Recombinant factor IX Fc prophylaxis reduces pain and increases levels of physical activity, with sustained, long-term improvements in patients with hemophilia B: post hoc analysis of phase III trials using patient-reported outcomes.

Background: Pain is a common symptom of hemophilia that may adversely affect patients' quality of life (QoL). Previous post hoc analyses of prophylaxis with recombinant factor IX Fc fusion protein (rFIXFc) have been published for adults and adolescents, demonstrating improvements in health-related QoL (HRQoL) when assessed by the haemophilia-specific QoL (HaemAQoL) questionnaire. Objective: To describe in depth the evolution of QoL, pain- and activity-related domains and questions for pediatric, adolescent, and adult patients with hemophilia B treated with rFIXFc prophylaxis. Design: A post hoc analysis of data from a series of clinical trials. Methods: This post hoc, long-term analysis assessed patient-reported outcomes (PROs) from the Kids B-LONG (NCT01440946: pediatric) and B-LONG (NCT01027364: adults and adolescents) parent studies and the B-YOND (NCT01425723: all age groups) extension study. Results: Ninety-two adult and adolescent patients that started in the B-LONG study were assessed, with a median (range) duration of follow-up of 58.9 (0.0-78.4) months. The Haem-A-QoL total score was significantly reduced from baseline by 4.45 (p ⩽ 0.01), as were the subdomains 'physical health' (9.10; p = 0.001), 'sports and leisure' (11.25; p ⩽ 0.01), 'treatment' (2.69; p = 0.05), and 'view of self' (5.81; p = 0.002). Thirty pediatric patients that started in the Kids B-LONG study were assessed, with a median (min-max) duration of follow-up of 36.7 (9.0-59.9) months. The high level of satisfaction demonstrated by the PROs at baseline was maintained. Conclusion: rFIXFc prophylaxis reduced perceived pain and increased levels of physical activity with sustained, long-term improvements in QoL in adult and adolescent patients with hemophilia B and maintained high QoL scores in pediatric patients.

Helping to reduce pain and increase physical activity in patients with hemophilia B People with hemophilia B do not produce factor IX (FIX) that works properly, so they need to be given additional FIX to help their blood clot. Recombinant factor IX Fc fusion protein (rFIXFc), is an extended half-life (meaning it remains active for longer than standard, unmodified FIX) treatment for hemophilia B. People with hemophilia B can experience episodes of bleeding, which can result in other symptoms, including pain, difficulty participating in sport, and poor mental health. This study shows that regularly taking rFIXFc over approximately 5 years to prevent or treat bleeds could also help to make these other symptoms better.

Improvement in pain-related quality of life in patients with hemophilia A treated with rFVIIIFc individualized prophylaxis: post hoc analysis from the A-LONG study.

BACKGROUND: Pain, a common symptom of hemophilia, begins early in life primarily due to joint bleeding. Recurrent bleeding adversely affects patients' pain-related physical functioning, which can negatively impact their quality of life (QoL). OBJECTIVE: Post hoc analysis of data from the A-LONG study (NCT01181128), to assess change over time in pain-related QoL in patients with severe hemophilia A treated prophylactically with recombinant factor VIII Fc fusion protein (rFVIIIFc). METHODS: Patients who completed Haem-A-QoL (17-65 years) and EQ-5D-3L (⩾12-65 years) questionnaires at baseline (BL) and end of study (EoS). Individual-level changes were assessed using three pain-related items of the Haem-A-QoL 'Physical Health' domain and the pain/discomfort item of EQ-5D-3L. Distributions of responses (EoS versus BL) were compared using McNemar's test. RESULTS: A significantly greater proportion of patients reported they did not experience painful swellings (n = 87; 66% versus 46%, p < 0.01) or pain in their joints (n = 89; 42% versus 27%; p < 0.05) at EoS versus BL. The proportion of patients who did not find it painful to move numerically increased at EoS versus BL (n = 86; 47% versus 38%; p = NS). A significantly greater proportion of patients reported no pain/discomfort at EoS versus BL (n = 116; 45% versus 34%; p < 0.05). CONCLUSION: This study reports the effect of FVIII prophylaxis on patient-reported measures of pain over time in patients with severe hemophilia A. The results of this post hoc analysis showed improvements in pain from BL to EoS in patients receiving rFVIIIFc individualized prophylaxis indicating effective pain management, a key component of patient care.

rFIXFc prophylaxis improves pain and levels of physical activity in haemophilia B: Post hoc analysis of B-LONG using haemophilia-specific quality of life questionnaires.

