I'm a cardiologist. My biology teacher in college died of cystic fibrosis at 28. He was a genius. Kind. Funny. Married to a beautiful woman, with two small children. The kind of man who made complex things feel clear and who stayed after class to help anyone who was struggling. I still think about him. About everything he never got to do. 2/ For most of the last century, this was the reality of cystic fibrosis. Thick mucus clogging the lungs and organs. Chronic infections. Progressive lung damage. Parents told their children might not reach adulthood. Bright, healthy-looking young adults gone in their 20s and 30s. It felt inevitable. 3/ Then something changed. In 2008, the median age at death for people with CF was 26. By 2022 it was 66. Median predicted survival for babies born with CF has risen into the mid-60s, and modeling suggests children who start the right treatment early can approach a normal lifespan. The disease that took my teacher is no longer the same disease. 4/ The turning point was Trikafta, approved in 2019. It doesn’t just manage symptoms. It corrects the broken protein at the root of the disease for about 90% of patients. The CFTR protein is supposed to move salt and water so mucus stays thin. In CF, mutations (most commonly F508del) make the protein fold wrong, get degraded, or fail to open. Mucus turns thick and sticky. Lungs fill with infection. 5/ Trikafta is a triple combination that fixes this in two ways: Two drugs (elexacaftor and tezacaftor) help the misfolded protein fold correctly and reach the cell surface instead of being destroyed. The third (ivacaftor) helps the channel open and stay open so salt and water can move properly. Mucus thins. Airways clear. The vicious cycle of infection and inflammation slows dramatically. 6/ The first week is often intense. Patients cough and bring up years of accumulated mucus as the lungs begin to clear. Then the change arrives: lung function rises (often 10–14 points), hospitalizations drop sharply, nutrition improves, and the constant background of illness lifts. Lung transplants for CF have plummeted. People who were once given a handful of years are now planning decades ahead. 7/ I think about my teacher a lot. About the wife and kids he left behind. About the lectures he never finished and the students he never got to teach. I also think about the kids diagnosed today who will grow up expecting to finish school, build careers, have families, and grow old—because a drug now corrects the protein that was killing them. Progress is real. It is not abstract. It is measured in the lives that used to be cut short and no longer are. He would have wanted this. GET UPDATES: substack.com/@afshineemrani