PARIS — Cailyn Fowler said she is doing well after starting a newly approved drug in February to treat her cystic fibrosis.

The 17-year-old is one of the first in the nation to be prescribed the drug ivacaftor.

Fowler was diagnosed with CF as an infant, and has spent her entire life in and out of the hospital. The disease creates a thick, sticky fluid in the lungs and other areas of the body. The mucus can cause severe, life-threatening health problems.

With her ability to absorb nutrients impaired, Fowler spends each night hooked up to a feeding tube, which delivers 3,000 calories of a thick formula into her stomach.

Despite this, she was unable to put on weight, tipping the scale at 86 pounds in February.

Her boyfriend, Brandon Compton, said he sees a difference in her now.

“She’s happier,” he said. “She has more energy. We actually went for a walk the other day. That’s big for me.”

Fowler said her chronic cough is virtually gone. She is also experiencing life for the first time without the debilitating disease sapping her strength.

“I have so much more energy,” she said. “All the time, even at night,” she said, eyes bright. “I’m not as tired in class any more. It seems like I know more. And at dance, I never take breaks anymore.”

Fowler’s doctors have also reduced her intake. Instead of five cans of formula a night, she now takes four cans. And she has been able to stop taking medications designed to stimulate her appetite.

“I’ve put on 12 pounds,” she said. “I weigh 97-and-a-half right now.”

Fowler has used some of her energy to promote charitable causes that will help to develop lifesaving treatments for others who suffer from CF.

Only 4 percent of CF sufferers have the genetic profile that can be treated by ivacaftor, which is marketed under the brand name Kalydeco by Vertex, the pharmaceutical company that spent 17 years developing the drug.

Fowler, who still has friends struggling to manage their CF, said she wants to do what she can to promote more research. She has seen two close childhood friends die for want of an effective treatment.

Vertex is working to develop ivacaftor that can be approved for young children with cystic fibrosis.

Fowler is doing her part. She wrote an ABC book that relates each letter of the alphabet to something related to CF.

The Barbara Bush Children’s Hospital at Maine Medical Center in Portland liked the book so much it published Fowler’s work, and uses it as an educational tool for families that face CF.

Fowler has also appeared on two radio stations and a local television station promoting awareness.

“I was talking about how much the hospital means to us,” she said.

The future seems bright for Fowler, who is now better able to pursue her career goals.

She said she would like to go to college and become an elementary school teacher.