Pre-therapeutic UGT1A1 genotyping to reduce the risk of irinotecan-induced severe toxicity: Ready for prime time

Irinotecan hydrochloride liposome HR070803 in combination with 5-fluorouracil and leucovorin in locally advanced or metastatic pancreatic ductal adenocarcinoma following prior gemcitabine-based therapy (PAN-HEROIC-1): a phase 3 trial

Liposomal irinotecan has shown promising antitumor activity in patients with advanced or metastatic pancreatic ductal adenocarcinoma (PDAC) who have undergone prior gemcitabine-based therapies. This randomized, double-blind, parallel-controlled, multicenter phase 3 study (NCT05074589) assessed the efficacy and safety of liposomal irinotecan HR070803 combined with 5-fluorouracil (5-FU) and leucovorin (LV) in this patient population. Patients with unresectable, locally advanced, or metastatic PDAC who had previously received gemcitabine-based therapies were randomized 1:1 to receive either HR070803 (60 mg/m2 anhydrous irinotecan hydrochloride, equal to 56.5 mg/m2 free base) or placebo, both in combination with 5-FU (2000 mg/m2) and LV (200 mg/m2), all given intravenously every two weeks. The primary endpoint of the study was overall survival (OS). A total of 298 patients were enrolled and received HR070803 plus 5-FU/LV (HR070803 group, n = 149) or placebo plus 5-FU/LV (placebo group, n = 149). Median OS was significantly improved in the HR070803 group compared to the placebo group (7.4 months [95% CI 6.1-8.4] versus 5.0 months [95% CI 4.3-6.0]; HR 0.63 [95% CI 0.48-0.84]; two-sided p = 0.0019). The most common grade ≥ 3 adverse events in the HR070803 group were increased gamma-glutamyltransferase (19.0% versus 11.6% in placebo group) and decreased neutrophil count (12.9% versus 0 in placebo group). No treatment-related deaths occurred in the HR070803 group, while the placebo group reported one treatment-related death (abdominal infection). HR070803 in combination with 5-FU/LV has shown promising efficacy and manageable safety in advanced or metastatic PDAC in the second-line setting, representing a potential option in this patient population.

UGT1A1*28 detection using high-resolution agarose gel electrophoresis

A new UGT1A1*28 detection method combining PCR and high-resolution agarose gel electrophoresis was developed. The viability of this method was demonstrated on 15 healthy adult volunteers. Subjects included 13 wild type homozygotes (86.7 %), 2 heterozygotes (13.3 %), and no mutant type homozygotes (0 %). The new UGT1A1*28 detection method results were fully consistent with DNA sequencing. PCR and agarose gel electrophoresis are common techniques with high-resolution agarose gels available commercially. These results support the clinical viability of this method potentially reducing UGT1A1*28 diagnosis complexity and cost.

UGT1A1 Testing in Breast Cancer: should it become routine practice in patients treated with antibody-drug conjugates?

The use of genetic testing to personalize therapeutic strategies in cancer is rapidly evolving and thus changing the landscape of treatment of oncologic patients. The UGT1A1 gene is an important component for the metabolism and glucoronidation of certain drugs, including irinotecan and sacituzumab govitecan (SG); therefore, various UGT1A1 polymorphisms leading to decreased function of the UGT1A1 enzyme may lead to increased risk of treatment-related side effects. Testing for UGT1A1 polymorphism is not routinely adopted in clinical practice; that is due to the lack of concise studies and recommendations concerning the clinical relevance of this test and its impact on the quality of life of cancer patients. The knowledge regarding UGT1A1 polymorphism and its clinical relevance will be reviewed in this article, as well as the published literature on the association between UGT1A1 polymorphism and the toxicity risk of irinotecan as well as sacituzumab govitecan. The current recommendations and guidelines on UGT1A1 testing will be discussed in detail in the hopes of providing guidance to oncologists in their clinical practice.

Pharmacogenetics testing (DPYD and UGT1A1) for fluoropyrimidine and irinotecan in routine clinical care: Perspectives of medical oncologists and oncology pharmacists

BACKGROUND

Despite robust evidence and international guidelines, to support routine pharmacogenetic (PGx) testing, integration in practice has been limited. This study explored clinicians' views and experiences of pre-treatment DPYD and UGT1A1 gene testing and barriers to and enablers of routine clinical implementation.

METHODS

A study-specific 17-question survey was emailed (01 February-12 April 2022) to clinicians from the Medical Oncology Group of Australia (MOGA), the Clinical Oncology Society of Australia (COSA) and International Society of Oncology Pharmacy Practitioners (ISOPP). Data were analysed and reported using descriptive statistics.

RESULTS

Responses were collected from 156 clinicians (78% medical oncologists, 22% pharmacists). Median response rate of 8% (ranged from 6% to 24%) across all organisations. Only 21% routinely test for DPYD and 1% for UGT1A1. For patients undergoing curative/palliative intent treatments, clinicians reported intent to implement genotype-guided dosing by reducing FP dose for DPYD intermediate metabolisers (79%/94%), avoiding FP for DPYD poor metabolisers (68%/90%), and reducing irinotecan dose for UGT1A1 poor metabolisers (84%, palliative setting only). Barriers to implementation included: lack of financial reimbursements (82%) and perceived lengthy test turnaround time (76%). Most Clinicians identified a dedicated program coordinator, i.e., PGx pharmacist (74%) and availability of resources for education/training (74%) as enablers to implementation.

