Tacrolimus intra-patient variability measures and its associations with allograft clinical outcomes in kidney transplantation.

AIMS: Tacrolimus (Tac) is commonly prescribed in solid organ transplantation to prevent immune-mediated damage to the graft. However, its pharmacokinetics show substantial variability between and within patients. Intra-patient variability of tacrolimus (Tac-IPV) has emerged as a novel marker to predict transplant outcomes. Numerous studies report varying associations between Tac-IPV and clinical outcomes, with Tac-IPV measures showing wide discrepancies among these studies. This inconsistency could be a significant factor that influences the various outcomes reported in different studies. Our review comprehensively assesses the relationship between various Tac-IPV measures and their associations with clinical outcomes in transplant patients. METHODS: A comprehensive literature search was conducted using the PubMed and Embase databases, covering the period from 2004 to March 31, 2023. The search focused on studies that examined the relationship between Tac-IPV and clinical outcomes in kidney transplantation (KT). The inclusion criteria were specific to studies addressing Tac-IPV, including measures such as standard deviation (SD), coefficient of variation (CV), time-weighted coefficient of variability (CV), mean absolute deviation (MAD), and Tac variability score (TVS). Clinical outcomes included the development of de novo donor-specific antibodies (dnDSA), rejection episodes, graft loss, and graft failure. RESULTS: Among the 33 studies that met the inclusion criteria, a notable proportion presented conflicting findings in their assessment of various Tac-IPV measures regarding dnDSA, rejection episodes, graft loss, and graft failure. CONCLUSIONS: Most studies have identified a correlation between high Tac-IPV and poor clinical outcomes; however, this relationship is multifactorial. Influencing factors include the metabolic status of KT patients, the timing of Tac-IPV calculations, and the criteria for defining high and low Tac-IPV thresholds, including the size and selection method. CV, MAD, and TWCV are the metrics that are most frequently used to determine Tac-IPV. Additionally, most of the methods for establishing Tac-IPV thresholds typically employ receiver operating characteristic (ROC) curves and median values. It is also notable that studies examining the clinical significance of Tac-IPV often include tacrolimus levels measured six months after kidney transplantation.

Sotorasib versus Docetaxel for treatment of US and Chinese patients with advanced non-small-cell lung cancer with KRAS p.G12C-mutated: A cost-effectiveness analysis to inform drug pricing.

BACKGROUND: The cost-effectiveness of sotorasib and its reasonable price in the United States (US) and China remain unknown. Our objective was to estimate the price at which sotorasib could be economical as second-line treatment for advanced non-small-cell lung cancer patients with Kirsten rat sarcoma viral oncogene homolog p.G12C-mutation in 2 countries. METHODS: We conducted an economic evaluation from the perspective of US and Chinese payers. To analyze US patients, we built a partitioned survival model. However, since we lacked Asian-specific overall survival data, we created a state transition model for the Chinese patients. We obtained patients' baseline characteristics and clinical data from CodeBreaK200, while utilities and costs were gathered from public databases and published literature. We calculated costs (US dollar), life years, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios. We conducted price simulation to guide pricing strategies. Additionally, we assessed the reliability of our results through sensitivity analyses, scenario analyses, and subgroup analyses. RESULTS: The incremental cost-effectiveness ratios of sotorasib compared to docetaxel were $1501,852 per quality-adjusted life-years (QALY) in the US and $469,106/QALY in China, respectively, which meant sotorasib was unlikely to be economical at the currently available price of $20,878 (240 × 120 mg) in both countries. Price simulation results revealed that sotorasib would be preferred at a price lower than $1400 at the willingness-to-pay threshold of $37,376 in China and a price lower than $2220 at the willingness-to-pay threshold of $150,000 in the US. Sensitivity, scenario, and subgroup analyses showed that these conclusions were generally robust, the model was most sensitive to the utilities of progression-free survival and post-progression survival. CONCLUSIONS: Sotorasib could potentially be a cost-effective therapy in the US and China following price reductions. Our evidence-based pricing strategy can assist decision-makers and clinicians in making optimal decisions. However, further analysis of budget impact and affordability is needed.