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The hysteria of the financial markets would be funny if it wasn't so serious. Tocagen announced that the interim analysis result was that the trial will be allowed to continue to the final readout. The money people took that as a failure and wiped out 1/3 of the value of the company in 1 day. In reality, nothing changed and the chances of success are the same as they were the day before. There are 3 possible outcomes to the analysis:
1. The data for Toca 511 is worse than for the control group in which case the trial would be stopped and declared a failure.
2. The data is so much better than expected that they stop the trial and try for FDA approval.
3. The data is about what is expected in which case they allow the data to mature so we get a good reading on how well the treatment works.
Keep in mind that we expect the immunotherapies (from experiences with other cancers) to work on a relatively small % of patients, but the benefit is that when they work, they usually work miracles and achieve long lasting benefits - something we just do not usually see with Glioblastomas. I have already seen a few long term survivors from the early Toca 511 trials.
This can result in the median survivals for the treatment group to actually be the same as that for the control arm - but the real benefit is in the long arm of the survivors. The median survival is defined as how long the middle person in the group survived. In this case with 403 patients enrolled it would be the average of the patients who died number 201 and 202. The analysis was based on 193 deaths, so the median was not even reached yet. It would have taken an unexpectedly large improvement to trigger a stoppage of the trial at this point.
In summary - this is NOT bad news. It is what was expected. I still feel that the treatment is valuable and will get FDA approval. Once it is approved, we can then easily experiment with ways to make it work better - in various combinations - so the majority of patients are helped. But before that happens, we still need to get each building block of the ultimate cocktail to get approved and be made available.