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Cancer vaccine begins Phase I clinical trials

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Re: Cancer vaccine begins Phase I clinical trials

#11
It looks like the more interesting part of this article is the accelerated process to move from early research to human trials. We have lots of ways of curing cancer in mice that never panned out in humans, but we have a better chance of finding solutions that work if we can remove some of the impediments to moving forward with trials. Faster progress is dependent on decreasing the time each iteration takes.

Re: Cancer vaccine begins Phase I clinical trials

#12

I'm interested in the other 50%. No affect? Less affect?

I'd like to know this too. If the assumption is that they are marching to death prior to vaccine administration can it get much worse than that?

Considering melanoma is lethal, and the treatment (radiating away the entire immune system) bring very risky, this new treatment has the potential to both lower the risk and increase survival rates. I'll be very interested to see if the side-effects are of any concern, or if we're one step closer to a cure.

Re: Cancer vaccine begins Phase I clinical trials

#13

I'm interested in the other 50%. No affect? Less affect?

I'd like to know this too. If the assumption is that they are marching to death prior to vaccine administration can it get much worse than that?

I guess it depends on the exact side effects, but if it causes more pain and suffering, then a more painful death is worse than a peaceful one, and on a per person basis - some may take the view they will die anyway and it's worth the risk as a last resort. But good question from the OP.

Re: Cancer vaccine begins Phase I clinical trials

#15
post #7
post #2

50 percent of mice treated with two doses of the vaccine...showed complete tumor regression. I would have thought clinical trials would require a higher success rate... is it only because it's the last resort and patients would otherwise die anyways?

It depends on the percentage of people who show complete tumor regression with existing approaches, and on the relative costs and side effects. For instance, if only 25 percent of people show complete tumor regression with existing approaches, then getting the number up to 50 percent is a huge deal. Or, if the percentage is in line with existing approaches but the cost is much lower, that's another big win.

Maybe you could even get 1-(1-0.25)*(1-0.5)=0.625 complete tumour regression with a combined treatment.

Re: Cancer vaccine begins Phase I clinical trials

#16

I'm interested in the other 50%. No affect? Less affect?

looks like they died after 55-60 days, instead of dying after Source Fig 7B : http://stm.sciencemag.org/content/1/8/8ra19/F7.large.jpg

For those without access to science: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2872791/figure/F...

(Note the figure quality on pubmed central is really crappy for some reason, but you should get the point, survival from 2 vaccinations is 47% (7/15 mice) shown by the blue line, black dotted line is blank injections)

Re: Cancer vaccine begins Phase I clinical trials

#17
Funny that this comes out the day after GlaxoSmithKline's melanoma vaccine failed in phase III.[0]

Some science background on how these work. The idea is that some cancer types express specific proteins that can theoretically be targeted by your immune system, similar to how your immune system can target proteins from the Influenza virus. The goal of these vaccines is to make your immune system recognize this protein (called an antigen) and mount an immune response to kill all the cancer cells expressing the antigen (usually unique to tumour cells).

The problem is in inducing the immune response, usually these antigens don't mount strong immune responses so the attack is too slow relative to the rate that cancer cells divide and spread. Sometimes you also end up stimulating the wrong immune response, as the human immune response is quite complicated. In fact, tumors naturally stimulate inflammation and angiogenesis (immune responses) to spread! To make matters worse, some tumours even suppress the capability of immune cells to fight in the local area, rendering this vaccine useless.

The normal operating procedure for these vaccines is to remove some immune cells from the patient, cause them to become sensitive to a specific antigen, mix them with an immune system stimulant and inject them back into the patient. The ultimate goal of all of these methods is to improve the immunogenicity (ability of the vaccine to elicit an immune response) of vaccines, these guys are not making a new vaccine. Rather, this is just a new delivery method.

A very promising drug called Stimuvax by Merck which used liposomes (and had 100% regression in mice vs 50% in this study) to increase immunogenicity failed as well[1] so this should be taken with great caution, researches were overly optimistic on previous vaccines such as Stimuvax. Although the idea for the Harvard/Dana-Farber study is incredibly novel.

[0]http://www.gsk.com/media/press-releases/2013/the-investigati... [1]https://en.wikipedia.org/wiki/Stimuvax

Re: Cancer vaccine begins Phase I clinical trials

#18
post #15
post #7

Earlier quoted context omitted.

It depends on the percentage of people who show complete tumor regression with existing approaches, and on the relative costs and side effects. For instance, if only 25 percent of people show complete tumor regression with existing approaches, then getting the number up to 50 percent is a huge deal. Or, if the percentage is in line with existing approaches but the cost is much lower, that's another big win.

Maybe you could even get 1-(1-0.25)*(1-0.5)=0.625 complete tumour regression with a combined treatment.

Presuming that each treatment has an independent chance of success.

Re: Cancer vaccine begins Phase I clinical trials

#19
post #15

Earlier quoted context omitted.

Maybe you could even get 1-(1-0.25)*(1-0.5)=0.625 complete tumour regression with a combined treatment.

Presuming that each treatment has an independent chance of success.

Actually it's more than likely that the combination will reduce the chance of success as chemotherapy will wipe out the immune system (generally). Although some groups have shown very preliminary results that the combination may work it has to be given in a specific timeframe (in the order of days) and would work in specific subsets of the population.
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