Correlation of UGT1A1(*)28 and (*)6 polymorphisms with irinotecan-induced neutropenia in Thai colorectal cancer patients

Genetic polymorphisms influencing deferasirox pharmacokinetics, efficacy, and adverse drug reactions: a systematic review and meta-analysis

Objective: Deferasirox is an iron-chelating agent prescribed to patients with iron overload. Due to the interindividual variability of deferasirox responses reported in various populations, this study aims to determine the genetic polymorphisms that influence drug responses. Methods: A systematic search was performed from inception to March 2022 on electronic databases. All studies investigating genetic associations of deferasirox in humans were included, and the outcomes of interest included pharmacokinetics, efficacy, and adverse drug reactions. Fixed- and random-effects model meta-analyses using the ratio of means (ROM) were performed. Results: Seven studies involving 367 participants were included in a meta-analysis. The results showed that subjects carrying the A allele (AG/AA) of ABCC2 rs2273697 had a 1.23-fold increase in deferasirox C_max (ROM = 1.23; 95% confidence interval [CI]:1.06-1.43; p = 0.007) and a lower Vd (ROM = 0.48; 95% CI: 0.36-0.63; p < 0.00001), compared to those with GG. A significant attenuated area under the curve of deferasirox was observed in the subjects with UGT1A3 rs3806596 AG/GG by 1.28-fold (ROM = 0.78; 95% CI: 0.60-0.99; p = 0.04). In addition, two SNPs of CYP24A1 were also associated with the decreased C_trough: rs2248359 CC (ROM = 0.50; 95% CI: 0.29-0.87; p = 0.01) and rs2585428 GG (ROM = 0.47; 95% CI: 0.35-0.63; p < 0.00001). Only rs2248359 CC was associated with decreased C_min (ROM = 0.26; 95% CI: 0.08-0.93; p = 0.04), while rs2585428 GG was associated with a shorter half-life (ROM = 0.44; 95% CI: 0.23-0.83; p = 0.01). Conclusion: This research summarizes the current evidence supporting the influence of variations in genes involved with drug transporters, drug-metabolizing enzymes, and vitamin D metabolism on deferasirox responses.

Rapid detection of the irinotecan-related UGT1A1*28 polymorphism by asymmetric PCR melting curve analysis using one fluorescent probe

BACKGROUND

Determination of UGT1A1 (TA)_n polymorphism prior to irinotecan therapy is necessary to avoid severe adverse drug effects. Thus, accurate and reliable genotyping methods for (TA)_n polymorphism are highly desired. Here, we present a new method for polymerase chain reaction (PCR) melting curve analysis using one fluorescent probe to discriminate the UGT1A1*1 [(TA)₆ ] and *28 [(TA)₇ ] genotypes.

METHODS

After protocol optimization, this technique was applied for genotyping of 64 patients (including 23 with UGT1A1*1/*1, 22 with *1/*28, and 19 with *28/*28) recruited between 2016 and 2021 in China-Japan Friendship Hospital. The accuracy of the method was evaluated by comparing the results with those of direct sequencing and fragment analysis. The intra- and inter-run precision of the melting temperatures (T_m s) were calculated to assess the reliability, and the limit of detection was examined to assess the sensitivity.

RESULTS

All genotypes were correctly identified with the new method, and its accuracy was higher than that of fragment analysis. The intra- and inter-run coefficients of variation for the T_m s were both ≤0.27%, with standard deviations ≤0.14°C. The limit of detection was 0.2 ng of input genomic DNA.

CONCLUSION

The developed PCR melting curve analysis using one fluorescent probe can provide accurate, reliable, rapid, simple, and low-cost detection of UGT1A1 (TA)_n polymorphism, and its use can be easily generalized in clinical laboratories with a fluorescent PCR platform.

Association of UGT1A1*6,*28 or ABCC2 c.3972C>T genetic polymorphisms with irinotecan induced toxicity in Asian cancer patients: Meta-analysis

