Aveo Shares Fall as FDA Questions Cancer Drug Survival Trend

Xconomy Boston — 

Cambridge, MA-based Aveo Oncology was fired up early this year when it hit the main goal of its pivotal clinical trial with a kidney cancer drug. But today some new questions have emerged about how much benefit its drug is offering to patients, which sent the company’s stock down more than 25 percent.

Aveo (NASDAQ: AVEO) said today in its quarterly financial report that the FDA has “expressed concern” about new results from a trial called TIVO-1 which show that 81 percent of patients who were randomly assigned to get Bayer and Onyx Pharmaceuticals’ sorafenib (Nexavar) were alive after one year, compared with 77 percent who got Aveo’s tivozanib. Aveo cautioned that not enough deaths have occurred in the entire trial of 517 patients to make this a final result, and median survival time for the two groups can’t yet be calculated.

The company said it believes it can address the FDA’s concerns, and still file its application to the FDA before the end of this year. But if the Aveo drug doesn’t help extend lives, it would nullify much of the perceived benefit announced earlier in the year, when Aveo said its drug was safe, and hit its main goal of keeping tumors from spreading a median time of 11.9 months, compared with 9.1 months for the Bayer/Onyx compound. Much is riding on the result. Aveo is counting on tivozanib to become its first marketed product, and to tap into a potentially large market of kidney cancer patients. About 61,000 new cases of kidney cancer (aka renal cell carcinoma) were diagnosed in the U.S. last year, and 13,000 people died from the disease, according to the American Cancer Society.

Shares of Aveo fell more than 26 percent to $9.77 at 11:50 am Eastern time.

Aveo said in today’s statement that basically it’s possible the preliminary survival data could be misleading. That’s because in cancer trials like this one, cancer patients whose disease worsens on one drug can then go on to get a second drug which may help them. In this case, Aveo said 53 percent of the patients who were randomly assigned to get the Bayer/Onyx drug went on to get subsequent therapy after their disease worsened—and “nearly all” of them were given Aveo’s tivozanib. By contrast, only 17 percent of the patients who were randomly assigned to initially get the Aveo drug went on to get a subsequent therapy. So it’s possible that the patients in the Bayer/Onyx control group may be ending up living longer at least partly because of the Aveo drug they got later on.

In any event, Aveo said it stands by its earlier claim that since its drug slows the spread of tumors, it is improving patients’ clinical outcomes.

“AVEO is conducting additional analyses to be included in the New Drug Application submission that demonstrate that the overall survival data from TIVO-1 are consistent with improved clinical outcomes in renal cell carcinoma patients receiving more than one line of therapy; analyses that the company believes will directly address this issue,” the company said in a statement.

Still, the findings raise significant questions for Aveo, which has been moving aggressively into a competitive market that includes not just Bayer and Onyx’s sorafenib (Nexavar) but also Pfizer’s sunitinib (Sutent) and axitinib (Inlyta), Roche/Genentech’s bevacizumab (Avastin), and GlaxoSmithKline’s pazopanib (Votrient). Aveo has not shied away from the challenge, staffing up its commercial team in anticipation of FDA approval, and preparing a head-to-head patient preference study called Taurus that pits its compound against Pfizer’s sunitinib (Sutent) in the kidney cancer field.

For more on the detailed results Aveo reported on the TIVO-1 study, see these results reported in May in advance of the American Society of Clinical Oncology meeting. For a replay of today’s Aveo conference call with investors, click here.