Non-melanoma skin cancers (NMSCs) are predominantly caused by solar UV radiation, and are the most common and most costly cancer in Australia. UV radiation depletes adenosine triphosphate (ATP) in skin cells, thereby depriving them of the energy required for efficient DNA repair. UV radiation also suppresses the skin’s immunity, thus hindering its cancer surveillance system. Nicotinamide (vitamin B3) has been shown to prevent UV radiation-induced ATP depletion and immunosuppression, and to enhance DNA repair. Our previous phase 2 clinical trials have shown nicotinamide to reduce premalignant actinic keratoses (AKs) by around one-third (P<0.001) and new NMSCs by 76% (P=0.010) in healthy human volunteers. Organ transplant recipients have a greatly elevated skin cancer risk due to chronic immunosuppression.
We aim to determine if nicotinamide reduces NMSCs and is safe in renal transplant recipients.
A phase 2 double-blinded randomised controlled trial was conducted. 22 immunosuppressed renal transplant recipients were randomised 1:1 to nicotinamide 500mg twice daily or placebo for 6 months. Skin checks were conducted every 2 months. The primary endpoint is the number of new NMSCs during the 6 month study period, and the secondary endpoints include new individual squamous cell and basal cell carcinomas, and AK counts. Renal function in all participants was also monitored during the study, in order to confirm the safety of nicotinamide in this patient group.
The study commenced recruitment July 2012 and completed recruitment March 2014. Data will be unblinded and analysed in September 2014. Thus far, 70 new histologically confirmed NMSC have arisen in this high-risk study population.
Nicotinamide is widely available, inexpensive and has excellent established safety profile for the general population. If nicotinamide shows evidence of chemopreventive efficacy and safety in the renal transplant recipient population, it could be instantly translated into clinical practice.