Genetic factors affecting drug disposition in Asian cancer patients

Clinical outcomes of chemotherapy in cancer patients with different ethnicities

BACKGROUND

Choosing the most effective chemotherapeutic agent with safest side effect profile is a common challenge in cancer treatment. Although there are standardized chemotherapy protocols in place, protocol changes made after extensive clinical trials demonstrate significant improvement in the efficacy and tolerability of certain drugs. The pharmacokinetics, pharmacodynamics, and tolerance of anti-cancer medications are all highly individualized. A driving force behind these differences lies within a person's genetic makeup.

RECENT FINDINGS

Pharmacogenomics, the study of how an individual's genes impact the processing and action of a drug, can optimize drug responsiveness and reduce toxicities by creating a customized medication regimen. However, these differences are rarely considered in the initial determination of standardized chemotherapeutic protocols and treatment algorithms. Because pharmacoethnicity is influenced by both genetic and nongenetic variables, clinical data highlighting disparities in the frequency of polymorphisms between different ethnicities is steadily growing.  Recent data suggests that ethnic variations in the expression of allelic variants may result in different pharmacokinetic properties of the anti-cancer medication. In this article, the clinical outcomes of various chemotherapy classes in patients of different ethnicities were reviewed.

CONCLUSION

Genetic and nongenetic variables contribute to the interindividual variability in response to chemotherapeutic drugs. Considering pharmacoethnicity in the initial determination of standard chemotherapeutic protocols and treatment algorithms can lead to better clinical outcomes of patients of different ethnicities.

Asia-Inclusive Clinical Research and Development Enabled by Translational Science and Quantitative Clinical Pharmacology: Toward a Culture That Challenges the Status Quo

Access lag to innovative therapies in Asian populations continues to present a challenge to global health. Recent progressive changes in the global regulatory landscape, including newer guidelines, are enabling simultaneous global drug development and near-simultaneous global drug registration. The International Conference on Harmonization (ICH) E17 guideline outlines general principles for the design and analysis of multiregional clinical trials (MRCTs). We posit that translational research and quantitative clinical pharmacology tools are core enablers for Asia-inclusive global drug development aligned with ICH E17 principles. Assessment of ethnic sensitivity should be initiated early in the development lifecycle to inform the need for, and extent of, Asian phase I ethno-bridging data. Relevant ethno-bridging data may be generated as standalone Asian phase I trials, as part of Western First-In-Human trials, or under accelerated development settings as a lead-in phase in an MRCT. Quantitative understanding of human clearance mechanisms and pharmacogenetic factors is vital to forecasting ethnic sensitivity in drug exposure using physiologically-based pharmacokinetic models. Stratification factors to control heterogeneity in MRCTs can be identified by reverse translational research incorporating pharmacometric disease models and model-based meta-analyses. Because epidemiological variations can extend to the molecular level, quantitative systems pharmacology models may be useful in forecasting how molecular variation in therapeutic targets or pathway proteins across populations might impact treatment outcomes. Through prospective evaluation of conservation in drug- and disease-related intrinsic and extrinsic factors, a pooled East Asian region can be implemented in Asia-inclusive MRCTs to maximize efficiency in substantiating evidence of benefit-risk for the region at-large with a Totality of Evidence approach.

Optimizing the prescription doses and tolerability of systemic therapy in head and neck cancer patients

PURPOSE OF REVIEW

Squamous cell carcinoma of the head and neck accounts for 330 000 deaths and 650 000 cases worldwide annually. Systemic therapy is an essential pillar of multimodal therapy despite being accompanied with substantial toxicity. This article reviews the latest advances in systemic therapy for the treatment of locoregionally advanced and reccurent/metastatic head and neck cancer from a tolerability perspective.

RECENT FINDINGS

Multiple recent attempts have been made to optimize tolerability (and efficacy) of systemic therapy utilizing new regimens, modified prescription doses, drugs such as immunotherapies or genotyping to tailor the systemic therapy to the individual patient.

