Search

Background A prognostic test was developed to guide adjuvant chemotherapy (ACT) decisions in early-stage non-small cell lung cancer (NSCLC) adenocarcinomas. The objective of this study was to compare the cost-utility of the prognostic test to the current standard of care (SoC) in patients with early-stage NSCLC. Materials and methods Lifetime costs (2014 U.S. dollars) and effectiveness (quality-adjusted life-years [QALYs]) of ACT treatment decisions were examined using a Markov microsimulation model from a U.S. third-party payer perspective. Cancer stage distribution and probability of receiving ACT with the SoC were based on data from an academic cancer center. The probability of receiving ACT with the prognostic test was estimated from a physician survey. Risk classification was based on the 5-year predicted NSCLC-related mortality. Treatment benefit with ACT was based on the prognostic score. Discounting at a 3% annual rate was applied to costs and QALYs. Deterministic one-way and probabilistic sensitivity analyses examined parameter uncertainty. Results Lifetime costs and effectiveness were $137,403 and 5.45 QALYs with the prognostic test and $127,359 and 5.17 QALYs with the SoC. The resulting incremental cost-effectiveness ratio for the prognostic test versus the SoC was $35,867/QALY gained. One-way sensitivity analyses indicated the model was most sensitive to the utility of patients without recurrence after ACT and the ACT treatment benefit. Probabilistic sensitivity analysis indicated the prognostic test was cost-effective in 65.5% of simulations at a willingness to pay of $50,000/QALY. Conclusion The study suggests using a prognostic test to guide ACT decisions in early-stage NSCLC is potentially cost-effective compared with using the SoC based on globally accepted willingness-to-pay thresholds. Implications for practice Providing prognostic information to decision makers may help some patients with high-risk early stage non-small cell lung cancer receive appropriate adjuvant chemotherapy while avoiding the associated toxicities and costs in patients with low-risk disease. This study used an economic model to assess the effectiveness and costs associated with using a prognostic test to guide adjuvant chemotherapy decisions compared with the current standard of care in patients with non-small cell lung cancer. When compared with current standard care, the prognostic test was potentially cost effective at commonly accepted thresholds in the U.S. This study can be used to help inform decision makers who are considering using prognostic tests.

BACKGROUND Next-generation sequencing (NGS) allows for simultaneous sequencing of multiple cancer susceptibility genes and, for an individual, may be more efficient and less expensive than sequential testing. The authors assessed the frequency of deleterious germline mutations among individuals with breast cancer who were referred for BRCA1 and BRCA2 (BRCA1/2) gene testing using a panel of 25 genes associated with inherited cancer predisposition. METHODS This was a cross-sectional study using NGS in 2158 individuals, including 1781 who were referred for commercial BRCA1/2 gene testing (cohort 1) and 377 who had detailed personal and family history and had previously tested negative for BRCA1/2 mutations (cohort 2). RESULTS Mutations were identified in 16 genes, most frequently in BRCA1, BRCA2, CHEK2, ATM, and PALB2. Among the participants in cohort 1, 9.3% carried a BRCA1/2 mutation, 3.9% carried a mutation in another breast/ovarian cancer susceptibility gene, and 0.3% carried an incidental mutation in another cancer susceptibility gene unrelated to breast or ovarian cancer. In cohort 2, the frequency of mutations in breast/ovarian-associated genes other than BRCA1/2 was 2.9%, and an additional 0.8% had an incidental mutation. In cohort 1, Lynch syndrome-related mutations were identified in 7 individuals. In contrast to BRCA1/2 mutations, neither age at breast cancer diagnosis nor family history of ovarian or young breast cancer predicted for other mutations. The frequency of mutations in genes other than BRCA1/2 was lower in Ashkenazi Jews compared with non-Ashkenazi individuals (P=.026). CONCLUSIONS Using an NGS 25-gene panel, the frequency of mutations in genes other than BRCA1/2 was 4.3%, and most mutations (3.9%) were identified in genes associated with breast/ovarian cancer. Cancer 2015;121:25–33. © 2014 American Cancer Society.

