The impact of cytochrome P450 3A5 genotype on early tacrolimus metabolism and clinical outcomes in lung transplant recipients

The impact of CYP3A5, NR1I2, and POR polymorphisms on tacrolimus dose-adjusted concentration and clinical outcomes in adult allogeneic haematopoietic stem cell transplantation

Polymorphisms in genes related to drug-metabolising enzymes may affect tacrolimus exposure. This study aimed to assess the influence of CYP3A5, NR1I2, and POR polymorphisms on tacrolimus pharmacokinetics and outcomes in allogeneic haematopoietic stem cell transplantation (HSCT).Forty-six adult patients receiving oral tacrolimus at an initial dose of 0.03 mg/kg/day for acute graft versus host disease (GVHD) prophylaxis after allogeneic HSCT were enrolled in this retrospective study. Genetic polymorphisms were detected in relation to concentration/dose (C/D) ratios of tacrolimus and the incidence of acute GVHD and acute kidney injury (AKI).The CYP3A5 *3/*3 genotype and co-administration of voriconazole were significantly associated with increased C/D ratios of tacrolimus (p < 0.05). NR1I2 8055CC presents a significantly higher tacrolimus C/D ratio compared with carriers of 8055CT and 8055TT genotypes in allogeneic HSCT recipients with the CYP3A5*1 allele (p = 0.033). Younger age and recipients with the CYP3A5*1 allele were significantly associated with higher incidence of II-IV acute GVHD post-transplantation.CYP3A5*3, NR1I2 8055C > T, and concomitant use of voriconazole are important determinants affecting tacrolimus pharmacokinetics. Moreover, CYP3A5*1 allele and younger age are independent risk factors for II-IV acute GVHD in HSCT recipients.

CYP3A4/5 genotypes and age codetermine tacrolimus concentration and dosage in pediatric heart transplant recipients

Tacrolimus (TAC) is the cornerstone of immunosuppressive therapy for pediatric heart transplantation (HTx) recipients. However, little information is known on the interaction of developmental and genetic variants on TAC disposition in this population, which makes TAC dose optimization more difficult. The aim of study was to investigate the relationship between genotypes and age on TAC concentrations and dosage during the early post-operation period in pediatric HTx recipients. Sixty-six pediatric HTx recipients were enrolled and divided into three groups according to the age (<6, ≥6-≤12, 12-18 years old). CYP3A4/5, POR and ABCB1 polymorphisms were genotyped. The associations between genotypes and age on TAC dose-adjusted trough concentrations (C₀/D), dose requirement as well as acute kidney injury (AKI) were evaluated. CYP3A5*3 and CYP3A4*1G were significantly correlated with TAC C₀/D and dose requirement in the pediatric recipients ≥ 6 years. The C₀/D in children aged ≥ 6-≤12 years and 12-18 years is 2.8 and 4.2 fold of these < 6 years old, respectively. TAC dose requirements in children aged < 6 years were 2.4 times and 3.5 times of these aged ≥ 6-≤12 years and 12-18 years, respectively. Among the same CYP3A5*3 or CYP3A4*1G genotypes, age was positively increased with TAC C₀/D and negatively correlated with targeted dose. No genetic variants were found to be associated with AKI during the early post-operation period. CYP3A4/5 genotypes and age should be taken into consideration to TAC dosage in pediatric HTx recipients.