Development and validation of a predictive model for estimating EGFR mutation probabilities in patients with non-squamous non-small cell lung cancer in New Zealand.

BACKGROUND: Targeted treatment with Epidermal Growth Factor Receptor (EGFR) tyrosine kinase inhibitors (TKIs) is superior to systemic chemotherapy in non-small cell lung cancer (NSCLC) patients with EGFR gene mutations. Detection of EGFR mutations is a challenge in many patients due to the lack of suitable tumour specimens for molecular testing or for other reasons. EGFR mutations are more common in female, Asian and never smoking NSCLC patients. METHODS: Patients were from a population-based retrospective cohort of 3556 patients diagnosed with non-squamous non-small cell lung cancer in northern New Zealand between 1 Feb 2010 and 31 July 2017. A total of 1694 patients were tested for EGFR mutations, of which information on 1665 patients was available for model development and validation. A multivariable logistic regression model was developed based on 1176 tested patients, and validated in 489 tested patients. Among 1862 patients not tested for EGFR mutations, 129 patients were treated with EGFR-TKIs. Their EGFR mutation probabilities were calculated using the model, and their duration of benefit and overall survival from the start of EGFR-TKI were compared among the three predicted probability groups: < 0.2, 0.2-0.6, and > 0.6. RESULTS: The model has three predictors: sex, ethnicity and smoking status, and is presented as a nomogram to calculate EGFR mutation probabilities. The model performed well in the validation group (AUC = 0.75). The probability cut-point of 0.2 corresponds 68% sensitivity and 78% specificity. The model predictions were related to outcome in a group of TKI-treated patients with no biopsy testing available (n = 129); in subgroups with predicted probabilities of < 0.2, 0.2-0.6, and > 0.6, median overall survival times from starting EGFR-TKI were 4.0, 5.5 and 18.3 months (p = 0.02); and median times remaining on EGFR-TKI treatment were 2.0, 4.2, and 14.0 months, respectively (p < 0.001). CONCLUSION: Our model may assist clinical decision making for patients in whom tissue-based mutation testing is difficult or as a supplement to mutation testing.

Screening for anaplastic lymphoma kinase (ALK) gene rearrangements in non-small-cell lung cancer in New Zealand.

BACKGROUND: Lung cancer is a major cause of death in New Zealand. In recent years, targeted therapies have improved outcomes. AIM: To determine the uptake of anaplastic lymphoma kinase (ALK) testing, and the prevalence, demographic profile and outcomes of ALK-positive non-small-cell lung cancer (NSCLC), in New Zealand, where no national ALK-testing guidelines or subsidised ALK tyrosine kinase inhibitor (TKI) therapies are available. METHODS: A population-based observational study reviewed databases to identify patients presenting with non-squamous NSCLC over 6.5 years in northern New Zealand. We report the proportion tested for ALK gene rearrangements and the results. NSCLC samples tested by fluorescence in situ hybridisation were retested by next generation sequencing and ALK immunohistochemistry. A survival analysis compared ALK-positive patients treated or not treated with ALK TKI therapy. RESULTS: From a total of 3130 patients diagnosed with non-squamous NSCLC, 407 (13%) were tested for ALK gene rearrangements, and patient selection was variable and inequitable. Among those tested, 34 (8.4%) had ALK-positive NSCLC. ALK-positive disease was more prevalent in younger versus older patients, non-smokers versus smokers and in Maori, Pacific or Asian ethnic groups than in New Zealand Europeans. Fluorescence in situ hybridisation, ALK immunohistochemistry and next generation sequencing showed broad concordance for detecting ALK-positive disease under local testing conditions. Among patients with ALK-positive metastatic NSCLC, those treated with ALK TKI survived markedly longer than those not treated with ALK TKI (median overall survival 5.12 vs 0.55 years). CONCLUSION: Lung cancer outcomes in New Zealand may be improved by providing national guidelines and funding policy for ALK testing and access to subsidised ALK TKI therapy.

Phase I drug-interaction study of effects of calcium and magnesium infusions on oxaliplatin pharmacokinetics and acute neurotoxicity in colorectal cancer patients.

