Good article. The only problem that I saw with it is it did not consider any scenarios under which A-7 could fail. I like to understand failure possibilities as well so I can go into an investment eyes wide open.
Vical completed a secondary sweep of active clinical sites at the end of March this year, and an update is expected at the next earnings call in May; independent assessment of response rates is ongoing. I expect that this may be the event that rekindles investor interest and initiates a run-up before the eventual data release. The size of the study is such that to maximize the statistical power for evaluation of the survival endpoint (treatment impact of immunotherapy may occur late, long tail effect may cause late separation of the Kaplan-Meier curves) there has been no interim look for efficacy, only several for safety. I also suspect that the event rate required to trigger unblinding is also high for the same reason. From the available data, I posit that the profound efficacy of Allovectin in an increased number of responders and a high pre-specified event rate (number of deaths) has led to trial unblinding being prolonged by two years.
What is trial success?
Since 2007 the landscape of melanoma trials has changed, with Yervoy and Zelboraf demonstrating improved survival. The primary endpoint under Vical’s Special Protocol Assessment is response rate, with overall survival being a secondary endpoint. This does not necessarily bind the FDA, and so it is probably fair to say that Vical must demonstrate improved overall survival to be absolutely sure of approval. Amgen is in the same position with Talimogene Laherparepvec. The next question is, then, by how much will overall survival need to be improved? We have the range of 2-4 months for Yervoy and Zelboraf (sicker trial populations). Yervoy and Zelboraf are not without significant serious side effects, and Zelboraf is only indicated in the
"Understanding immunotherapy, the Vical melanoma data and Phase III trial design are challenging but worthwhile, as the market has significantly underestimated the probability of success, creating a near-term, high-return opportunity coupled with a pipeline safety net."
Actually I met an Oncology professor from UT MDACC few days ago- I asked him about VICL and what does he think of Allovectin and Melanoma (He was not aware of the trial - And by the way Agop is the Melanoma head at MDACC and has written about A-7)
He did not say anything which we already did not know -
After this I asked him is there any miracle cancer drug - he said Ibrutanib and every body knows about it !