Effects of UGT1A1*6 and UGT1A1*28 genetic polymorphisms on irinotecan‐induced severe toxicities in Asian cancer patients are inconclusive. Also, ABCC2 c.3972C>T may affect toxicity of irinotecan. The aim was to assess the aggregated risk of neutropenia or diarrhea in Asian cancer patients taking irinotecan and inherited UGT1A1*6, UGT1A1*28, or ABCC2 c.3972C>T genetic variants. A PubMed literature search for eligible studies was conducted. Odds ratios (ORs) were measured using RevMan software where p values <0.05 were statistically significant. Patients that inherited both UGT1A1*6 and UGT1A1*28 genetic variants (heterozygous: UGT1A1*1/*6 + *1/*28 and homozygous: UGT1A1*6/*6 + *28/*28) were significantly associated with increased risk of neutropenia and diarrhea compared to patients with UGT1A1*1/*1 (neutropenia: OR 2.89; 95% CI 1.97–4.23; p < 0.00001; diarrhea: OR 2.26; 95% CI 1.71–2.99; p < 0.00001). Patients carrying homozygous variants had much stronger effects in developing toxicities (neutropenia: OR 6.23; 95% CI 3.11–12.47; p < 0.00001; diarrhea: OR 3.21; 95% CI 2.13–4.85; p < 0.00001) than those with heterozygous variants. However, patients carrying the ABCC2 c.3972C>T genetic variant were not significantly associated with neutropenia (OR 1.67; 95% CI 0.98–2.84; p = 0.06) and were significantly associated with a reduction in irinotecan‐induced diarrhea (OR 0.31; 95% CI 0.11–0.81; p = 0.02). Asian cancer patients should undergo screening for both UGT1A1*6 and UGT1A1*28 genetic variants to reduce substantially irinotecan‐induced severe toxicities.

Chemotherapy-induced neutropenia and treatment efficacy in advanced non-small-cell lung cancer: a pooled analysis of 6 randomized trials

Background

Chemotherapy-induced neutropenia (CIN) has been demonstrated to be a prognostic factor in several cancer conditions. We previously found a significant prognostic value of CIN on overall survival (OS), in a pooled dataset of patients with advanced non-small-cell lung cancer (NSCLC) receiving first line chemotherapy from 1996 to 2001. However, the prognostic role of CIN in NSCLC is still debated.

Methods

We performed a post hoc analysis pooling data prospectively collected in six randomized phase 3 trials in NSCLC conducted from 2002 to 2016. Patients who never started chemotherapy and those for whom toxicity data were missing were excluded. Neutropenia was categorized on the basis of worst grade during chemotherapy: absent (grade 0), mild (grade 1–2), or severe (grade 3–4). The primary endpoint was OS. Multivariable Cox model was applied for statistical analyses. In the primary analysis, a minimum time (landmark) at 180 days from randomization was applied in order to minimize the time-dependent bias.

Results

Overall, 1529 patients, who received chemotherapy, were eligible; 572 of them (who received 6 cycles of treatment) represented the landmark population. Severe CIN was reported in 143 (25.0%) patients and mild CIN in 135 (23.6%). At multivariable OS analysis, CIN was significantly predictive of prognosis although its prognostic value was entirely driven by severe CIN (hazard ratio [HR] of death 0.71; 95%CI: 0.53–0.95) while it was not evident with mild CIN (HR 1.21; 95%CI: 0.92–1.58). Consistent results were observed in the out-of-landmark group (including 957 patients), where both severe and mild CIN were significantly associated with a reduced risk of death.

Conclusion

The pooled analysis of six large trials of NSCLC treatment shows that CIN occurrence is significantly associated with a longer overall survival, particularly in patients developing severe CIN, confirming our previous findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08323-4.

Pharmacogenomics research and its clinical implementation in Thailand: Lessons learned from the resource-limited settings

Several barriers present challenges to implementing pharmacogenomics into practice. This review will provide an overview of the current pharmacogenomics practices and research in Thailand, address the challenges and lessons learned from delivering clinical pharmacogenomic services in Thailand, emphasize the pharmacogenomics implementation issues that must be overcome, and identify current pharmacogenomic initiatives and plans to facilitate clinical implementation of pharmacogenomics in Thailand. Ever since the pharmacogenomics research began in 2004 in Thailand, a multitude of pharmacogenomics variants associated with drug responses have been identified in the Thai population, such as HLA-B∗15:02 for carbamazepine and oxcarbazepine, HLA-B∗58:01 for allopurinol, HLA-B∗13:01 for dapsone and cotrimoxazole, CYP2B6 variants for efavirenz, CYP2C9∗3 for phenytoin and warfarin, CYP3A5∗3 for tacrolimus, and UGT1A1∗6 and UGT1A1∗28 for irinotecan, etc. The future of pharmacogenomics guided therapy in clinical settings across Thailand appears promising because of the availability of evidence of clinical validity of the pharmacogenomics testing and support for reimbursement of pharmacogenomics testing.

