Immunosuppressant therapy adherence and graft failure among pediatric renal transplant recipients

Once-daily extended-release versus twice-daily standard-release tacrolimus in kidney transplant recipients: a systematic review

BACKGROUND

A simplified dosing regimen may improve drug compliance in kidney transplant recipients and long-term graft outcomes. We aimed to identify, appraise, and synthesize the current evidence comparing the relative safety and efficacy of the recently introduced daily versus standard twice-daily tacrolimus administration.

METHODS

We systematically reviewed all randomized controlled trials and observational studies that compared the outcomes of daily versus twice-daily tacrolimus formulation in kidney transplant recipients. Medline (from 1948 to July week 4 2011), Embase (1980 to 2011 week 31), the Cochrane Library (1991 to June 2011), and conference proceedings were searched without language restriction.

RESULTS

Six randomized controlled trials (n=2499) and 15 observational studies (n=2886) were included in the review. There were no significant differences in biopsy-proven acute rejection (two trials, n=1093; risk ratio [RR; confidence interval (CI)], 1.24 [0.93-1.65]; P=0.15; I=0%), patient survival (three trials, n=1156; RR [CI], 0.99 [0.97-1.02]; P=0.55; I=32%), and graft survival (three trials, n=1156; RR [CI], 0.99 [0.97-1.02]; P=0.67; I=0%) between the two formulations at 12 months. Similar results for acute rejection (five studies, n=391; RR [CI], 0.99 [0.93-1.06]; P=0.84; I=0%) and overall patient survival (two studies, n=218; RR [CI], 1.02 [0.94-1.10]; P=0.62; I=0%) were observed in observational studies.

CONCLUSIONS

Once-daily tacrolimus appears to be as effective as twice-daily tacrolimus up to 12 months after kidney transplantation.

Analysis of tacrolimus and creatinine from a single dried blood spot using liquid chromatography tandem mass spectrometry

Long term therapeutic drug monitoring and assessment of renal function are required in renal transplant recipients on immunosuppressant therapy such as tacrolimus. Dry blood spots (DBS) have been used successfully in the clinic for many years and offers a convenient, simple and non-invasive method for repeated blood tests. We developed and performed a preliminary validation of a method for the analysis of tacrolimus and creatinine from a single DBS using liquid chromatography-tandem mass spectrometric (LC-MS/MS). Tacrolimus and creatinine were extracted from a 6mm punch with a mixture of methanol/acetonitrile containing ascomycin and deuterated creatinine as internal standards. A 10 μl aliquot of the extract was analyzed directly after dilution for creatinine with normal phase high performance liquid chromatography and multiple reaction monitoring. The remainder of the extract was processed and analyzed for tacrolimus. The lower limit of quantification for tacrolimus was 1 ng/ml with accuracy of 0.34% bias and precision (CV) of 11.1%. The precision ranged from 1.33% to 7.68% and accuracy from -4.44% to 11.6% bias for the intra- and inter-day analysis. The lower limit of quantification of creatinine was 0.01 mg/dL with precision of 7.94%. Accuracy was based on recovery of additional creatinine spiked into whole blood samples and ranged from -2.45% bias at 5 mg/dL to 3.75% bias at 0.5 mg/dL. Intra- and inter-day precision was from 3.48 to 4.11%. The assay was further validated with DBS prepared from pediatric renal transplant recipients. There was excellent correlation between the levels of tacrolimus and creatinine obtained from the clinical laboratory and the DBS method developed. After additional validation, this assay may have a significant impact on compliance with medication intake as well as potentially lowering the cost associated with intravenous blood draws in clinical laboratories.

Factors predictive of medication nonadherence after renal transplantation: a French observational study

BACKGROUND

There have been few prospective studies on the natural history of nonadherence (NA) in kidney transplant recipients (KTRs) over time. The objective of this study was to prospectively evaluate the rate of and risk factors for NA in a French cohort of KTRs.

METHOD

A total of 312 KTRs from eight French transplantation centers were included in this prospective, noninterventional cohort study. A computer-learning software package (the Organ Transplant Information System) was made available to all patients.

RESULTS

Using the four-item Morisky scale, we showed that 17.3%, 24.1%, 30.7%, and 34.6% of patients were nonadherent at posttransplant month 3 (M3), M6, M12, and M24, respectively. Young age was predictive of NA at M6, M12, and M24. Surprisingly, simple treatment regimens including a small number of doses per day and a small number of tablets per day were associated with NA at M3 and M12, respectively. Other factors predictive of NA included failure to use the Organ Transplant Information System software package at M6 and patient reports of adverse events at M12 and M24. Importantly, we observed that physicians underestimated the prevalence of adverse events when compared to patient self-reporting.