CONCLUSION

PGx testing is not routinely practised despite robust evidence for its impact on clinical decision making in curative and palliative settings. Research data, education and implementation studies may overcome clinicians' hesitancy to follow guidelines, especially for curative intent treatments, and may overcome other identified barriers to routine clinical implementation.

Personalizing adjuvant therapy for patients with colorectal cancer

The current standard-of-care adjuvant treatment for patients with colorectal cancer (CRC) comprises a fluoropyrimidine (5-fluorouracil or capecitabine) as a single agent or in combination with oxaliplatin, for either 3 or 6 months. Selection of therapy depends on conventional histopathological staging procedures, which constitute a blunt tool for patient stratification. Given the relatively marginal survival benefits that patients can derive from adjuvant treatment, improving the safety of chemotherapy regimens and identifying patients most likely to benefit from them is an area of unmet need. Patient stratification should enable distinguishing those at low risk of recurrence and a high chance of cure by surgery from those at higher risk of recurrence who would derive greater absolute benefits from chemotherapy. To this end, genetic analyses have led to the discovery of germline determinants of toxicity from fluoropyrimidines, the identification of patients at high risk of life-threatening toxicity, and enabling dose modulation to improve safety. Thus far, results from analyses of resected tissue to identify mutational or transcriptomic signatures with value as prognostic biomarkers have been rather disappointing. In the past few years, the application of artificial intelligence-driven models to digital images of resected tissue has identified potentially useful algorithms that stratify patients into distinct prognostic groups. Similarly, liquid biopsy approaches involving measurements of circulating tumour DNA after surgery are additionally useful tools to identify patients at high and low risk of tumour recurrence. In this Perspective, we provide an overview of the current landscape of adjuvant therapy for patients with CRC and discuss how new technologies will enable better personalization of therapy in this setting.

Individual Irinotecan Therapy Under the Guidance of Pre-Treated UGT1A1*6 Genotyping in Gastric Cancer

Background: Severe delayed diarrhea and hematological toxicity limit the use of irinotecan. Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) is a critical enzyme in irinotecan metabolism. The study aims to investigate the safety and efficacy of irinotecan under the guidance of the pre-treatment UGT1A1 genotype in the second-line treatment of gastric cancer. Methods: This study involved 110 patients. Irinotecan was injected intravenously every 3 weeks, and the dose of irinotecan was determined by polymorphism of the UGT1A1 gene, which was divided into three groups (125 mg/m2: GG type; 100 mg/m2: GA type; 75 mg/m2: AA type). The primary end point was overall survival (OS), the secondary end points were progression-free survival (PFS) and safety. Results: One hundred and seven patients received irinotecan treatment and three patients with AA type received paclitaxel treatment. Among 107 patients, there were no significant differences in PFS (4.8 m vs 4.9 m vs 4.4 m; p = 0.5249) and OS (9.3 m vs 9.3 m vs NA; p = 0.6821) among patients with GG/GA/AA subtypes after dose adjustment. For the patient with homozygosity mutation, treatment was switched to paclitaxel. There were no significant differences in PFS and OS among patients with different alleles or after dose adjustment (p > 0.05). There was a significant difference in the risk of delayed diarrhea (p = 0.000), leukopenia (p = 0.003) and neutropenia (p = 0.000) in patients with different UGT1A1*6 genotypes, while no difference in patients with different UGT1A1*28 genotypes. Additionally, grade 3/4 diarrhea, neutropenia, and leukopenia were significantly more common in AA genotype patients compared to GG (2%, 19%, 24%) or GA (23%, 31%, 31%) genotype patients. Conclusion: Individual irinotecan treatment shows encouraging survival and tolerability outcomes in patients with GG/GA subtype. Irinotecan may be not suitable for patients with AA subtype.

Photoinduced electron transfer detection method for identifying UGT1A1*28 microsatellites

During development of a novel detection method for the UDP-glucuronosyl transferase 1A1 (UGT1A1)*28, the fluorescence intensity of a dye conjugated to cytosine (C) at the end of a DNA strand decreased upon hybridization with guanine (G). This phenomenon is referred to as photoinduced electron transfer (PeT). Using this phenomenon, we devised a method for the naked-eye detection of UGT1A1*28 (thymine-adenine (TA)-repeat polymorphism). Fluorescently labeled single-stranded DNA (ssDNA) oligonucleotides (probes) were designed and hybridized with complementary strand DNAs (target DNAs). Base pair formation at the blunt end between fluorescently labeled C (probe side) and G (target side), induced dramatic fluorescence quenching. Additionally, when the labeled-CG pair formed near the TA-repeat sequence, different TA-repeat numbers were discriminated. However, obtaining enough target DNA for this probe by typical polymerase chain reaction (PCR) was difficult. To enable the practical use of the probe, producing sufficient target DNA remains problematic.

UGT1A1 genotype-guided dosing of irinotecan: time to prioritize patient safety

Tweetable abstract Pretreatment UGT1A1 genotyping and a 70% irinotecan dose intensity in poor metabolizers is safe, feasible, cost-effective and essential for safe irinotecan treatment in cancer patients. It is time to update guidelines to swiftly enable the implementation of UGT1A1 genotype-guided irinotecan dosing in routine oncology care.

