Pharmacogenomics Variation in Drug Metabolizing Enzymes and Transporters in Relation to Docetaxel Toxicity in Lebanese Breast Cancer Patients: Paving the Way for OMICs in Low and Middle Income Countries

Integrating pharmacogenomics in three Middle Eastern countries' healthcare (Lebanon, Qatar, and Saudi Arabia): Current insights, challenges, and strategic directions

BACKGROUND AND OBJECTIVES

Pharmacogenomics (PGx) leverages genomic information to tailor drug therapies, enhancing precision medicine. Despite global advancements, its implementation in Lebanon, Qatar, and Saudi Arabia faces unique challenges in clinical integration. This study aimed to investigate PGx attitudes, knowledge implementation, associated challenges, forecast future educational needs, and compare findings across the three countries.

METHODS

This cross-sectional study utilized an anonymous, self-administered online survey distributed to healthcare professionals, academics, and clinicians in Lebanon, Qatar, and Saudi Arabia. The survey comprised 18 questions to assess participants' familiarity with PGx, current implementation practices, perceived obstacles, potential integration strategies, and future educational needs.

RESULTS

The survey yielded 337 responses from healthcare professionals across the three countries. Data revealed significant variations in PGx familiarity and educational involvement. Qatar and Saudi Arabia participants were more familiar with PGx compared to Lebanon (83%, 75%, and 67%, respectively). Participation in PGx-related talks was most prevalent in Saudi Arabia (96%), followed by Qatar (53%) and Lebanon (35%). Key challenges identified included test cost and reimbursement, insufficient physician knowledge, and lack of infrastructure. Lebanon reported the highest concern for test costs (16%), compared to the lowest in Saudi Arabia (5%). Despite these challenges, a strong consensus emerged on PGx's potential to improve patient outcomes, with over 86% of respondents in all three countries expressing this belief. Educational interest areas varied by country, with strong interest in PGx for cancer chemotherapy in Saudi Arabia and Lebanon and for diabetes mellitus in Qatar.

CONCLUSION

This study highlights the significant influence of varied educational backgrounds and infrastructural limitations on PGx implementation across Lebanon, Qatar, and Saudi Arabia. The findings emphasize the need for targeted strategies in each country to address these distinct barriers. Integrating PGx education into healthcare training programs and clinical workflows could unlock PGx's potential to optimize patient care.

Pharmacogenomics in Lebanon: current status, challenges and opportunities

Pharmacogenomics (PGx) research and applications are of utmost relevance in Lebanon considering its population genetic diversity. Moreover, as a country with regional leadership in medicine and higher education, Lebanon holds a strong potential in contributing to PGx research and clinical implementation. In this manuscript, we first review and evaluate the available PGx research conducted in Lebanon, then describe the current status of PGx practice in Lebanon while reflecting on the local and regional challenges, and highlighting areas for action, and opportunities to move forward. We specifically expand on the status of PGx at the American University of Beirut Faculty of Medicine and Medical Center as a case study and guide for the further development of local and regional comprehensive PGx research, teaching, and clinical implementation programs. We also delve into the status of PGx knowledge and education, and prospects for further advancement such as with online courses and certificates.

Discovery and identification of the prognostic significance and potential mechanism of FMO2 in breast cancer

BACKGROUND

Flavin containing dimethylaniline monoxygenase 2 (FMO2), is downexpressed in diverse tumors and displays vital roles in tumorigenesis. However, the prognostic value and potential mechanism of FMO2 in breast cancer remain unclear.

METHODS

The expression of FMO2 was analyzed and the relationship between FMO2 expression level and clinical indicators in breast cancer was analyzed. Then the prognostic value of FMO2 in breast cancer was assessed. The FMO2-correlated genes were obtained, and the highest-ranked gene was chosen. The expression, therapeutic responder analysis, and gene set enrichment analysis of the highest-ranked gene were conducted.

