidine and platinum-containing chemotherapy. After a median follow-up of 5.7 months, the median duration of response (DoR) of ENHERTU was 8.1 months (95% CI: 4.1-NE). The median progression-free survival (PFS) was 5.5 months (95% CI: 4.2-7.3). An exploratory endpoint of confirmed disease control rate (DCR) of 81% (95% CI: 70.6-89.0) was seen. The overall safety profile of ENHERTU in DESTINY-Gastric02 was consistent with that seen in DESTINY- Gastric01. The most common grade 3 or higher drug-related treatment-emergent adverse events seen in DESTINY-Gastric02 were anemia (7.6%), neutropenia (7.6%), nausea (3.8%), fatigue (3.8%), vomiting (1.3%), diarrhea (1.3%), decreased appetite (1.3%) and decreased platelet count (1.3%). Seven patients (8.9%) discontinued treatment due to drug-related treatment-emergent adverse events. There were six cases (7.6%) of treatment-related interstitial lung disease (ILD) or pneumonitis reported, as determined by an independent adjudication committee. The majority (83%) were low grade (grade 1 or grade 2), with one grade 5 (ILD or pneumonitis-related death).