SUMMARY

Although treatment benefit has to be weighed against potential toxicity, it is reasonable to anticipate potential side effects of systemic therapies. In a vulnerable elderly or Asian patient population upfront dose modifications of cytotoxic chemotherapies might be reasonable. Special attention should be laid on the patient's nutritional status and early intervention recommended. Dihydropyrimidine dehydrogenase genotyping can predict 5-fluorouracil toxicity and identify patients for whom alternative regimens are more suitable. As for immune checkpoint inhibitor therapy, despite being well tolerated, the identification of biomarkers to predict reduced tolerability or severe toxicity would be highly desirable.

Chronic medical conditions and late effects after acute myeloid leukaemia in adolescents and young adults: a population-based study

BACKGROUND

Curative-intent treatment of acute myeloid leukaemia (AML) can lead to multiple chronic medical conditions ('late effects'). Little is known about the burden of late effects in adolescent and young adult (AYA, 15-39 years) survivors of AML. We aimed to estimate the cumulative incidence and investigate the main predictors of late effects among these patients.

METHODS

During 1996-2012, 1168 eligible AYAs with AML who survived ≥2 years after diagnosis were identified in the California Cancer Registry. Late effects were reported from State hospital discharge data, and patients were followed through 2014. Hazard ratios and 95% confidence intervals of late effects occurrence were estimated using Cox proportional hazard models, adjusted for sociodemographic and clinical factors.

RESULTS

The most common late effects at 10 years after diagnosis were: endocrine (26.1%), cardiovascular (18.6%) and respiratory (6.6%), followed by neurologic (4.9%), liver/pancreatic (4.3%), renal (3.1%), avascular necrosis (2.7%) and second primary malignancies (2.4%). Of 1168 survivors, 547 (46.8%) received a haematopoietic stem cell transplant (HSCT). After multivariable adjustments, AYAs who underwent HSCT or had a non-favourable risk AML experienced ∼2-fold or higher increased likelihood of all late effects. Additionally, AYAs of Hispanic, Black or Asian/Pacific Islander (vs non-Hispanic White) race/ethnicity and those who resided in lower socio-economic neighbourhoods were at higher risk of numerous late effects.

CONCLUSIONS

Our findings underscore the need for long-term surveillance for the prevention, early detection and treatment of late effects, and can inform the development of AYA-focused consensus-based guidelines that will ultimately improve the quality of life and survival of these young vulnerable patients.

Neurocognitive and Behavioral Outcomes of Chinese Survivors of Childhood Lymphoblastic Leukemia

Background

Increasing attention has been dedicated to investigate modifiable risk factors of late effects in survivors of childhood cancer. This study aims to evaluate neurocognitive and behavioral functioning in a relatively young cohort of survivors of childhood acute lymphoblastic leukemia (ALL) in Hong Kong, and to identify clinical and socio-environmental factors associated with these outcomes.

Methods

This analysis included 152 survivors of childhood ALL who were ≥5 years post-diagnosis (52% male, mean [SD] age 23.5[7.2] years at evaluation, 17.2[7.6] years post-diagnosis). Survivors completed performance-based neurocognitive tests, and reported their emotional and behavioral symptoms using the Child/Adult Behavior Checklist. Socio-environmental variables (living space, fatigue, physical activity, family functioning, and academic stress) were self-reported using validated questionnaires. Clinical variables and chronic health conditions were extracted from medical charts. Multivariable linear modeling was conducted to test identify factors associated with neurocognitive/behavioral outcomes, adjusting for current age, sex, age at diagnosis and cranial radiation. An exploratory mediation analysis was performed to examine the mediating effects of risk factors on neurocognitive and behavioral outcomes.

