ABSTRACT
BACKGROUND: Clinical trials in cystic fibrosis (CF) have been hindered by the paucity of well characterised and clinically relevant outcome measures. AIM: To evaluate a range of conventional and novel biomarkers of CF lung disease in a multicentre setting as a contributing study in selecting outcome assays for a clinical trial of CFTR gene therapy. METHODS: A multicentre observational study of adult and paediatric patients with CF (>10 years) treated for a physician-defined exacerbation of CF pulmonary symptoms. Measurements were performed at commencement and immediately after a course of intravenous antibiotics. Disease activity was assessed using 46 assays across five key domains: symptoms, lung physiology, structural changes on CT, pulmonary and systemic inflammatory markers. RESULTS: Statistically significant improvements were seen in forced expiratory volume in 1 s (p<0.001, n=32), lung clearance index (p<0.01, n=32), symptoms (p<0.0001, n=37), CT scores for airway wall thickness (p<0.01, n=31), air trapping (p<0.01, n=30) and large mucus plugs (p=0.0001, n=31), serum C-reactive protein (p<0.0001, n=34), serum interleukin-6 (p<0.0001, n=33) and serum calprotectin (p<0.0001, n=31). DISCUSSION: We identify the key biomarkers of inflammation, imaging and physiology that alter alongside symptomatic improvement following treatment of an acute CF exacerbation. These data, in parallel with our study of biomarkers in patients with stable CF, provide important guidance in choosing optimal biomarkers for novel therapies. Further, they highlight that such acute therapy predominantly improves large airway parameters and systemic inflammation, but has less effect on airway inflammation.
Subject(s)
Anti-Bacterial Agents/administration & dosage , Cystic Fibrosis/drug therapy , Forced Expiratory Volume/physiology , Lung Diseases/drug therapy , Lung/physiopathology , Tomography, X-Ray Computed , Adolescent , Adult , Anti-Bacterial Agents/therapeutic use , Biomarkers/blood , C-Reactive Protein/metabolism , Child , Cystic Fibrosis/diagnosis , Cystic Fibrosis/physiopathology , Female , Humans , Injections, Intravenous , Interleukin-6/blood , Leukocyte L1 Antigen Complex/blood , Lung/diagnostic imaging , Lung Diseases/diagnosis , Lung Diseases/physiopathology , Male , Recurrence , Treatment Outcome , Young AdultABSTRACT
A detailed comparison of recombinant adeno-associated viral (rAAV) vectors of serotypes 2, 5, and 8 was performed in mice and nonhuman primates. Differences within the capsid proteins and viral terminal repeats of rAAV-2 and -5 did not significantly influence their ability to transduce murine liver. However, vectors pseudotyped with AAV-8 capsid (rAAV-2/8) mediated transgene expression more rapidly and from lower doses than possible with rAAV-2 and -5, although expression declined from peak values in a distinct dose-dependent manner prior to reaching steady-state levels. Nevertheless, at all time points and vector doses, rAAV-2/8 transgene levels were 17- to 84-fold higher than with rAAV-2 or -5 due to a more rapid conversion of the single-stranded genome to transcriptionally active stable duplex DNA. In nonhuman primates, liver-targeted administration of rAAV-5 and rAAV-2/8 vectors established therapeutic levels of transgene expression. The importance of preexisting serotype immunity was highlighted by the inability to achieve successful transduction in the presence of serotype-specific antibodies, although this impediment was successfully avoided through the use of alternative serotypes. In summary, serotype-specific differences in transduction biology and the appreciation of preexisting immunity will likely influence the selection of the rAAV serotype for future clinical trials.