RESULTS

FMO2 was downregulated in breast cancer and was closely related to clinical indicators. Patients with decreased FMO2 expression showed poor overall survival, post-progression survival, relapse-free survival, and distant metastasis-free survival. FMO2 correlates with N/ER/PR subgroups in breast cancer and patients with high FMO2 levels were sensitive to anti-programmed cell death protein 1, anti-programmed death-ligand 1, and anti-cytotoxic T-lymphocyte antigen 4 immunotherapies. Mechanically, FMO2 was positively and highly correlated with secreted Frizzled-related protein 1 (SFRP1), which was downregulated in breast cancer due to hypermethylation. Moreover, SFRP1 was correlated to pathological complete response and relapse-free survival status at 5 years regardless of any chemotherapy, hormone therapy, and anti-HER2 therapy. Gene set enrichment analysis revealed enrichment of component and coagulation cascades, focal adhesion, protein export, and spliceosome.

CONCLUSIONS

FMO2 was lower expressed in breast cancer than normal tissues and contributes to subtype classification and prognosis prediction with co-expressed SFRP1.

Cross-Ancestry Genome-Wide Association Study Defines the Extended CYP2D6 Locus as the Principal Genetic Determinant of Endoxifen Plasma Concentrations

The therapeutic efficacy of tamoxifen is predominantly mediated by its active metabolites 4-hydroxy-tamoxifen and endoxifen, whose formation is catalyzed by the polymorphic cytochrome P450 2D6 (CYP2D6). Yet, known CYP2D6 polymorphisms only partially determine metabolite concentrations in vivo. We performed the first cross-ancestry genome-wide association study with well-characterized patients of European, Middle-Eastern, and Asian descent (n = 497) to identify genetic factors impacting active and parent metabolite formation. Genome-wide significant variants were functionally evaluated in an independent liver cohort (n = 149) and in silico. Metabolite prediction models were validated in two independent European breast cancer cohorts (n = 287, n = 189). Within a single 1-megabase (Mb) region of chromosome 22q13 encompassing the CYP2D6 gene, 589 variants were significantly associated with tamoxifen metabolite concentrations, particularly endoxifen and metabolic ratio (MR) endoxifen/N-desmethyltamoxifen (minimal P = 5.4E-35 and 2.5E-65, respectively). Previously suggested other loci were not confirmed. Functional analyses revealed 66% of associated, mostly intergenic variants to be significantly correlated with hepatic CYP2D6 activity or expression (ρ = 0.35 to -0.52), and six hotspot regions in the extended 22q13 locus impacting gene regulatory function. Machine learning models based on hotspot variants (n = 12) plus CYP2D6 activity score (AS) increased the explained variability (~ 9%) compared with AS alone, explaining up to 49% (median R² ) and 72% of the variability in endoxifen and MR endoxifen/N-desmethyltamoxifen, respectively. Our findings suggest that the extended CYP2D6 locus at 22q13 is the principal genetic determinant of endoxifen plasma concentration. Long-distance haplotypes connecting CYP2D6 with adjacent regulatory sites and nongenetic factors may account for the unexplained portion of variability.

Association between Breast Cancer Polygenic Risk Score and Chemotherapy-Induced Febrile Neutropenia: Null Results

BACKGROUND

The hypothesis that breast cancer (BC) susceptibility variants are linked to chemotherapy-induced toxicity has been previously explored. Here, we investigated the association between a validated 313-marker-based BC polygenic risk score (PRS) and chemotherapy-induced neutropenia without fever and febrile neutropenia (FNc) in Asian BC patients.

METHODS

This observational case-control study of Asian BC patients treated with chemotherapy included 161 FNc patients, 219 neutropenia patients, and 936 patients who did not develop neutropenia. A continuous PRS was calculated by summing weighted risk alleles associated with overall, estrogen receptor- (ER-) positive, and ER-negative BC risk. PRS distributions neutropenia or FNc cases were compared to controls who did not develop neutropenia using two-sample t-tests. Odds ratios (OR) and corresponding 95% confidence intervals were estimated for the associations between PRS (quartiles and per standard deviation (SD) increase) and neutropenia-related outcomes compared to controls.

