AstraZeneca and Daiichi Sankyo’s Enhertu (trastuzumab deruxtecan) has been granted Breakthrough Therapy Designation (BTD) in the US for the treatment of patients with HER2-positive unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma who have received two or more prior regimens including trastuzumab.
The Food and Drug Administration’s (FDA) BTD is designed to accelerate the development and regulatory review of potential new medicines that are intended to treat a serious condition and address a significant unmet medical need. The new medicine needs to have shown encouraging early clinical results that demonstrate substantial improvement on a clinically significant endpoint over available medicines.
“Current therapy options are limited for patients with HER2-positive metastatic gastric cancer and for those who relapse, there are no approved HER2-targeted medicines. We look forward to working with the FDA to further explore the potential of Enhertu to become an important new treatment and the first antibody drug conjugate for this devastating disease,” says José Baselga, Executive Vice President, R&D Oncology, AstraZeneca.
The DESTINY-Gastric-01 trial
The FDA granted BTD based on data from the registrational Phase II DESTINY-Gastric01 trial and data from the Phase I trial published in The Lancet Oncology. In DESTINY-Gastric01, patients treated with Enhertu, a HER2-directed antibody drug conjugate (ADC), demonstrated a statistically significant and clinically meaningful improvement in objective response rate (ORR), the primary endpoint, and overall survival (OS), a key secondary endpoint, versus patients treated with investigator’s choice of chemotherapy (irinotecan or paclitaxel monotherapy).
The overall safety and tolerability profile of Enhertu (6.4 mg/kg) in DESTINY-Gastric01 was consistent with that seen in the Phase I trial. The most common adverse events were haematologic and gastrointestinal including neutrophil count decrease, anaemia, nausea and decreased appetite. There were cases of drug-related interstitial lung disease (ILD) and pneumonitis, the majority of which were Grade 1 and 2, with two Grade 3 and one Grade 4. No ILD-related deaths (Grade 5) occurred in patients with gastric cancer in the Phase I trial or in the Phase II DESTINY-Gastric01 trial.
Enhertu received SAKIGAKE designation in March 2018 by Japan’s Ministry of Health, Labour and Welfare (MHLW) for potential use in the same HER2-positive gastric cancer patient population and was recently submitted to the MHLW for approval. This is the second BTD granted for Enhertu in the US. Enhertu received BTD in 2017 for HER2-positive metastatic breast cancer and received approval in December 2019.
Photo of José Baselga: AstraZeneca