Can population differences in chemotherapy outcomes be inferred from differences in pharmacogenetic frequencies?

An evaluation of cancer aging research group (CARG) score to predict chemotherapy toxicity in older Iranian patients with cancer

Objectives

This study aimed to evaluate the predictive value of the Cancer Aging Research Group (CARG) in Iranian patients as a representative of the Middle East North Africa (MENA) region population.

Methods

This prospective longitudinal study involved patients 65 years and older starting a new cytotoxic chemotherapy regimen. We did general (including Karnofsky performance status, KPS) and CARG-based assessments before chemotherapy. Chemotherapy toxicities were recorded during chemotherapy courses. The predictive values of CARG and KPS were evaluated using the area under the receiver-operating characteristic curve (AUC-ROC). Chemotherapy toxicities were sub-analyzed per hematologic and nonhematologic types.

Results

Chemotherapy-related toxicity was reported in 23.6 % of patients. The corresponding area under the receiver-operating characteristic curve (AUC-ROC) was 0.56 (95 %CI, 0.40–0.69) for total toxicity, 0.67 (95 % CI, 0.48–0.78) for hematologic toxicity, and 0.39 (95 %CI, 0.21–0.66) for nonhematologic toxicity.

Conclusions

CARG model had an acceptable ability to predict hematologic toxicities; however, its efficacy for total and nonhematologic toxicities was limited.

Pathological response to neoadjuvant chemoradiotherapy for oesophageal squamous cell carcinoma: multicentre East Asian and Dutch database comparison

BACKGROUND

Patients with different ethnic and genetic backgrounds may respond differently to anticancer therapies. This study aimed to assess whether patients with oesophageal squamous cell carcinoma (OSCC) treated with neoadjuvant chemoradiotherapy (nCRT) in East Asia had an inferior pathological response compared with patients treated in Northwest Europe.

METHODS

Patients with OSCC who underwent nCRT according to the CROSS regimen (carboplatin and paclitaxel with concurrent 41.4 Gy radiotherapy) followed by oesophagectomy between June 2012 and April 2020 were identified from East Asian and Dutch databases. The primary outcome was pCR, defined as ypT0 N0. Groups were compared using propensity score matching, adjusting for sex, Charlson Co-morbidity Index score, tumour location, cT and cN categories, interval between nCRT and surgery, and number of resected lymph nodes.

RESULTS

Of 725 patients identified, 133 remained in each group after matching. A pCR was achieved in 37 patients (27.8 per cent) in the Asian database and 58 (43.6 per cent) in the Dutch database (P = 0.010). The rate of ypT1-4 was higher in Asian than Dutch data (66.2 and 49.6 per cent; P = 0.004). The ypN1-3 rate was 44.4 per cent in the Asian and 33.1 per cent in the Dutch data set. Clear margins were achieved in 92.5 per cent of Asian and 95.5 per cent of Dutch patients.

CONCLUSION

Regional differences in responses to CROSS nCRT for oesophageal cancer were apparent, the origin of which will need evaluation.

Use of the Cancer and Aging Research Group Predictive Model for Chemotherapy-Related Toxic Effects in a Multiethnic, Older Adult Asian Population

IMPORTANCE

The Cancer and Aging Research Group (CARG) prediction model for chemotherapy-related toxic effects has been developed but not yet validated in older Asian adults. In view of differences in drug metabolism and toxic effect reporting in the Asian population, the ability of this tool to guide the cancer treatment decision-making process in older Asian adults needs to be assessed.

OBJECTIVE

To examine the validity of the CARG predictive model in a multiethnic Asian cohort of older adults.

DESIGN, SETTING, AND PARTICIPANTS

In this prognostic study, patients of various Asian ethnicities 70 years or older with a solid tumor diagnosis receiving chemotherapy at the National University Cancer Institute, Singapore, were accrued from June 1, 2017, to January 1, 2019. Their risks of chemotherapy-related toxic effects were calculated using the CARG tool. A geriatric assessment was performed, and the treating oncologist (blinded to the CARG scores) was asked to give an estimated likelihood of toxic effects (low, medium, or high). Chemotherapy-related toxic effects were recorded during each clinic visit. Validation of the prediction model was performed by calculating the area under the receiver operating characteristic curve. Multivariate analyses were performed to identify variables in other domains in the geriatric assessment predicting for severe toxic effects.

