An expensive cystic fibrosis drug is making a difference in the life of Whitehorse teenager, Larissa Rueckenbach.

Rueckenbach, 13, has a rare mutation of cystic fibrosis. Kalydeco, the newly-approved drug to treat her condition costs as much as $350,000 a year.

She was recently accepted into a compassionate care program by Vertex, the pharmaceutical company that makes the drug.

Larissa's mother, Heike, says her daughter has been on the medication for over two weeks and it has made a huge difference.

"It's day 16 on Kalydeco; it only took four or five days to start seeing changes in her," she said. "It's amazing. They call it a miracle drug and it truly is a miracle drug."  

Rueckenbach says Larissa already suffers from much less coughing and fewer stomach aches. She says the stiffness in Larissa's joints has improved and she is now able to brush her own hair. 

Cystic fibrosis is a genetic disease that fills a person's lungs with mucus, affecting the ability to breathe. Larissa Rueckenbach​ is one of about 100 Canadians with the mutation of the disease that Kalydeco treats. 

After a year of negotiations, the Pan-Canadian Drug Alliance and the drug company recently agreed to a price that will allow provincial and territorial drug plans to cover the cost of the drug.

Late last week, Ontario became the first jurisdiction to cover the cost.

Rueckenbach encourages people to write Yukon MP, Ryan Leef, and Yukon Health Minister, Doug Graham, to get the cost of the drug covered under the Yukon health plan.