) -- Forgive me, for I have sinned. It's been three weeks since my last Biotech Stock Mailbag. Vacation is over, so let's get back to your questions.
Richard G. asks, "Your take on biotech
Oncolytics is conducting a two-stage, randomized phase III study of a cancer-killing virus, Reolysin, in combination with the chemotherapy backbone paclitaxel and carboplatin (versus the chemo backbone alone) in patients with platinum-refractory head-and-neck cancer.
Results from stage one of the Reolysin study are expected any day, if they aren't overdue already. Enrollment of the first 80 patients in stage one was concluded in early April, with all patients on the drug and evaluable for 12-week scans by the middle to end of June. It's reasonable, therefore, for Oncolytics to have progression-free survival (PFS) data available for release in August. With the end of the month almost upon us, the clock is ticking.
Predicting the outcome of the Reolysin phase III study is exceedingly difficult because there just isn't much prior data on the drug to look at. Oncolytics conducted a couple of small single-arm (uncontrolled) studies of Reolysin plus paclitaxel-carboplatin in head-and-neck cancer patients previously with reported response rates in the 31% to 33% range. The mean overall survival from one of the phase II studies (24 patients) was eight months; survival in the other study (14 patients) was never reported. Again, without a control arm for comparison, the survival data from these earlier Reolysin studies is impossible to interpret.
While it's hard to be optimistic about Reolysin, there are ample reasons to be cautious. Oncolytics took more than a year longer than expected to enroll 80 head-and-neck cancer patients into stage one of the phase III study. The company blamed strict enrollment criteria for the delay but a lack of interest or confidence in Reolysin among doctors and enrolling centers could also have played a factor.
The idea of using viruses -- either modified or unmodified -- to infect and kill cancer has been around for a long time but has never succeeded in late-stage clinical trials. Reolysin is an unmodified, naturally occurring virus believed to have a preference for replicating inside of -- and killing -- cancer cells.