AstraZeneca’s $7B ADC succeeds where Roche failed, improving survival in gastric cancer
Another day, another win for Enhertu.
The antibody-drug conjugate AstraZeneca promised up-to $7 billion to partner on has had a quite a few months, beginning with splashy results in a Phase II breast cancer trial, a rapid approval and, earlier this month, breakthrough designations in both non-small cell lung cancer and gastric cancer.
Now, at ASCO, the British pharma and their Japanese partner, Daiichi Sankyo, have shown off the data that led to the gastric cancer designation, which they’ll take back to the FDA. In a pivotal, 187-person Phase II trial, Enhertu shrunk tumors in 42.9% of third-line patients with HER2-positive stomach cancer, compared with 12.5% in a control arm where doctors prescribed their choice of therapy. Progression-free survival was 5.4 months for Enhertu compared to 3.5 months for the control.
Most crucially, the drug proved more effective in extending patients’ lives; the median overall survival was 12.5 months for Enhertu, compared to 8.4 months in the control.
“Once patients with HER2-positive metastatic gastric cancer progress following initial treatment with an anti-HER2 regimen, there are limited options and no approved HER2-targeted therapies,” lead investigator Kohei Shitara said in a statement. “Based on the compelling results of the DESTINY-Gastric01 trial, Enhertu has the potential to become a new standard of care for these patients.”
The positive results are particularly noteworthy because a key rival drug failed against gastric cancer. Kadcyla, Roche’s blockbuster HER2 targeting antibody drug conjugate, flopped 5 years ago in a Phase II/III trial in second-line patients. That trial was part of what dampened sales for the drug, which once held the $2 billion-plus promise that Enhertu now holds but has ultimately peaked around $1 billion.
The data add to what has quickly emerged as a successful ASCO for AstraZeneca and CEO Pascal Soriot, who has spent much of his nearly decade-long tenure reinventing the ailing British Pharma’s cancer R&D engine. Last night, they released much-anticipated data from their Tagrisso non-small cell lung cancer trial, showing that after 2 years of follow up, 90% of patients were tumor-free. They were not able, though, to yet show a survival benefit.