The cell cycle progression (CCP) test (Prolaris) is a novel prognostic assay that provides accurate risk of prostate cancer-specific disease progression and disease specific mortality when combined with standard clinicopathologic parameters. This prospective study evaluated the impact of the CCP report on physician treatment recommendations for prostate cancer.Physicians ordering the CCP test in clinical practice completed surveys regarding treatment recommendations before and after they received and discussed the test results with patients. Clinicians also rated the influence of the test result on treatment decisions. Treatment selections were confirmed via third-party audit of patient charts following final survey responses.Overall, 65% of cases showed a change between intended treatment pre- and post-CCP test reporting. Pre-CCP testing, 164 of 305 cases received a recommendation for interventional treatment. Post-CCP test, interventional therapy was recommended for 103 of these cases, a reduction of 37.2%. Conversely, 141 of 305 cases were recommended pre-CCP testing for non-interventional treatment; 108 of these remained with non-interventional treatment while 33 shifted to interventional options, a 23.4% increase. There was a 49.5% reduction in surgical interventions and a 29.6% reduction in radiation treatment. A third-party audit identified 80.2% concordance between the post-CCP testing treatment recommendation and actual treatment. Re-assignment to intervention or non-intervention generally correlated with the result of the CCP report. Study limitations included physician selection of patients for testing, no evaluation of patient input in therapeutic choice, and other potential treatment decision factors not queried by the survey.Based on responses of ordering physicians, the CCP report adds meaningful new information to risk assessment for localized prostate cancer patients. Test results led to changes in treatment with reductions and increases in interventional treatment that were directionally aligned with prostate cancer risk specified by the test.

BACKGROUND This study sought to determine the prevalence of PALB2 mutations in a cohort referred for diagnostic testing for hereditary breast cancer. METHODS Sanger sequencing was used to analyze the entire coding region and flanking introns of PALB2 in anonymized DNA samples from 1479 patients. Samples were stratified into a “high-risk” group, 955 samples from individuals predicted to have a high probability of carrying a mutation in BRCA1 or BRCA2 based on their personal and family history, and a “lower-risk” group consisting of 524 samples from patients with breast cancer, but fewer risk factors for being a BRCA1 or BRCA2 mutation carrier. All patients were known to be negative for deleterious sequence mutations and large rearrangements in BRCA1 and BRCA2. RESULTS We identified 12 disease-associated PALB2 mutations among the 1479 patients (0.8%). The PALB2 mutations included 8 nonsense, 3 frameshift mutations and a splice-site mutation. The mutation prevalence for the high-risk population was 1.05% (95% CI = 0.5-1.92), whereas that for the lower-risk population was 0.38% (95% CI = 0.05-1.37). We identified 59 PALB2 variants of uncertain significance (VUS) among 57 of the 1479 patients (3.9%). CONCLUSIONS These results suggest that PALB2 mutations occur at a frequency of ∼1% in patients with hereditary breast cancer. Cancer 2014;120:963–967. © 2013 American Cancer Society.

BACKGROUND: This study assessed BRCA1 and BRCA2 mutation prevalence in an unselected cohort of patients with triple-negative breast cancer (BC). METHODS: One hundred ninety-nine patients were enrolled. Triple negativity was defined as

The cell cycle progression test is a validated molecular assay that assesses prostate cancer specific disease progression and mortality risk when combined with clinicopathological parameters. We present the results from PROCEDE-1000, a large, prospective registry designed to evaluate the impact of the cell cycle progression test on shared treatment decision making for patients newly diagnosed with prostate cancer.Untreated patients with newly diagnosed prostate adenocarcinoma were enrolled in the study and the cell cycle progression test was performed on the initial prostate biopsy tissue. A set of 4 sequential surveys tracked changes relative to initial therapy recommendations (before cell cycle progression) based on clinicopathological parameters following physician review of the cell cycle progression test result, physician/patient review of the cell cycle progression test results and a minimum of 3 months of clinical followup (actual treatment).Of the 1,596 patients enrolled in this registry 1,206 were eligible for analysis. There was a significant reduction in the treatment burden recorded at each successive evaluation (p0.0001), with the mean number of treatments per patient decreasing from 1.72 before the cell cycle progression test to 1.16 in actual followup. The cell cycle progression test caused a change in actual treatment in 47.8% of patients. Of these changes 72.1% were reductions and 26.9% were increases in treatment. For each clinical risk category there was a significant change in treatment modality (intervention vs nonintervention) before vs after cell cycle progression testing (p=0.0002).The cell cycle progression test has a significant impact in assisting physicians and patients reach personalized treatment decisions.

