Assessment of cancer risk associated with 7-nitroso-3-(trifluoromethyl)-5,6,7,8-tetrahydro[1,2,4] triazolo-[4,3-a]pyrazine-contaminated sitagliptin use: A retrospective cohort study.

AIMS/INTRODUCTION: A recent US Food and Drug Administration report highlighted concerns over nitrosamine (7-nitroso-3-(trifluoromethyl)-5,6,7,8-tetrahydro[1,2,4] triazolo-[4,3-a]pyrazine [NTTP]) impurities in sitagliptin, prompting investigations into its safety profile. The present study aimed to determine if the use of NTTP-contaminated sitagliptin, in comparison with other dipeptidyl peptidase-4 (DPP-4) inhibitors, is associated with an increased cancer risk.

MATERIALS AND METHODS

This retrospective cohort study secondarily used the National Database of Health Insurance Claims and Specific Health Checkups of Japan, encompassing data on >120 million individuals. The study involved patients who initiated DPP-4 inhibitor therapy (sitagliptin or other DPP-4 inhibitors) and continued its exclusive use for 3 years. Sitagliptin users were compared with other DPP-4 inhibitor users for assessing the occurrence of cancers, as defined by diagnosis codes. Further analyses focused on specific types of cancer, using either diagnosis codes or a combination of diagnosis and procedure codes. We also carried out various sensitivity analyses, including those with different exposure periods.

RESULTS

Sitagliptin users (149,120 patients, 388,356 person-years) experienced 9,643 cancer incidences (2,483.0/100,000 person-years) versus 12,621 incidences (2,504.4/100,000 person-years) among other DPP-4 inhibitor users (199,860 patients, 503,952 person-years), yielding a minimal difference (incidence rate ratio 0.99, 95% confidence interval 0.97-1.02). A multiple Cox proportional hazards model showed no significant association between sitagliptin use and overall cancer incidence (hazard ratio 1.01, 95% confidence interval 0.98-1.04). Findings were also consistent across cancer types and sensitivity analyses.

CONCLUSIONS

We observed no evidence to suggest an increased cancer risk among patients prescribed NTTP-contaminated sitagliptin, although continued investigation is needed.