Association of UGT1A1*6 polymorphism with irinotecan-based chemotherapy reaction in colorectal cancer patients: a systematic review and a meta-analysis

Colorectal cancer (CRC) is a leading cause of cancer-related deaths across the world. Irinotecan (IRI) is commonly used to treat CRC, and IRI-based chemotherapy is linked with adverse reaction and the efficacy of the treatment regimen. The gene UGT1A1 plays a central role in the IRI metabolic pathway. A polymorphism UGT1A1*6 has been widely researched which may be related to response of IRI-based chemotherapy in CRC. All relevant studies were strictly searched from PubMed, Embase, Cochrane Library and Web of Science databases to explore the associations between UGT1A1*6 and response of IRI-based chemotherapy with CRC. Nine articles comprising 1652 patients were included in the final combination. Meta-analysis showed G allele or GG had a lower risk of severe late-onset diarrhea compared with A/AA in allele model and homozygote model (G vs. A: OR = 0.53, 95% CI: 0.28–0.99, P=0.05; GG vs. AA: OR = 0.48, 95% CI: 0.23–0.99, P=0.05), no significant association was observed in other models. In addition, a significant association between UGT1A1*6 and neutropenia was observed in all models (G vs. A: OR = 0.57, 95% CI: 0.46–0.71, P=0.00; GG vs. AA: OR = 0.28, 95% CI: 0.17–0.45, P=0.01; GA vs. AA: OR = 0.42, 95% CI: 0.26–0.70, P=0.00; GG+GA vs. AA: OR = 0.32, 95% CI: 0.20–0.52, P=0.00; GG vs. AA+GA: OR = 0.40, 95% CI: 0.22–0.71, P=0.00), whereas, no relationship was found between UGT1A1*6 and clinical response among the different genotypes. UGT1A1*6 may be considered as a biomarker for IRI-based chemotherapy in CRC.

Pharmacogenetic impact of UGT1A1 polymorphisms on pulmonary neuroendocrine tumours treated with metronomic irinotecan-based chemotherapy in Chinese populations

OBJECTIVES

To evaluate the effects of UGT1A1*6 and UGT1A1*28 polymorphisms on the safety and efficacy of metronomic irinotecan-based chemotherapy (IBC) in Chinese patients with pulmonary neuroendocrine tumours (PNTs).

METHODS

Sixty-eight PNT patients who received metronomic IBC were observed. The quantitative fluorescent polymerase chain reaction was used to detect UGT1A1*6 and UGT1A1*28 polymorphisms. The follow-up data were collected to investigate the relationship between different genotypes and adverse drug reactions. The clinical outcomes of metronomic IBC were also evaluated.

KEY FINDINGS

In the genotype-toxicity association analysis, patients with homozygous UGT1A1*6 had the highest incidence of grade 3-4 diarrhoea (P = 0.010). Compared to other groups, patients with the haplotype of UGT1A1*28 showed a trend towards an increased incidence of grade 4 neutropaenia (P = 0.047). A higher incidence of grade 3-4 leucopaenia was found in groups with UGT1A1*1/*28 (P = 0.023) and UGT1A1*28/*28 (P = 0.022). Grade 1 total bilirubin elevation was associated with the homozygous UGT1A1*6 mutation (P = 0.027) or any UGT1A1*6 variants (P = 0.047). However, neither UGTA1A*28 nor UGT1A1*6 showed any significant association with tumour response or clinical outcomes.

CONCLUSIONS

The impact of UGT1A1 polymorphisms varies in different irinotecan-based chemotherapies. UGT1A1*6 and UGTA1A*28 were useful for the prediction of irinotecan-related severe toxicity in Chinese PNT patients treated with metronomic IBC.

Genetic and clinical risk factors associated with phenytoin-induced cutaneous adverse drug reactions in Thai population

OBJECTIVE

This study aimed to describe the genetic and clinical risk factors associated with phenytoin-induced cutaneous adverse drug reactions (PHT-induced cADRs) in Thai patients.

METHOD

A retrospective case-control study was conducted among 88 PHT- cADRs (25 SJS/TEN, 37 DRESS/DIHS and 26 MPE) compared to 70 PHT-tolerant controls during 2008-2017. Genotyping was performed by Taqman RT-PCR (EPHX1 337 T > C, EPHX1 416A > G and CYP2C9*3), pyrosequencing (UGT1A1*28, UGT1A1*6) and polymerase chain reaction-sequence-specific oligonucleotide probe (HLA-B). Chi-squared test and binary logistic regression were used to identify factors associated with PHT-cADRs.