INTRODUCTION: Recurrent bleeding in severe haemophilia B causes painful hemarthroses and reduces capacity for physical activity. Recombinant factor IX Fc fusion protein (rFIXFc) prophylaxis results in low annualised bleeding rates, with the potential to improve patients' health-related quality of life (HRQoL). AIM: To present a post hoc analysis of data from B-LONG describing change over time in patient-reported outcomes associated with pain and physical activity. METHODS: Patients (≥12 years) who received weekly dose-adjusted or interval-adjusted rFIXFc prophylaxis and completed the Haemophilia-Specific QoL questionnaire for adolescents (Haemo-QoL) or adults (Haem-A-QoL) at baseline (BL) and end of study (EoS). Individual level changes in items of the 'Physical Health' and 'Sports and Leisure' domains, categorised as 'never/rarely/seldom' or 'sometimes/often/all the time', were analysed using McNemar's test to compare distribution of responses at EoS versus BL. RESULTS: At EoS versus BL, a significantly greater proportion of patients did not experience painful swellings (64% vs. 44%; P = .004), painful joints (44% vs. 28%; P = .003) or pain when moving (54% vs. 41%; P = .026). Additionally, at EoS versus BL, patients were less likely to avoid participating in sports like football (30% vs. 8%; P = .002), avoid sports due to their haemophilia (47% vs. 27%; P = .007), or experience difficulty walking as far as they wanted (63% vs. 43%; P = .001). The proportion of patients who played sports as much as the general population was numerically increased (52% vs. 37%; P = .033) at EoS versus BL. CONCLUSION: Results of the analysis suggest that over time, rFIXFc prophylaxis is associated with significant improvements in pain and physical functioning. This contributes to previous evidence of overall HRQoL improvements in patients with haemophilia B treated with rFIXFc.

Addressing the issue of bias in observational studies: Using instrumental variables and a quasi-randomization trial in an ESME research project.

PURPOSE: Observational studies using routinely collected data are faced with a number of potential shortcomings that can bias their results. Many methods rely on controlling for measured and unmeasured confounders. In this work, we investigate the use of instrumental variables (IV) and quasi-trial analysis to control for unmeasured confounders in the context of a study based on the retrospective Epidemiological Strategy and Medical Economics (ESME) database, which compared overall survival (OS) with paclitaxel plus bevacizumab or paclitaxel alone as first-line treatment in patients with HER2-negative metastatic breast cancer (MBC). PATIENTS AND METHODS: Causal interpretations and estimates can be made from observation data using IV and quasi-trial analysis. Quasi-trial analysis has the same conceptual basis as IV, however, instead of using IV in the analysis, a "superficial" or "pseudo" randomized trial is used in a Cox model. For instance, in a multicenter trial, instead of using the treatment variable, quasi-trial analysis can consider the treatment preference in each center, which can be informative, and then comparisons of results between centers or clinicians can be informative. RESULTS: In the original analysis, the OS adjusted for major factors was significantly longer with paclitaxel and bevacizumab than with paclitaxel alone. Using the center-treatment preference as an instrument yielded to concordant results. For the quasi-trial analysis, a Cox model was used, adjusted on all factors initially used. The results consolidate those obtained with a conventional multivariate Cox model. CONCLUSION: Unmeasured confounding is a major concern in observational studies, and IV or quasi-trial analysis can be helpful to complement analysis of studies of this nature.

Antigen Mass May Influence Trastuzumab Concentrations in Cerebrospinal Fluid After Intrathecal Administration.