Results

As compared to population norms, a minority of survivors developed mild-moderate impairment in motor processing speed (36.2%), memory (9.2%) and attention measures (4.0%-10.5%). Survivors also reported attention problems (12.5%), sluggish cognitive tempo (23.7%) and internalizing (depressive, anxiety and somatic symptoms) problems (17.1%). A minority of survivors developed mild-moderate treatment-related chronic conditions (n=37, 24.3%). As compared to survivors without chronic conditions, survivors with chronic conditions had more executive dysfunction (B=5.09, standard error [SE]=2.05; P=0.014) and reported more attention problems (B=5.73, SE=1.43; P<0.0001). Fatigue and poor family functioning was associated with multiple measures of behavior problems (all P<0.001). A lower level of physical activity was correlated with more self-reported symptoms of inattention (B= -1.12, SE=0.38, P=0.004) and sluggish cognitive tempo (B=-1.22, SE=0.41, P=0.003). Exploratory analysis showed that chronic health conditions were associated with behavioral measures through fatigue as the mediator.

Conclusion

The majority of young Chinese survivors of ALL had normal cognitive and behavioral function. Regular monitoring of behavioral function should be performed on survivors who develop treatment-related chronic conditions. Health behavior and socio-environment factors may be potentially modifiable risk factors associated with health outcomes in survivors.

Cardiotoxicity After Anthracycline Chemotherapy for Childhood Cancer in a Multiethnic Asian Population

Background: Anthracyclines are widely used to treat childhood cancers; however, they cause cardiotoxicity. To address the paucity of clinical data from Asian populations, this study investigated the epidemiology of pediatric anthracycline-induced cardiotoxicity, during and after chemotherapy, in a multiethnic Asian population. Procedure: This was a single-center, retrospective analysis of 458 anthracycline-treated pediatric oncology patients at KK Women's and Children's Hospital, a tertiary children's hospital in Singapore from 2005 through 2015. We investigated cardiotoxicity (defined as left ventricular fractional shortening <28% on echocardiography) and its risk factors using univariate logistic regression as well as survival estimates through the Kaplan-Meier method to compare survival distribution between patients with and without cardiotoxicity. Results: Over a follow-up period of almost 4 years, we found that 7% (32/458) of the cohort developed cardiotoxicity, with 37.5% (12/32) of these manifesting as clinical heart failure, whilst the rest were asymptomatic. The cardiotoxic cohort demonstrated a significantly higher mortality rate compared to the non-cardiotoxic group at 46.9 vs. 19.2% (p < 0.001), of whom 3 (9.4%) died from end-stage heart failure. We found that traditional predictors such as female sex, age at diagnosis, and cumulative doxorubicin equivalent dose were not predictors of cardiotoxicity. Conclusion: Our study reaffirms that freedom from symptoms does not ensure normal heart function and suggests that children with abnormal ventricular systolic function have higher mortality risk compared to those with normal systolic function. The findings contribute to improved understanding of the Asian burden to aid development of measures to prevent or reduce the risk of cardiotoxicity.

Different response rates to chemotherapy between Japanese and German esophageal squamous cell carcinoma: patients may be influenced by ERCC1 or ABCB1

Aim: To find out differences in biomarkers between Japanese and German patients responsible for response after neoadjuvant radio/chemotherapy and survival for esophageal squamous cell carcinoma. Materials & methods: A total of 60 patients from Japan and 127 patients from Germany with esophageal squamous cell carcinoma were analyzed according to three SNPs by real-time PCR. Results: The distribution of the genotypes of ERCC1 rs16115 and ABCB1 C3435T rs1045642 was significantly different between both patients' groups. Japanese patients had significantly less good response to 5-fluorouracil/cisplatin chemotherapy. The influence of the three SNPs on response varied between patients from Japan and Germany. Conclusion: Different expressions of ERCC1 and ABCB1 SNPs of Japanese patients compared with the German patients partially explain the different response.

Spatial Variation in Lung Cancer Mortality and Related Men-Women Disparities in Iran from 2011 to 2014

Purpose

Lung cancer is considered as a common cause of cancer mortality. The disease represents the second and third causes of deaths from cancer among Iranian women and men, respectively. The present study aimed to evaluate the spatial variations in relative risk of lung cancer mortality in Iran and its relation to common risk factors between men and women and specific risk factors among women.

