Although results of first trial were ‘modest and variable’, second bigger trial aims to combine gene therapy with other treatments for longer term benefitsA treatment to help those with cystic fibrosis may be available within five years, say scientists who who have been working for decades to develop a gene therapy for the disease.The results of a year-long trial showed only a small and variable improvement in the lung capacity of those children and adults who took part, but scientists now believe they have proved gene therapy is possible in treating cystic fibrosis.