BACKGROUND: Calcium and magnesium (Ca/Mg) infusions have been suggested as an effective intervention for preventing oxaliplatin-induced neurotoxicity, but the effects of Ca/Mg infusions on oxaliplatin pharmacokinetics, motor nerve hyperexcitability and acute neurotoxicity symptoms are unclear. METHODS: In this double blind crossover study, colorectal cancer patients undergoing oxaliplatin-based chemotherapy were randomised to receive Ca/Mg (1g Ca Gluconate plus 1g MgSO4) on cycle 1 and placebo (vehicle alone) on cycle 2, or to receive the same treatments in the opposite sequence. Study endpoints included plasma pharmacokinetics of intact oxaliplatin and free platinum; electromyography (EMG) detection of abnormal spontaneous high-frequency motor unit action potential discharges; and patient-reported acute neurotoxicity symptoms and their preferred study treatment for reducing these symptoms. RESULTS: Nineteen of 20 enrolled patients completed the study. Plasma pharmacokinetics of intact oxaliplatin and free platinum were similar when oxaliplatin was given with Ca/Mg or placebo (ratio of geometric means of AUC0-t with Ca/Mg or placebo: intact oxaliplatin, 0.95 (90% CI, 0.90 - 1.01); free platinum, 0.99 (90% CI, 0.94 - 1.05)). EMG motor nerve hyperexcitability scores were similar with Ca/Mg and placebo (mean difference in EMG score between Ca/Mg and placebo: -0.3 (95% CI, -2.2 - 1.6)). Patient-reported acute neurotoxicity symptoms were similar in frequency with Ca/Mg and placebo. For reducing neurotoxic symptoms, fewer patients preferred Ca/Mg than placebo or neither treatment (26% versus 74%; P<0.01). CONCLUSIONS: Ca/Mg infusions do not alter the clinical pharmacokinetics of oxaliplatin and do not seem to reduce its acute neurotoxicity. TRIAL REGISTRATION: Trial registration identifier ACTRN12611000738921.

Population-based incidence rates and increased risk of EGFR mutated non-small cell lung cancer in Maori and Pacifica in New Zealand.

BACKGROUND: Non-squamous non-small cell lung cancer (NSCLC) patients with Epidermal Growth Factor Receptor (EGFR) mutation benefit from targeted treatments. Previous studies reported EGFR mutation-positive proportions among tested non-squamous NSCLC patients. However, incidence rates and population risk of EGFR mutation-positive and EGFR mutation-negative non-squamous NSCLC have not been assessed. This study therefore aimed to estimate the population-based incidence rates of EGFR mutation-positive and EGFR mutation-negative non-squamous NSCLC in different population groups defined by sex, ethnic group and smoking status. METHODS: This study included data from all non-squamous NSCLC patients diagnosed in northern New Zealand between 1/02/2010 and 31/07/2017 (N = 3815), obtained from a population-based cancer registry. Age-specific incidence rates, WHO age-standardised rates (ASRs) and rates adjusted for incomplete testing were calculated for EGFR mutation-positive and EGFR mutation-negative diseases for the study cohort as a whole and subgroups of patients. RESULTS: Among 3815 patients, 45% were tested for EGFR mutations; 22.5% of those tested were EGFR mutation-positive. The ASR of EGFR mutation-positive NSCLC was 5.05 (95%CI 4.71-5.39) per 100,000 person-years. ASRs for EGFR mutation-positive NSCLC were higher for females than males: standardised incidence ratio (SIR) 1.50 (1.31-1.73); higher for Pacifica, Asians and Maori compared with New Zealand Europeans: SIRs 3.47 (2.48-4.85), 3.35 (2.62-4.28), and 2.02 (1.43-2.87), respectively; and, only slightly increased in ever-smokers compared with never-smokers: SIR 1.25 (1.02-1.53). In contrast, the ASR of EGFR mutation-negative NSCLC was 17.39 (16.75-18.02) per 100,000 person-years, showing a strong association with smoking; was higher for men; highest for Maori, followed by Pacifica and then New Zealand Europeans, and lowest for Asians. When corrected for incomplete testing, SIRs by sex, ethnicity and smoking, for both diseases, remained similar to those based on tested patients. CONCLUSION: The population risk of EGFR mutation-positive NSCLC was significantly higher for Maori and Pacifica compared with New Zealand Europeans.

