The Pittsburgh Vitamin D Study: Vitamin D Supplementation in Vitamin D-deficient Subjects at Risk of Lung Cancer

Smoking avoidance or cessation are essential to the prevention of lung cancer. However, not all smokers are able to quit smoking and, importantly, former smokers remain at increased risk of lung cancer compared to never smokers. Despite smoking prevention/cessation programs and treatment advances, lung cancer is still the leading cause of cancer-related mortality in the United States with more than 158,000 individuals expected to die from this disease in 2015. Effective and safe prevention strategies are expected to be more successful in reducing lung cancer deaths than treatment of established disease.

NF-kappaB (NF-kB) pathway activation underlies smoking-related inflammation and lung carcinogenesis, and those agents which suppress NF-κB signaling may have the potential to prevent lung cancer. Recent preclinical data from our group and others indicate that the active metabolite of vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], has lung cancer chemopreventive activity. Because systemic 1,25(OH)2D3 administration is complicated by its hypercalcemia-inducing properties, the investigators propose to use oral supplementation with vitamin D3 (cholecalciferol) to safely achieve chemopreventive 1,25(OH)2D3 levels within the lung.

This randomized, placebo-controlled Phase IIb study aims to evaluate the ability of 4,000 IU oral vitamin D3/day (in combination with a daily multivitamin) to safely convert vitamin D3-deficient subjects at risk of lung cancer to a vitamin D3-sufficient state.

Study participants will be recruited from among Pittsburgh Lung Screening Study Extension (PLuSS-X) and PLuSS-XX participants not diagnosed with lung cancer, and from among the patient population seen by the PI of this protocol. The study consists of two stages, a screening and an intervention stage, with their own consent forms. In Stage 1 (the screening stage), the vitamin D3 status of subjects potentially eligible for participation in the intervention will be determined; in Stage 2 (the intervention stage), supplementation with oral vitamin D3 will be evaluated.

Participants who fulfill the eligibility criteria and provided signed consent for Stage 2 will be randomized in a 2:1 ratio to receive: (A) 4,000 IU vitamin D3 plus a multivitamin (containing 400 IU vitamin D3) daily for one year, or (B) a placebo vitamin D3 pill plus a multivitamin daily for one year. Both groups will contain equal numbers of current and ex-smokers; in total 120 subjects will be randomized. To evaluate whether supplementation safely corrects vitamin D3 deficiency in this population, blood samples will be obtained at baseline, 3, 6, and 12 months of intervention for evaluation of 25(OH)D3 and serum calcium. The collected blood will also be used to facilitate biomarker assessment. Pulmonary function tests (PFTs) will be obtained at baseline and repeated after 12 months to determine whether supplementation has an effect on lung function. Sputum and nasal epithelium will be collected at baseline, 6 months and 12 months to facilitate biomarker assessment.

- Study Objectives Primary Objective: To establish the 12-month conversion rate (i.e., proportion of subjects whose baseline vitamin D3 deficiency is corrected after 12 months of supplementation).

Secondary Objectives: To determine the 3-month and 6-month conversion rates and examine the effect of vitamin D3 supplementation in current and former smokers. Additionally, to examine the effects of vitamin D3 supplementation on biomarkers of lung cancer risk, inflammation, and pulmonary function.