Oral nicotinamide ineffective in preventing keratinocyte cancers

Nicotinamide therapy was not effective in lowering the rates of keratinocyte cancers or actinic keratoses in immunosuppressed solid-organ transplant recipients, according to a phase 3 trial.

“Nicotinamide has been shown to reduce the development of actinic keratoses and keratinocyte cancers in immunocompetent persons, but its effects in transplant recipients are unclear,” Nicholas C. Allen, MPH, of the department of dermatology at The University of Sydney and Westmead Hospital in New South Wales, Australia, and colleagues wrote. “Given the affordability and safety profile of nicotinamide and the related absence of changes to baseline immune responses, nicotinamide has been suggested as a potential chemopreventive agent in this patient population.”

In this multicenter, double-blind, placebo-controlled, phase 3 trial, researchers assessed the role of oral nicotinamide in the chemoprevention of keratinocyte cancers in solid-organ transplant recipients. The 158 participants had undergone kidney, liver, heart or lung transplantation at least 12 months prior to the study and were randomly assigned to receive 500 mg of nicotinamide (n = 79) or placebo (n = 79) twice daily for 12 months.

Results showed that after 12 months of treatment, there were 207 new keratinocyte cancers in the nicotinamide group and 210 in the placebo group, resulting in a rate ratio of 1 (95% CI, 0.8-1.3). Rates of squamous-cell carcinomas (rate ratio = 1.4; 95% CI, 0.8-2.3) and basal-cell carcinomas (rate ratio = 0.9; 95% CI, 0.6-1.2) were similar between groups. Transplant type did not influence outcomes.

Adverse events were similar between groups and included infections and infestations predominantly in the respiratory system, urinary tract and skin.

The authors noted that their findings contradict the findings of the Oral Nicotinamide to Reduce Actinic Cancer trial, which showed a 23% lower rate of keratinocyte cancer among patients taking oral nicotinamide vs. placebo. However, the authors note that their sample size of 158 was below the 254 target due to slow recruitment and the expiration of the trial drugs. As a result, the trial ended early.

The authors emphasized the importance of wearing sunscreen as a preventive measure in light of the fact that fewer than 50% of participants used sunscreen.

“Poor adherence to this preventive measure in recipients of organ transplants is a persisting impediment to the effectiveness of sunscreen in preventing sun damage that can lead to neoplastic lesions, despite reasonable levels of knowledge regarding sun protection as a preventive measure.”