AstraZeneca's (AZN.US) investigational gastric cancer drug doubled patient survival time in a late-stage trial, adding weight to another potential blockbuster. The antibody-drug conjugate (ADC) called sone-ve helped patients whose gastric cancer had spread and who had failed other treatments live 5 months longer than those receiving chemotherapy and other anti-cancer drugs.
Susan Galbraith, AstraZeneca's executive vice president of oncology hematology R&D, said these results reinforce AstraZeneca's belief that antibody-drug conjugates—a class of complex targeted therapies—could replace chemotherapy in the treatment of many tumors. AstraZeneca has set a potential annual sales expectation of $3 billion to $5 billion for the drug, whose full name is sonesitatug vedotin. The drug targets a protein on the inner lining of the stomach wall that is expressed in certain gastric cancers.
In research presented Sunday at the European Society for Medical Oncology (ESMO) conference, the drug helped patients whose disease had still progressed after first-line treatment live longer, but the benefit was greater for those who received the drug after already undergoing two lines of treatment. Salah-Eddine Al-Batran, managing director of the Frankfurt Institute of Clinical Cancer Research, said that for this type of patient, sone-ve is likely to become a new treatment strategy. He was not involved in the study.
However, Al-Batran said more data is needed before the drug is widely used in earlier lines of treatment. The drug failed to show it could delay disease progression, which Galbraith said may be because disease progression in gastric cancer is difficult to measure. Ahead of the conference, industry research analysts said that if sone-ve could demonstrate a convincing survival benefit, its annual sales could reach up to $2.2 billion.
In the study, patients treated with older drugs dropped out due to side effects at a higher rate than the sone-ve group, while treatment-related deaths were roughly comparable. Dave Fredrickson, executive vice president of AstraZeneca's oncology business unit, said AstraZeneca is communicating with health regulators about these data.
There is already one approved drug targeting the same protein—Astellas Pharma Inc.'s Vyloy—which targets the same protein called Claudin 18.2. But it is only suitable for patients whose tumors express much higher levels of the protein, limiting the number of patients eligible for treatment. Other pharmaceutical companies are also pursuing the same target. In a separate gastric cancer patient population, Takeda Pharmaceutical's arcotatug tavatecan helped subjects live more than 3 months longer, with related data presented at the conference. Phuong Khanh Morrow, Takeda's head of oncology therapeutic area, said the difference with Takeda's drug is fewer gastrointestinal side effects. She said its mechanism of action "really reduces the risk of any nausea, vomiting and diarrhea."
Other data AstraZeneca presented at the conference included a late-stage trial of its blockbuster drug Tagrisso (osimertinib) combined with Orpathys (savolitinib) in treating a type of non-small cell lung cancer patient. Compared with chemotherapy, this combination regimen delayed disease progression by more than 2 months and extended survival by nearly 5 months. These patients are particularly difficult to treat because of overexpression of a certain protein in their cancer cells. Natasha Leighl, a professor in the Department of Medicine at the University of Toronto, said these data are likely to "change the standard of care." Researchers said both Tagrisso and Orpathys are tablets that can be taken at home, and the safety profiles of both drugs are manageable.
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