CONCLUSION

Our observed rate of medication NA in France is consistent with rates reported in previous studies. We found variability in NA risk factors over time as well as an unexpected risk factor (simple treatment regimens). These findings will be useful in developing effective adherence-promoting interventions.

Improved adherence to tacrolimus once-daily formulation in renal recipients: a randomized controlled trial using electronic monitoring

BACKGROUND

With effective agents available to prevent posttransplantation acute organ rejection, medication adherence becomes a key factor for successful treatment outcomes after renal transplantation. A once-daily, modified-release oral formulation of tacrolimus has been developed to simplify dosing and improve medication adherence.

METHODS

Adherence Measurement in Stable Renal Transplant Patients Following Conversion From Prograft to Advagraf is a randomized multicenter controlled trial to evaluate adherence between a tacrolimus once-daily regimen and a tacrolimus twice-daily regimen using an electronic monitor to document drug intake. After enrolment, all patients continued the twice-daily regimen for 3 months and then were randomized 2:1 between the two formulations and followed for 6 months. Adherence was decomposed into patients' persistence and implementation of each regimen.

RESULTS

Two hundred nineteen patients (45% male; 3±2 years after transplantation) were analyzed (145 once daily and 74 twice daily). At 6 months after randomization, 81.5% of the once-daily group and 71.9% of the twice-daily group remained persistent with the treatment (P=0.0824). Among patients who remained engaged with the regimen, 88.2% of the once-daily group and 78.8% of the twice-daily group (P=0.0009) took the prescribed number of daily doses. When the patients took the twice-daily regimen, the average percentage of missed doses was 11.7% in the morning and 14.2% in the evening (P=0.0035).

CONCLUSIONS

Regimen implementation of tacrolimus once daily is significantly superior to the twice-daily regimen. There was a residual prevalence of suboptimal adherence that will have to be countered by means other than reformulation and regimen simplification. Electronically compiled dosing histories provide detailed data on patient adherence that can be used for efficient medication management.

Drug-related problem in children with chronic kidney disease

Drug therapies in the management of chronic kidney disease (CKD) are complex and specialised and have a high potential for drug-related problem (DRP). In adult CKD populations, the identification and resolution of DRP has been shown to have beneficial effects on disease management, adherence and knowledge of treatment, patient's quality of life, hospitalisation rate and length of stay and cost to the healthcare system. The focus of this article is the review of published studies on DRP in children with CKD. There is a lack of information on the epidemiology of DRP in this patient group, and research in this area is therefore needed to better understand and manage DRP in children with CKD.

Impact of recipient age on whole organ pancreas transplantation

AIM

The goal of this study was to assess the impact of recipient age on post-transplant outcome.

METHODS

All pancreas transplants performed at Indiana University between 2003 and 2011 were reviewed. Demographic data were compared using standard chi-square and ANOVA testing. Standard Cox regression survival analysis was performed using a direct entry method for covariates.

RESULTS

Patients (n = 405) were divided by decade: <30 yr (n = 37), 30-39 (n = 109), 40-49 (n = 156), 50-59 (n = 85), and ≥ 60 yr of age (n = 18). Group demographics did not differ except for median ischemia time, which was between 7.0 and 8.5 h (p = 0.02). Early graft loss and one yr graft and patient survival were similar between the groups. Long-term patient survival demonstrated a trend toward decreased five-yr survival with increasing recipient age (p = NS). Graft survival at five yr by Cox regression was the lowest for the <30 yr group (74%), while all other groups were similar around 80% (p = NS).

CONCLUSION

No statistically significant differences in pancreas transplant outcomes were demonstrated when recipients were stratified by recipient age. These results suggest that older recipients can successfully undergo pancreas transplantation and expect five-yr outcomes similar to those seen in younger recipients.