MAIN OUTCOMES AND MEASURES

Grade 3 to 5 toxic effects and hospitalization.

RESULTS

The study included 200 patients (median age, 74 years [range, 70-89 years]; 110 [55.0%] male; 177 [88.5%] Chinese, 17 [8.5%] Malay, 4 [2.0%] Indian, and 2 [1.0%] other ethnicities [according to Singapore's national system of race classification]). A total of 137 patients (68.5%) experienced grade 3 to 5 toxic effects, and 131 (65.5%) required hospitalization. The area under the receiver operating characteristic curve for the CARG chemotoxicity prediction model was 0.74 (95% CI, 0.67-0.82), retaining good discrimination in the study population.

CONCLUSIONS AND RELEVANCE

This prognostic study conducted in a multiethnic Asian cohort of older adults supports the validity of the CARG predictive model in this population, predicting which older adults are at risk of chemotherapy-related toxic effects.

Pharmacogenetic testing-guided treatment for oncology: an overview of reviews

Pharmacogenetics is the relationship between an individual's genetic variations and their response to pharmacological treatment. We conducted an overview of reviews on the use of post-treatment pharmacogenetic testing for oncology, based on clinically relevant gene-drug pairs. We conducted a search on Medline, Embase and Cochrane Library, from their inception to 18 June 2020. We selected six eligible systematic reviews. The most studied drug categories were estrogen agonists/antagonists and fluoropyrimidines associated with cytochrome P450 and dihydropyrimidine dehydrogenase genes (CYP2D6 and DPYD), but many studies were classified as being of critically low or low quality. There is a need for more high-quality primary studies and systematic reviews that assess the risk of bias, with consistent definitions of clinical outcomes to consider the benefits of pharmacogenetic testing for oncology.

Regional Variations in Clinical Trial Outcomes in Oncology

BACKGROUND

It is unknown how often regional differences in oncology trials are observed. Based on our study findings, we quantified regional variation in registration studies in oncology and developed a question guide to help clinicians evaluate regional differences.

METHODS

Using FDA archives, we identified registration studies in solid tumor malignancies from 2010 to 2020. We extracted the baseline study characteristics and participating countries and determined whether the primary publication reported a regional subgroup analysis. For studies presenting outcomes stratified by region, we extracted the stratified hazard ratios (HRs) and extracted or calculated the test for heterogeneity. We performed a random effects meta-analysis and a pairwise comparison to determine whether outcomes differed between high-income versus mixed-income regions.

RESULTS

We included 147 studies in our final analysis. Studies supporting FDA drug approval have become increasingly multinational over time (β = 0.5; P=.04). The median proportion of countries from high-income groups was 81.2% (range, 44%-100%), with no participation from low-income countries in our cohort. Regional subgroup analysis was presented for 78 studies (53%). Regional heterogeneity was found in 17.8% (8/45) and 18% (8/44) of studies presenting an overall survival (OS) and progression-free survival endpoint, respectively. After grouping regions by income level, we found no difference in OS outcomes in high-income regions compared with mixed-income regions (n=20; HR, 0.95; 95% CI, 0.84-1.07). To determine whether regional variation is genuine, clinicians should evaluate the data according to the following 5 questions: (1) Are the regional groupings logical? (2) Is the regional difference on an absolute or relative scale? (3) Is the regional difference consistent and plausible? (4) Is the regional difference statistically significant? (5) Is there a clinical explanation?

CONCLUSIONS

As registration studies in oncology become increasingly international, regional variations in trial outcomes may be detected. The question guide herein will help clinicians determine whether regional variations are likely to be clinically meaningful or statistical anomalies.

Impact of UGT1A1 Polymorphisms on Febrile Neutropenia in Pancreatic Cancer Patients Receiving FOLFIRINOX: A Single-Center Cohort Study