Methods

In this ecological study, the lung cancer mortality data were analyzed in Iran during 2011–2014. Besag, York, and Mollie’s (BYM) model and shared component model (SCM) were used to compare the spatial variations of the relative risk of lung cancer mortality by applying OpenBUGS version 3.2.3 and R version 3.6.1.

Results

The median age for death due to lung cancer in Iran is 74 years. During 2011–2014, the age-standardized lung cancer mortality rates among men and women were 12 and 5 per 100,000 individuals, respectively. In addition, almost similar spatial patterns were observed for both men and women. Further, risk factors, which are shared between men and women, were considered as the main cause of variation of lung cancer mortality relative risk in the regions under study for both men and women. The highest impact of the women-specific risk factors was estimated in northeastern and southwestern of the country while the lowest was related to Gilan province in northern part of Iran.

Conclusion

Based on the spatial pattern, lung cancer risk factors are at relatively high levels in most parts of Iran, especially in the northwest of the country. Regarding the women, the high-risk regions were considerably extended. Further, the highest concentration of the specific risk factors among women was observed in the eastern, central, and southwestern parts. The smoking effect, and the second-smoking effect and environmental pollutions could play more significant roles for men and women, respectively.

Model-Based Population Pharmacokinetic Analysis of Nivolumab in Chinese Patients With Previously Treated Advanced Solid Tumors, Including Non-Small Cell Lung Cancer

Nivolumab is the first anti–programmed death‐1 agent approved in China for treatment of locally advanced or metastatic non–small cell lung cancer (NSCLC). Here, we characterize the population pharmacokinetics (PPK) of nivolumab monotherapy in Chinese patients with previously treated advanced/recurrent solid tumors, including NSCLC and nasopharyngeal cancer (NPC), using data from 2 predominantly Chinese (CheckMate 077 and 078), and 5 global (MDX1106‐01, CA209‐003, and CheckMate 017, 057, and 063) studies. The PPK model was developed by reestimating parameters of a prior global population model with Chinese patient data. Model reestimates showed nivolumab pharmacokinetics (PK) to be linear and dose proportional. Race did not have a clinically meaningful effect on nivolumab clearance. Body weight, Asian race, sex, and performance status had significant effects on clearance. Baseline clearance was 9% lower in the Asian versus the global population but not considered clinically relevant. Change in time‐varying clearance and predicted nivolumab exposures with 3 mg/kg every 2 weeks (Q2W) were similar in Chinese, non‐Chinese Asian, and non‐Asian patients. In Chinese patients, the predicted nivolumab exposure with a 240‐mg Q2W regimen was ∼25% higher than with 3 mg/kg Q2W, but ∼62% lower than that of a previously evaluated, well‐tolerated regimen of 10 mg/kg Q2W (global population). Differences in nivolumab baseline clearance and exposures between patients with NPC and NSCLC were not clinically meaningful (<20%). Overall, PPK analysis demonstrated that nivolumab was not sensitive to race when evaluated in Chinese and non‐Asian patients and exhibited similar PK in NSCLC and NPC.

Clinical ascertainment of health outcomes in Asian survivors of childhood cancer: a systematic review

Purpose

Survivorship in children with cancer comes at a cost of developing chronic treatment-related complications. Yet, it is still an under-researched area in Asia, which shares the largest proportion of the global childhood cancer burden given its vast population. This systematic review summarizes existing literature on clinically ascertained health outcomes in Asian survivors of childhood cancer.

Methods

A search was conducted on Ovid Medline and EMBASE for studies that focused on survivors of childhood cancer from countries in East and Southeast Asia; adopted post-treatment clinical ascertainment of organ-specific toxicities or/and secondary malignancy. Studies were excluded if health outcomes were assessed during the acute treatment.