RESULTS

Multivariate analysis showed that HLA-B*46:01 was significantly associated with all PHT-induced cADRs (OR 2.341; 95% CI, 1.078-5.084; P = .032). Age of ≥60 years showed a significant association with PHT-induced SJS/TEN (OR 3.600; 95% CI, 1.214-10.672; P = .021). CYP2C9*3 was almost reaching statistically associated with an increased risk of PHT-induced SJS/TEN (OR 4.800; 95% CI, 0.960-23.990; P = .056). While HLA-B*56:02/04 was found to have a significant association with PHT-induced DRESS/DIHS (OR 29.312; 95% CI, 1.213-707.994; P = .038). Moreover, female gender and HLA-B*40:01 were associated with an increased risk of PHT-induced MPE at OR 5.734; 95% CI, 0.910-58.351; P = .042 and OR 3.647; 95% CI, 1.193-11.147; P = .023, respectively.

CONCLUSION

Both clinical (advanced age, female gender) and genetic factors (HLA-B*46:01, CYP2C9*3, HLA-B*56:02/04 and HLA-B*40:01) contributed to the risk of PHT-induced cADRs. Further studies with larger sample size may be warranted to confirm these findings and also the influence of EPHX1 gene.

Optimum patient selection for irinotecan-containing regimens in metastatic colorectal cancer: Literature review and lessons from clinical practice

Metastatic colorectal cancer (mCRC) accounts for over 20% of CRC cases and is associated with a poor prognosis. Irinotecan is an important first- and second-line chemotherapy option for mCRC. In this review, we summarize the clinical efficacy and safety of irinotecan-based regimens for the treatment of mCRC and discuss various tumor- and patient-related factors that affect the clinical response, survival, and toxicity associated with these regimens. Uridine diphosphate glucuronosyltransferase (UGT) gene polymorphisms such as UGT1A1*28/*6, age, performance status, serum lactate dehydrogenase levels, and bilirubin levels could be important considerations for predicting outcomes and tolerability with irinotecan-based regimens. The role of tumor location; chemotherapy backbone; and emerging evidence on the presence of microsatellite instability-high status, consensus molecular subtype 4 tumors, and signet-ring morphology in predicting response to irinotecan-based therapy have also been highlighted. Careful consideration of these factors will help guide clinicians in optimizing the selection of mCRC patients for irinotecan-based treatment.

Long non-coding RNA polymorphisms and prediction of response to chemotherapy based on irinotecan in patients with metastatic colorectal cancer

BACKGROUND

Colorectal cancer is the fourth cause of cancer related death. Drug resistance and toxicity remain major clinical issues. HOTAIR and MALAT1 are long non-coding RNAS that affect cellular proliferation, apoptosis and drug resistance; their up-regulation has been linked with a poor prognosis.

OBJECTIVE

Investigation of the association between rs4759314 HOTAIR and rs3200401 MALAT1 polymorphisms and irinotecan-based chemotherapy in terms of drug efficacy and toxicity.

METHODS

Samples from 98 patients receiving different regimens of irinotecan-based therapy were included. Efficacy and toxicity were evaluated. KRAS mutation, rs3200401 HOTAIR and rs4759314 MALAT1 polymorphisms genotyping in the tumors and peripheral blood respectively were performed with PCR.

RESULTS

Neither rs3200401 MALAT1 nor rs4759314 HOTAIR polymorphism are associated with response to treatment regimens. Rs4759314 was also not associated with increased toxicity in patients receiving irinotecan-based regimens. CT genotype of rs3200401 was associated with significantly reduced overall survival. An association between KRAS mutation and AG/GG genotypes in the rs4759314 was detected.

CONCLUSIONS

CT genotype of rs3200401 MALAT1 polymorphism could serve as a toxicity biomarker. Carriers of the G allele of the rs4759314 HOTAIR are more likely to be carriers of KRAS mutations too. However, further studies in larger patient populations are required.