FOLFIRINOX (oxaliplatin, leucovorin, irinotecan, and 5-fluorouracil) is a first-line chemotherapy for metastatic pancreatic cancer (PC). Chemotherapy-induced neutropenia is one of the most serious adverse events associated with advanced PC. Although UGT1A1 polymorphisms are associated with the metabolism of irinotecan, their role as surrogate markers for FOLFIRINOX-induced neutropenia has not been confirmed. We investigated risk factors for FN-in particular, UGT1A1 polymorphisms-in PC patients receiving FOLFIRINOX, using a single-center cohort registry. To investigate the association between UGT1A1 polymorphisms and FN, we divided patients into three groups based on the predicted UGT1A1 phenotype: extensive metabolizer (EM) vs. intermediate metabolizer (IM) vs. poor metabolizer (PM). A total of 154 patients (FN group (n = 31) vs. non-FN group (n = 123)) receiving first-line FOLFIRINOX were identified between December 2017 and July 2020. The Cox regression analysis showed that female sex (HR: 2.20; p = 0.031), Eastern Cooperative Oncology Group performance status = 1 (HR: 2.83; p = 0.008), UGT1A1 IM (HR: 4.30; p = 0.004), and UGT1A1 PM (HR: 4.03; p = 0.028) were statistically significant risk factors for FN. We propose that UGT1A1 is the strongest predictive factor for FN and that this gene should be screened prior to the administration of chemotherapy.

Endogenous metabolic markers for predicting the activity of dihydropyrimidine dehydrogenase

Five‐fluorouracil (5‐FU) is a chemotherapeutic agent that is mainly metabolized by the rate‐limiting enzyme dihydropyrimidine dehydrogenase (DPD). The DPD enzyme activity deficiency involves a wide range of severities. Previous studies have demonstrated the effect of a DPYD single nucleotide polymorphism on 5‐FU efficacy and highlighted the importance of studying such genes for cancer treatment. Common polymorphisms of DPYD in European ancestry populations are less frequently present in Koreans. DPD is also responsible for the conversion of endogenous uracil (U) into dihydrouracil (DHU). We quantified U and DHU in plasma samples of healthy male Korean subjects, and samples were classified into two groups based on DHU/U ratio. The calculated DHU/U ratios ranged from 0.52 to 7.12, and the two groups were classified into the 10th percentile and 90th percentile for untargeted metabolomics analysis using liquid chromatography‐quantitative time‐of‐flight‐mass spectrometry. A total of 4440 compounds were detected and filtered out based on a coefficient of variation below 30%. Our results revealed that six metabolites differed significantly between the high activity group and low activity group (false discovery rate q‐value < 0.05). Uridine was significantly higher in the low DPD activity group and is a precursor of U involved in pyrimidine metabolism; therefore, we speculated that DPD deficiency can influence uridine levels in plasma. Furthermore, the cutoff values for detecting DPD deficient patients from previous studies were unsuitable for Koreans. Our metabolomics approach is the first study that reported the DHU/U ratio distribution in healthy Korean subjects and identified a new biomarker of DPD deficiency.

Inferred Ancestral Origin of Cancer Cell Lines Associates with Differential Drug Response

Disparities between risk, treatment outcomes and survival rates in cancer patients across the world may be attributed to socioeconomic factors. In addition, the role of ancestry is frequently discussed. In preclinical studies, high-throughput drug screens in cancer cell lines have empowered the identification of clinically relevant molecular biomarkers of drug sensitivity; however, the genetic ancestry from tissue donors has been largely neglected in this setting. In order to address this, here, we show that the inferred ancestry of cancer cell lines is conserved and may impact drug response in patients as a predictive covariate in high-throughput drug screens. We found that there are differential drug responses between European and East Asian ancestries, especially when treated with PI3K/mTOR inhibitors. Our finding emphasizes a new angle in precision medicine, as cancer intervention strategies should consider the germline landscape, thereby reducing the failure rate of clinical trials.

Neoadjuvant approach as a platform for treatment personalization: focus on HER2-positive and triple-negative breast cancer

The neoadjuvant setting provides unquestionable clinical benefits for high-risk breast cancer (BC) patients, mainly in terms of expansion of locoregional treatment options and prognostic stratification. Additionally, it is also emerging as a strategical tool in the research field. In the present review, by focusing on HER2-positive and triple-negative subtypes, we examined the role of the neoadjuvant setting as a research platform to facilitate and rationalize the placement of escalation strategies, promote the adoption of biomarker-driven approaches for the investigation of de-escalated treatments, and foster the conduction of comprehensive translational analyses, thus ultimately aiming at pursuing treatment personalization. The solid prognostic role of pathologic complete response after neoadjuvant therapy, and its use as a surrogate endpoint to accelerate the drug approval process were discussed. In this context, available data on escalated treatment strategies capable of enhancing pathologic complete response (pCR) rate or improving prognosis of patients with residual disease (RD) after neoadjuvant treatment, were comprehensively reviewed. We also summarized evidence regarding the possibility of obtaining pCR with de-escalated strategies, with particular emphasis on the role of biomarker-driven approaches for patient selection. Pitfalls of the dichotomy of pCR/RD were also deepened, and data on alternative/complementary biomarkers with a possible clinical relevance in this regard were reviewed.

