Word last week that the U.S. Food and Drug Administration had approved a drug developed by a Cambridge biotech company to treat a rare form of cystic fibrosis that affects about 1,200 people upped the ante for a lab in neighboring Charlestown trying to find a cure for the other 69,000 sufferers of the disease.

“It’s a huge milestone,” Richard Fitzpatrick, chief operating officer of the Flatley Discovery Lab, said of Vertex Pharmaceuticals’ new drug, Kalydeco. “But it will only be effective for roughly 3 to 6 percent of the CF population. Now our job is to find (drugs) that can help the other 95 percent.”