The partners are pushing to expand Enhertu’s list of indications beyond its standing uses in breast, lung and gastric cancers.
AstraZeneca and Daiichi Sankyo continue to rack up wins for their lead antibody-drug conjugate Enhertu, with a Phase III readout on Monday pointing to the drug’s strong potential in gastric cancer, with an eye toward adding yet another indication to the drug’s roster.
Results from the late-stage Destiny-Gastric04 study showed that Enhertu resulted in a “statistically significant and clinically meaningful improvement” in overall survival in patients with HER2-positive unresectable and/or metastatic gastric or gastroesophageal junction cancer. The study deployed the antibody-drug conjugate (ADC) as a second-line therapy and compared it against ramucirumab and paclitaxel.
Given these signals of “superior efficacy,” an independent data monitoring committee has recommended that the trial be unblinded ahead of schedule, as per the companies’ announcement.
The partners did not provide specific data on Monday, instead promising to do so at an upcoming medical congress. The two companies will also share these findings with regulatory health authorities, with an eye toward “approval in regions where Enhertu is not currently indicated as a second-line option” in gastric and gastroesophageal junction cancer, Ken Takeshita, global head of Oncology R&D at Daiichi Sankyo, said in a statement.
“Enhertu is the first HER2 directed medicine to demonstrate an improvement in overall survival in a randomized phase 3 trial in the second-line metastatic setting of patients with HER2 positive gastric cancer,” Takeshita added.
Enhertu is an ADC that targets the HER2 protein, commonly found on cancer cells, and carries a topoisomerase I inhibitor payload. Since it was first approved in 2019, the therapy has secured several indications for various types of breast, lung and gastric cancer. Most recently, Enhertu in January secured a label expansion, allowing its use in breast cancer patients with low or ultralow expression levels of HER2.
In gastric cancer, Enhertu bagged its first approval in January 2021 under the FDA’s accelerated pathway, backed by Phase II data showing significant survival and response rate improvements in patients with gastric or gastroesophageal junction cancers. In the press announcement on Monday, Takeshita said the partners will also use Destiny-Gastric04’s findings to “secure full approval in regions where Enhertu is conditionally approved.”
AstraZeneca and Daiichi Sankyo also recently won the FDA’s approval for another ADC they are working on together. Datroway, which also carries a topoisomerase I inhibitor but instead targets the TROP2 protein, was cleared in January for the treatment of HR-positive and HER2-negative breast cancers.
