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ORAL 23 - Prevention and Cancer Risk (ID 121)
- Event: WCLC 2015
- Type: Oral Session
- Track: Prevention and Tobacco Control
- Presentations: 1
ORAL23.02 - Pioglitazone for the Chemoprevention of Lung Cancer (ID 2419)
10:45 - 12:15 | Author(s): B. Bagwell
Prior clinical studies have shown that the oral prostacyclin agonist iloprost improves bronchial dysplasia in former smokers. Prostacyclin is a PPAR gamma agonist, and epidemiologic and pre-clinical studies suggest PPAR gamma agonists like pioglitazone may chemoprevent lung cancer. Based on these promising results, a double-blind, placebo controlled, phase II trial of pioglitazone in subjects at increased risk for lung cancer was sponsored by the Department of Veterans Affairs.
Subjects were selected for the trial if they met one the following criteria: current or former smoker (> 10 pack years); biopsy proven endobronchial dysplasia; airflow obstruction (FEV1/FVC < 0.70); or at least mild sputum cytologic atypia. Fluorescent bronchoscopy was performed with biopsy of 6 standard endobronchial sites and all other abnormally appearing areas. Subjects also had pulmonary function testings and quantitative high resolution CT scans at the start and completion of the trial. Subjects were then randomized to oral pioglitazone or placebo for 6 months and then a second fluorescent bronchoscopy with repeat biopsy of all the central airway areas sampled on the first bronchoscopy. The endobronchial biopsies were scored on a 1-8 scale based on WHO criteria. The primary endpoint for the study is change in maximum (worst) endobronchial histology.
A total of 90 subjects (46 pioglitazone, 44 placebo) have been enrolled in the trial, with 76 completing both bronchoscopies. Subjects are well matched in terms of age, gender, tobacco exposure, and sputum cytology. No significant differences in lung function were observed between the treatment groups. While the investigators remain blinded in regards to treatment group, aggregate data is available. Overall, mild dysplasia or worse was seen in 26% of the initial biopsies. Similar to prior studies, current smokers exhibited more dysplasia at baseline compared to former smokers (32.4% vs. 16.6%) and also had more angiogenic squamous dysplasia (11.7% vs. 3.2%). Our primary endpoint is change in maximum histology, and histologic scores from matched biopsies in all participants showed a change of at least 1 grade in 50.2% (25.9% improved, 24.3% progressed). More histologic changes were observed in current smokers (59.2%) than former smokers (41.7%). Summary data for the non-normal biopsy pairs (ie those with a histologic score of at least 2 on baseline biopsy) showed that the majority of pairs (73.7%) changed by at least one grade. Current smokers exhibited more progression (29.3%) compared to former smokers (14.6%).
The pioglitazone lung cancer chemoprevention trial is currently in progress. The treatment has been well tolerated and histologic changes were observed in many of the subjects.
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