Nonadherence to oral mercaptopurine and risk of relapse in Hispanic and non-Hispanic white children with acute lymphoblastic leukemia: a report from the children's oncology group.

PURPOSE: Systemic exposure to mercaptopurine (MP) is critical for durable remissions in children with acute lymphoblastic leukemia (ALL). Nonadherence to oral MP could increase relapse risk and also contribute to inferior outcome in Hispanics. This study identified determinants of adherence and described impact of adherence on relapse, both overall and by ethnicity. PATIENTS AND METHODS: A total of 327 children with ALL (169 Hispanic; 158 non-Hispanic white) participated. Medication event-monitoring system caps recorded date and time of MP bottle openings. Adherence rate, calculated monthly, was defined as ratio of days of MP bottle opening to days when MP was prescribed. RESULTS: After 53,394 person-days of monitoring, adherence declined from 94.7% (month 1) to 90.2% (month 6; P < .001). Mean adherence over 6 months was significantly lower among Hispanics (88.4% v 94.8%; P < .001), patients age ≥ 12 years (85.8% v 93.1%; P < .001), and patients from single-mother households (80.6% v 93.1%; P = .001). A progressive increase in relapse was observed with decreasing adherence (reference: adherence ≥ 95%; 94.9% to 90%: hazard ratio [HR], 4.1; 95% CI,1.2 to 13.5; P = .02; 89.9% to 85%: HR, 4.0; 95% CI, 1.0 to 15.5; P = .04; < 85%: HR. 5.7; 95% CI, 1.9 to 16.8; P = .002). Cumulative incidence of relapse (± standard deviation) was higher among Hispanics (16.5% ± 4.0% v 6.3% ± 2.2%; P = .02). Association between Hispanic ethnicity and relapse (HR, 2.6; 95% CI, 1.1 to 6.1; P = .02) became nonsignificant (HR, 1.8; 95% CI, 0.6 to 5.2; P = .26) after adjusting for adherence and socioeconomic status. At adherence rates ≥ 90%, Hispanics continued to demonstrate higher relapse, whereas at rates < 90%, relapse risk was comparable to that of non-Hispanic whites. CONCLUSION: Lower adherence to oral MP increases relapse risk. Ethnic difference in relapse risk differs by level of adherence-an observation currently under investigation.

Outcomes of renal transplantation in recipients with Wegener's granulomatosis.

Wegener's granulomatosis (WG) is the leading cause of rapidly progressive glomerulonephritis-induced end-stage renal disease (ESRD). In this study, we compared transplant outcomes between recipients with ESRD caused by WG to recipients with ESRD secondary to other causes. Using OPTN/UNOS data from 1996 to 2007, 919 recipients with WG were identified. Post-transplant outcomes included rates of delayed graft function, acute rejection within one-yr post-transplant, overall and death-censored graft survival, and patient survival and were compared between recipients with ESRD secondary to WG versus ESRD from other causes. Recipients with ESRD because of WG had superior unadjusted and adjusted rates of graft loss, patient death, and functional graft loss (adjusted hazard ratio [HR] 0.711, 0.631, and 0.625 respectively, p < 0.001). When we compared the WG cohort to a non-WG, non-diabetic population, the HR for graft loss was still significant, but patient death and death-censored graft loss were not. Subgroup analysis of recipients aged over 60 confirmed that WG recipients had better unadjusted outcomes. This study supports the notion that renal transplantation is an effective treatment option for patients with ESRD secondary to WG. They fare similarly, if not better, than other patients.