Effects of Nicotinamide in Patients With Chronic Lymphocytic Leukemia With History of Non-melanoma Skin Cancers

This is a randomized, phase II, double-blind, placebo-controlled trial with planned crossover to the intervention arm after 1 year. Consenting patients with CLL who have had at least one NMSC diagnosed in the past year will be randomized to receive either oral nicotinamide 500 mg twice daily (BID) for 1 year or oral placebo 1 tablet twice daily for 1 year. Patients will be stratified according to CLL therapy and the number of prior NMSC. At the end of 1 year, patients will undergo dermatologic examination and the number of new NMSC will be quantified. The number of patients who develop new NMSC in each arm will be documented. At this time, patients will be unblinded and all patients will receive Nicotinamide 500 mg BID for an additional year. At the end of this second year, patients will again undergo dermatologic examination, and the number of new NMSC will be quantified. The number of patients who develop NMSC will be documented. Skin biopsies will be taken for correlative studies. Enrollment will be split into two parts separated by an interim analysis. Part 1 will accrue 40 patients: 20 to each arm. After 40 patients have completed their 12 month visit an interim futility analysis will be conducted prior to recruiting more patients. The study will stop if the difference in the number of patients with NMSC between control and treatment arms is 0 or less (i.e., absolutely no evidence that the treatment is better than control). If the trial is not stopped, the investigators will proceed with Part 2 and recruit 46 more patients.