G551D & Kalydeco

Cystic Fibrosis is a genetic disease which leads to a defect in the CFTR protein. This protein functions as a chloride channel. The channel defect leads to thick mucus in the lungs and digestive system, which causes frequent chest infections, lung damage and poor digestion. Other organs can also be affected. Approximately 1:25 people in Australia are a carrier and 1:2500 have CF.

A new medication, Kalydeco, is a CFTR potentiator. This means it helps the CFTR at the cell surface to open, leading to thinner mucus, less infection / inflammation and healthier lungs. Kalydeco helps people who have the G551D mutation, which is present in 7.4% of the Australian CF population and 4% worldwide. This is the first medication that addresses the underlying cause of CF, instead of treating the symptoms.

Follow these links for more information about Kalydeco:
Trial Results: Journal Article and YesToKalydeco campaign (Australian reimbursement campaign)

These are images from Vertex presentations in March and October 2012. They show the PFT increase and sweat chloride decrease seen in the trial with G551D and Kalydeco (Ivacaftor):

FEV1 is a common measure of lung function. In the phase 3 trial the average improvement was 10.5% (absolute) from placebo over the 48 weeks.

Sweat chloride is a measure of CFTR function. In the phase 3 trial sweat chloride changed from 100 to 52 on average. Values above 60 are associated with the diagnosis of CF.

Sources: Peter Mueller March 2012 Presentation and the October 2012 Vertex Investor Presentation (no longer available)