Detailed results from the positive Phase II DESTINY-Gastric02 trial showed that Enhertu (trastuzumab deruxtecan), the AstraZeneca and Daiichi Sankyo Company, Limited (Daiichi Sankyo) HER2-directed antibody drug conjugate (ADC), provided a clinically meaningful and durable tumour 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 (ESMO) Congress 2021.
Gastric cancer is associated with a poor prognosis, particularly in the advanced stages of the disease, with only 5% to 10% of metastatic patients surviving five years globally.1,2 Approximately one in five gastric cancers are HER2-positive.3,4
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% as assessed by independent central review (ICR). Three (3.8%) complete responses (CR) and 27 (34.2%) partial responses (PR) were observed in patients treated with Enhertu.
These results were consistent with those from the registrational DESTINY-Gastric01 Phase II trial previously published in The New England Journal of Medicine.
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.
Eric Van Cutsem, MD, PhD, University Hospitals Leuven, said: "While the benefit of a HER2-targeted therapy in the first-line metastatic gastric cancer setting has been well-established, the disease will eventually progress. The positive results of DESTINY-Gastric02 show a strong response rate and reinforce the established efficacy and safety profile of Enhertu in patients who are in need of additional therapeutic options."
Susan Galbraith, Executive Vice President, Oncology R&D, said: "The data from DESTINY-Gastric02 reaffirm the clinical significance of the potential benefit of Enhertu in patients with advanced gastric cancer. Patients often experience disease progression following initial therapies, and then face limited treatment options, so today's news brings hope to both patients and treating physicians."
Gilles Gallant, Senior Vice President, Global Head, Oncology Development, Daiichi Sankyo, said: "The encouraging results from DESTINY-Gastric02 are consistent with those previously seen in the pivotal DESTINY-Gastric01 trial. This additional data will support our ongoing discussions with global health authorities as we work toward Enhertu becoming an option for patients with HER2-positive metastatic gastric cancer."
