** British drug developer's
** Reports positive data from one mid-stage study of itstreatment for cystic fibrosis, a disease that causes lunginfections and limits the ability to breathe overtime
** Patients in the trial treated with RPL554 showedstatistically significant increase in average forced expiratoryvolume in one second;
** Stock has risen 38 pct in 2018(Reporting by Mrinalini Krothapalli)