TROP-2 directed antibody-drug conjugates (ADCs): The revolution of smart drug delivery in advanced non-small cell lung cancer (NSCLC)

BACKGROUND

Antibody drug conjugates (ADCs) represent a revolutionary drug class in cancer therapy, combining the precision of targeted therapy with the cytotoxic effects of chemotherapy. Promising activity of novel ADCs, namely Trastuzumab Deruxtecan and Patritumab Deruxtecan, has been observed in hard-to treat molecular subtypes, such as HER2-positive and heavily pretreated EGFR-mutant Non-Small Cell Lung Cancer (NSCLC). However, therapeutic advances are expected in certain subgroups of lung cancer patients, including non-oncogene-addicted NSCLC after failure of current standard of care (e.g., immunotherapy with or without chemotherapy, chemo-antiangiogenic treatment). Trophoblastic Cell Surface Antigen 2 (TROP-2) is a surface transmembrane glycoprotein member of the epithelial cell adhesion molecule (EpCAM) family. TROP-2 represents a promising therapeutic target in refractory non-oncogene-addicted NSCLC.

METHODOLOGY

We performed a systematic literature search of the clinical trials about TROP-2 directed ADCs in NSCLC referenced in the pubmed.gov database, Cochrane Library database and clinicaltrial.gov database.

RESULTS

First-in-humans ADCs targeting TROP-2, namely Sacituzumab Govitecan (SN-38) and Datopotamab Deruxtecan (Dxd), yielded promising activity signals in NSCLC with a manageable safety profile. Most common grade ≥ 3 adverse events (AEs) of Sacituzumab Govitecan included neutropenia (28 %), diarrhea (7 %), nausea (7 %), fatigue (6 %), and febrile neutropenia (4 %). Nausea and stomatitis were the most common all grade AEs with Datopotamab Deruxtecan; dyspnea, amylase increase, hyperglycemia and lymphopenia were reported as grade ≥ 3 AEs in less than 12 % of patients.

CONCLUSION

As more effective strategies are needed for patients with refractory non-oncogene-addicted NSCLC, the design of novel clinical trials with ADCs targeting TROP-2 is encouraged as both a monotherapy or combination strategy with existing agents (e.g., monoclonal antibodies targeting immune checkpoint inhibitors or chemotherapy).

iPSC-derived organ-on-a-chip models for personalized human genetics and pharmacogenomics studies

Genome-wide association studies (GWAS) have now correlated hundreds of genetic variants with complex genetic diseases and drug efficacy. Functional characterization of these factors remains challenging, particularly because of the lack of human model systems. Molecular and nanotechnological advances, in particular the ability to generate patient-specific PSC lines, differentiate them into diverse cell types, and seed and combine them on microfluidic chips, have led to the establishment of organ-on-a-chip (OoC) platforms that recapitulate organ biology. OoC technology thus provides unique personalized platforms for studying the effects of host genetics and environmental factors on organ physiology. In this review we describe the technology and provide examples of how OoCs may be used for disease modeling and pharmacogenetic research.

Correlation of UGT1A1 Gene Polymorphisms or Prior Irinotecan Treatment and Treatment Outcomes of Nanoliposomal-Irinotecan plus 5-Fluorouracil/Leucovorin for Pancreatic Ductal Adenocarcinoma: A Multicenter, Retrospective Cohort Study (HGCSG2101)

The effects of UGT1A1 gene polymorphisms or prior irinotecan treatment on treatment outcomes of nanoliposomal-irinotecan plus 5-fluorouracil/leucovorin (nal-IRI+5-FU/LV) in patients with unresectable pancreatic ductal adenocarcinoma (PDAC) are not established. This multicenter, retrospective cohort study compared treatment outcomes in patients with UGT1A1*1/*1 and those with UGT1A1*1/*6 or *1/*28 genotypes. We also analyzed the impact of prior irinotecan treatment on survival outcomes in 54 patients treated with nal-IRI+5-FU/LV. Comparable effectiveness was found regardless of the UGT1A1 genotypes. While no significant differences were found, grade ≥3 neutropenia and febrile neutropenia were more frequent in patients with UGT1A1*1/*6 or *1/*28 than in those with UGT1A1*1/*1 genotypes (grade ≥3 neutropenia, 50.0% vs. 30.8%, p = 0.24; febrile neutropenia, 9.1% vs. 0.0%, p = 0.20, respectively). No significant difference in progression-free survival (PFS) and overall survival (OS) was observed between irinotecan-naïve-patients and other patients. However, irinotecan-resistant patients showed significantly shorter PFS (hazard ratio (HR) 2.83, p = 0.017) and OS (HR 2.58, p = 0.033) than other patients. Our study indicated that patients with UGT1A1*1/*6 or *1/*28 may be prone to neutropenia, though further study is needed. The survival benefit of nal-IRI+5-FU/LV could be maintained in patients without disease progression after irinotecan therapy.

The Uridine diphosphate (UDP)-glycosyltransferases (UGTs) superfamily: the role in tumor cell metabolism

UDP-glycosyltransferases (UGTs), important enzymes in biotransformation, control the levels and distribution of numerous endogenous signaling molecules and the metabolism of a wide range of endogenous and exogenous chemicals. The UGT superfamily in mammals consists of the UGT1, UGT2, UGT3, and UGT8 families. UGTs are rate-limiting enzymes in the glucuronate pathway, and in tumors, they are either overexpressed or underexpressed. Alterations in their metabolism can affect gluconeogenesis and lipid metabolism pathways, leading to alterations in tumor cell metabolism, which affect cancer development and prognosis. Glucuronidation is the most common mammalian conjugation pathway. Most of its reactions are mainly catalyzed by UGT1A, UGT2A and UGT2B. The body excretes UGT-bound small lipophilic molecules through the bile, urine, or feces. UGTs conjugate a variety of tiny lipophilic molecules to sugars, such as galactose, xylose, acetylglucosamine, glucuronic acid, and glucose, thereby inactivating and making water-soluble substrates, such as carcinogens, medicines, steroids, lipids, fatty acids, and bile acids. This review summarizes the roles of members of the four UGT enzyme families in tumor function, metabolism, and multiple regulatory mechanisms, and its Inhibitors and inducers. The function of UGTs in lipid metabolism, drug metabolism, and hormone metabolism in tumor cells are among the most important topics covered.