Chemotherapy-Induced Neutropenia as a Prognostic and Predictive Marker of Outcomes in Solid-Tumor Patients

Chemotherapy-induced neutropenia (CIN) is one of the most common side effects seen in cancer patients. As an adverse event, it is deemed undesirable since it often constitutes a dose-limiting toxicity for cytotoxic agents leading to treatment delays and/or dose reductions. It is also associated with a financial cost component from diagnostic work-up and treatment of patients with chemotherapy-induced febrile neutropenia (CIFN). Neutropenia is commonly accompanied by a decrease in other hematopoietic lineages (anemia and/or thrombocytopenia). Dosing of chemotherapeutic agents is based on the severity of adverse effects seen. Depending on the degree of neutropenia, chemotherapeutic agents may be put on hold until count recovery and growth factor support might be added to allow for dosing as scheduled. However, neutropenia appears to be more than just an adverse event. While CIFN by itself constitutes an adverse event, the appearance of just CIN is not necessarily a marker of poor outcome. In fact, it rather appears to be a surrogate marker of response and/or survival in patients treated with cytotoxic regimens. Here we present evidence in different tumor types treated with different regimens on the role CIN plays as a marker for improved outcomes. If CIN is a surrogate prognostic and/or potentially predictive marker of response, chemotherapy doses may need to be escalated to achieve neutropenia. In addition, instead of reducing treatment doses for safety concerns, the addition of growth factor support and alternative dosing schemes may be strategies to consider.

Effects of ABCC2 and SLCO1B1 Polymorphisms on Treatment Responses in Thai Metastatic Colorectal Cancer Patients Treated with Irinotecan-Based Chemotherapy

Purpose:

Irinotecan is an anticancer medicine which is used mostly in metastatic colorectal cancer (mCRC) treatment as second or third line chemotherapy. Several factors affect its efficacy and toxicity, including pharmacogenomics. This study aimed to investigate the impacts of ABCC2 and SLCO1B1 polymorphisms on treatment responses in irinotecan-based chemotherapy in 49 Thai mCRC patients.

Materials and Methods:

Forty-nine participants with mCRC enrolled in this study received irinotecan-based chemotherapy from January to June 2017. Genotypic analyses of ABCC2 (C>T, rs717620) and SLCO1B1 (A>G, rs2306283) were performed. Treatment responses were evaluated after at least three cycles of chemotherapy were given.

Results:

Allele frequencies of ABCC2 (C>T) and SLCO1B1 (A>G) were found at 18.37% and 78.57%, respectively. Neither was associated with treatment responses. However, combined genotypes of ABCC2 and SLCO1B1 tended to be associated with clinical benefits in terms of partial responses (PR) and stable disease (SD). All patients (100%) with at least one variant allele of SLCO1B1 and ABCC2 were in a PR or SD group, while patients with other genotypes had progressive disease (PD) at 45.5% to 70%, (p = 0.059).

Conclusion:

The combined effect of ABCC2 and SLCO1B1 polymorphisms tended to be associated with treatment responses in irinotecan-based treated mCRC patients. Therefore, such polymorphisms could be factors impacting inter-individual variation of irinotecan efficacy in Thai mCRC patients.

Uridine 5'-diphospho-glucronosyltrasferase: Its role in pharmacogenomics and human disease

Biotransformation is an enzyme-catalyzed process in which the body converts endogenous compounds, xenobiotics and toxic substances into harmless or easily excreted metabolites. The biotransformation reactions are classified as phase I and II reactions. Uridine 5'-diphospho (UDP)-glucuronosyltransferases (UGTs) are a superfamily of phase II enzymes which have roles in the conjugation of xenobiotics or endogenous compounds, including drugs and bilirubin, with glucuronic acid to make them easier to excrete. The method the human body uses to achieve glucuronidation may be affected by a large interindividual variation due to changes in the sequences of the genes encoding these enzymes. In the last five years, the study of the genetic variants of the UGTs at a molecular level has become important due to its association with several diseases and the ability to predict adverse events due to drug metabolism. In the present review, the structure and the prominent genetic variants of the UGT1A subfamily and their metabolic and clinical implications are described.

Examination of multiple UGT1A and DPYD polymorphisms has limited ability to predict the toxicity and efficacy of metastatic colorectal cancer treated with irinotecan-based chemotherapy: a retrospective analysis

Background

To evaluate a new UGT1A and DPYD polymorphism panel to better predict irinotecan-induced toxicity and the clinical response in Chinese patients with metastatic colorectal cancer (mCRC).

Methods

The genotypes of UGT1A (UGT1A1*6, UGT1A1*27, UGT1A1*28, UGT1A7*2, UGT1A7*3, UGT1A7*4 and UGT1A9*22) and DPYD (DPYD*5, DPYD c.1896 T > C, and DPYD*2A) were examined by direct sequencing in 661 mCRC patients receiving irinotecan-based chemotherapy. The influences of UGT1A and DPYD polymorphisms on severe irinotecan-induced toxicities and clinical outcomes were assessed.

