A systematic review and meta-analysis examined the link between a specific genetic variant and side effects from cyclophosphamide in patients with systemic lupus erythematosus and lupus nephritis. The analysis combined data from five studies, though the total number of patients was not reported. Researchers found a significant association between the CYP2C19*2 genetic polymorphism and a protective effect against drug-induced toxicity. The statistical odds ratio was 0.28 with a p-value of .021.
The study authors note that the evidence has low certainty due to small sample sizes and potential confounding factors. Variability in how outcomes were measured across the different studies also limits the strength of the conclusions. There was a potential for publication bias, meaning studies with negative results might not have been included.
Readers should understand that this research shows an association, not a direct cause-and-effect relationship. While the findings suggest this genetic marker could help predict toxicity, the results are based on limited data. Clinicians should consider these limitations when evaluating the potential utility of genetic testing for this specific drug.