Comprehensive biomarker analyses identifies HER2, EGFR, MET RNA expression and thymidylate synthase 5'UTR SNP as predictors of benefit from S-1 adjuvant chemotherapy in Japanese patients with stage II/III gastric cancer

Purpose: A comprehensive molecular analysis was conducted to identify prognostic and predictive markers for adjuvant S-1 chemotherapy in stage II/III Japanese gastric cancer (GC) patients and to evaluate their potential suitability for alternative cytotoxic or targeted drugs.

Experimental Design: We investigated genetic polymorphisms of enzymes potentially involved in 5-fluoruracil (5-FU) metabolism as well as platinum resistance, previously identified genomic subtypes potentially predicting 5-FU benefit, and mRNA expression levels of receptor tyrosine kinases and KRAS as potential treatment targets in a single institution cohort of 252 stage II/III GC patients treated with or without S-1 after D2 gastrectomy.

Results: 88% and 62% GC had a potentially 5-FU sensitive phenotype by SNP analyses of TS 3'UTR, and TS 5'UTR, respectively. 24%, 46%, 40%, 5%, and 44% GC had a potentially platinum sensitive phenotype by SNP analyses of GSTP1, ERCC1 rs11615, ERCC1 rs3212986, ERCC2, and XRCC1, respectively. High HER2, EGFR, FGFR2, or MET mRNA expression was observed in 49%, 66%, 72%, and 54% GC, respectively. High HER2 expression was the only significant prognosticator (HR=3.912, 95%CI: 1.706-8.973, p=0.0005). High HER2 (p=0.031), low EGFR (p=0.124), high MET (p=0.165) RNA expression, and TS 5'UTR subtype 2R/2R, 2R/3C, or 3C (p=0.058) were significant independent predictors for S-1 resistance.

Conclusions: The present study suggests that platinum-based or RTK targeted agents could be alternative treatment options for a substantial subgroup of Japanese GC patients currently treated with S-1. HER2, EGFR, MET, and TS 5'UTR SNP appear to be promising predictive markers for S-1 resistance warranting validation in an independent GC series.

Insights Into Breast Cancer in the East vs the West: A Review

Importance

During the past few decades, the incidence of breast cancer (BC) has been increasing rapidly in East Asia, and BC is currently the most common cancer in several countries. The rising incidence is likely related to changing lifestyle and environmental factors in addition to the increase in early diagnosis with BC awareness and screening. The understanding and management of BC are generally based on research and data from the West. However, emerging differences in BC epidemiology and tumor and host biology in Asian populations may be clinically relevant.

Observations

A higher proportion of premenopausal BCs occur in Asia, although this factor is possibly an age-cohort effect. Although the relative frequencies of different immunohistochemical subtypes of BC may be similar between the East and West, the higher prevalence of luminal B subtypes with more frequent mutations in TP53 may be confounded by disparities in early detection. In addition, Asian BCs appear to harbor a more immune-active microenvironment than BCs in the West. The spectra of germline mutations in BC predisposition genes and single-nucleotide polymorphisms contributing to BC risk vary with ethnicity as well. Differences in tolerability of certain cytotoxic and targeted agents used in BC treatment may be associated with pharmacogenomic factors, whereas the lower body mass of the average woman in East Asia may contribute to higher toxicities from drugs administered at fixed doses. Phenotypic characteristics, such as lower breast volume, may influence the type of surgery performed in East Asian women. On the other hand, increased breast density may affect the sensitivity of mammography in detecting BCs, limiting the benefits of screening mammography.

Conclusions and Relevance

Breast cancer has become a major health problem in Asia. The inclusion of more women from Asia in clinical trials and epidemiologic and translational studies may help unravel the interethnic heterogeneity of BCs and elucidate the complex interplay between environmental and intrinsic factors in its pathogenesis. These insights may help to refine prevention, diagnosis, and management strategies for BC in the setting of ethnic diversity.