Results

In the cohort studied here, the incidence of UGT1A1*6, UGT1A1*28, UGT1A7*2, UGT1A7*3, UGT1A9*22, DPYD*5, and DPYD c.1896 T > C variants were 34.8%, 24.2%, 34.3%, 39.4%, 81.8%, 48.4% and 20.4%, respectively. UGT1A1*27 and DPYD*2A had low frequencies and UGT1A7*4 was not found. A total of 59 patients (8.9%) suffered severe diarrhea and 136 patients (20.6%) suffered severe neutropenia. UGT1A1*28 heterozygotes (OR = 2.263, 95%CI 1.395–3.670), UGT1A1*28 homozygotes (OR = 5.910, 95%CI 1.138–30.672) and UGT1A1*6 homozygotes (OR = 4.737, 95%CI 1.946–11.533) were independent risk factors for severe neutropenia. UGT1A polymorphisms were not found to relate to severe diarrhea. DPYD*5 was determined to be an independent risk factor for severe diarrhea (OR = 2.143, 95%CI 1.136–4.041). Neither DPYD*5 nor DPYD c.1896 T > C was found to relate to severe neutropenia. In the first-line irinotecan-based treatment, UGT1A1*28 and DPYD*5 contributed to higher response rates (P = 0.043 and P = 0.019, respectively), while DPYD*5 was found to associate with better progression-free survival (P = 0.015). UGT1A1*27 contributed to worse overall survival (P < 0.001).

Conclusion

Results still showed UGT1A1*6 and UGT1A1*28 to be partially associated with irinotecan-induced toxicity and clinical response. An examination of more UGT1A loci, except for UGT1A1*6 and UGT1A1*28, was not helpful to improve the predictive value of irinotecan-based toxicity and efficacy. An examination of DPYD*5 assisted in the prediction of severe diarrhea.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3406-2) contains supplementary material, which is available to authorized users.

Relationship between UGT1A1*6/*28 gene polymorphisms and the efficacy and toxicity of irinotecan-based chemotherapy

Purpose

A retrospective study was performed to analyze the relationship between uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) *6/*28 gene polymorphisms and adverse reactions associated with irinotecan (CPT-11)-based chemotherapy. The correlation between UGT1A1 polymorphisms and the clinical efficacy of CPT-11 was also analyzed, along with the influence of age and tumor type.

Patients and methods

Patients administered a CPT-11-based regimen in the Beijing Cancer Hospital from April 2015 to September 2016 were included in our study (n=81). Blood samples for detecting UGT1A1 were collected from each patient after various administration regimens.

Results

Colorectal cancer patients with the UGT1A1*6 mutant genotype had a significantly higher risk of severe delayed diarrhea than that of wild-type individuals when administered a CPT-11 dose ≥130 mg/m² (P=0.042); the same phenomenon was observed when the UGT1A1*6 and UGT1A1*28 mutant genotypes were considered together (P=0.028). However, in lung cancer patients administered a low dose of CPT-11, UGT1A1*6/*28 variants were not significantly associated with severe neutropenia or delayed diarrhea. Furthermore, adult patients with the UGT1A1*6 mutation were more likely to develop severe delayed diarrhea than did wild-type adults (P=0.013); however, the difference was not significant in elderly patients. No significant differences in tumor response were found among the different genotypes (P>0.05).

Conclusion

Thus, age and tumor type influence our ability to predict adverse reactions based on UGT1A1 gene polymorphisms in cancer patients. Further, UGT1A1 gene polymorphisms are not correlated with the efficacy of CPT-11-based regimens.

UGT1A1*6 polymorphisms are correlated with irinotecan-induced neutropenia: a systematic review and meta-analysis

