SOUTH SAN FRANCISCO (TheStreet) -- Oxigene's (OXGN) experimental cancer drug Zybrestat, when used in combination with Roche's (RHHBY) Avastin, delayed the re-growth of ovarian cancer, according to results from a phase II study released Tuesday night.
The news was a surprise and sent shares of tiny Oxigene soaring 134% to $5.65 in Tuesday's after-hours trading session. Oxigene has a tiny float and a very large retail shareholder ownership base, so Wednesday's volatility should be fun to watch.
Oxigene has been developing Zybrestat for various cancers without much success for years, but the company might have finally found a winning lottery ticket. The company was flinty with details from the ovarian cancer study so there's still a lot of data we don't have but need to know before understanding how Zybrestat may fit into the ovarian cancer treatment picture, if at all.
But from nothing there is now hope. To give you a sense of just how lost in the wilderness Oxigene had become, here's a five-year chart:
OXGN data by YCharts
Yes, you're reading this correctly. Account for all the reverse stock splits and Oxigene was a $500-plus stock in 2009.
The phase II study, conducted by the non-profit Gynecologic Oncology Group, not Oxigene, enrolled 107 women with platinum-sensitive and resistant, recurrent ovarian cancer. The patients were randomized to receive either Roche's Avastin alone, or a combination of Zybrestat and Avastin.
On the study's primary endpoint, the combination of Zybrestat and Avastin reduced the risk of tumor regrowth or death (progression-free survival) by 32% compared to Avastin alone. The result was statistically significant. Oxigene did not report the median progression-free survival for the patients in the study.
Response rate (tumor shrinkage) for patients treated with the Zybrestat/Avastin combination was no different, statistically, from patients treated with Avastin alone. An analysis of overall survival in the study is not ready.
The overall survival data from this study is very important because convincing FDA to approve a drug for ovarian cancer that doesn't help patients live longer is a real challenge. Roche's Avastin is not approved for ovarian cancer in the U.S. despite a positive study reported in 2011 demonstrating a 52% reduction in the risk of tumor regrowth or death with a combination of Avastin plus chemotherapy compared to chemotherapy alone. The study -- dubbed AURELIA -- demonstrated overall survival favored Avastin but the trend was not statistically significant. European regulators found the AURELIA study convincing enough for approval but Roche has so far not submitted the data to the FDA. (A Roche spokesman said an FDA submission is planned for later this year.)
Last June, Amgen (AMGN) reported results from a phase III study in which the combination of trebananib and chemotherapy reduced the risk of tumor re-growth or death (PFS) by 34% compared to chemotherapy alone. This study is also still being followed for overall survival.
Both the Roche and Amgen studies are much larger than the Zybrestat study conducted by GOG, so Oxigene would likely need to conduct a larger, phase III study as well to confirm the findings announced Tuesday.
Oxigene has previously studied Zybrestat in thyroid cancer and non-small cell lung cancer.
Zybrestat belongs to a class of cancer drugs known as vascular disrupting agents (VDAs) that are designed to target and destroy blood vessels within tumors, thereby depriving them of oxygen and nutrients. VDAs are supposed to work against existing or more mature tumor blood vessels, compared to anti-angiogenesis inhibitors like Roche's Avastin, which work by preventing tumors from developing new blood vessels.