Results

Fifty-nine studies, enrolling a total of 13,442 subjects, were conducted on survivors of leukemia (34%), CNS tumor (14%), and cohorts of survivors with heterogeneous cancer diagnoses (52%). The studies used different medical evaluation methods to assess cardiovascular (15%), metabolic and infertility (32%), and neurological/neurocognitive (20%) outcomes in survivors. The collective findings suggest potential differences in the prevalence of certain late effects (e.g., secondary malignancy and obesity) among Asian and non-Asian populations, which may reflect differences in treatment regimens, practice, genetic variations, or/and socioeconomic disparity.

Conclusions

We recommend developing collaborative initiatives to build a regional repository of systematically assessed health outcomes and biospecimens to investigate treatment, social-environmental and genetic predictors, and interventions for late effects in this population.

Implications for Cancer Survivors

The existing types of chronic health problems identified in this review suggest the need for active screening, better access to survivorship care, and promotion of protective health behavior in Asia.

Electronic supplementary material

The online version of this article (10.1007/s11764-019-00759-9) contains supplementary material, which is available to authorized users.

Genotype-guided versus traditional clinical dosing of warfarin in patients of Asian ancestry: a randomized controlled trial

BACKGROUND

Genotype-guided warfarin dosing has been shown in some randomized trials to improve anticoagulation outcomes in individuals of European ancestry, yet its utility in Asian patients remains unresolved.

METHODS

An open-label, non-inferiority, 1:1 randomized trial was conducted at three academic hospitals in South East Asia, involving 322 ethnically diverse patients newly indicated for warfarin (NCT00700895). Clinical follow-up was 90 days. The primary efficacy measure was the number of dose titrations within the first 2 weeks of therapy, with a mean non-inferiority margin of 0.5 over the first 14 days of therapy.

RESULTS

Among 322 randomized patients, 269 were evaluable for the primary endpoint. Compared with traditional dosing, the genotype-guided group required fewer dose titrations during the first 2 weeks (1.77 vs. 2.93, difference -1.16, 90% CI -1.48 to -0.84, P < 0.001 for both non-inferiority and superiority). The percentage of time within the therapeutic range over 3 months and median time to stable international normalized ratio (INR) did not differ between the genotype-guided and traditional dosing groups. The frequency of dose titrations (incidence rate ratio 0.76, 95% CI 0.67 to 0.86, P = 0.001), but not frequency of INR measurements, was lower at 1, 2, and 3 months in the genotype-guided group. The proportions of patients who experienced minor or major bleeding, recurrent venous thromboembolism, or out-of-range INR did not differ between both arms. For predicting maintenance doses, the pharmacogenetic algorithm achieved an R² = 42.4% (P < 0.001) and mean percentage error of -7.4%.

CONCLUSIONS

Among Asian adults commencing warfarin therapy, a pharmacogenetic algorithm meets criteria for both non-inferiority and superiority in reducing dose titrations compared with a traditional dosing approach, and performs well in prediction of actual maintenance doses. These findings imply that clinicians may consider applying a pharmacogenetic algorithm to personalize initial warfarin dosages in Asian patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00700895 . Registered on June 19, 2008.

Exposure-response relationship of ramucirumab in East Asian patients from RAINBOW: a randomized clinical trial in second-line treatment of gastric cancer

BACKGROUND

Ramucirumab is a recombinant human IgG1 neutralizing monoclonal antibody specific for vascular endothelial growth factor receptor-2. Second-line ramucirumab, in conjunction with paclitaxel (ramucirumab 8 mg/kg or placebo in combination with 80 mg/m2 paclitaxel), has been shown to be effective and safe in patients with advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma in RAINBOW, a global phase III randomized clinical trial. We conducted an exploratory exposure-response analysis of efficacy and safety of ramucirumab in East Asian patients from the RAINBOW trial.

METHODS

Using sparse pharmacokinetic samples collected in the RAINBOW trial, a population pharmacokinetic analysis was conducted to predict ramucirumab minimum trough concentration at steady state (C min,ss) using a nonlinear mixed-effect modeling approach. Kaplan-Meier and Cox proportional hazards analyses were conducted to evaluate ramucirumab exposure (C min,ss) and efficacy relationship by overall survival and progression-free survival. Exposure-safety relationships were assessed descriptively.