Irinotecan (IRI) chemotherapy toxicities can be severe, and may result in treatment delay, morbidity and in some rare cases death. Neutropenia is a life-threatening side effect of irinotecan, and UDP glucuronosyltransferases (UGTs) gene polymorphisms could predict the side effects in cancer patients and then reduce IRI-induced toxicity by preventative treatment or a decrease in dose. Both UGT1A1*6 and *28 were reliably demonstrated to be risk factors for IRI-induced neutropenia, with tests for both polymorphisms potentially being particularly useful in Asian cancer patients. However, some researchers reported that UGT1A1*6 could predict IRI-induced toxicities in Asian populations, controversial conclusions still remained. Thus, the association between UGT1A1*6 polymorphisms and IRI-induced severe toxicity in cancer patients is still needed to be explored. Therefore, this study aims to investigate the association between UGT1A1*6 polymorphisms and IRI-related severe neutropenia in cancer patients on a large scale. A total of 12 studies that included 746 wild genotype (G/G) cases and 394 variant genotype (G/A and A/A) cases were included on the basis of inclusion criteria. Then we assessed the methodologies quality; odds ratio (OR), risk difference (RD) and 95% confidence intervals (95% CI) were used to assess the strength of association. Overall, an increased risk of severe neutropenia in cancer patients with UGT1A1*6 polymorphisms was found. Patients with recessive models (GA + AA vs. GG) of UGT1A1*6 showed an increased risk (OR 2.03, 95% CI 1.54-2.68; RD = 0.11, P < 0.001). Specifically, the heterozygous variant of UGT1A1*6 showed an increased risk (OR 1.83, 95% CI 1.36-2.46; RD = 0.09, P < 0.001), and homozygous mutation showed also high risk (OR 2.95, 95% CI 1.83-4.75; RD = 0.18, P < 0.001) for severe neutropenia. Subgroup meta-analysis revealed that for patients harboring both heterozygous and homozygous variants, cancer types, low dose of IRI and the duration of treatment also presented comparably increased risk in suffering severe neutropenia. As for country, in China and Japan, there was a statistically increased severe neutropenia with variant genotype of UGT1A1*6 (China: GA + AA vs. GG, OR 1.83, 95% CI 1.28-2.59; RD = 0.08, P = 0.001; Japan: GA + AA vs. GG, OR 2.39, 95% CI 1.45-3.92; RD = 0.15, P = 0.001). In conclusion, in this meta-analysis, the UGT1A1*6 polymorphisms were associated with an increased risk of IRI-induced neutropenia in cancer patients, and increased incidences of severe neutropenia could be correlated with diverse regions, cancer type, low dose of IRI and the duration of treatment.

Pharmacogenomics in Asia: a systematic review on current trends and novel discoveries

While early pharmacogenomic studies have primarily been carried out in Western populations, there has been a notable increase in the number of Asian studies over the past decade. We systematically reviewed all pharmacogenomic studies conducted in Asia published before 2016 to highlight trends and identify research gaps in Asia. We observed that pharmacogenomic research in Asia was dominated by larger developed countries, notably Japan and Korea, and mainly driven by local researchers. Studies were focused on drugs acting on the CNS, chemotherapeutics and anticoagulants. Significantly, several novel pharmacogenomic associations have emerged from Asian studies. These developments are highly encouraging for the strength of regional scientific and clinical community and propound the importance of discovery studies in different populations.

Determination of irinotecan, SN-38 and SN-38 glucuronide using HPLC/MS/MS: Application in a clinical pharmacokinetic and personalized medicine in colorectal cancer patients

BACKGROUND

Irinotecan (CPT-11) is chemotherapy used mainly in the metastatic colorectal cancer. The purpose of this study was to develop and validate the LC-MS/MS for the simultaneous determination of CPT-11, SN-38, and SN-38G.

METHODS

A 100 μL of plasma was prepared after protein precipitation and analyzed on a C18 column using 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile as mobile phases. The mass spectrometer worked with multiple reaction monitoring (MRM) in positive scan mode. The standard curves were linear on a concentration range of 5-10 000 ng/mL for CPT-11, 5-1000 ng/mL for SN-38, and 8-1000 ng/mL for SN-38G.

RESULTS

In this assay, the intra and interday precision consisted of ≤9.11% and ≤11.29% for CPT-11, ≤8.70% and 8.31% for SN-38, and ≤9.90 and 9.64% for SN-38G.

CONCLUSION

This method was successfully used to quantify CPT-11, SN-38, and SN-38G and applied to a pharmacokinetic study.