Genotyping of UGT1A1*80 as an Alternative to UGT1A1*28 Genotyping in Spain

Background: The variant rs34983651 (UGT1A1*28) and its genotyping are used to prevent irinotecan-induced toxicity. Several variants are in close linkage disequilibrium. Our objective was to evaluate the potential correlation of genotyping UGT1A1*80 instead of UGT1A1*28 in different populations. Methods: We studied SNPs in linkage disequilibrium with UGT1A1*28 in several populations and selected rs887829 to develop an inexpensive and rapid genotyping method and compare it with the one we currently use for UGT1A1*28 genotyping. Samples from cancer patients (n = 701) already tested using PCR and electrophoresis prior to treatment with irinotecan for rs34983651 (UGT1A1*28) in a Spanish hospital were genotyped for rs887829 (UGT1A1*80) using real-time PCR with a TaqMan probe. Results: We observed a complete match for both genotypes, except in one sample. This method was 100% efficient in correctly genotyping *28/*28 patients, 99.68% efficient for *1/*28, and 100% efficient for *1/*1. Linkage disequilibrium between populations showed the Iberian population to be the most suitable for the clinical use of UGT1A1*80. This method is less expensive and the time to decision is shorter. Conclusion: Genotyping of rs887829 using the proposed method may be used to substitute genotyping of rs34983651 as a pharmacogenetics test in cancer patients prior to starting irinotecan-based treatments, mainly in the Iberian population. In addition, it is less expensive than other conventional methods and easy to implement, with a shorter time to decision than UGT1A1*28.

Counteractions of a Novel Hydroalcoholic Extract from Lens Culinaria against the Dexamethasone-Induced Osteoblast Loss of Native Murine Cells

The cytoprotective effects of a novel hydroalcoholic extract (0.01–5 mg/mL) from Lens culinaria (Terre di Altamura Srl) were investigated within murine native skeletal muscle fibers, bone marrow cells, and osteoblasts, and in cell lines treated with the apoptotic agent staurosporine (2.14 × 10⁻⁶ M), the alkylating drug cisplatin (10⁻⁴ M), the topoisomerase I inhibitor irinotecan (10⁻⁴ M), the antimitotic pro-oxidant doxorubicin (10⁻⁶ M), and the immunosuppressant dexamethasone (2 × 10⁻⁶ M). An amount of 10g of plant material was used to obtain a 70% ethanol/water product, following two-step extraction, evaporation, lyophilization, and storage at −20 °C. For the murine osteoblasts, doxorubicin reduced survival by −65%, dexamethasone by −32% and −60% after 24 and 48 h of incubation time, respectively. The extract was effective in preventing the osteoblast count-reduction induced by dexamethasone; it was also effective at preventing the inhibition of mineralization induced by dexamethasone. Doxorubicin and cisplatin caused a significant reduction in cell growth by −77% for bone marrow cells, −43% for irinotecan, and −60% for dexamethasone, but there was no evidence for the cytoprotective effects of the extract in these cells. Staurosporine and doxorubicin caused a fiber death rate of >−40% after 18 and 24 h of incubation, yet the extract was not effective at preventing these effects. The extract was effective in preventing the staurosporine-induced reduction of HEK293 proliferation and colony formation in the crystal violet DNA staining and the clonogenic assays. It was also effective for the cisplatin-induced reduction in HEK293 cell proliferation. The extract, however, failed to protect the SHSY5Y neurons against cisplatin and irinotecan-induced cytotoxicity. A UV/VIS spectroscopy analysis showed three peaks at the wavelengths of 350, 260, and 190 nm, which correspond to flavonoids, proanthocyanins, salicylates, and AA, constituting the extract. These data suggest the possible development of this extract for use against dexamethasone-induced bone loss and renal chemotherapy-induced damage.

Model-Based Prediction of Irinotecan-Induced Grade 4 Neutropenia in Advanced Cancer Patients: Influence of Demographic and Clinical Factors

Severe neutropenia is the major dose-liming toxicity of irinotecan-based chemotherapy. The objective was to assess to what extent a population pharmacokinetic/pharmacodynamic model including patient-specific demographic/clinical characteristics, individual pharmacokinetics, and absolute neutrophil counts (ANCs) can predict irinotecan-induced grade 4 neutropenia. A semimechanistic population pharmacokinetic/pharmacodynamic model was developed to describe neutrophil response over time in 197 patients with cancer receiving irinotecan. For covariate analysis, sex, race, age, pretreatment total bilirubin, and body surface area were evaluated to identify significant covariates on system-related parameters (mean transit time (MTT) and ɣ) and sensitivity to neutropenia effects of irinotecan and SN-38 (SLOPE). The model-based simulation was performed to assess the contribution of the identified covariates, individual pharmacokinetics, and baseline ANC alone or with incremental addition of weekly ANC up to 3 weeks on predicting irinotecan-induced grade 4 neutropenia. The time course of neutrophil response was described using the model assuming that irinotecan and SN-38 have toxic effects on bone marrow proliferating cells. Sex and pretreatment total bilirubin explained 10.5% of interindividual variability in MTT. No covariates were identified for SLOPE and γ. Incorporating sex and pretreatment total bilirubin (area under the receiver operating characteristic curve (AUC-ROC): 50%, 95% CI 50-50%) or with the addition of individual pharmacokinetics (AUC-ROC: 62%, 95% CI 53-71%) in the model did not result in accurate prediction of grade 4 neutropenia. However, incorporating ANC only at baseline and week 1 in the model achieved a good prediction (AUC-ROC: 78%, 95% CI 69-88%). These results demonstrate the potential applicability of a model-based approach to predict irinotecan-induced neutropenia, which ultimately allows for personalized intervention to maximize treatment outcomes.