System for integrated adherence monitoring: real-time non-adherence risk assessment in pediatric kidney transplantation

This study reports initial results of the development of the SIAM, a non-adherence risk assessment system for tacrolimus and sirolimus for the pediatric kidney transplant population. Forty-eight youths between 10 and 25 yr of age diagnosed with chronic kidney disease or a kidney transplant used an electronic pill bottle (EM; time stamps each bottle opening) to dispense their medication for at least 30 days or until their next clinic appointment. Youth also completed a self-report adherence measure, and standard deviations were calculated for the last four medication serum trough levels obtained for each patient. Estimation models were developed for each medication (i.e., SIAM(TACRO) and SIAM(SIRO) ) to assign weights to these clinically available adherence measures (self-report and trough levels) for the calculation of a non-adherence risk composite score. SIAM(TACRO) models included both self-report and tacrolimus trough levels and significantly predicted EM. For sirolimus, the model predictive of adherence as measured by EM consisted of the standard deviation of sirolimus trough levels only (SIAM(SIRO) ). Non-adherence risk can be effectively assessed using clinically available assessment tools. However, the best methods for using self-report and trough levels to predict non-adherence likely differ based on the medication for which adherence is being assessed.

Abrogation of antibodies improves outcome of renal transplantation

INTRODUCTION

Antibodies are known to cause rejection and therefore are detrimental to graft survival. We describe two protocols of clonal stimulation deletion (CSD) pretransplant followed by grafting with no conventional immunosuppression (IS).

METHODS

CSD was employed in 54 patients of mean age, 28.7 years and mean human leukocyte antigen A/B/DR match, 3.25. The two protocols both employed stimulation with donor-specific transfusions and stem cells with deletion using total lymphoid irradiation in group 1 (n = 29) or bortezomib in group 2 (n = 25). Other adjuvants in both protocols were cyclophosphamide, rabbit antithymocyte globulin, and rituximab. Stimulation and deletion were monitored by lymphocyte crossmatches and detection of donor-specific antibodies (DSA). Posttransplant monitoring included serum creatinine (SCr) measurements and antibody detection at regular intervals. Graft biopsy performed in the event of dysfunction was managed by standard guidelines. Rescue IS was initiated upon a rise in SCr or DSA.

RESULTS

Mean follow-up in group 1 is 3.28 years and 2.11 years in group 2. There was 100% graft and patient survivals in both cohorts with 23 patients without IS and stable graft function with an SCr of 1.3 mg/dL. All acute rejection episodes, which occurred among 24.1% of group 1 and 20% of group 2, were rescued with therapy evolving as a SCr of 1.6 to 1.9. The majority of rejections were antibody-combined with T-cell-mediated responses. We did not observe untoward effects of the protocol.

CONCLUSION

Abrogation of antibodies improved renal transplant outcomes.

Monitoring nonadherence and acute rejection with variation in blood immunosuppressant levels in pediatric renal transplantation

BACKGROUND

Acute rejection associated with medication nonadherence is a major cause of allograft loss in pediatric kidney transplant patients. There is currently no reliable method to detect medication nonadherence and prevent allograft rejection.

METHODS

In 46 pediatric patients who underwent renal transplantation between 2002 and 2003, the variation of serum drug levels was studied as a potential objective tool to monitor medication nonadherence. Tacrolimus (TAC) and mycophenolic acid (MPA) trough levels were measured from 1 to 12 months posttransplant, and standard deviation (SD) and percent coefficient of variation (CV%) were calculated. Because SD increased as mean trough levels rose, CV% (CV%=SD/mean multiplied by 100%) was used to eliminate this confounding effect.

RESULTS

Ten of 46 patients had biopsy-proven rejection. The median TAC CV% was 53.4% in patients with biopsy-proven rejection, which was significantly higher than 30% in those without rejection (P=0.005). Median MPA CV% was 51.9% in patients without rejection and 45.1% in patients with rejection (P=NS). High TAC CV% correlated with increased risk for rejection, whereas MPA CV% did not.

CONCLUSION

The TAC CV% seems to be a useful and superior marker, compared with SD alone, for assessing medication nonadherence and the possibility of allograft rejection in pediatric renal transplantation.

[Chronic kidney insufficiency in children]

Chronic kidney insufficiency (CKI) in children: Failure to thrive, feeding disorders and/or excessive thirst must evoke CKI in children. More than 50% of renal diseases in children with CKI are congenital or inherited. Major issues are growth, nutrition and renal osteodystrophy. Psychological and social management are crucial aspects of the therapeutic project. Peritoneal dialysis is the renal replacement therapy of choice, especially in children under 2 years, with an important risk of peritonitis. Kidney transplant, which can be performed in children more than 10 kg, is the best treatment of end-stage renal failure in children. Pediatric transplant specificities are increased risks of thrombosis, post-transplant lymphoproliferative disorders in EBV-negative recipients, and poor compliance to medication during adolescence.

