UGT1A1 Polymorphism for Irinotecan Dose Escalation in Patients with BRAF-Mutated Metastatic Colorectal Cancer Treated with First-Line Bevacizumab and FOLFIRI

Real-World Outcomes of First-Line FOLFIRI Plus Bevacizumab with Irinotecan Dose Escalation versus FOLFOXIRI Plus Bevacizumab in BRAFV600E-Mutant Metastatic Colorectal Cancer: The Preliminary Data from a Single-Center Observational Study

Background and Objectives: Approximately 5-10% of all patients with metastatic colorectal cancer (mCRC) harbor a BRAFV600E mutation. These patients exhibit distinct metastatic patterns, poor prognosis, and heterogenous survival outcomes. The findings from the TRIBE study indicated that the administration of FOLFOXIRI plus bevacizumab as first-line treatment extended the median duration of overall survival (OS). In this study, we explored the effects of UGT1A1 polymorphism on the outcomes of irinotecan dose escalation versus FOLFOXIRI plus bevacizumab in patients with BRAFV600E-mutant mCRC. Materials and Methods: We retrospectively reviewed the medical records of 25 patients who had received a diagnosis of BRAFV600E-mutant mCRC between October 2015 and August 2022. All patients underwent UGT1A1 genotyping before receiving bevacizumab plus FOLFIRI. The primary end point was progression-free survival (PFS), and secondary endpoints were OS and adverse events (AEs). The two treatment arms were compared in terms of 6-month PFS and 12-month OS. Results: Over a median follow-up duration of 15.0 (interquartile range, 10.0-30.5) months, no significant differences were noted between the treatment arms in severe AEs (SAEs), 6-month PFS, or 12-month OS (all p < 0.05). Regarding AEs, the FOLFIRI plus bevacizumab regimen was associated with a lower incidence of anorexia than was the FOLFOXIRI plus bevacizumab regimen (p = 0.042). Conclusions: Our findings indicate that FOLFIRI plus bevacizumab with irinotecan dose escalation is an effective first-line treatment regimen for patients with BRAFV600E-mutant mCRC. This regimen leads to acceptable clinical outcomes with manageable AEs. However, the effects on survival and safety outcomes could only be speculated, and further studies are needed because of the sample size, the follow-up for the OS evaluation, and the non-uniformity in all the variables considered in the two groups.

Gut microbiota composition in chemotherapy and targeted therapy of patients with metastatic colorectal cancer

Studies have reported the effects of the gut microbiota on colorectal cancer (CRC) chemotherapy, but few studies have investigated the association between gut microbiota and targeted therapy. This study investigated the role of the gut microbiota in the treatment outcomes of patients with metastatic CRC (mCRC). We enrolled 110 patients with mCRC and treated them with standard cancer therapy. Stool samples were collected before administering a combination of chemotherapy and targeted therapy. Patients who had a progressive disease (PD) or partial response (PR) for at least 12 cycles of therapy were included in the study. We further divided these patients into anti-epidermal growth factor receptor (cetuximab) and anti-vascular endothelial growth factor (bevacizumab) subgroups. The gut microbiota of the PR group and bevacizumab-PR subgroup exhibited significantly higher α-diversity. The β-diversity of bacterial species significantly differed between the bevacizumab-PR and bevacizumab-PD groups (P = 0.029). Klebsiella quasipneumoniae exhibited the greatest fold change in abundance in the PD group than in the PR group. Lactobacillus and Bifidobacterium species exhibited higher abundance in the PD group. The abundance of Fusobacterium nucleatum was approximately 32 times higher in the PD group than in the PR group. A higher gut microbiota diversity was associated with more favorable treatment outcomes in the patients with mCRC. Bacterial species analysis of stool samples yielded heterogenous results. K. quasipneumoniae exhibited the greatest fold change in abundance among all bacterial species in the PD group. This result warrants further investigation especially in a Taiwanese population.