Factors associated with overall survival in a population-based cohort of non- squamous NSCLC patients from northern New Zealand: A comparative analysis by EGFR mutation status.

BACKGROUND: Previous studies have reported inconsistent results regarding the effect of epidermal growth factor receptor (EGFR) mutations on overall survival in patients with non-squamous non-small-cell lung cancer (NSCLC). This study assesses the effect of EGFR mutation on overall survival, and how the effects of other survival predictors differ by EGFR mutation status. METHODS: The study used a population- based cohort of 1534 non-squamous NSCLC patients diagnosed in northern New Zealand between 1st February 2010 and 31st July 2017. Cox regression survival analyses were used to explore the associations between clinicopathological factors and overall survival by EGFR mutation status. The factors included were age at diagnosis, sex, ethnicity, smoking status, performance status, metastasis status and tumour site. RESULTS: In this cohort, 20% had anEGFR mutation. The median overall survival times were 0.8 years and 2.79 years in EGFR-mutation-negative and -positive groups, respectively (p < 0.0001). Metastasis at diagnosis showed large effects on overall survival in both EGFR-mutation- negative (hazard ratio (HR) = 3.6) and mutation-positive (HR = 3.3) groups. In subgroup analyses by mutation status and metastasis, females had lower survival only if they were mutation-positive; Maori had lower survival (than European New Zealanders) only if the disease was metastatic, and tumour site had significant effects only in patients without metastasis. Age, performance status and smoking status showed consistent effects in all subgroups. CONCLUSION: EGFR mutation status and metastasis are the main predictors for overall survival in non-squamous NSCLC patients. The effects of sex, ethnicity and tumour site vary depending on EGFR mutation and metastasis status.

Incomplete uptake of EGFR mutation testing and its impact on estimation of mutation prevalence in patients with non-squamous NSCLC: A population-based study in New Zealand.

BACKGROUND: Epidermal Growth Factor Receptor (EGFR) mutation testing is recommended for patients with non-squamous non-small cell lung cancer (NSCLC) but not all eligible patients get tested, which may bias the mutation prevalence estimated. This study aims to examine trends in the uptake of EGFR mutation testing in patients with non-squamous NSCLC in New Zealand; to develop a composite metric that quantifies the influences of demographic and clinico-pathological factors on the testing uptake; and to estimate the prevalence of EGFR mutation if all patients were tested. METHODS: This population-based study involved all patients who were diagnosed with non-squamous NSCLC in four health regions in New Zealand between January 2010 and December 2015. Eligible patients were identified from the New Zealand Cancer Registry and information on EGFR mutation testing was obtained through linkage to TestSafe, a clinical information sharing service, and laboratory records. RESULTS: Of 2701 eligible patients, 1059 (39.2%) were tested for EGFR mutation. The testing prevalence increased (3.7% in 2010 to 64.6% in 2014) and the influences of demographic and clinic-pathological factors decreased from 2010 to June 2014, and remained stable afterward. Of the tested patients, 229 (21.6%) were mutation positive with a decreasing trend observed from 2010 (43.8%) to June 2014 (16.8%). The best-fit log-linear model estimated the prevalence of EGFR mutation, if all patients were tested, as 15.5% (95% CI: 13.2%-18.0%). CONCLUSION: The methods described here allowed a more accurate estimation of the prevalence of EGFR mutation.

Predicting effects on oxaliplatin clearance: in vitro, kinetic and clinical studies of calcium- and magnesium-mediated oxaliplatin degradation.

This study evaluated the impact of calcium and magnesium on the in vitro degradation and in vivo clearance of oxaliplatin. Intact oxaliplatin and Pt(DACH)Cl2 were measured in incubation solutions by HPLC-UV. A clinical study determined changes in plasma concentrations of calcium and magnesium in cancer patients and their impact on oxaliplatin clearance. Kinetic analyses modelled oxaliplatin degradation reactions in vitro and contributions to oxaliplatin clearance in vivo. Calcium and magnesium accelerated oxaliplatin degradation to Pt(DACH)Cl2 in chloride-containing solutions in vitro. Kinetic models based on calcium and magnesium binding to a monochloro-monooxalato ring-opened anionic oxaliplatin intermediate fitted the in vitro degradation time-course data. In cancer patients, calcium and magnesium plasma concentrations varied and were increased by giving calcium gluconate and magnesium sulfate infusions, but did not alter or correlate with oxaliplatin clearance. The intrinsic in vitro clearance of oxaliplatin attributed to chloride-, calcium- and magnesium-mediated degradation predicted contributions of <2.5% to the total in vivo clearance of oxaliplatin. In conclusion, calcium and magnesium accelerate the in vitro degradation of oxaliplatin by binding to a monochloro-monooxalato ring-opened anionic intermediate. Kinetic analysis of in vitro oxaliplatin stability data can be used for in vitro prediction of potential effects on oxaliplatin clearance in vivo.