RESULTS

PRS distributions were not significantly different in any of the comparisons. Higher PRS_overall quartiles were negatively correlated with neutropenia or FNc. However, the associations were not statistically significant (PRS per SD increase OR neutropenia: 0.91 [0.79-1.06]; FNc: 0.87 [0.73-1.03]). No dose-dependent trend was observed for the ER-positive weighted PRS (PRS_ER-pos) and ER-negative weighted PRS (PRS_ER-neg).

CONCLUSION

BC PRS was not strongly associated with chemotherapy-induced neutropenia or FNc.

Impact of variants in ATP-binding cassette transporters on breast cancer treatment

There has been substantial interest in the impact of ATP-binding cassette (ABC) transporter variability on breast cancer drug resistance. Here, we provide a systematic review of ABC variants in breast cancer therapy. Notably, most studies used small heterogeneous cohorts and their identified associations lack statistical stringency, replication and mechanistic support. We conclude that commonly studied ABC polymorphisms are not suitable to accurately predict therapy response or toxicity in breast cancer patients and cannot guide treatment decisions. However, recent research shows that ABC transporters harbor a plethora of rare variants with individually small effect sizes, and we argue that a shift in strategy from target variant interrogation to comprehensive profiling might hold promise to drastically improve the predictive power of outcome models.

ABCB1 and ABCC2 genetic polymorphism as risk factors for neutropenia in esophageal cancer patients treated with docetaxel, cisplatin, and 5-fluorouracil chemotherapy

PURPOSE

The combination of docetaxel, cisplatin and 5-fluorouracil (DCF) is a newly developed chemotherapy regimen for esophageal cancer. Severe neutropenia is dose-limiting toxicity of docetaxel and it is well known to be frequently occurred during DCF chemotherapy. This study aimed to investigate the relationship between severe neutropenia and genetic polymorphisms in patients treated with preoperative DCF chemotherapy.

METHODS

A total of 158 patients were investigated for their absolute neutrophil count (ANC) within the first cycle of DCF chemotherapy at the National Cancer Center (NCC) Hospital East. DNA samples obtained from the NCC Biobank Registry were used for the analysis of nine genetic polymorphisms related to docetaxel pharmacokinetics. These genotypes were evaluated for their association with severe neutropenia, and further their risk factors were examined using a multivariate logistic regression.

RESULTS

A total 81 (51.3%) patients developed severe neutropenia. Multivariate analysis revealed that age (OR 1.054; CI 1.008-1.102, P = 0.022), baseline ANC (OR 1.019; CI 1.002-1.037, P = 0.030), ABCB1 3435C>T (OR 2.191; CI 1.087-4.417, P = 0.028) and ABCC2 *+9383C>G (OR 2.342; CI 1.108-4.948, P = 0.026) were significant risk factors for severe neutropenia development. The results from this study showed that age, ANC, ABCB1 3435C>T, and ABCC2 *+9383 G>C increased the incidence of severe neutropenia with the number of identified risk factors.

CONCLUSIONS

In addition to age and baseline ANC, ABCB1 3435C>T and ABCC2 *+9383C>G were identified as independent predictors for severe neutropenia in esophageal cancer patients treated with DCF chemotherapy.

Genetic associations of docetaxel-based chemotherapy-induced myelosuppression in Chinese Han population

WHAT IS KNOWN AND OBJECTIVE

Myelosuppression, an adverse drug reaction (ADR), often causes medical treatment termination in cancer patients. It has been known that genetic components, such as single-nucleotide polymorphisms (SNPs), influence the risk of myelosuppression at the individual-patient level. However, due to ethnic variation in frequency of genetic polymorphisms, results reported in Caucasian patients may not be generalizable to the Chinese Han population. Until now, few researches on myelosuppression included Chinese Han patients. In this study, we conducted a systematic study of potential biomarkers for docetaxel-induced myelosuppression in Han Chinese patients.