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.

Drug-Drug Interactions and Disease Status Are Associated with Irinotecan-induced Hepatotoxicity: A Cross-Sectional Study in Shanghai

Irinotecan-induced hepatotoxicity can cause severe clinical complications in patients; however, the underlying mechanism and factors affecting hepatotoxicity have rarely been investigated. In this cross-sectional study, we screened all clinical, demographic, medication and genetic variables among 126 patients receiving irinotecan and explored potential associations with the incidence and time to onset of irinotecan-induced hepatotoxicity. Approximately 38.9% of the patients suffered from hepatotoxicity after irinotecan administration. The presence of cardiovascular diseases (CVDs) increases the incidence of hepatotoxicity approximately 2.9-fold and doubles the hazard of time to hepatotoxicity. Patients with liver metastasis had a more than 4-fold higher risk of hepatotoxicity and a 3.5-fold increased hazard of time to hepatotoxicity compared to those without liver metastasis. Patients who took CYP3A inducers had a 4.4-fold increased incidence of hepatotoxicity, and furthermore, concomitant use of platinum-based antineoplastics revealed 4.2 times the hazard of time to hepatotoxicity compared to those receiving antimetabolites. The cumulative dose of irinotecan (5-9 cycles) increased hepatotoxicity by 8.5 times. However, the genotypes and phenotypes of UGT1A1*28/*6 failed to be predictive factors of hepatotoxicity. The findings of this study suggest that irinotecan-induced hepatotoxicity is not directly associated with genetic variables but is mostly related to concomitant use of CYP3A inducers and platinum, as well as the presence of liver metastasis and CVD. Thus, close monitoring of liver function is recommended, especially in patients with liver impairment or using CYP3A inducers and platinum antineoplastic drugs, which may be the best way to prevent hepatotoxicity. This article is protected by copyright. All rights reserved.

UGT1A1 Allele Test Not Only Minimizes the Toxicity But Also Maximizes the Therapeutic Effect of Irinotecan in the Treatment of Colorectal Cancer: A Narrative Review

Background

Irinotecan is a first-line agent in the systematic treatment of colorectal cancer (CRC). Adjusting the dose of irinotecan according to the uridine diphosphate glucuronosyltransferase (UGT) 1A1 genotype reflects the principle of individualized and precision medicine, and may improve the chemotherapy response and survival of CRC.

Methods

To summarize the feasibility, efficacy and safety of high dose irinotecan in CRC patients with UGT1A1 wild-type or heterozygous alleles, PubMed, EMBASE, MEDLINE and the Cochrane Central Register of Controlled Trials online databases were searched from the date of creation to October 22, 2021.

Results

A total of 1,186 related literatures were searched, and 14 studies were included for review according to the inclusion criteria. The results indicated that the maximum tolerated dose of irinotecan in CRC patients with UGT1A1 wild-type or heterozygous variant was significantly higher than the conventional recommended dose. Chemotherapy based on high dose irinotecan improved the clinical efficacy in mCRC patients with UGT1A1*28 wild-type and heterozygous variant, and the toxicity was tolerated, as reflected in most studies.

Conclusions

We are optimistic about the application of high dose irinotecan for mCRC patients with UGT1A1*28 wild-type or heterozygous variant, which will provide a relatively clear direction for future research and certain norms for clinical practice.

Characteristics and Clinical Implication of UGT1A1 Heterozygous Mutation in Tumor

BACKGROUND

The literature recommends that reduced dosage of CPT-11 should be applied in patients with UGT1A1 homozygous mutations, but the impact of UGT1A1 heterozygous mutations on the adverse reactions of CPT-11 is still not fully clear.

METHODS

A total of 107 patients with UGT1A1 heterozygous mutation or wild-type, who were treated with CPT-11 from January 2018 to September 2021 in Peking University Third Hospital, were retrospectively enrolled. The adverse reaction spectra of patients with UGT1A1*6 and UGT1A1*28 mutations were analyzed. Adverse reactions were evaluated according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) 5.0. The efficacy was evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. The genotypes of UGT1A1*6 and UGT1A1*28 were detected by digital fluorescence molecular hybridization.