RESULTS

Two hundred and twenty-two East Asian patients were included in this exposure-response analysis. Higher ramucirumab C min,ss was associated with longer overall survival (p = 0.0115) and progression-free survival (p = 0.0179) in this patient cohort. Patients with higher ramucirumab C min,ss (≥56.87 ng/ml median) had higher incidences of grade ≥3 leukopenia and neutropenia, but not febrile neutropenia or hypertension.

CONCLUSIONS

This exploratory analysis suggests a positive relationship between efficacy and ramucirumab exposure with manageable toxicities in East Asian patients from RAINBOW, consistent with the overall exposure-response analysis from this trial. A regimen with a higher dosage of ramucirumab warrants further consideration for East Asian patients with gastric/GEJ cancer.

EGFR kinase inhibitors and gastric acid suppressants in EGFR-mutant NSCLC: a retrospective database analysis of potential drug interaction

Background

Erlotinib and gefitinib are weak base drugs whose absorption and clinical efficacy may be impaired by concomitant gastric acid suppressive (AS) therapy, yet proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2As) are widely indicated in non-small cell lung cancer (NSCLC) patients for the prevention and treatment of erlotinib-induced gastrointestinal injury and corticosteroid-associated gastric irritation. We assessed the clinical relevance of this potential drug-drug interaction (DDI) in a retrospective cohort of EGFR-mutant NSCLC patients.

Results

The AS usage rate was 35%. In the overall cohort, AS users did not experience poorer OS (HR: 1.47, 95% CI: 0.92 – 2.35, P = 0.10; median, 11.4 versus 17.5 months) or PFS (HR = 1.37, 95% CI: 0.89 – 2.12, P = 0.16; median, 7.6 versus 8.7 months) compared with non-users in multivariate Cox regression analysis. However, subgroup analyses indicated that AS usage was associated with significantly poorer OS and PFS in patients who had fewer or milder comorbidities (Charlson comorbidity index ≤ 2), those with Karnofsky performance status < 90, and never-smokers.

Materials and Methods

A retrospective database analysis of 157 patients given erlotinib or gefitinib for EGFR-mutant advanced NSCLC from two institutions was conducted. Patients were classified as AS-users if the periods of AS and anti-EGFR therapy overlapped by ≥ 30%. Overall survival (OS) and progression-free survival (PFS) were assessed according to AS usage.

Conclusions

Concomitant AS therapy did not have an adverse impact on OS and/or PFS in the overall cohort. Our subgroup findings should be regarded exploratory and require replication in a large prospective cohort.

Value of a molecular screening program to support clinical trial enrollment in Asian cancer patients: The Integrated Molecular Analysis of Cancer (IMAC) Study

The value of precision oncology initiatives in Asian contexts remains unresolved. Here, we review the institutional implementation of prospective molecular screening to facilitate accrual of patients into biomarker-driven clinical trials, and to explore the mutational landscape of advanced tumors occurring in a prospective cohort of Asian patients (n = 396) with diverse cancer types. Next-generation sequencing (NGS) and routine clinicopathological assays, such as immunohistochemistry, copy number analysis and in situ hybridization tests, were performed on tumor samples. Actionable biomarker results were used to identify eligibility for early-phase, biomarker-driven clinical trials. Overall, NGS was successful in 365 of 396 patients (92%), achieving a mean depth of 1,943× and coverage uniformity of 96%. The median turnaround time from sample receipt to return of genomic results was 26.0 days (IQR, 19.0-39.0 days). Reportable mutations were found in 300 of 365 patients (82%). Ninety-one percent of patients at study enrollment indicated consent to receive incidental findings and willingness to undergo genetic counseling if required. The most commonly mutated oncogenes included KRAS (19%), PIK3CA (16%), EGFR (5%), BRAF (3%) and KIT (3%); while the most frequently mutated tumor suppressor genes included TP53 (40%), SMARCB1 (12%), APC (8%), PTEN (6%) and SMAD4 (5%). Among 23 patients enrolled in genotype-matched trials, median progression-free survival was 2.9 months (IQR, 1.5-4.0 months). Nine of 20 evaluable patients (45%; 95% CI, 23.1-68.5%) derived clinical benefit, including 3 partial responses and 6 with stable disease lasting ≥ 8 weeks.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer is the fifth most common cancer worldwide. In "Western" countries, most people are either diagnosed at an advanced stage, or develop a relapse after surgery with curative intent. In people with advanced disease, significant benefits from targeted therapies are currently limited to HER-2 positive disease treated with trastuzumab, in combination with chemotherapy, in first-line. In second-line, ramucirumab, alone or in combination with paclitaxel, demonstrated significant survival benefits. Thus, systemic chemotherapy remains the mainstay of treatment for advanced gastric cancer. Uncertainty remains regarding the choice of the regimen.