Bilirubin metabolism and UDP-glucuronosyltransferase 1A1 variants in Asians: Pathogenic implications and therapeutic response

In the Asian general population, at least six single-nucleotide variants (SNVs) in the UDP-glucuronosyltransferase (UGT) 1A1 gene have been identified: -3279T>G, -53A(TA)₆ TAA>A(TA)₇ TAA, 211G>A, 686C>A, 1091C>T, and 1456T>G. Each of these six SNVs was observed in at least four ethnic groups of the 12 Asian populations studied. In East Asian populations, the descending frequency of these six SNVs was as follows: -3279G>[-53A(TA)₇ TAA, 211A]>(686A, 1091T)>1456G. Because of the presence of linkage disequilibrium and the expulsion phenomenon, when the SNVs -3279G, -53A(TA)₇ TAA, 211A, and 686A were simultaneously involved, 15 instead of the estimated 81 genotypes were observed. Those carrying 686AA or 1456GG developed Gilbert's syndrome or Crigler-Najjar syndrome type 2. Both -53A(TA)₇ TAA/A(TA)₇ TAA and 211AA are the main causes of Gilbert's syndrome in East Asian populations. In East Asian populations, the 211AA genotype is the main cause of neonatal hyperbilirubinemia, whereas -53A(TA)₇ TAA/A(TA)₇ TAA exerts a protective effect on hyperbilirubinemia development in neonates fed with breast milk. Both 211A and -53A(TA)₇ TAA are significantly associated with adverse drug reactions induced by irinotecan (one of the most widely used anticancer agents) in Asians. However, at least three common SNVs (-3279G, -53A(TA)₇ TAA, and 211A) should be comprehensively analyzed. This study investigated the clinical significance of these six SNVs and demonstrated that examining UGT1A1 variants in Asian populations is considerably challenging.

Irinotecan dose reduction in metastatic colorectal cancer patients with homozygous UGT1A1*28 polymorphism: a single-center case series

OBJECTIVE

The UGT1A1*28 polymorphism reduces UGT1A1 enzymatic activity, which may increase the risk of severe toxicity in patients who receive standard-dose irinotecan, such as severe neutropenia and diarrhea. This real-world study assessed the optimal irinotecan dose in terms of efficacy and toxicity in metastatic colorectal cancer (mCRC) patients homozygous for the UGT1A1*28 polymorphism and receiving FOLFIRI plus bevacizumab or cetuximab as first-line therapy.

METHODS

We analyzed toxicity and treatment outcomes in seven mCRC patients who were homozygous for UGT1A1*28 and received FOLFIRI plus bevacizumab or cetuximab, with an initial irinotecan dose of 120 mg/m².

RESULTS

Six of the seven patients tolerated 120 mg/m² irinotecan without requiring dose reductions in subsequent cycles. The overall response and disease control rates were 43.0% (3/7) and 71.4% (5/7), respectively. The median progression-free survival and overall survival were 11.0 and 33.0 months, respectively. Only one severe adverse event, grade III neutropenia (2.5%), was observed.

CONCLUSIONS

mCRC patients homozygous for the UGT1A1*28 allele can tolerate irinotecan at an initial dose of 120 mg/m² with favorable oncological outcomes and toxicity profiles. Further prospective studies are warranted to optimize irinotecan-based chemotherapy in these patients.

Comparison of Next-Generation Sequencing and Polymerase Chain Reaction for Personalized Treatment-Related Genomic Status in Patients with Metastatic Colorectal Cancer

Personalized treatments based on the genetic profiles of tumors can simultaneously optimize efficacy and minimize toxicity, which is beneficial for improving patient outcomes. This study aimed to integrate gene alterations associated with predictive and prognostic outcomes in patients with metastatic colorectal cancer (mCRC) with polymerase chain reaction (PCR) and in-house next-generation sequencing (NGS) to detect KRAS, NRAS, and BRAF mutations. In the present study, 41 patients with mCRC were assessed between August 2017 and June 2019 at a single institution. The overall concordance between NGS and PCR results for detecting KRAS, NRAS, and BRAF mutations was considerably high (87.8–92.7%), with only 15 discrepant results between PCR and NGS. Our companion diagnostic test analyzes KRAS, NRAS, and BRAF as a panel of CRC molecular targets; therefore, it has the advantages of requiring fewer specimens and being more time and cost efficient than conventional testing for separate analyses, allowing for the simultaneous analysis of multiple genes.