Objectives: Patients with hereditary cancer syndromes are at high risk for a second primary cancer. Early identification of these patients after an initial cancer diagnosis is the key to implementing cancer risk-reducing strategies. Methods: A commercial laboratory database was searched for women with a history of both breast and ovarian or colorectal and endometrial cancer who underwent genetic testing for hereditary breast and ovarian cancer (HBOC) or Lynch syndrome (LS). Results: Among women with both breast and ovarian cancer, 22.4% (2,237/9,982) had a BRCA1 or BRCA2 mutation. Among women with both colorectal and ovarian cancer, 28.1% (264/941) had a mutation associated with LS. In 66.6% of BRCA1 or BRCA2 mutation carriers and in 58.3% of LS mutation carriers, >5 years passed between the cancer diagnoses. Of patients with HBOC and LS, 56 and 65.2%, respectively, met the National Comprehensive Cancer Network guidelines for hereditary cancer testing after their initial diagnosis based on their personal cancer history alone. Conclusions: A substantial number of women tested for LS or HBOC after being diagnosed with two successive primary cancers were diagnosed with a hereditary cancer syndrome. In many cases, the time interval between the diagnoses was long enough to allow for the implementation of surveillance and/or prophylactic measures. © 2014 S. Karger AG, Basel

e16572Background: Risk of prostate cancer-specific disease progression and mortality may be assessed using the cell cycle progression (CCP) test. A large prospective registry (P1000, n=1206) recent...

Background. 5-Fluorouracil (5-FU) is administered based on standard body surface area (BSA) dosing. BSA administration results in highly variable exposure, measured as the area under the concentration-time curve (AUC). An immunoassay (OnDose®; Myriad Genetic Laboratories, Inc., Salt Lake City, UT) that measures plasma 5-FU concentration and reports an AUC in mg · h/L has been developed to optimize therapy using pharmacokinetic (PK) dosing. The results of an analysis to model the 5-FU AUC-dose relationship are presented. Methods. A set of 589 sequential patients from a clinical database receiving 5-FU, leucovorin, and oxaliplatin (the FOLFOX6 regimen) for colorectal cancer (CRC) treatment was analyzed. A subset including only patients who had at least two consecutive cycles tested, received 1,600–3,600 mg/m2 of continuous infusion 5-FU during the initial test cycle, and had a blood sample collected after ≥18 hours, was used to conduct regression modeling of the change in AUC versus change in dose. Results. A simple regression model with R2 = 0.51 developed over n = 307 cycle-pair observations characterizes the AUC-Dose relationship as: change in AUC = 0.02063 * dose change. The model suggests that dose changes in the range of 145–727 mg/m2 would be sufficient to adjust the AUC to a potential therapeutic threshold of >20 mg · h/L for most patients. Conclusions. 5-FU is an ideal candidate for PK dose optimization. Because individual factors other than dose change may also affect the change in AUC, longitudinal PK monitoring in all cycles and dose adjustment to ensure AUC in the desired range of 20–30 mg · h/L are recommended.

63 Background: The cell cycle progression (CCP) test is a validated molecular assay that assesses risk of prostate cancer−specific disease progression and mortality when combined with standard clinicopathologic parameters. PROCEDE−1000 is the largest prospective registry to evaluate CCP test impact on personalizing prostate cancer treatment. Results of an interim analysis are presented. Methods: Untreated patients with newly diagnosed (≤6 months), clinically localized prostate adenocarcinoma were enrolled (n=816). The physician’s initial therapy recommendation (pre−CCP) was recorded on the first questionnaire. The CCP test was then conducted on prostate biopsy tissue. Three post−CCP questionnaires recorded the physician’s revised treatment recommendation, physician/patient treatment decision, and actual treatment administered. Changes in treatments between the pre-CCP and post−CCP questionnaires demonstrated the impact of CCP testing on treatment decisions at each stage. Results: Visual analog scale measurements indicated a significant increase (p=0.0125) in the physician’s likelihood of recommending non−interventional treatment post−CCP test; there was an increase in active surveillance from the initial interventional therapy recommendation. From pre−CCP therapy recommendation, the CCP score caused a change in actual treatment administered in 44% of patients; 72% of changes were reductions in treatment. Reductions occurred in radical prostatectomy (27%), radiation therapy (44% primary; 56% adjuvant), brachytherapy (46% interstitial; 66% HDR) and hormonal therapy (33% neoadjuvant; 68% concurrent) treatments. While 35.9% of patients were recommended for conservative management pre−CCP testing, there was a 6.5% increase in non−interventional treatments during actual follow−up. Overall, there was a significant reduction in the number of treatment options at each successive evaluation (p