RESULTS

There were 43 patients with UGT1A1*6 heterozygous mutation, 26 patients with UGT1A1*28 heterozygous mutation, 8 patients with UGT1A1*6 and UGT1A1*28 double heterozygous mutations, 61 patients with heterozygous mutation at any gene locus of UGT1A1*6 and UGT1A1*28. Logistic regression analysis showed that the presence or absence of vomiting (P=0.013) and mucositis (P=0.005) was significantly correlated with heterozygous mutation of UGT1A1*28, and the severity of vomiting (P<0.001) and neutropenia (P=0.021) were significantly correlated with heterozygous mutation of UGT1A1*6. In colorectal cancer, UGT1A1*6 was significantly correlated to diarrhea (P=0.005), and the other adverse reactions spectrum was similar to that of the whole patient cohort, and efficacy and prognosis were similar between patients with different genotypes and patients treated with reduced CPT-11 dosage or not.

CONCLUSIONS

In clinical use, heterozygous mutations of UGT1A1*6 and UGT1A1*28 are related to the risk and severity of vomiting, diarrhea, neutropenia and mucositis in patients with Pan-tumor and colorectal cancer post CPT-11 therpy. In colorectal cancer, UGT1A1*6 is significantly related to diarrhea post CPT-11 use, efficacy and prognosis is not affected by various genotypes or CPT-11 dosage reduction.

The Value of Pharmacogenetics to Reduce Drug-Related Toxicity in Cancer Patients

Many anticancer drugs cause adverse drug reactions (ADRs) that negatively impact safety and reduce quality of life. The typical narrow therapeutic range and exposure-response relationships described for anticancer drugs make precision dosing critical to ensure safe and effective drug exposure. Germline mutations in pharmacogenes contribute to inter-patient variability in pharmacokinetics and pharmacodynamics of anticancer drugs. Patients carrying reduced-activity or loss-of-function alleles are at increased risk for ADRs. Pretreatment genotyping offers a proactive approach to identify these high-risk patients, administer an individualized dose, and minimize the risk of ADRs. In the field of oncology, the most well-studied gene-drug pairs for which pharmacogenetic dosing recommendations have been published to improve safety are DPYD-fluoropyrimidines, TPMT/NUDT15-thiopurines, and UGT1A1-irinotecan. Despite the presence of these guidelines, the scientific evidence showing the benefits of pharmacogenetic testing (e.g., improved safety and cost-effectiveness) and the development of efficient multi-gene genotyping panels, routine pretreatment testing for these gene-drug pairs has not been implemented widely in the clinic. Important considerations required for widespread clinical implementation include pharmacogenetic education of physicians, availability or allocation of institutional resources to build an efficient clinical infrastructure, international standardization of guidelines, uniform adoption of guidelines by regulatory agencies leading to genotyping requirements in drug labels, and development of cohesive reimbursement policies for pretreatment genotyping. Without clinical implementation, the potential of pharmacogenetics to improve patient safety remains unfulfilled.

Implementing Pre-Therapeutic UGT1A1 Genotyping in Clinical Practice: A Real-Life Study

Current guidelines recommend pre-therapeutic UGT1A1 genotyping to guide irinotecan dosing, but the usefulness of this approach remains to be clarified. In 247 patients with advanced gastrointestinal cancers undergoing irinotecan-based chemotherapy, we prospectively performed UGT1A1*28 genotyping and we analyzed the incidence of severe neutropenia according to genotype-guided dose reductions. Overall, 28 (11.3%) and 92 (37.2%) patients were homozygous or heterozygous UGT1A1*28 carriers, respectively. Grade ≥ 3 neutropenia was reported in 39% of homozygous patients receiving an upfront dose reduction of irinotecan (median 40%, range 22–58%), in 20% of heterozygous or wild-type patients receiving full dose (OR_{vs*28/*28 genotype} = 0.38; 95% CI: 0.14–1.03; p = 0.058), and in 15.3% of those receiving a reduced dose for clinical reasons (OR _{vs*28/*28 genotype} = 0.28, 95% IC: 0.12–0.67; p = 0.004). Occurrence of severe neutropenia was inversely associated with dose reduction in UGT1A1*28 homozygous carriers (OR_{x10 unit} = 0.62, 95% CI: 0.27–1.40, p = 0.249) and UGT1A1 heterozygous or wild-type patients (OR_{x10 unit} = 0.87, 95% CI: 0.59–1.28, p = 0.478). Incidence of severe neutropenia was related to irinotecan doses and UGT1A1 polymorphisms. Upfront irinotecan dose reductions do not reduce the burden of grade ≥ 3 neutropenia in UGT1A1*28 homozygous carriers.

UGT1A1 genotype-guided dosing of irinotecan: A prospective safety and cost analysis in poor metaboliser patients

AIM

To determine the safety, feasibility, pharmacokinetics, and cost of UGT1A1 genotype-guided dosing of irinotecan.

PATIENTS AND METHODS

In this prospective, multicentre, non-randomised study, patients intended for treatment with irinotecan were pre-therapeutically genotyped for UGT1A1∗28 and UGT1A1∗93. Homozygous variant carriers (UGT1A1 poor metabolisers; PMs) received an initial 30% dose reduction. The primary endpoint was incidence of febrile neutropenia in the first two cycles of treatment. Toxicity in UGT1A1 PMs was compared to a historical cohort of UGT1A1 PMs treated with full dose therapy, and to UGT1A1 non-PMs treated with full dose therapy in the current study. Secondary endpoints were pharmacokinetics, feasibility, and costs.

RESULTS

Of the 350 evaluable patients, 31 (8.9%) patients were UGT1A1 PM and received a median 30% dose reduction. The incidence of febrile neutropenia in this group was 6.5% compared to 24% in historical UGT1A1 PMs (P = 0.04) and was comparable to the incidence in UGT1A1 non-PMs treated with full dose therapy. Systemic exposure of SN-38 of reduced dosing in UGT1A1 PMs was still slightly higher compared to a standard-dosed irinotecan patient cohort (difference: +32%). Cost analysis showed that genotype-guided dosing was cost-saving with a cost reduction of €183 per patient.