METHODS

We examined 61 SNPs in 36 genes that code for drug transporters, metabolism enzymes, nuclear receptors and DNA repair pathway in 110 Chinese Han patients receiving docetaxel-based chemotherapy. Genotyping was conducted using the Sequenom MassARRAY system. Significant SNPs were identified by logistic regression, and gene-gene interactions were investigated by generalized multifactor dimensionality reduction (GMDR) analysis.

RESULTS AND DISCUSSION

Our results revealed that 11 SNPs in nine genes (SLC15A1, SLCO1A2, CYP2D6, FMO3, UGT1A1, NAT2, SULT2A1, PXR and HNF4α) were associated with docetaxel-induced myelosuppression. GMDR analyses suggested that a 3-locus model: SLC15A1 rs2297322-PXR rs3732359-FMO3 rs2266782 was an appropriate predictive model of docetaxel-induced myelosuppression (P = .017, Testing Bal.Acc = 0.653, CV Consistency = 10/10).

WHAT IS NEW AND CONCLUSION

Our findings suggest multiple novel predictive biomarkers of docetaxel-induced myelosuppression: SLC15A1 rs2297322, PXR rs3732359 and FMO3 rs2266782. These discoveries should help in advancing future personalized therapy of docetaxel-based chemotherapy specific to Chinese Han patients.

The role of single-nucleotide polymorphism (SNPs) in toxicity of induction chemotherapy based on cisplatin and paclitaxel in patients with advanced head and neck cancer

BACKGROUND

Induction chemotherapy in locally-advanced head and neck squamous cell carcinoma (LAHNSCC) patients is potentially associated to serious adverse events. Biomarkers associated with toxicity could tailor its indication. This study evaluated the association between single-nucleotide polymorphisms (SNPs) in metabolic genes and toxicity to induction chemotherapy.

METHODS

59 LAHNSCC phase II clinical trial patients (NCT00959387) were assessed regarding 47 metabolic genes (366 SNPs). Toxicities were graded (CTCAE 3.0) and statistical analysis was performed.

RESULTS

The SNPs rs8187710 (ABCC2) and rs1801131 (MTHFR) were associated to increased risk of gastrointestinal toxicity, whereas the SNPs rs3788007 (ABCG1) and rs4148943 (CHST3) were associated to decreased risk. Two other SNPs, rs2301159 (SLC10A2) and rs2470890 (CYP1A2), were associated with increased risk of hematological toxicity. Nevertheless, these SNPs did not remain significant after adjusting for multiple comparisons.

CONCLUSIONS

This study could not demonstrate relationship between SNPs and toxicity to induction chemotherapy in LAHNSCC patients. The small number of patients may have affected the results.

GSTP1 rs1695 is associated with both hematological toxicity and prognosis of ovarian cancer treated with paclitaxel plus carboplatin combination chemotherapy: a comprehensive analysis using targeted resequencing of 100 pharmacogenes

Purpose

To find genetic variants that predicted toxicity and/or efficacy of paclitaxel plus carboplatin combination therapy (TC therapy).

Patients and methods

In a retrospective case-control study, we analyzed 320 patients who had received TC therapy for gynecological cancers (ovarian, fallopian tube, peritoneal, uterine, and cervical cancers) and collected their germline DNA. We performed a comprehensive pharmacogenomic analysis using a targeted resequencing panel of 100 pharmacogenes. For 1,013 variants passing QC, case-control association studies and survival analyses were conducted.