1542 Background: Patients with Hereditary Breast and Ovarian cancer (HBOC) or Lynch syndrome (LS) hereditary cancer syndromes are at a greater risk for developing second cancers after an initial ca...

e18509 Background: Uncertainty exists in identifying patients with early stage NSCLC that will benefit from ACT. High-risk patients may go untreated and low-risk patients may be unnecessarily burde...

e16055 Background: Improved prognostic markers that provide individual patient risk stratification are a pressing need in prostate cancer. The cell cycle progression (CCP) test (Prolaris, Myriad Ge...

1509 Background: Multigene panels are increasingly used for assessing hereditary cancer risk due to their ability to analyze numerous cancer susceptibility genes in parallel. Our aim was to study t...

277 Background: Improved prognostic markers that provide individual patient risk stratification are a pressing need in prostate cancer. The CCP signature test (Prolaris, Myriad Genetic Laboratories, Inc.) is a novel prognostic assay that has been validated in multiple cohorts and provides accurate risk of prostate cancer-specific disease progression and disease specific mortality risk when combined with standard clinicopathologic parameters. This study evaluated clinicians’ judgment regarding the clinical utility of the CCP test in a prospective registry. Methods: Clinicians ordering the CCP signature test commercially were asked to complete a survey regarding their treatment recommendations before and after they received the CCP test result. In addition, clinicians were asked how influential the CCP test result was in making therapeutic decisions on a 5 point scale (0=None, 5=Very High). Results: Currently, 368 patients have been enrolled and 47 clinicians have completed surveys on the influence of the CCP signature test in 58 cases. In five additional surveys, the therapeutic decision was undecided pre-test, post-test or both. In 77% of cases [95% CI: 65%-86%], there was a change recorded between the therapy initially planned and the therapy actually selected. The table shows the change in intended therapeutic burden from pre-CCP test to post-CCP test. In 30 of 58 cases [52%; 95% CI 39%-64%], clinicians indicated they would reduce the intended therapeutic burden post-CCP test. The CCP signature test influenced treatment selection to a ‘High’ or ‘Very High’ degree in 37 men (62%) and had “Low” or “No” influence in only 3% of cases. Conclusions: Based on the judgment of ordering physicians, the CCP score appears to add meaningful new information to risk assessment for localized prostate cancer patients. Test results led to major changes in treatment decisions with a significant increase in conservative management options, including active surveillance or watchful waiting. [Table: see text]

1544 Background: BRCA1/2 deleterious mutation identification among triple-negative breast cancer (TNBC) patients has gained importance due to cancer-risk management implications for patients and their relatives, and also has an emerging role in guiding treatment selection for therapies such as PARP inhibitors. The National Comprehensive Cancer Network (NCCN) currently recommends BRCA1/2 testing for TNBC patients diagnosed at age 5,000 Ashkenazi Jewish and > 65,000 non-Ashkenazi Jewish breast cancer patients undergoing commercial BRCA1/2 testing were analyzed. Age at diagnosis, ethnicity, and provider-reported TN status were obtained from test requisition forms completed by ordering providers, and correlated with test results. Neither the accuracy nor definitive criteria used for TN status reported was independently verified. Results: Incidence of TNBC was reported as 9.7% among non-Ashkenazi patients and 16.5% within the subset with African ancestry. Incidence of TNBC was reported as 4.5% among Ashkenazi patients, but this is likely affected by test ordering for this population. The Table displays the BRCA1/2mutation rates classified by ethnicity and age-group. Conclusions: This study provides the most robust estimate to date of BRCA1/2 mutation prevalence among TNBC patients of all ages. The mutation rates seen among TNBC patients diagnosed after age 60 also illustrate the importance of testing such patients who may not meet the current NCCN HBOC testing criteria. [Table: see text]

