Here's why Napster billionaire Sean Parker just invested $250 million in a new kind of cancer treatment

Another big name has joined the research effort for a new kind of cancer treatment called immunotherapy, which uses the immune system to fight cancer cells.

Sean Parker, the internet billionaire who co-founded Napster and is a former Facebook president, gave $250 million on Wednesday to launch the Parker Institute that will help with the research and development of cancer immunotherapy treatments.

Unlike chemotherapy, which involves administering powerful drugs that kill both cancerous and healthy cells (most healthy cells can repair themselves), immunotherapies harness the power of the immune system to help it identify and knock out just the cancerous cells.

For example, using something called a PD-1 inhibitor, which goes after a type of protein called PD-1 that stops the immune system from fighting cancerous cells, the immunotherapy effectively helps the immune system take its foot off the breaks. Others, like cancer vaccines, activate the immune system in other ways, pushing the immune system to work harder against cancer cells.

Cancer in the crosshairs

In the past few months, many big names have started piling on initiatives with a particular focus in accelerating research in cancer immunotherapy.

For example, Vice President Joe Biden and the Obama administration have asked for a $1 billion initiative for a "cancer moonshot" which will in part focus on immunotherapy. Former New York Mayor Michael Bloomberg and others pledged $125 million to create a new immuno-oncology focused cancer institute at Johns Hopkins. And Dr. Patrick Soon-Shiong, the CEO of NantWorks, set up a Cancer MoonShot2020 coalition that aims to bring together all the people developing immunotherapies to bridge research gaps. Pharmaceutical companies also have many types of these treatments already in clinical trials, and investors expect many of them will generate billions in sales in the next couple of years.

Immunotherapy for cancer isn't particularly new, so why all the recent attention and investments?

Essentially, it comes down to the fact that we're finally getting to see the results.

The Cancer Research Institute (CRI), which has been exploring cancer immunotherapy since the 1950s, is one of the many partners that will be working with the Parker Institute.

"It's when you see the successes and durable responses," Cancer Research Institute CEO Jill O'Donnell-Tormey told Business Insider. One clear example of this is former president Jimmy Carter, who has been cancer-free since December 2015 after having his melanoma treated in part with an immunotherapy called Keytruda.

While the results are promising, they still aren't perfect. Some recently approved drugs, take Keytruda for example, only work about 30% of the time. That's still better than the average response rate of chemotherapy treatments on their own in cases of metastatic melanoma. Still, when they do work, these treatments appear able to ward off cancer longer than other other existing treatments like chemotherapy.

What's within reach?

CRI CEO O'Donnell-Tormey said that right now, cancer immunotherapy researchers need to find specific antigens, or toxins that illicit a response by the immune system, to target. This will help ensure that the immunotherapy works in every single person. And although immunotherapy has come along way in the past few years, it's still far from having cracked the code.

"It requires a lot of money, and there are no guarantees," said O'Donnell-Tormey. "Many times we're funding only 10% of the research grants that come in."

Plus, it's hard to predict what will work and when it will work, so saying a certain amount of money will surely lead to a solution doesn't exactly cut it. "We can't say what the actual amount is that you really need to do it."

But in the meantime, having the momentum certainly doesn't hurt.