- An experimental antibody drug from AstraZeneca and Daiichi Sankyo delayed disease progression compared to standard chemotherapy, meeting a key goal in a Phase 3 trial of patients with a common form of lung cancer, the companies said Monday.
- The medicine, called datopotamab deruxtecan, hasn’t yet led to a statistical improvement in survival versus chemo, the trial’s other main objective. AstraZeneca and Daiichi said the study will continue while investigators wait to see whether an “early trend” in survival leads to a meaningful difference, the companies said. They didn’t provide details beyond the summary findings.
- The two companies did disclose, however, that there were deaths in the study from a type of lung scarring. It’s unclear whether those deaths were linked to treatment. But the side effect, interstitial lung disease, has been seen in testing of datopotamab deruxtecan and other drugs like it. AstraZeneca shares fell almost 9% on Monday.
The partnership between AstraZeneca and Daiichi is best known for Enhertu, a drug that’s now cleared for use in multiple cancer settings and became the first targeted therapy for what’s known as “HER2 low disease.” Analysts expect the drug to generate more than $4 billion in yearly revenue as its use grows with time.
Next in line is datopotamab deruxtecan. Like Enhertu, it’s an antibody-drug conjugate or ADC, a medicine that chemically links an antibody to a tumor-killing toxin. The drug is also part of a lucrative alliance between the two companies, with AstraZeneca in 2020 promising to pay Daiichi up to $6 billion for partial rights.
The study the two companies reported on Monday, which compares datopotamab deruxtecan to the chemotherapy docetaxel in previously treated non-small cell lung cancer patients, is the drug’s first definitive test.
The data have been anticipated by investors and analysts, as a positive result could position datopotamab deruxtecan as a possible replacement for chemotherapy in one of the most common forms of cancer. Jefferies analyst Peter Welford has estimated that success in this study, and eventually earlier treatment lines, could unlock a sales opportunity of up to $14 billion annually at peak.
The study is also notable as the first Phase 3 test of a drug targeting TROP2, a protein overexpressed in all types of lung cancer. There are no approved TROP2-targeting therapies for lung tumors; datopotamab deruxtecan has a chance to become the first. Ken Takeshita, Daiichi’s global head of oncology research, said in a statement that the partners will discuss the findings from the Phase 3 trial with regulators.
Yet the summary results have left analysts with questions about the drug’s impact. In a Monday research note, SVB Securities analyst Andrew Berens wrote that the statement didn’t include details or commentary that the results were “clinically relevant,” leading to speculation that the findings may be “less robust than anticipated.”
It’s possible that “the Trop2-targeted ADC mechanism is not as superior to docetaxel as had been hoped,” added RBC Capital Markets’ analyst Brian Abrahams. “Validation for the Trop2 mechanism [is] possible, but not entirely clear,” he wrote.
Key study details are coming at a forthcoming medical meeting, with analysts expecting a presentation at either the European Society for Medical Oncology or the World Conference on Lung Cancer.
The results have implications not only for AstraZeneca and Daiichi, but Gilead Sciences, which has a competing TROP2-targeting drug, Trodelvy, in late-stage testing in lung cancer. Results from Gilead’s study are expected next year.
That’s also likely when to expect another update on datopotamab deruxtecan’s lung cancer study, SVB’s Berens wrote.