Results

GSTP1 rs1695 showed the smallest p value for hematotoxicity association, and the ¹⁰⁵Ile wild type allele had a significantly higher risk of severe hematotoxicity (neutropenia G4, thrombocytopenia ≥ G3 and anemia ≥ G3) than the ¹⁰⁵Val allele (p=0.00034, odds ratio=5.71 (95% confidence interval:1.77-18.44)). Next, we assessed 5-year progression-free survival (PFS) and overall survival (OS) in 56 advanced ovarian cancer patients who received tri-weekly TC as a first-line chemotherapy. Patients with the ¹⁰⁵Ile/¹⁰⁵Ile genotype showed significantly better PFS (p=0.00070) and OS (p=0.0012) than those with the ¹⁰⁵Ile/¹⁰⁵Val or ¹⁰⁵Val/¹⁰⁵Val genotype.

Conclusion

Our study indicates that the GSTP1 rs1695 ¹⁰⁵Ile/¹⁰⁵Ile genotype is associated with both severe hematotoxicity and high efficacy of TC therapy, identifying a possible prognostic indicator for patients with TC therapy.

Independent replication of polymorphisms predicting toxicity in breast cancer patients randomized between dose-dense and docetaxel-containing adjuvant chemotherapy

Introduction

Although pharmacogenomics has evolved substantially, a predictive test for chemotherapy toxicity is still lacking. We compared the toxicity of adjuvant dose-dense doxorubicin-cyclophosphamide (ddAC) and docetaxel-doxorubicin-cyclophosphamide (TAC) in a randomized multicenter phase III trial and replicated previously reported associations between genotypes and toxicity.

Results

646 patients (97%) were evaluable for toxicity (grade 2 and higher). Whereas AN was more frequent after ddAC (P < 0.001), TAC treated patients more often had PNP (P < 0.001). We could replicate 2 previously reported associations: TECTA (rs1829; OR 4.18, 95% CI 1.84-9.51, P = 0.001) with PNP, and GSTP1 (rs1138272; OR 2.04, 95% CI 1.13-3.68, P = 0.018) with PNP.

Materials and methods

Patients with pT1-3, pN0-3 breast cancer were randomized between six cycles A60C600 every 2 weeks or T75A50C500 every 3 weeks. Associations of 13 previously reported single nucleotide polymorphisms (SNPs) with the most frequent toxicities: anemia (AN), febrile neutropenia (FN) and peripheral neuropathy (PNP) were analyzed using logistic regression models.

Conclusions

In this independent replication, we could replicate an association between 2 out of 13 SNPs and chemotherapy toxicities. These results warrant further validation in order to enable tailored treatment for breast cancer patients.

The Pharmacogenetics Laboratory of the Department of Pharmacology and Toxicology at the American University of Beirut Faculty of Medicine

The pharmacogenetics (PGx) laboratory at the Department of Pharmacology and Toxicology at the American University of Beirut Faculty of Medicine was established in October 2007. Several projects on the genetic polymorphisms of drug metabolizing enzymes and transporters with treatment of noncommunicable diseases such as cardiac diseases and cancers are ongoing. We have been applying the 'candidate gene' PGx approach, and recently started using higher throughput analyses. The more recent research projects are geared towards performing more extensive genotyping and including bigger and more representative population samples such as by developing research registries and prospectively following up patients. Furthermore, many technologies and research applications, such as next-generation sequencing and pharmacoepigenetics that complement and enhance PGx research and applications, are being actively pursued.

Donors FMO3 polymorphisms affect tacrolimus elimination in Chinese liver transplant patients

AIM

Flavin-containing monooxygenase (FMO) variants were potentially involved in tacrolimus metabolism in kidney transplantion. The influences of FMO3 genotypes on tacrolimus elimination in Chinese liver transplant patients remained unclear.

PATIENTS & METHODS

FMO3 SNPs and CYP3A5 rs776746 were analyzed in 110 Chinese patients.

RESULTS

Donor FMO3 rs1800822 allele T and rs909530 allele T were associated with fast tacrolimus elimination. Combination of polymorphisms of donor FMO3 rs1800822 and rs909530 genotype impacted on tacrolimus elimination (p = 0.0221). The number of donor rs1800822 allele T and rs909530 allele T was confirmed to be an independent predictor of the tacrolimus concentration-to-dose ratios for weeks 2, 3 and 4 in the multivariate analysis.

