3.3. Metabolite Ratio Analysis
The most common rationale for obtaining 6MP metabolites in both cohorts was inadequate myelosuppression (47% vs. 70%; OR=0.54 (95% CI, 0.31-0.94); P =0.04). In many cases, patients had multiple reasons for metabolite collection in addition to inadequate myelosuppression including hepatotoxicity, rash, and GI upset.
There were significant decreases in the median metabolite ratios (6MMP:6TGN) when assessing the pre-initiation of allopurinol ratios to the post-initiation of allopurinol ratios in the allopurinol cohort (median (IQR); 86.7 (54.8-127.7) vs. 3.6 (1.7-11.4);P< 0.0001). (Table 2 and Figure 3).