127 Background: In the US, most prostate cancers are treated with surgery or radiation, despite many having low malignant potential. If low cancer progression risk can be established, some men can be spared treatment. PSA, Gleason score and clinical stage work well for population risk assessment but lack precision for individuals. Molecular analysis can refine risk assessment as demonstrated by a cell cycle progression score (CCP) predictive of prostate cancer aggressiveness in 4 separate cohorts. In these studies, CCP typically ranged from −2 to +3 with each 1−unit increase corresponding to approximately a doubling of risk. We characterized the CCP distribution using recent samples from a typical US urology multi−centered clinical setting and determined the analytic success rate of the assay. Methods: Formalin fixed, prostate biopsy tissue from 300 patients diagnosed with adenocarcinoma within the last 12 months was analyzed. CCP is calculated by measuring the relative RNA expression of 31 cell cycle progression genes. Patients were recruited from 15 geographically diverse community urology practices. Results: CCP could be measured for 98% of samples (294/300). This study showed a normal distribution for the CCP ranging from −2 to 3.2 (median = −0.3, SD=0.92). There was little correlation of CCP with PSA, age, or body mass index. Correlation with Gleason score was similar to those in prior studies (r=0.494). A relative classification of cancer aggressiveness based on CCP of ~ 1200 patients from multiple cohorts has been developed. The 294 evaluable patients were cross−classified by AUA risk and cancer aggressiveness (see table). CCP further stratified patients within each AUA risk classification. Conclusions: CCP is a novel assay that can facilitate risk stratification for men with prostate adenocarcinoma. [Table: see text]

447 Background: Dihydropyrimidine dehydrogenase (DPYD) is the major enzyme that metabolizes 5-Fluoruracil (5-FU), a component of many chemotherapy regimens. Patients with a DPYD gene mutation have higher 5-FU plasma levels, leading to a 50-60% risk of a grade 3-4 toxicity. DPYD mutations have an estimated prevalence of 3-5% in the general population, but full sequencing is rarely performed in published studies. Analyses of the largest set of full DPYD gene sequencing test results from a commercial laboratory database are presented. Methods: A set of 3,083 patients was analyzed. Patient demographics (age, gender, ethnicity) and pre-test grade 3-4 toxicity status (none, 5-FU related, other) were obtained from the test request form. Descriptive analyses were performed to estimate mutation prevalence overall, and by toxicity and ancestry classifications, as well as to characterize mutations of interest. A subset of 24 patients tested for DPYD mutations in response to high 5-FU exposure levels was also analyzed. Results: The overall DPYD mutation prevalence was 7.3%. Mutations were present in 4.7% and 10.3% of patients experiencing none and at least one 5-FU related toxicity pre-test, respectively. Among patients with toxicities pre-test, the prevalence increased from 7.8% to 31.6% for those experiencing a single to all four toxicity types. Among 5-FU related toxicities, mutation prevalence was highest (18.5%) for hematopoietic events. The previously reported founder mutation IVS14+1G>A had a relative prevalence 42.7%, but 30.9% of these mutations were seen in patients not reporting a Western/Northern European ancestry. Among the subset of patients with high 5-FU exposure levels, 29% had a DPYD mutation showing a genetic causality. Conclusions: 5-FU in chemotherapy regimens remains widespread, yet DPYD gene testing utilization remains minimal. Most testing occurs post-treatment in response to a severe toxicity rather than pre-treatment, which would permit physicians to adapt treatment and reduce toxicity risk. Compared to previous studies, this study using full sequencing data from 3083 patients provides robust estimates of DPYD mutation prevalence and helps characterize DPYD mutations of particular interest.

343 Background: MYH-associated polyposis is an autosomal recessive syndrome caused by biallelic mutations in the base excision repair gene MYH. Initial reports indicated that a majority of European biallelic individuals carried two founder mutations, Y165C and G382D. A common MYH analysis strategy involves evaluation of the two founder mutations (FMs) with subsequent full sequencing only if one of the FMs is identified. This study aimed to determine the sensitivity of full MYH sequencing over the strategy described above in a cohort of individuals that has undergone genetic testing by a commercial laboratory. Methods: A retrospective analysis was performed on 1,522 individuals who had clinical MYH testing ordered either independently or in conjunction with APC gene analysis. All patients underwent MYH analysis for Y165C and G382D. Subsequent full gene sequencing was performed for all patients, except for those biallellic for the two FMs. Demographic, personal, and family cancer histories were collected on the test request form. Results: 86 biallelic individuals were identified, with 47 carrying two FMs, 18 carrying one FM and one mutation identified on sequencing, and 21 carrying biallelic mutations identified only on full sequencing. 21/86 (24.4%) biallelic MYH mutation carriers would have been missed by FM analysis only. The mutation spectrum is distributed among different ethnicities (Table). The majority of individuals met clinical criteria for a polyposis syndrome, with 21 individuals reporting more than 99 adenomas (24.4%) and 50 individuals reporting 20-99 adenomas (58.1%). Conclusions: Analysis of only the two MYH FMs would miss 24% of biallelic individuals in our cohort. Due to the ethnicity distribution of mutations, it is difficult to predict who would be missed by this strategy. Consideration of MYH full sequencing is warranted to achieve highest clinical sensitivity. [Table: see text]