OBJECTIVES

To assess the efficacy of chemotherapy versus best supportive care (BSC), combination versus single-agent chemotherapy and different chemotherapy combinations in advanced gastric cancer.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE and Embase up to June 2016, reference lists of studies, and contacted pharmaceutical companies and experts to identify randomised controlled trials (RCTs).

SELECTION CRITERIA

We considered only RCTs on systemic, intravenous or oral chemotherapy versus BSC, combination versus single-agent chemotherapy and different chemotherapy regimens in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified studies and extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

We included 64 RCTs, of which 60 RCTs (11,698 participants) provided data for the meta-analysis of overall survival. We found chemotherapy extends overall survival (OS) by approximately 6.7 months more than BSC (hazard ratio (HR) 0.3, 95% confidence intervals (CI) 0.24 to 0.55, 184 participants, three studies, moderate-quality evidence). Combination chemotherapy extends OS slightly (by an additional month) versus single-agent chemotherapy (HR 0.84, 95% CI 0.79 to 0.89, 4447 participants, 23 studies, moderate-quality evidence), which is partly counterbalanced by increased toxicity. The benefit of epirubicin in three-drug combinations, in which cisplatin is replaced by oxaliplatin and 5-FU is replaced by capecitabine is unknown.Irinotecan extends OS slightly (by an additional 1.6 months) versus non-irinotecan-containing regimens (HR 0.87, 95% CI 0.80 to 0.95, 2135 participants, 10 studies, high-quality evidence).Docetaxel extends OS slightly (just over one month) compared to non-docetaxel-containing regimens (HR 0.86, 95% CI 0.78 to 0.95, 2001 participants, eight studies, high-quality evidence). However, due to subgroup analyses, we are uncertain whether docetaxel-containing combinations (docetaxel added to a single-agent or two-drug combination) extends OS due to moderate-quality evidence (HR 0.80, 95% CI 0.71 to 0.91, 1466 participants, four studies, moderate-quality evidence). When another chemotherapy was replaced by docetaxel, there is probably little or no difference in OS (HR 1.05; 0.87 to 1.27, 479 participants, three studies, moderate-quality evidence). We found there is probably little or no difference in OS when comparing capecitabine versus 5-FU-containing regimens (HR 0.94, 95% CI 0.79 to 1.11, 732 participants, five studies, moderate-quality evidence) .Oxaliplatin may extend (by less than one month) OS versus cisplatin-containing regimens (HR 0.81, 95% CI 0.67 to 0.98, 1105 participants, five studies, low-quality evidence). We are uncertain whether taxane-platinum combinations with (versus without) fluoropyrimidines extend OS due to very low-quality evidence (HR 0.86, 95% CI 0.71 to 1.06, 482 participants, three studies, very low-quality evidence). S-1 regimens improve OS slightly (by less than an additional month) versus 5-FU-containing regimens (HR 0.91, 95% CI 0.83 to 1.00, 1793 participants, four studies, high-quality evidence), however since S-1 is used in different doses and schedules between Asian and non-Asian population, the applicability of this finding to individual populations is uncertain.

