(FORTUNE Magazine) – Jenifer Estess was just 35 years old--the same age as Lou Gehrig--when she was diagnosed with the degenerative disease named for the baseball great, which affects 30,000 people in the U.S. The successful theater producer lost her ability to walk, to talk, to swallow, and eventually to breathe. Because of weakened diaphragm and chest muscles caused by the debilitating neuromuscular illness, officially known as ALS, most patients eventually face respiratory failure within two to five years of diagnosis. The doctors told her there was nothing she could do.

She disagreed. Along with her two sisters, Meredith, a fashion buyer, and Valerie, an advertising executive, Jenifer started a campaign that has revolutionized ALS research and serves as a model for how outsiders can force radical change in the scientific establishment. This month Jenifer's memoir, Tales From the Bed: On Living, Dying, and Having It All, which she wrote literally from her bed, hits stores. And an HBO documentary, Three Sisters: Searching for a Cure, airs May 19.

When Jenifer was diagnosed back in 1997, the sisters quit their day jobs and founded Project ALS in Jenifer's Manhattan apartment. They persuaded some of the biggest names in neuroscience to join the advisory board, which decides what projects to fund. With help from Jenifer's extensive celebrity network from the theater world, the foundation raised $20 million in less than six years.

Faced with a disease that not only has no cure but also no treatment, the Estess sisters immediately knew they would have to approach ALS from a new angle if they wanted to save Jenifer. "Our guiding principle has been to try to run academic science more like a business," says Valerie. So instead of following the government model (where grants can take nine months or longer to clear and are doled out in small increments), Project ALS began cutting scientists six-figure checks in a couple of weeks. Fast cash proved so tempting that researchers from different disciplines have been willing to shed the prestige of heading their own labs to join forces and pool their knowledge--nearly unheard-of in medical research. "They have really catalyzed research in ALS," says Dr. Robert H. Brown, professor of neurology at Harvard Medical School and director of the Day Neuromuscular Lab at Massachusetts General Hospital, which receives Project ALS funding. "Now there are many more ideas in the pipeline than there ever have been."

Among its accomplishments, Project ALS has pioneered ALS research using stem-cell therapy, which had never been used to battle the disease before. In a major breakthrough, scientists last year at Johns Hopkins found that stem cells can be directed to become healthy new motor neurons (the cells that are destroyed by the disease) and prolong life in ALS animals. And an Estess-funded gene-therapy project is expected to go to human trials by the end of the year, close to lightning speed for medical research. Biotech companies are starting to take notice: Ceregene Inc. in San Diego and Curis Inc. in Cambridge have both recently teamed up with Project ALS, and trials with Celebrex, the arthritis drug from Pfizer, are also underway.

The Estess sisters have said they're committed to Project ALS for the foreseeable future, but "I don't want to be doing this forever," says Meredith. "One day you hope there is a cure."

As for Jenifer, she lost her battle against ALS in December, at the age of 40. But if her sisters have their way, one day, instead of dying from Lou Gehrig's disease, people with ALS will be known as living with Jenifer Estess's disease. --Cora Daniels