"We quickly realized there was nothing to help the situation, so out of a sense of desperation and wanting to feel like we were doing something for the cause, we, along with some friends, started Hilarity For Charity in the form of a comedy variety show," Rogen, 32, tells PEOPLE. "We started the charity because there was really nothing else we could do."
"Comedy is 'the something' we're actually capable of doing," he says. "Because it's such a bummer, we thought it might be nice to, in some way, make it fun for people."
Rogen says the project has "grown a lot and become something much bigger," and he is hopeful about what the charity can achieve.
"It would be nice ultimately to discover a cure," the actor says. "I hope we're able to capture the attention of more young people, and get the disease the type of funding it deserves."
For more of our interview with Rogen, pick up the latest issue of PEOPLE, on newsstands now