The U.S. Food and Drug Administration recently approved a breakthrough treatment, which was tested in Boston, for people with a rare but often deadly lung disease called pulmonary arterial hypertension.Like many patients, Mike Bennett said the drug has already had a dramatic impact on his life.Diagnosed with PAH more than two decades ago, he remembers when he felt the first symptoms."I was playing basketball and I was bicycling and doing all the things I wanted to do when, suddenly, I couldn't," he said. "And my condition was getting worse."As Bennett quickly discovered, PAH causes blood vessels in the lungs to become narrower, blocked or destroyed.The damage slows blood flow, forcing the heart to work even harder."They gave me three years to live without severe medical intervention," Bennett said. "At the time, that was a lung transplant or a heart-lung transplant."But so far, Bennett has avoided both.Instead, he's moved from one medication to another over the past 25 years.He said he was always pushing to be part of the next clinical trial."Psychologically for me, it was important to get a new drug because I just needed hope," Bennett said. "I needed to know that there was something else out there."That's when the father of four joined a local trial for Sotatercept.    Recently approved by the FDA, the drug is designed to capture proteins in the bloodstream that cause blood vessels to narrow."It diminishes this growth," said Dr. Ioana Preston, director of the Pulmonary Hypertension Center at Tufts Medical Center. "Kind of like, if you think of a cancer or a tumor that grows, and you find an agent that suppresses this growth. This is the same type of effect that Sotatercept has on the blood vessels in the lungs."Preston worked with the pharmaceutical giant Merck to help develop the drug for her patients, including Bennett."He improved his ability to function at home, in his family, at work," Preston said. "He had more stamina."Today, Bennett administers a shot of Sotatercept himself, once every three weeks.With the new medication, which is now marketed as Winrevair, Bennett said he's been able to discontinue an intravenous treatment. The switch means "Dad" no longer has to wear a catheter in his chest that can't get wet.He surprised his two youngest sons last year by swimming with them for the first time."I have the ability to participate in activities that I haven't been able to do in years," Bennett said. "And that was a sea change for me."