Spit it out? What can we expect novel therapies to do for patients with cystic fibrosis (CF)? Everyone wants a cure, but how will we know if we have achieved it? Mortality is only applicable if Methuselah was the principle investigator, because survival curves are so flat. Horsley et al (see page 532) have studied the response of 46 biomarkers to intravenous antibiotic treatment of CF pulmonary exacerbations (also known as CF lung attack, see Thorax passim) and ingeniously used the results to suggest which of these biomarkers might be useful for following the response to novel therapies, in their case the gene therapy trial. They studied five domains (symptoms, physiology, CT, and pulmonary and systemic inflammatory markers), and the winners were physiological (spirometry, lung clearance index), symptoms, CT scores (airway wall thickness, air trapping and large mucus plugs) and serum (C-reactive protein, interleukin 6 and...]]>