30 Background: PALB2 has been identified as a breast cancer susceptibility gene conferring ~ 2-4 fold increased risk of breast cancer. A number of studies have estimated the PALB2 mutation prevalence to range from 0.5% - 2.9% in populations of breast cancer patients. We performed an analysis to determine the PALB2 mutation prevalence in a large U.S. referral testing population. Methods: DNA samples were anonymized from two subsets of patients: 955 early onset breast cancer patients with severe family history, and 524 patients with later onset of breast cancer and/or less severe family history. All patients were negative for deleterious sequence mutations or large rearrangements in BRCA1 and BRCA2. Results: We identified 10 disease associated PALB2 mutations in the high risk group of 955 patients and 2 deleterious PALB2 mutations in the lower risk group of 524 patients. Identified PALB2 mutations included 8 nonsense, 3 frameshift mutations and a splice site mutation. The mutation prevalence for the high risk population was 1.05% (95% C.I., 0.5 -1.92) whereas that for the lower risk population was 0.38% (95% C.I., 0.05-1.37). The observed rate of PALB2 variants of unknown significance (VUS) identified in this study was ~5% (78 VUS were in 75 of the 1479 patients that were tested). Our variant classification program which successfully decreased the VUS rate in BRCA1 and BRCA2 is similarly expected to enhance mutation classification on an on-going basis for PALB2 genetic testing. Conclusions: Genetic testing for PALB2 may be indicated as a reflex test for breast cancer patients who test negative for BRCA1 and BRCA2.

1550 Background: Among the anticipated social and cost-saving benefits to identifying a mutation in a CA predisposition gene in an individual is the subsequent opportunity to perform SST in close relatives to confirm risk status and to guide risk-reducing interventions. Despite ample research into uptake of primary genetic testing for Lynch syndrome (LS) and hereditary breast ovarian syndrome (HBOS) among moderate- and high-risk individuals, few studies have focused on the resultant cascade of SST that is predicted to follow in families. Methods: Administrative data on 2,631 consecutive single-site mutation tests performed over a 3-month interval (12/1/10-2/28/11) were obtained from a commercial genetic testing database maintained by Myriad Genetic Laboratories. 14 subjects (29 tests) were excluded due to multiple entries. Demographic, personal/family history (hx), and provider data are collected on a Test Requisition Form included in kits. All statistical tests are 2-sided (α=0.05). Results: Women had SST more often than men (HBOS 82.8%; LS 65.5%). Mean age at time of SST was 42.7 yrs, and was higher for HBOS than LS (p=0.01). Among subjects with hx of CA, mean age at CA diagnosis (dx) was similar (HBOS 48.6; LS 48.7 yrs). Subjects reported CA in >1 relatives (range 1-16) with a mean age at dx 40.1 yrs. Compared to HBOS, those tested for LS were more likely to report CA in a 1st degree relative (81.3 vs 74.4%, p=0.001) and a lower age of youngest CA dx in the family (p

3627 Background: 5-fluorouracil (5-FU) remains the cornerstone of colorectal cancer (CRC) therapy and its dosing is based on body surface area (BSA). Although convenient, BSA dosing disregards factors that impact 5-FU PK such as genotype, age, gender, etc. Thus, patients receiving the same BSA based dose show a wide range of 5-FU plasma levels (measured as AUC in mg · h/L), resulting in ineffective or toxic doses affecting therapy outcome. An optimal therapeutic AUC target range of 20-30 mg · h/L has been proposed. Methods: Plasma samples from the initial treatment cycle of 927 CRC patients who received 2,400 mg/m2 continuous infusion of 5-FU over 44-48 hours, with or without bevacizumab, were tested for 5-FU exposure using an immune-based assay (OnDose). AUC results were analyzed to evaluate gender and age effects. Results: There are 391 (42.2%) female and 536 (57.8%) male patients with age ranging from 17-93 years (mean/SD: 58.5/11.8). See table. These analyses indicate that in comparison to the proposed optimal AUC target range of 20-30 mg · h/L, females receive supra-optimal doses compared to males (p=0.0083). Age also affects the 5-FU AUC (p=0.0002), with younger patients more likely to receive suboptimal doses than older patients. Conclusions: BSA dosing is an unreliable indicator of exposure and may lead to under dosing in males and younger patients, and overdosing in females and older patients, potentially resulting in corresponding diminished efficacy or increased toxicity. Data suggest that therapy could be optimizedby 5-FU dose adjustment in subsequent cycles based on PK monitoring so that AUC values will converge towards the target range irrespective of gender or age. A large clinical trial is in progress to validate these findings. [Table: see text]