CONCLUSION

UGT1A1 genotype-guided dosing significantly reduces the incidence of febrile neutropenia in UGT1A1 PM patients treated with irinotecan, results in a therapeutically effective systemic drug exposure, and is cost-saving. Therefore, UGT1A1 genotype-guided dosing of irinotecan should be considered standard of care in order to improve individual patient safety.

Is dose modification or discontinuation of nilotinib necessary in nilotinib-induced hyperbilirubinemia?

Nilotinib is a specific breakpoint cluster region-Abelson leukemia virus-tyrosine kinase inhibitor that is used as an effective first- or second-line treatment in imatinib-resistant chronic myelogenous leukemia (CML) patients. Hepatotoxicity due to nilotinib is a commonly reported side effect; however, abnormal liver function test (LFT) results have been reported in asymptomatic cases. When alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels are more than five-fold the upper limit of the normal (ULN) or when the serum total bilirubin level is more than three-fold the ULN, dose modification or discontinuation of nilotinib is recommended, resulting in decreased levels of hematological indicators in certain patients with CML. Nilotinib-induced hyperbilirubinemia typically manifests as indirect bilirubinemia without elevated ALT or AST levels. Such abnormal liver functioning is thus not attributed to the presence of a true histologic lesion of the liver. The underlying mechanism may be related to the inhibition of uridine diphosphate glucuronosyltransferase activity. Therefore, nilotinib dose adjustment is not recommended for this type of hyperbilirubinemia, and in the absence of elevated liver enzyme levels or presence of abnormal LFT findings, physicians should consider maintaining nilotinib dose intensity without modifications.

All You Need to Know About UGT1A1 Genetic Testing for Patients Treated With Irinotecan: A Practitioner-Friendly Guide

Irinotecan is an anticancer agent widely used for the treatment of solid tumors, including colorectal and pancreatic cancers. Severe neutropenia and diarrhea are common dose-limiting toxicities of irinotecan-based therapy, and UGT1A1 polymorphisms are one of the major risk factors of these toxicities. In 2005, the US Food and Drug Administration revised the drug label to indicate that patients with UGT1A1*28 homozygous genotype should receive a decreased dose of irinotecan. However, UGT1A1*28 testing is not routinely used in the clinic, and specific reasons include lack of access to concise information on this wide issue as well as mixed recommendations by regulatory and professional entities. To assist oncologists in assessing whether and when to use UGT1A1 genetic testing in patients receiving irinotecan-based therapies, this article provided (1) essential knowledge of UGT1A1 polymorphisms; (2) an update on the impact of UGT1A1 polymorphisms on efficacy and toxicity of contemporary irinotecan-based regimens; (3) dosing adjustments based upon the UGT1A1 genotypes, and (4) recommendations from currently available guidelines from the US and international scientific consortia and major oncology societies.

Pharmacogenomics in solid cancers and hematologic malignancies: Improving personalized drug prescription

The discovery of molecular alterations involved in oncogenesis is evolving rapidly and has led to the development of new innovative targeted therapies in oncology. High-throughput sequencing techniques help to identify genomic targets and to provide predictive molecular biomarkers of response to guide alternative therapeutic strategies. Besides the emergence of these theranostic markers for the new targeted treatments, pharmacogenetic markers (corresponding to genetic variants existing in the constitutional DNA, i.e., the host genome) can help to optimize the use of chemotherapy. In this review, we present the current clinical applications of constitutional PG and the recent concepts and advances in pharmacogenomics, a rapidly evolving field that focuses on various molecular alterations identified on constitutional or somatic (tumor) genome.

Case report of sacituzumab govitecan-hziy-induced neutropenia in a patient with metastatic triple-negative breast cancer and a uridine diphosphate glucuronosyltransferase family 1 member A1 poor metabolizer genotype

INTRODUCTION

Sacituzumab govitecan-hziy, approved in 2020 for treatment of metastatic triple-negative breast cancer, provides a new option for a population with a historically poor prognosis with standard chemotherapy. Uridine diphosphate glucuronosyltransferase family 1 member A1 poor metabolizers are at increased risk for profound neutropenia. This case discusses clinical implications of the uridine diphosphate glucuronosyltransferase family 1 member A1*28/*28 genotype in patients receiving sacituzumab govitecan-hziy.

CASE REPORT

A 38-year-old otherwise healthy pre-menopausal female of South Asian descent was diagnosed with non-metastatic, hormone receptor-positive, and human epidermal growth factor receptor 2-negative breast cancer. This was treated with neoadjuvant chemotherapy and multiple lines of subsequent therapies. Upon finding bone metastasis, an additional six lines of therapy ensued. In total, 3.5 years post-diagnosis, sacituzumab govitecan-hziy was started for disease transformation to triple-negative status.

MANAGEMENT AND OUTCOME

Sacituzumab govitecan-hziy was initiated at the Food and Drug Administration-approved 10 mg/kg/dose on days 1 and 8 of a 21-day cycle. Grade 4 neutropenia occurred after one dose. Pharmacogenomics testing identified the patient as a uridine diphosphate glucuronosyltransferase family 1 member A1*28 homozygous expressor. Sacituzumab govitecan-hziy was dose-reduced, and granulocyte colony-stimulating factor was administered due to the severity of neutropenia. The patient continued on sacituzumab govitecan-hziy until disease progression.

