AstraZeneca and Daiichi Sankyo’s Enhertu (trastuzumab deruxtecan) has been recommended for approval in the European Union (EU) as monotherapy for the treatment of adult patients with advanced HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma who have received a prior trastuzumab-based regimen.
Enhertu is a specifically engineered HER2-directed antibody drug conjugate (ADC) being jointly developed and commercialised by AstraZeneca and Daiichi Sankyo.
The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency based its positive opinion on results from the DESTINY-Gastric02 and the DESTINY-Gastric01 Phase II trials.
In DESTINY-Gastric02, conducted in patients from North America and Europe, updated results showed treatment with Enhertu resulted in a confirmed objective response rate (ORR) of 41.8% as assessed by independent central review (ICR). Median duration of response (DoR) was 8.1 months and median overall survival (OS) was 12.1 months. Primary results from the DESTINY-Gastric02 Phase II trial were presented at the 2021 European Society for Medical Oncology (ESMO) Congress, with the updated data presented at ESMO 2022.1
In DESTINY-Gastric01, conducted in patients from Japan and South Korea, updated results showed treatment with Enhertu resulted in an ORR of 51.3% versus 14.3% with chemotherapy (irinotecan or paclitaxel). Patients treated with Enhertu had a 40% reduction in the risk of death versus patients treated with chemotherapy (based on a hazard ratio of 0.60; 95% confidence interval: 0.42-0.86, p=0.01) with a median OS of 12.5 months versus 8.9 months. Additionally, confirmed ORR, a major efficacy outcome, was 42.0% with Enhertu versus 12.5% with chemotherapy as assessed by ICR. The primary analysis was published in The New England Journal of Medicine,2 with the updated data presented at the 2021 American Society of Clinical Oncology Annual Meeting.
Susan Galbraith, Executive Vice President, Oncology R&D, AstraZeneca, said: “Gastric cancer is usually diagnosed in the advanced stage in many European countries and patients face high mortality rates. If approved, Enhertu would be the first HER2-directed medicine for patients with advanced gastric cancer in the European Union in more than a decade.”
Ken Takeshita, Global Head, Oncology R&D, Daiichi Sankyo, Inc, said: “Enhertu is the first HER2-directed medicine to demonstrate a significant improvement in overall survival compared to chemotherapy in patients with gastric cancer following initial treatment with a HER2-directed medicine in the advanced or metastatic setting. The CHMP opinion recognises the high unmet need in this patient population and brings us one step closer to bringing this medicine to patients with gastric cancer in Europe.”
In both trials, the safety profiles observed in patients treated with Enhertu were consistent with those seen in other trials of Enhertu with no new safety signals identified.
Enhertu is approved in the US and several other countries for locally advanced or metastatic HER2-positive gastric cancer.
Notes
HER2-positive gastric cancer
Gastric (stomach) cancer is the fifth most common cancer worldwide and the fourth highest leading cause of cancer mortality, with a five-year global survival rate of 5% to 10% for advanced or metastatic disease.3-5 Approximately one million new patients were diagnosed with gastric cancer in 2020, with 768,000 deaths reported globally.6 In Europe, approximately 136,000 cases of gastric cancer are diagnosed annually, and Eastern Europe has the second highest incidence of gastric cancer worldwide after Eastern Asia.5-6 Gastric cancer is the sixth leading cause of cancer death in Europe and is typically diagnosed in the advanced stage. Even when diagnosed in earlier stages of the disease, the survival rate remains modest.5-7
Approximately one in five gastric cancers are HER2-positive.8,9 HER2 is a tyrosine kinase receptor growth promoting protein expressed on the surface of many types of tumours including breast, gastric, lung and colorectal cancers.8 HER2 overexpression may be associated with a specific HER2 gene alteration known as HER2 amplification.9
Recommended first-line treatment for HER2-positive advanced or metastatic gastric cancer is combination chemotherapy plus trastuzumab, an anti-HER2 medicine, which has been shown to improve survival outcomes when added to chemotherapy.10 For patients with metastatic gastric cancer that progresses following initial treatment with a trastuzumab-based regimen, treatment options are limited, and in many regions in the world there are no additional HER2 directed medicines available.2,11,12
DESTINY-Gastric02
DESTINY-Gastric02 is an open-label, single-arm Phase II trial in Western patients evaluating the efficacy and safety of Enhertu (6.4mg/kg) in patients with HER2-positive metastatic and/or unresectable gastric or GEJ adenocarcinoma with disease progression on or after a trastuzumab-containing regimen.
The primary endpoint of DESTINY-Gastric02 is confirmed ORR based on ICR. Secondary endpoints include progression-free survival (PFS), OS, DoR and safety.
