Aveo Oncology ($AVEO) gave investors the jitters Thursday, revealing an issue in survival data from a pivotal trial for its lead cancer drug tivozanib. The experimental treatment fared worse than Onyx Pharmaceuticals ($ONXX) and Bayer's Nexavar in an early assessment of overall survival (OS), and Aveo has decided to probe the issue before it asks the FDA for approval of tivozanib.
U.S. regulators "expressed concern" about the overall survival data from the developer's key TIVO-1 study, the company reported in its second-quarter earnings today, saying that 81% of patients who got Nexavar were alive after a year compared with 77% among patients on Aveo's drug. Aveo was quick to note that the overall survival statistics from the study are incomplete because, as Xconomy reported, too few patients from the 517-patient study have died to establish median figures. Yet the OS trend is unexpected because the company reported in January that patients on tivozanib lived an impressive 2.8 months longer without their cancer progressing than those on Nexavar.
"Aveo is conducting additional analyses to be included in the NDA submission that demonstrate that the OS data from TIVO-1 are consistent with improved clinical outcomes in [kidney cancer] patients receiving more than one line of therapy; analyses that the company believes will directly address this issue," the company said. The analysis could push back the company's submission of a New Drug Application for tivozanib from the third quarter to the fourth quarter of 2012.
Aveo's shares lost more than a quarter of their value after the company reported the OS issue Thursday, closing down 26.7% to $9.75 per share. Tivozanib is the company's most advanced drug, and any hitch in the data package on the program can severely damage its stock price.
Yet there's a chance that the company's analysis could resolve the issue. For now, the company points out that 53% of patients from the Nexavar arm of the trial went on to get treated with tivozanib compared with 17% of those on tivozanib that got a subsequent treatment. Did treatment on tivozanib impact the higher overall survival number for the arm with patients randomized to Nexavar?
"We believe that's the key driver in this discordance … between the overall survival endpoint and the [progression-free survival] endpoint," Aveo Chief Medical Officer William Slichenmyer said during a call with investors.
Until the analysis yields some definite answers, the company faces some unwelcome questions about whether its drug improves treatment for patients with kidney cancer. Aveo follows a bunch of pharma outfits that already have treatments on the market for renal cell carcinoma, which is the most common form of kidney cancer, and the developer knows that it must show some strong benefits for its drug to be a hit.
- here's the release
- read Xconomy's article
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