Cystic fibrosis (CF) is an autosomal recessive disorder caused by dysfunction of the CF Transmembrane
Conductance Regulator (CFTR) channel. The care of patients with CF has rapidly evolved with the
development of CFTR modulators, novel pharmaceuticals that address the basic CF defect and restore CFTR
function. Despite the success of one of these, the potentiator ivacaftor, there is still pronounced variance in
drug efficacy, as measured in individuals’ phenotypic response to therapy and their in vitro cellular response
when assessed with cell-based biomarkers. Ivacaftor is metabolized by cytochrome P450 (CYP3A enzymes),
which are responsible for both hepatic and tissue-specific metabolism, including in airway epithelia. Genetic
variation in these enzymes cause altered activity, resulting in variation in efficacy in many drugs. The
preliminary data demonstrate CYP3A variants may be associated with drug efficacy, and the ability to detect
ivacaftor metabolism in vitro in individual patients’ epithelia that the applicant personally co-developed. To
maximize efficacy of ivacaftor, and thus, any therapy including it, it is essential to understand
pharmacogenetics and effect of variability of CYP3A enzyme activity on the metabolism of ivacaftor. The
Specific Aims are: 1) conduct a pilot study in people to determine population pharmacokinetics of ivacaftor in
plasma and epithelia, and correlate drug exposure with drug response 2) to determine frequencies of genetic
variants of these enzymes in the CF population and measure association with clinical efficacy; 3) compare the
contribution of CYP3A isoforms to ivacaftor metabolism and understand impact in primary epithelial cells on
CFTR activity. Ivacaftor is a significant component of many combination therapies, so understanding its
variation in metabolism and impact on efficacy is the first key step to understanding pharmacogenetics in
complex combinations, and will set the stage for an independent career focused on precision-directed
therapeutics in CF.
The applicant has dedicated her professional life to becoming a physician-scientist, studying pediatric
pulmonology in general and cystic fibrosis in particular. To achieve this, she accepted a faculty position at the
University of Alabama at Birmingham, where a supportive research environment in the Department of
Pediatrics and School of Medicine, as well as the Gregory Fleming James Cystic Fibrosis Research Center,
has made career advancement and approach to independence possible. To accomplish the goals of this
research, the candidate has assembled a mentoring team with decades of experience in clinical trials,
pharmacology, genetics, statistics, pharmacogenetics, and drug metabolism to advise and guide her during her
career development. She also proposes to undertake formal training in pharmacology, advanced statistics,
clinical trial conduct, and genetics to complement her prior medical and graduate studies and acquire the
relevant skills to transition to independence.