CAMBRIDGE, Mass. ( TheStreet) -- Aveo Pharmaceuticals ( AVEO) will be presenting updated data on its kidney cancer drug tivozanib, including a more detailed look at overall survival, at a medical meeting next week. The new tivozanib data may help alleviate investor concerns about the drug's chance for FDA approval, although I suspect worries about tivozanib's commercial potential will linger. Before Aveo can market tivozanib, FDA must approve, which is why the new data to be presented at the American Society of Clinical Oncology Genitourinary Symposium are important. Embargoes on the new tivozanib data lift Tuesday, Feb. 12 at 6 pm, with the actual presentation scheduled for Feb. 16. The most important presentation will be an update on two-year overall survival from the "TIVO-1" phase III study that compared tivozanib to Nexavar, marketed by Bayer and Onyx Pharmaceuticals ( ONXX). The only survival data presented previously from the study -- which has given Aveo headaches ever since -- showed one-year survival of 77% for tivozanib patients compared to 81% for Nexavar patients. The FDA raised concerns about this unfavorable survival trend, which naturally, set investors on edge. At next week's ASCO GU meeting, we'll get more details on the final overall survival in both arms, including medians, the Kaplan-Meier curves, hazard ratio and p value. Certain patient subset analyses will also be presented. Best case would be for the negative survival trend to reverse itself. Absent that (and I don't believe the survival benefit will tip in tivozanib's favor), the new data are more likely to address Aveo's argument that patient crossover skewed survival in Nexavar's favor. What we know already is that more than 60% of the patients randomized to the Nexavar arm later received tivozanib or some other therapy upon tumor progression. These Nexavar crossover patients are living longer because they benefited from treatment with two active kidney cancer drugs, Aveo believes. Meantime, only 24% of patients chosen to begin the trial in the tivozanib arm went on to a subsequent therapy. FDA is reviewing tivozanib with an approval decision date of July 28. An FDA advisory panel is expected to review the kidney cancer drug, although no date has been set. A May or June panel meeting is likely.
The survival question has been an overhang on Aveo shares but the TIVO-1 study did meet its progression-free survival endpoint. Tivozanib delayed the time before patients' kidney cancer started to grow by a median 11.9 months compared to 9.1 months for Nexavar -- a difference that was statistically significant and which achieved the study's primary endpoint. Tivozanib was also better tolerated than Nexavar, with fewer dose reductions and treatment discontinuations due to adverse events. "Tivozanib is approvable," said one investor who's bearish on Aveo but not currently short the stock. "The FDA isn't dumb, there was massive crossover in this study. Plus, it's the first kidney cancer trial in which a drug was compared to an active control, so to ding them for that is dumb." However, this Aveo bear believes tivozanib runs into trouble once approved because it will be the ninth drug marketed for kidney cancer and the fifth drug to share a similar mechanism of action. Pfizer's ( PFE) Sutent has been the market-leading kidney cancer drug but has recently lost ground to GlaxoSmithKline's ( GSK) Votrient. Aveo is running a follow-on study comparing tivozanib against Sutent, with results expected in 2014. A successful study may convince doctors to use tivozanib over Sutent but won't necessarily help against Votrient. "I'm hoping Aveo shares rally into tivozanib's approval because it so I can short the launch," said the Aveo bear investor. Aveo bulls believe tivozanib's efficacy is comparable to current crop of leading kidney cancer drugs but safer and easier to tolerate, which will drive market share and sales. RBC Capital's Adnan Butt says tivozanib is worth almost $13 per share to Aveo if the drug's peak market share reaches 15% in the U.S. and 10% in the Europe. Aveo shares closed Friday at $7.98. -- Reported by Adam Feuerstein in Boston. Follow @AdamFeuerstein