DISCUSSION

Sacituzumab govitecan-hziy's propensity to cause neutropenia is multifactorial. Although incidence of all-grade neutropenia from sacituzumab govitecan-hziy is elevated for uridine diphosphate glucuronosyltransferase family 1 member A1*28 homozygous expressors, this does not translate to increased risk for febrile neutropenia. Detailed guidance is lacking regarding empiric dose adjustments or prophylactic granulocyte colony-stimulating factor for these patients.¹ Currently, pre-sacituzumab govitecan-hziy pharmacogenomics testing to identify uridine diphosphate glucuronosyltransferase family 1 member A1 poor metabolizers is not recommended, and the cost-effectiveness of this approach is unclear.

Microbiota-Host-Irinotecan Axis: A New Insight Toward Irinotecan Chemotherapy

Irinotecan (CPT11) and its active metabolite ethyl-10-hydroxy-camptothecin (SN38) are broad-spectrum cytotoxic anticancer agents. Both cause cell death in rapidly dividing cells (e.g., cancer cells, epithelial cells, hematopoietic cells) and commensal bacteria. Therefore, CPT11 can induce a series of toxic side-effects, of which the most conspicuous is gastrointestinal toxicity (nausea, vomiting, diarrhea). Studies have shown that the gut microbiota modulates the host response to chemotherapeutic drugs. Targeting the gut microbiota influences the efficacy and toxicity of CPT11 chemotherapy through three key mechanisms: microbial ecocline, catalysis of microbial enzymes, and immunoregulation. This review summarizes and explores how the gut microbiota participates in CPT11 metabolism and mediates host immune dynamics to affect the toxicity and efficacy of CPT11 chemotherapy, thus introducing a new concept that is called "microbiota-host-irinotecan axis". Also, we emphasize the utilization of bacterial β-glucuronidase-specific inhibitor, dietary interventions, probiotics and strain-engineered interventions as emergent microbiota-targeting strategies for the purpose of improving CPT11 chemotherapy efficiency and alleviating toxicity.

HomeoboxC6 promotes metastasis by orchestrating the DKK1/Wnt/β-catenin axis in right-sided colon cancer

Patients with right-sided colon cancer (RCC) generally have a poorer prognosis than those with left-sided colon cancer (LCC). We previously found that homeobox C6 (HOXC6) was the most significantly upregulated gene in RCC compared to LCC. However, it remains unclear whether HOXC6 plays a role in tumor proliferation and metastasis. Our study aimed to explore the potential oncogenic role and the detailed molecular mechanism of HOXC6 in RCC. In this study, HOXC6 was validated to be overexpressed in RCC and associated with poor prognosis. Furthermore, overexpression of HOXC6 promoted the migration and invasion of colon cancer cells through inducing EMT by activating the Wnt/β-catenin signaling pathway and inhibition of DKK1 secretion. Lastly, we preliminary explored the translational effect of HOXC6 and found that silencing of HOXC6 made HCT116 and HT29 cells more sensitive to irinotecan.

UGT1A1 Guided Cancer Therapy: Review of the Evidence and Considerations for Clinical Implementation

Multi-gene assays often include UGT1A1 and, in certain instances, may report associated toxicity risks for irinotecan, belinostat, pazopanib, and nilotinib. However, guidance for incorporating UGT1A1 results into therapeutic decision-making is mostly lacking for these anticancer drugs. We summarized meta-analyses, genome-wide association studies, clinical trials, drug labels, and guidelines relating to the impact of UGT1A1 polymorphisms on irinotecan, belinostat, pazopanib, or nilotinib toxicities. For irinotecan, UGT1A1*28 was significantly associated with neutropenia and diarrhea, particularly with doses ≥ 180 mg/m2, supporting the use of UGT1A1 to guide irinotecan prescribing. The drug label for belinostat recommends a reduced starting dose of 750 mg/m2 for UGT1A1*28 homozygotes, though published studies supporting this recommendation are sparse. There was a correlation between UGT1A1 polymorphisms and pazopanib-induced hepatotoxicity, though further studies are needed to elucidate the role of UGT1A1-guided pazopanib dose adjustments. Limited studies have investigated the association between UGT1A1 polymorphisms and nilotinib-induced hepatotoxicity, with data currently insufficient for UGT1A1-guided nilotinib dose adjustments.

Genetic Polymorphisms and Pharmacotherapy for Prostate Cancer

The therapeutic landscape of pharmacotherapy for prostate cancer has dramatically evolved, and multiple therapeutic options have become available for prostate cancer patients. Therefore, useful biomarkers to identify suitable candidates for treatment are required to maximize the efficacy of pharmacotherapy. Genetic polymorphisms such as single-nucleotide polymorphisms (SNPs) and tandem repeats have been shown to influence the therapeutic effects of pharmacotherapy for prostate cancer patients. For example, genetic polymorphisms in the genes involved in androgen receptor signaling are reported to be associated with the therapeutic outcome of androgen-deprivation therapy as well as androgen receptor-pathway inhibitors. In addition, SNPs in genes involved in drug metabolism and efflux pumps are associated with therapeutic effects of taxane chemotherapy. Thus, genetic polymorphisms such as SNPs are promising biomarkers to realize personalized medicine. Here, we overview the current findings on the influence of genetic polymorphisms on the outcome of pharmacotherapy for prostate cancer and discuss current issues as well as future visions in this field.