Family strategies for achieving medication adherence in pediatric kidney transplantation

BACKGROUND

Although nonadherence is well documented and strategies for adherence have been shown to be critical to overcoming barriers and improving overall adherence rates, it is unknown how family strategy use is related to adherence in the pediatric renal transplant population.

OBJECTIVES

The aims of this study were to assess (a) the strategies used by adolescents with kidney transplants and their caregivers to adhere to the posttransplant oral medication regimen and (b) the relationship of these strategies to objective adherence rates.

METHODS

Semistructured interviews to assess self-management were administered to 17 adolescents (14-18 years) and 17 caregivers. Adherence to oral immunosuppressant medication, measured via electronic monitors, was determined also for a subset of 13 dyads.

RESULTS

Common strategies endorsed by families included the following: making it part of the routine (88.2%), verbal reminders by caregiver (82.4%), caregiver verifying medication was taken (76.5%), placing medication in a convenient location (76.5%), and using a pillbox (70.6%). A greater number of family-endorsed strategies were correlated with higher levels of adherence. Of those strategies spontaneously endorsed, only caregiver reminders to take medication and caregiver verification that medications were taken were related significantly to higher adherence rates.

DISCUSSION

The findings highlight the importance of identification and use of specific strategies to improve adherence rates of pediatric renal transplant recipients and emphasize the need for continued caregiver involvement in the promotion of adherence to the treatment regimen.

Variability in tacrolimus blood levels increases the risk of late rejection and graft loss after solid organ transplantation in older children

  Late graft rejection impairs the long-term function of organ transplants in children. Previous studies suggest patients with wide variation in tacrolimus levels may have higher rates of late kidney and liver graft rejection. The reproducibility of this finding and impact on graft and recipient survival have not been reported. We investigated factors associated with late rejection > 6 months post-transplant in 144 heart, kidney, liver, and lung transplant recipients (ages 8-18, ≥ 1-yr survivors, receiving tacrolimus-based immunosuppression), comparing late rejectors (n = 61, 42%) to non-rejectors (no rejection > 6 months); groups had similar mean tacrolimus concentrations ≤ 6 months post-transplant. For all organ types, increased standard deviation in intrapatient tacrolimus blood levels was an independent risk factor for late rejection (OR 1.6 [CI 1.1-2.1]; p = 0.02). Each 1-point increase in s.d. > 2 of tacrolimus level > 6 months post-transplant associated with 1.58 increase in hazard of graft loss (p = 0.003). Graft survival (conditional on one-yr survival) was significantly better for those with s.d. < 2 at > 6 months post-transplant: 98% at three and five yr, versus 88%, 70%, at three and five yr, in patients with s.d. > 2 (p = 0.003). In conclusion, high s.d. in serial tacrolimus concentrations associated with increased risk of late rejection and graft loss in pediatric organ transplant recipients, providing opportunities for screening and interventions.

Diagnosis in Pediatric Transplant Biopsies

Infant recipients have better survival after solid organ transplantation than older children and adults possibly due to immune tolerance. Over the past two decades, postsurgical complications have markedly decreased, and multidrug immunosuppressive regimens have become effective in preventing and treating rejection. Immunocompromised for life, these patients are susceptible to both the usual bacterial as well as opportunistic infections that often involve the lung. Post-transplant lymphoproliferative disease seems to be decreasing even further in frequency. This article focuses on the findings seen on biopsy, usually of the transplanted organ, and also of other sites affected by post-transplant complications.

Optimizing medication adherence: an ongoing opportunity to improve outcomes after kidney transplantation

Nonadherence of transplant recipients to prescribed medical regimens has been identified as a major cause of allograft failure. Although recent studies offer new insight into the clinical phenotypes of nonadherence, advances in defining risk factors and appropriate interventions have been limited because of variable definitions, inadequate clinical metrics, and the challenges associated with healthcare delivery. Significant nonadherence is estimated to occur in 22% of renal allograft recipients and may be a component of allograft loss in approximately 36% of patients. It is associated with increased incidence of rejection (acute and chronic) and, consequently, shortened renal allograft survival, requiring reinstitution of costly chronic renal replacement therapy with an incumbent effect on morbidity and mortality. The economic effect of nonadherence approaches similar magnitude. Identification of risk factors, coupled with measures that effectively address them, can have a positive effect at many levels--medically, socially, and economically. Further advances are likely to be dependent on improving interactions between patients and caregivers, broadening immunosuppressant availability, and newer therapeutics that move toward simpler regimens.