CONCLUSION

Donor's FMO3 polymorphisms might affect tacrolimus elimination.

Role of genetic variation in docetaxel-induced neutropenia and pharmacokinetics

Docetaxel is used for treatment of several solid malignancies. In this study, we aimed for predicting docetaxel clearance and docetaxel-induced neutropenia by developing several genetic models. Therefore, pharmacokinetic data and absolute neutrophil counts (ANCs) of 213 docetaxel-treated cancer patients were collected. Next, patients were genotyped for 1936 single nucleotide polymorphisms (SNPs) in 225 genes using the drug-metabolizing enzymes and transporters platform and thereafter split into two cohorts. The combination of SNPs that best predicted severe neutropenia or low clearance was selected in one cohort and validated in the other. Patients with severe neutropenia had lower docetaxel clearance than patients with ANCs in the normal range (P=0.01). Severe neutropenia was predicted with 70% sensitivity. True low clearance (1 s.d.<mean clearance) was identified in 80% of cases. These models however did not reach statistical significance. To improve the predictive value of these models, the addition of non-genetic influencing factors is needed.

Are pharmacogenomic biomarkers an effective tool to predict taxane toxicity and outcome in breast cancer patients? Literature review

PURPOSE

Breast cancer is a heterogeneous disease, characterized by various molecular phenotypes that correlate with different prognosis and response to treatments. Taxanes are some of the most active chemotherapeutic agents for breast cancer; however, their utilization is limited, due to hematologic and cumulative neurotoxicity on treated patients. To understand why only some patients experience severe adverse effects and why patients respond and develop resistance with different rates to taxane therapy, the metabolic pathways of these drugs should be completely unraveled. The variant forms of several genes, related to taxane pharmacokinetics, can be indicative markers of clinical parameters, such as toxicity or outcome.

METHODS

The search of the data has been conducted through PubMed database, presenting clinical data, clinical trials and basic research restricted to English language until June 2015.

RESULTS

We studied the literature in order to find any possible association between the major pharmacogenomic variants and specific taxane-related toxicity and patient outcome. We found that the data of these studies are sometimes discordant, due to both the small number of enrolled patients and the heterogeneity of the examined population.

CONCLUSIONS

Among all analyzed genes, only CYP1B1 and ABCB1 resulted the strongest candidates to become biomarkers of clinical response to taxane therapy in breast cancer, although their utilization still remains an experimental procedure. In the future, greater studies on genetic polymorphisms should be performed in order to identify differentiating signatures for patients with higher toxicity and with resistant or responsive outcome, before the administration of taxanes.

Tamoxifen metabolism predicts drug concentrations and outcome in premenopausal patients with early breast cancer

Tamoxifen is the standard-of-care treatment for estrogen receptor-positive premenopausal breast cancer. We examined tamoxifen metabolism via blood metabolite concentrations and germline variations of CYP3A5, CYP2C9, CYP2C19 and CYP2D6 in 587 premenopausal patients (Asians, Middle Eastern Arabs, Caucasian-UK; median age 39 years) and clinical outcome in 306 patients. N-desmethyltamoxifen (DM-Tam)/(Z)-endoxifen and CYP2D6 phenotype significantly correlated across ethnicities (R(2): 53%, P<10(-77)). CYP2C19 and CYP2C9 correlated with norendoxifen and (Z)-4-hydroxytamoxifen concentrations, respectively (P<0.001). DM-Tam was influenced by body mass index (P<0.001). Improved distant relapse-free survival (DRFS) was associated with decreasing DM-Tam/(Z)-endoxifen (P=0.036) and increasing CYP2D6 activity score (hazard ratio (HR)=0.62; 95% confidence interval (CI), 0.43-0.91; P=0.013). Low (<14 nM) compared with high (>35 nM) endoxifen concentrations were associated with shorter DRFS (univariate P=0.03; multivariate HR=1.94; 95% CI, 1.04-4.14; P=0.064). Our data indicate that endoxifen formation in premenopausal women depends on CYP2D6 irrespective of ethnicity. Low endoxifen concentration/formation and decreased CYP2D6 activity predict shorter DRFS.

