Association of The Common CYP1A1*2C Variant (Ile462Val Polymorphism) with Chronic Myeloid Leukemia (CML) in Patients Undergoing Imatinib Therapy

Polymorphisms of Drug-Metabolizing Enzymes and Transporters Contribute to the Individual Variations of Erlotinib Steady State Trough Concentration, Treatment Outcomes, and Adverse Reactions in Epidermal Growth Factor Receptor-Mutated Non-Small Cell Lung Cancer Patients

Background

Erlotinib is presently the first line treatment for non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) active mutation. An increasing number of evidences show that the treatment efficacy and toxicities are considerably heterogeneous among individuals. Hence, it is necessary to find biological predictors for further individualized treatment of erlotinib in NSCLC patients.

Methods

Our present study enrolled 87 cases of NSCLC patients who had been administrated erlotinib with a fixed dose (150 mg/d). Eleven polymorphisms in seven genes of drug-metabolizing enzymes and transporters were genotyped and the steady state trough concentrations were also determined.

Results

There were significant variances in the steady-state erlotinib trough plasma concentrations, ranging from 315.6 ng/ml to 4479.83 ng/ml. Erlotinib steady state trough concentration was remarkably lower in current smoking patients. The steady state trough concentration of GG in rs1048943 of CYP1A1 was significantly higher than that of AA allele carriers. The polymorphism of CYP1A2 was significantly associated with the severity of skin rash, and the development of diarrhea was associated with SNPs in ABCB1 and CYP3A5. We also observed that GG allele in CYP1A1 was accompanied with a longer PFS in our study.

Conclusion

A large variability of erlotinib steady state trough concentration was found among Chinese Han population. SNPs in CYP1A1 appeared to influence the steady state trough concentration of erlotinib. Correlation between CYP1A2 polymorphisms and severity of skin rash was observed, together with the correlation between the development of diarrhea and SNPs in ABCB1 and CYP3A5.

Pharmacology of tyrosine kinase inhibitors in chronic myeloid leukemia; a clinician's perspective

OBJECTIVE

In this review, we have summarized the pharmacokinetics, pharmacodynamics and adverse effects of imatinib, dasatinib, nilotinib, bosutinib, ponatinib and radotinib with focus on pharmacogenomic studies with clinical end points. We have discussed the key phase 3 trials of tyrosine kinase inhibitors (TKI) comparing with each other, treatment free remission (TFR) and selection of TKI. Upcoming concepts and related trials in the management of chronic myeloid leukemia (CML) along with future directions have been touched upon.

EVIDENCE ACQUISITION

PubMed, Embase, Google, Cochrane library and Medline were searched to identify relevant literature for the review. Clinicaltrial.gov was searched for upcoming data and trials.

RESULTS

There are lot of gap in pharmacokinetics and pharmacodynamics of TKI. Imatinib appears to be the safest TKI. Newer TKI's achieve better achievement of therapeutic milestones, deeper molecular response and less chances of progression of CML compared to imatinib. Newer TKI appears to be better choice for achieving TFR. When the objective is survival, imatinib is still the TKI of choice. Primary prophylaxis with antiplatelet drugs for TKI having cardiovascular and thromboembolic side effects should be considered.

CONCLUSION

Pharmacogenetic data of TKI is still immature to guide in therapeutic decision making in clinical practice. There is need for further research in pharmacology and pharmacogenomics of newer TKI's. Randomized controlled trials are required to decide the optimum TKI for TFR. Safe and effective TKI for targeting T315I mutation, CML accelerated phase and blast crisis are an active area of research.

Genetic polymorphisms associated with adverse reactions of molecular-targeted therapies in renal cell carcinoma

The prognosis of patients with metastatic renal cell carcinoma has drastically improved due to the development of molecular-targeted drugs and their use in clinical practice. However, these drugs cause some diverse adverse reactions in patients and sometimes affect clinical outcomes of cancer therapy. Therefore, predictive markers are necessary to avoid severe adverse reactions, to establish novel and effective prevention methods, and to improve treatment outcomes. Some genetic factors involved in these adverse reactions have been reported; however, perspectives on each adverse response have not been integrated yet. In this review, genetic polymorphisms relating to molecular-targeted therapy-induced adverse reactions in patients with renal cell carcinoma are summarized in the points of pharmacokinetic and pharmacodynamic mechanisms. We also discuss about the relationship between systemic drug exposure and adverse drug reactions.