Don't Get Burned by the Next Cell Genesys

I don't want to make the blanket statement that all uncontrolled phase II studies lead inevitably to failure. But it's also no coincidence that companies which choose to invest wisely in controlled phase II drug studies -- and I think of Genentech (DNA Quote) with Avastin and Onyx Pharmaceuticals (ONXX Quote) with Nexavar -- ended up with positive phase III studies and highly successful and profitable cancer drugs.

The failure of GVAX should also finally put an end to those who want to directly tie a patient's immune response to a cancer vaccine to real clinical benefit, i.e. prolonged survival.

Back in February, Cell Genesys reported that researchers analyzing blood samples from prostate cancer patients in the phase II study (yes, that same uncontrolled phase II study) found two antibody, or immune, responses to GVAX Prostate that correlated positively with significantly longer survival.

Again, here's what I wrote back then:

"Interesting, except for the fact that in order to find the two antigens responsible for this immune response, the researchers looked at dozens of different antigens -- including some they previously though would be linked to an immune response -- but found nothing.

What this tells us is that Cell Genesys had to go deep-sea fishing with a very large net to find some positive data to report. That's not necessarily a bad thing, but it certainly doesn't prove that GVAX Prostate is doing what it needs to do most -- helping prostate cancer patients live longer. "

This didn't work for Cell Genesys, nor did it work for Genitope (GTOP Quote) and Favrille (FVRL Quote) for their two respective but failed non-Hodgkin's lymphoma vaccines.

If a cancer vaccine, or immunotherapy, is ever proven to be truly effective in fighting cancer, it will by definition work by stimulating the immune system to detect and kill cancer cells.

Two problems here that investors should be worried about: 1) No cancer vaccine has worked yet -- and the list of failures grows ever longer; and 2) clearly, something more has to happen with these cancer vaccines than just stimulating the immune system for them to work.