EGFR Mutation Testing of non-squamous NSCLC: Impact and Uptake during Implementation of Testing Guidelines in a Population-Based Registry Cohort from Northern New Zealand.

BACKGROUND: Since 2013, clinical practice guidelines recommend EGFR mutation testing of non-squamous NSCLC to select advanced-stage patients for first-line treatment using EGFR-TKIs. OBJECTIVE: We aimed to determine population-based trends in the real-world uptake and impact in routine practice of these recently updated testing guidelines. PATIENTS AND METHODS: A population-based observational study was conducted of notifications to the New Zealand Cancer Registry of patients eligible for EGFR testing diagnosed in northern New Zealand between January 2010 and April 2014. The main study variable was EGFR mutation testing. Main outcome measures (overall survival and dispensing of EGFR-TKIs) were extracted from prospectively archived electronic databases until October 2015. RESULTS: The population-based cohort of 1857 patients had an average age of 70 years. Most had adenocarcinoma and metastatic disease at diagnosis. EGFR testing was undertaken in 500 patients (27%) with mutations detected in 109 patients (22%). EGFR testing increased during the period of study from <5% to 67% of patients (P < 0.0001). Full uptake of testing by all eligible patients was limited by a lack of availability of specimens for testing and variable testing referral practices. The proportion of patients treated with EGFR-TKIs decreased during the same time period, both among untested patients (from 12.2% to 2.8% (P < 0.0001)) and in the population as a whole (from 13.7% to 10.6% (P < 0.05)). EGFR testing was associated with prolonged overall survival (Adjusted HR = 0.76 (95% CI, 0.65-0.89) Log-rank P < 0.0001) due at least in part to the much longer overall survival achieved by mutation-positive patients, of whom 79% received EGFR-TKIs. Compared to untested EGFR-TKI-treated patients, mutation-positive EGFR-TKI-treated patients received EGFR-TKIs for longer, and survived longer both from the start of EGFR-TKI treatment and date of their diagnosis. CONCLUSIONS: In this real world setting, high uptake of EGFR testing was achieved and associated with major changes in EGFR-TKI prescribing and improved health outcomes. Modifiable factors determined testing uptake. Study registration ACTRN12615000998549.

Lung cancer mutation testing: a clinical retesting study of agreement between a real-time PCR and a mass spectrometry test.

To investigate the clinical validity and utility of tests for detecting Epidermal Growth Factor Receptor (EGFR) gene mutations in non-squamous non-small cell lung cancer patients, tumour DNA extracts from 532 patients previously tested by the cobas EGFR Mutation Test (RT-PCR test) were retested by the Sequenom/Agena Biosciences MassArray OncoFocus mass spectrometry test (MS test). Valid results from both tests were available from 470 patients (88%) for agreement analysis. Survival data were obtained for 513 patients (96%) and 77 patients (14%) were treated with EGFR tyrosine kinase inhibitors (TKIs). Agreement analysis revealed moderately high positive (79.8%), negative (96.9%) and overall percentage agreement (93.2%) for the detection of EGFR mutations. However, EGFR mutations were detected by one test and not by the other test in 32 patients (7%). Retesting of discordant samples revealed false-positive and false-negative results generated by both tests. Despite this, treatment and survival outcomes correlated with the results of the RT-PCR and MS tests. In conclusion, this study provides evidence of the clinical validity and utility of the RT-PCR and MS tests for detection of EGFR mutations that predict prognosis and benefit from EGFR-TKI treatment. However, their false-positive and false-negative test results may have important clinical consequences.