579 Background: 5-Fluorouracil (5-FU) remains the cornerstone of colorectal cancer (CRC) therapy and its dosing is based on body surface area (BSA). Although convenient, BSA dosing disregards factors that impact 5-FU PK such as genotype, age, gender, etc. Thus, patients receiving the same BSA based dose show a wide range of 5-FU plasma levels (measured as AUC in mg·h/L), resulting in ineffective or toxic doses affecting therapy outcome. An optimal therapeutic AUC target range of 20-30 mg·h/L has been proposed. Methods: Plasma samples from the initial treatment cycle of 927 CRC patients who received 2400 mg/m2 continuous infusion of 5-FU over 44-48 hours, with or without bevacizumab, were tested for 5-FU exposure using an immune-based assay (OnDose). AUC results were analyzed to evaluate gender and age effects. Results: There are 391 (42.2%) female and 536 (57.8%) male patients with age ranging from 17-93 years (mean/SD: 58.5/11.8). These analyses indicate that in comparison to the proposed optimal AUC target range of 20-30 mg·h/L, females receive supra-optimal doses compared to males (p=0.0083). Age also affects the 5-FU AUC (p=0.0002), with younger patients more likely to receive sub-optimal doses than older patients. Conclusions: BSA dosing is an unreliable indicator of exposure and may lead to under dosing in males and younger patients, and overdosing in females and older patients, potentially resulting in corresponding diminished efficacy or increased toxicity. Data suggest that therapy could be optimized by 5-FU dose adjustment in subsequent cycles based on PK monitoring so that AUC values will converge towards the target range irrespective of gender or age. A large clinical trial is in progress to validate these findings.

547 Background: 5-fluorouracil (5-FU) is an ideal candidate for pharmacokinetic (PK) dosing. 5-FU is administered based on standard BSA dosing. BSA administration results in highly variable PK and exposure, and potential underdosing in about 50% of patients. Patients with higher 5-FU AUC levels derive greater clinical benefit but with increased risk of toxicity. An immunoassay (OnDose) that measures 5-FU concentration in plasma and reports a computed AUC in mg·h/L has been developed to aid optimization of therapy using PK dosing. The results of an analysis to model the 5-FU AUC-dose change relationship from our clinical database are presented. Methods: A set of 585 sequential patients from our database receiving FOLFOX6 regimen with 5-FU continuous infusion (CI) over 41-48 hours, with or without bevacizumab, for the adjuvant and metastatic treatment of CRC was used for the preliminary analyses. A subset restricted to include only patients that had at least two consecutive cycles tested, received 1,600-3,600 mg/m2 at the initial test cycle, and had blood sample collection times ≥ 18 hours was used to conduct regression modeling of change in AUC versus change in dose. Outliers such as AUC values < 5 mg·h/L and > 50 mg·h/L were excluded from the analysis. Results: Our analysis corroborates previous findings that large variability in 5-FU PK measurements exists during the early part of the infusion cycle. The following simple regression model with an R2=0.51 developed over N=307 cycle-pair observations characterizes the AUC-dose relationship as: change in AUC (mg·h/L) = 0.02063 * dose change (mg/m2). Conclusions: The above model suggests that dose changes ranging from 145 to 720 mg/m2 would be sufficient to adjust the AUC to a potential therapeutic threshold of >20 mg·h/L for most patients. Assuming a 2,400 mg/m2 baseline dose, a maximum 720 mg/m2 dose increase would correspond to a 30% increase, but would likely be needed only by 10% of the patient population with low AUC readings. Our data from the US clinical setting indicate that it is possible to optimize 5-FU therapy by adjusting the dose based on AUC measurement. [Table: see text] [Table: see text]