AUTHORS' CONCLUSIONS

Chemotherapy improves survival (by an additional 6.7 months) in comparison to BSC, and combination chemotherapy improves survival (by an additional month) compared to single-agent 5-FU. Testing all patients for HER-2 status may help to identify patients with HER-2-positive tumours, for whom, in the absence of contraindications, trastuzumab in combination with capecitabine or 5-FU in combination with cisplatin has been shown to be beneficial. For HER-2 negative people, all different two-and three-drug combinations including irinotecan, docetaxel, oxaliplatin or oral 5-FU prodrugs are valid treatment options for advanced gastric cancer, and consideration of the side effects of each regimen is essential in the treatment decision. Irinotecan-containing combinations and docetaxel-containing combinations (in which docetaxel was added to a single-agent or two-drug (platinum/5-FUcombination) show significant survival benefits in the comparisons studied above. Furthermore, docetaxel-containing three-drug regimens have increased response rates, but the advantages of the docetaxel-containing three-drug combinations (DCF, FLO-T) are counterbalanced by increased toxicity. Additionally, oxaliplatin-containing regimens demonstrated a benefit in OS as compared to the same regimen containing cisplatin, and there is a modest survival improvement of S-1 compared to 5-FU-containing regimens.Whether the survival benefit for three-drug combinations including cisplatin, 5-FU, and epirubicin as compared to the same regimen without epirubicin is still valid when second-line therapy is routinely administered and when cisplatin is replaced by oxaliplatin and 5-FU by capecitabine is questionable. Furthermore, the magnitude of the observed survival benefits for the three-drug regimens is not large enough to be clinically meaningful as defined recently by the American Society for Clinical Oncology (Ellis 2014). In contrast to the comparisons in which a survival benefit was observed by adding a third drug to a two-drug regimen at the cost of increased toxicity, the comparison of regimens in which another chemotherapy was replaced by irinotecan was associated with a survival benefit (of borderline statistical significance), but without increased toxicity. For this reason irinotecan/5-FU-containing combinations are an attractive option for first-line treatment. Although they need to be interpreted with caution, subgroup analyses of one study suggest that elderly people have a greater benefit form oxaliplatin, as compared to cisplatin-based regimens, and that people with locally advanced disease or younger than 65 years might benefit more from a three-drug regimen including 5-FU, docetaxel, and oxaliplatin as compared to a two-drug combination of 5-FU and oxaliplatin, a hypothesis that needs further confirmation. For people with good performance status, the benefit of second-line chemotherapy has been established in several RCTs.

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.

Evolving landscape of tumor molecular profiling for personalized cancer therapy: a comprehensive review

INTRODUCTION

Tumour molecular profiling has been at the crossroads of large-scale integrative genomic studies and major clinical trials over the past 5 years and has provided roadmaps for better disease stratification and therapeutic management.

AREAS COVERED

We review the landscape of precision oncology trials in Asia, Europe and the United States, and emerging insights gained from recently reported studies such as the SHIVA and CUSTOM trials. Changes in the molecular portraits of human cancers and the immune contexture of the tumor microenvironment during treatment may predict the course of tumor progression, including the development of treatment resistance. 'Liquid biopsy' approaches that harness circulating tumor cells, cell-free DNA and exosomes may provide a non-invasive means of monitoring the parent tumor in real-time. Several molecular signatures are being evaluated as biomarkers for emerging immunologic approaches, such as the mismatch-repair deficiency status and nonsynonymous mutation burden in anti-PD-1 immune checkpoint blockade. Finally, we review the current actionability and future clinical impact of multigene panel and next-generation sequencing (NGS)-based profiling.

EXPERT OPINION

In the future, molecular profiling may help to fulfill unmet needs for predictive biomarkers in novel immunotherapeutic approaches, while ongoing precision trials are laying the foundations for clinical uptake of NGS testing.