Predictors of Hand-Foot Syndrome and Pyridoxine for Prevention of Capecitabine-Induced Hand-Foot Syndrome: A Randomized Clinical Trial

Importance

Hand-foot syndrome (HFS) is a common adverse effect of capecitabine treatment.

Objective

To compare the incidence and time to onset of grade 2 or greater HFS in patients receiving pyridoxine vs placebo and to identify biomarkers predictive of HFS.

Design, Setting, and Participants

This single-center, randomized double-blind, placebo-controlled phase 3 trial conducted at National Cancer Centre Singapore assessed whether oral pyridoxine could prevent the onset of grade 2 or higher HFS in 210 patients scheduled to receive single-agent capecitabine chemotherapy for breast, colorectal, and other cancers.

Interventions

Patients were randomized to receive concurrent pyridoxine (200 mg) or placebo daily for a maximum of 8 cycles of capecitabine, with stratification by sex and use in adjuvant or neoadjuvant vs palliative setting. Patients were withdrawn from the study on development of grade 2 or higher HFS or cessation of capecitabine.

Main Outcomes and Measures

Primary end point was the incidence of grade 2 or higher HFS in patients receiving pyridoxine. Secondary end points included the time to onset (days) of grade 2 or higher HFS and identification of biomarkers predictive of HFS, including baseline folate and vitamin B12 levels, as well as genetic polymorphisms with genome-wide arrays.

Results

In this cohort of 210 patients (median [range] age, 58 [26-82] years; 162 women) grade 2 or higher HFS occurred in 33 patients (31.4%) in the pyridoxine arm vs 39 patients (37.1%) in the placebo arm (P = .38). The median time to onset of grade 2 or higher HFS was not reached in both arms. In univariate analysis, the starting dose of capecitabine (odds ratio [OR], 1.99; 95% CI, 1.32-3.00; P = .001), serum folate levels (OR, 1.27; 95% CI, 1.10-1.47; P = .001), and red blood cell folate levels (OR, 1.25; 95% CI, 1.08-1.44; P = .003) were associated with increased risk of grade 2 or higher HFS. In multivariate analyses, serum folate (OR, 1.30; 95% CI, 1.12-1.52; P < .001) and red blood cell folate (OR, 1.28; 95% CI, 1.10-1.49; P = .001) were the only significant predictors of grade 2 or higher HFS. Grade 2 or higher HFS was associated with 300 DNA variants at genome-wide significance (P < 5 × 10-8), including a novel DPYD variant (rs75267292; P = 1.57 × 10-10), and variants in the MACF1 (rs183324967, P = 4.80 × 10-11; rs148221738, P = 5.73 × 10-10) and SPRY2 (rs117876855, P < 1.01 × 10-8; rs139544515, P = 1.30 × 10-8) genes involved in wound healing.

Conclusions and Relevance

Pyridoxine did not significantly prevent or delay the onset of grade 2 or higher HFS. Serum and red blood cell folate levels are independent predictors of HFS.

Trial Registration

clinicaltrials.gov Identifier: NCT00486213.

Pharmacogenetics-Guided Phase I Study of Capecitabine on an Intermittent Schedule in Patients with Advanced or Metastatic Solid Tumours

The FDA-approved starting dosage of capecitabine is 1,250 mg/m², and market research indicates that U.S. physicians routinely prescribe 1,000 mg/m². Retrospective analyses however report reduced toxicity and efficacy in a subset of patients with the 3R/3R genotype of the thymidylate synthase gene enhancer region (TSER). This study sought to develop TSER genotype-specific guidelines for capecitabine dosing. Capecitabine was dose-escalated in advanced and/or metastatic cancer patients with TSER 3R/3R (Group A; N = 18) or 2R/2R + 2R/3R (Group B; N = 5) from 1,250 to 1,625 mg/m² b.i.d., every 2 weeks on/1 week off for up to 8 cycles. Parent and metabolites pharmacokinetics, adverse events, and tumour response were assessed. The maximum tolerated and recommended doses in 3R/3R patients are 1,625 mg/m² and 1,500 mg/m². At 1,500 mg/m², one in nine 3R/3R patients experienced a dose-limiting toxicity. Dosing guidelines for 2R/2R + 2R/3R remain undetermined due to poor accrual. The results indicate that 3R/3R patients may be amenable to 1,500 mg/m² b.i.d. on an intermittent schedule, and is the first to prospectively validate the utility of TSER pharmacogenetic-testing before capecitabine treatment.