Clinical Outcomes of Patients with Peritoneal Metastasis-Only Colorectal Cancer Treated with First-Line Bevacizumab and FOLFIRI Through Irinotecan Dose Escalation According to UGT1A1 Polymorphism: Compared to Liver Metastasis-Only, and Lung Metastasis-Only

Background

The prognosis of metastatic colorectal cancer (mCRC) depends on the metastatic site and systemic therapy regimen. Peritoneal metastases are associated with a relatively unfavorable prognosis among patients with mCRC. In this article, we present the treatment outcomes of patients with peritoneal carcinomatosis (PC)-only, liver metastasis (LiM)-only, and lung metastasis (LuM)-only CRC.

Methods

Overall, 206 mCRC patients with single-site metastasis and who had received treatment from January 2014 to December 2018 were recruited. Among 206 patients with mCRC, 15 had PC-only mCRC, 145 had LiM-only mCRC, and 46 had LuM-only mCRC. They attended regular follow-ups until November 2020, and the median follow-up period was 24.7 months (5.1–41.3 months). Patients’ characteristics, including clinical data, gene mutation profiles, and clinical outcomes, were evaluated. All patients with PC-only CRC were treated with first-line bevacizumab and FOLFIRI, and the irinotecan dose escalation depended on UGT1A1 polymorphism.

Results

Of the 206 patients, no statistical difference was observed between the PC-only, LiM-only, and LuM-only groups in terms of age, primary tumor location, RAS mutation status, BRAF mutation status, and epidermal growth factor receptor overexpression (all P > 0.05). Patients with PC-only CRC had a median progression-free survival (mPFS) of 18.0 months and a median overall survival (mOS) of 24.6 months. Patients with LiM-only or LuM-only CRC had mPFS of 18.2 and 26.6 months and mOS of 25.0 and 44.5 months, respectively. No significant differences regarding PFS and OS (both P > 0.05) between the three groups of patients with mCRC were observed.

Conclusion

Our study revealed that in patients with PC-only mCRC treatment of first-line bevacizumab and FOLFIRI through irinotecan dose escalation according to UGT1A1 polymorphism could confer such patients with comparable outcomes to that of patients with LiM-only and LuM-only mCRC.

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.

BRAF, MEK, and EGFR Triplet Inhibitors as Salvage Therapy in BRAF-Mutated Metastatic Colorectal Cancer-A Case Series Study Target Therapy of BRAF-Mutated mCRC

Backgroundand objectives: Patients with BRAF-mutated metastatic colorectal cancer have considerably poorer responses to conventional systemic treatment. The real-world effects of triplet therapy with BRAF, mitogen-activated protein kinase kinase, and epidermal growth factor receptor inhibitors in Asia have not been well-reported. Materials and Methods: This single-center case series included patients with BRAF-mutated metastatic colorectal cancer undergoing triplet therapy after failure of prior systemic treatment from 2016 to 2020. The primary outcome was progression-free survival, and secondary outcomes were overall survival, response rate, disease control rate, and adverse events. Results: Nine eligible patients with BRAF-mutated metastatic colorectal cancer receiving triplet therapy were enrolled, with a median follow-up time of 14.5 months (range, 1-26). Most patients (88.8%) had two or more prior systemic treatments, and the triplet regimen was mainly dabrafenib, trametinib, and panitumumab. The overall response rate and disease control rate were 11.1% and 33.3%, respectively. Median progression-free survival and overall survival were 2.9 and 7.4 months, respectively, and a trend toward better overall survival was found with left-sided metastatic colorectal cancer compared with right-sided disease (9.2 vs. 6.9 months, p = 0.093). Adverse events were mostly Grade 1-2, including nausea, hypertension, gastrointestinal symptoms, and skin disorders. Conclusions: In this single-center case series, triplet therapy with BRAF, mitogen-activated protein kinase kinase, and epidermal growth factor receptor inhibitors in BRAF-mutated metastatic colorectal cancer had an acceptable safety profile and reasonable efficacy.