- A new cancer drug developed by Daiichi Sankyo and AstraZeneca met one of its two main goals in a breast cancer trial, helping patients who had progressed on earlier-line treatments live longer than those receiving chemotherapy without their disease getting worse, the companies said Friday.
- The trial tested the drug, known as datopotamab deruxtecan, in HER2-low or -negative patients whose tumors were sensitive to hormone treatments before their cancer returned. AstraZeneca and Daiichi didn’t release detailed data, and stated that the trial hadn’t gone on long enough to tell if patients given their treatment lived longer overall, the trial’s other main goal.
- The data suggest the companies’ drug could present a threat to Gilead’s similarly acting medicine Trodelvy, which gained approval in a similar setting earlier this year. HR-positive, HER2-negative breast cancer is the most common form of the disease.
Datopotomab deruxtecan is a combination of an antibody and a chemotherapy drug, designed to home in on a protein expressed on cancer cells before delivering the toxic chemical. This type of drug, pioneered by the drugmaker Wyeth, now part of Pfizer, is becoming more common in cancer treatment.
Trodelvy and datopotamab deruxtecan both bind to a protein called TROP-2. The Gilead drug is growing in importance for the California-based company and could reach blockbuster status this year, having generated sales of $482 million through the first six months of 2023.
In the Phase 3 TROPION-Breast01 trial, AstraZeneca and Daiichi compared datopotamab deruxtecan to chemotherapy in patients whose tumors can’t be removed by surgery or have spread outside the breast tissue. Before entering the trial, participants must have first progressed on endocrine therapy and at least one line of chemo.
The progression-free survival benefit for datopotamab deruxtecan was seen at an interim analysis, AstraZeneca and Daiichi said. They companies described that outcome as both statistically significant and clinically meaningful. In this same setting, Trodelvy reduced the risk of progression by 34% and risk of death by 21%.
The rates of interstitial lung disease, a type of lung scarring, were low with datopotamab deruxtecan, the companies said. This side effect has been seen in other trials of drug, which could limit its use.
The announcement suggests that datopotamab deruxtecan could be a significant rival to Trodelvy, RBC Capital Markets analyst Brian Abrahams wrote in a note to clients, adding he “would not be surprised to see pressure on Trodelvy's peak $2.1 [billion] U.S. sales opportunity in breast [cancer].”
”That said, we note [Gilead’s management] remains confident that Trodelvy's entrenchment in breast cancer can limit any negative read-throughs,” he wrote.