Predictive Value of UGT1A1*28 Polymorphism In Irinotecan-based Chemotherapy

The UGT1A1*28 polymorphism was suggested to be significantly connected with irinotecan-induced toxicity and response to chemotherapy. However, the results of previous studies are controversial. Hence we carried out a meta-analysis to investigate the effect of UGT1A1*28 polymorphism on severe diarrhea, neutropenia, and response of patients who had undergone irinotecan-based chemotherapy. The PubMed, Web of Science, Wanfang, and CNKI databases were searched for clinical trials assessing the association of UGT1A1*28 polymorphism with severe diarrhea, neutropenia, and response to irinotecan-based chemotherapy. The combined odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the relationship under a fixed- or random-effects model. Fifty-eight studies including 6087 patients with cancer were included. Our results showed that patients carrying the TA6/7 and TA7/7 genotypes had a greater prevalence of diarrhea and neutropenia than those with the TA6/6 genotype (TA6/7+TA7/7 vs. TA6/6: diarrhea, OR = 2.18, 95%CI = 1.68-2.83; neutropenia, OR = 2.15, 95%CI = 1.71-2.70), particularly patients with metastatic colorectal cancer. Stratified analysis showed that Asians with the TA6/7 and TA7/7 genotypes were more likely to have diarrhea and neutropenia, and Caucasians with the TA6/7 and TA7/7 genotypes were more likely to have neutropenia than other groups. However, patients with the TA6/7+TA7/7 genotypes showed a higher response than patients with TA6/6 genotype (OR = 1.20, 95%CI = 1.07-1.34), particularly Caucasians (OR = 1.23, 95%CI = 1.06-1.42) and patients with metastatic colorectal cancer (OR = 1.24, 95%CI = 1.05-1.48). Our data showed that the UGT1A1*28 polymorphism had a significant relationship with toxicity and response to irinotecan-based chemotherapy. This polymorphism may be useful as a monitoring index for cancer patients receiving irinotecan-based chemotherapy.

Pharmacogenomics in Pediatric Oncology: Review of Gene-Drug Associations for Clinical Use

During the 3rd congress of the European Society of Pharmacogenomics and Personalised Therapy (ESPT) in Budapest in 2015, a preliminary meeting was held aimed at establishing a pediatric individualized treatment in oncology and hematology committees. The main purpose was to facilitate the transfer and harmonization of pharmacogenetic testing from research into clinics, to bring together basic and translational research and to educate health professionals throughout Europe. The objective of this review was to provide the attendees of the meeting as well as the larger scientific community an insight into the compiled evidence regarding current pharmacogenomics knowledge in pediatric oncology. This preliminary evaluation will help steer the committee’s work and should give the reader an idea at which stage researchers and clinicians are, in terms of personalizing medicine for children with cancer. From the evidence presented here, future recommendations to achieve this goal will also be suggested.

UGT1A1 gene polymorphism is associated with toxicity and clinical efficacy of irinotecan-based chemotherapy in patients with advanced colorectal cancer

OBJECTIVES

To investigate the relationship between uridine diphosphate glucoronosyltransferase 1A1 (UGT1A1)*28/*6 and toxicity and clinical efficacy of irinotecan-based chemotherapy in patients with advanced colorectal cancer (CRC) in Xinjiang Uygur and Han population.

METHODS

A total of 183 patients (Uygur, 114; Han, 69) with advanced CRC who received the irinotecan-based chemotherapy were enrolled in this retrospective analysis. Polymerase chain reaction amplification and direct sequencing method were used for UGT1A1*28 and UGT1A1*6 polymorphism detection. The patients were followed up to analyze the relationship between different genotypes with adverse reactions and the clinical outcome of irinotecan-based chemotherapy.

RESULTS

Significant differences were found in genotype frequencies of UGT1A1*28 and UGT1A1*28/*6 between Uygur and Han (P = 0.02 and P = 0.002). Uygur and Han patients carrying wild UGT1A1*28 and *6 genotypes appeared to have significantly lower diarrhea incidence (I/II and III/IV) than those carrying mutant genotypes (all P < 0.05). In Uygur patients, UGT1A1*28 genotypes were related with objective response rate and disease control rate (P < 0.05). Compared with *1 allele *1/*1, *1 allele *1/*28*1/*28 mutant of UGT1A1*28 was associated with shorter OS in both Uygur and Han ethnicities (all P < 0.05). Compared with double allele variants (DW), single allele variants (SV), and double allele variants (DV) of UGT1A1*28/*6 were associated with shorter overall survival (OS) in Uygur and Han (all P < 0.05). Cox regression analysis revealed factors significantly influencing OS, including UGT1A1*28, UGT1A1*6, combined genotypes and chemotherapy line in Ugyur, and only combined genotypes in Han (all P < 0.05).

CONCLUSION

UGT1A1 gene polymorphism predicts irinotecan-related adverse reactions in advanced CRC patients of Xinjiang Uygur and Han nationality; UGT1A1 gene polymorphism is correlated with efficacy and prognosis in Uygur nationality, but only related to prognosis in Han nationality in irinotecan-based chemotherapy.