Genetic Variations of Drug Transporters Can Influence on Drug Response in Patients Treated with Docetaxel Chemotherapy

Purpose

Dose-limiting toxicities of docetaxel are widely considered to be neutropenia, anemia, skin toxicity, and nausea. One of the factors that limit the use of docetaxel is its unpredictability of inter-individual variation in toxicity.

Materials and Methods

In order to identify the genetic factors that affect the risk of docetaxel-induced toxicities, we recruited patients who received docetaxel chemotherapy. We genotyped 92 patients with single-nucleotide polymorphisms (SNPs) in 5 genes: CYP3A4 (CYP3A4^*1B, CYP3A4^*18, and CYP3A4^*3), CYP3A5 (CYP3A5^*2 and CYP3A5^*3), ABCB1 (C1236T, G2677G/T, and C3435T), SLCO1B3 (rs11045585), and ABCC2 (rs12762549).

Results

Out of 92 patients, 70 had grade 3 or 4 neutropenia; 4 had grade 1 or 2; and 18 had no toxicity (76.1%, 4.3%, and 19.6%, respectively). The findings of the SNP analysis showed that patients with TT genotype of ABCB1 3435C>T polymorphism showed significantly higher risk of neutropenia and anemia (p=0.029 and p=0.044, respectively). There were significant associations between docetaxel-induced leucopenia and 2677G/T of ABCB1 and rs12762549 of ABCC2 (p=0.025 and p=0.028, respectively). In a multivariate analysis, we observed that patients carrying 2677G>T in ABCB1might be associated with higher risk of chemo-resistance when treated with docetaxel (odds ratio [OR], 6.48; confidence interval, 1.92 to 21.94; p=0.003). In a subgroup analysis of non-small cell lung cancer patients, a significant association of tumor response with G2677T/A (OR, 4.54) in ABCB1 and SLCO1B3 (OR, 9.44) was observed.

Conclusion

Our data suggest that ABCB1 (2677G/T) and SLCO1B3 (rs11055585) might be major genetic predictors of docetaxel-related toxicities in patients receiving docetaxel chemotherapy.

Effects of single-nucleotide polymorphisms of FMO3 and FMO6 genes on pharmacokinetic characteristics of sulindac sulfide in premature labor

This study aimed to investigate the effects of polymorphisms of the flavin-containing mono-oxygenase 3 (FMO3) and flavin-containing mono-oxygenase 6 (FMO6) genes on the pharmacokinetics of sulindac sulfide, the active metabolite of sulindac, in patients with preterm labor. Ten single-nucleotide polymorphisms (SNPs) were genotyped, and plasma sulindac sulfide concentrations were measured at 0, 1.5, 4, and 10 hours after drug administration. The area under the curve from time 0 to the last sampling time point (AUC(last)) for sulindac sulfide was obtained. The AUC(last) of sulindac sulfide was significantly higher in patients with variant-type homozygotes of FMO3 (rs909530) than those with ancestral alleles or heterozygotes. FMO3 (rs2266780) was in complete linkage disequilibrium with FMO6 (rs7885012), and there was marginal significance between the genotypes (P = 0.049). From multiple linear regression models, FMO3 (rs909530) was found to have significant influence on the AUClast of sulindac sulfide after adjusting for gestational age, weight, and all studied SNPs. The predictive contribution of rs909530 to the variability of sulindac sulfide AUC(last) was 27.0%. In conclusion, the results of this study could help clinicians predict the efficacies and side effects of sulindac in the development of individualized treatment of patients with preterm labor.