Intravenous administration of monoclonal antibodies leads to low concentrations in the central nervous system, which is a serious concern in neuro-oncology, especially in leptomeningeal carcinomatosis of HER2-overexpressing breast cancer. Case reports of i.t. administrations of trastuzumab have shown promising results in these patients but dosing regimens are empirical in absence of pharmacokinetic (PK) study. With a population PK approach, we described the fate of trastuzumab after i.t. administration in 21 women included in a phase I-II clinical trial. Trastuzumab was administered by i.t. route every week for 8 weeks and both cerebrospinal fluid (CSF) and serum were sampled to measure trough concentrations. Some patients showed noticeable CSF concentration fluctuations predicted using a target-mediated drug disposition. This target was latent and produced with a delayed feedback. Apparent volumes of distribution were close to physiological volumes (V1  = 3.25 L, V2  = 0.644 L, for serum and CSF, respectively). Estimated (constant) transfer from serum to CSF was very slow (k12  = 0.264 mg/day) whereas estimated half-life of transfer from CSF to serum was rapid (2.2 days). From the individual parameters of patients, a single i.t. administration of 150 mg of trastuzumab corresponded to median mean residence times of 3.8 days and 15.6 days in CSF and serum, respectively. Survival without neurological relapse was not related to trastuzumab exposure. This study confirms that transfer of trastuzumab from serum to CSF is very limited and that this monoclonal antibody, when administered by i.t. route, is rapidly transferred to the serum.

Combination of Olaparib and Radiation Therapy for Triple Negative Breast Cancer: Preliminary Results of the RADIOPARP Phase 1 Trial.

PURPOSE: Preclinical studies have evidenced that triple-negative breast cancer (TNBC) cell lines are more sensitive to poly (ADP-ribose) polymerase inhibitors. This provides a strong rationale for developing a new therapeutic approach for TNBC management based on poly (ADP-ribose) polymerase inhibition. The primary goal of the RADIOPARP phase 1 trial was to evaluate the dose-limiting toxicities (DLT) and the maximum tolerated dose of olaparib combined with locoregional radiation therapy. METHODS AND MATERIALS: RADIOPARP was a single institutional phase 1 trial which evaluated olaparib-radiation therapy combination in patients with inflammatory, locoregionally advanced or metastatic TNBC who received neoadjuvant chemotherapy. Radiation therapy delivered 50 Gy to the breast or to the chest wall. Lymph nodes could be included in target volumes according to local guidelines. The dose-finding toxicity-based study was conducted in sequential and adaptive Bayesian scheme using the time-to-event continual reassessment method, with 4 olaparib dose levels (50 mg, 100 mg, 150 mg, and 200 mg twice per day). RESULTS: Twenty-four patients with Eastern Cooperative Oncology Group Performance Status of 0 or 1 were enrolled from September 2017 to November 2019. Twenty-one patients (87.5%) received the olaparib-radiation therapy combination after breast surgery owing to residual disease after neoadjuvant chemotherapy, and the 3 other patients (12.5%) had unresectable tumors which were refractory to neoadjuvant chemotherapy. All patients received full course combination treatment as follows: 4 patients (pts) at 50 mg twice a day, 8 pts at 100 mg twice a day, 7 pts at 150 mg twice a day, and 5 pts at 200 mg twice a day. No DLT was observed. CONCLUSIONS: Olaparib was escalated to the maximum target dose of 200 mg twice a day without DLT. Further follow-up is needed to evaluate the late toxicities. Pending the long-term results of the RADIOPARP trial, we suggest using 200 mg of olaparib twice per day for future trials.

Phase I study of vinblastine in combination with nilotinib in children, adolescents, and young adults with refractory or recurrent low-grade glioma.

BACKGROUND: New rescue regimens are needed for pediatric refractory/recurrent low-grade glioma. Nilotinib is a tyrosine kinase inhibitor that has potential synergistic effects with vinblastine on angiogenesis, tumor cell growth, and immunomodulation. METHODS: This phase I trial aimed to determine the recommended doses of this combination for phase II trials (RP2D) using the dual-agent Bayesian continual reassessment method. Nilotinib was given orally twice daily (BID) in combination with once-weekly vinblastine injections for a maximum of 12 cycles of 28 days (clinicaltrials.gov, NCT01884922). RESULTS: Thirty-five pediatric patients were enrolled across 4 dose levels. The median age was 7 years and 10 had neurofibromatosis type 1. Patients had received a median of 3 prior treatment lines and 25% had received more than 4 previous treatment lines. Dose-limiting toxicity (DLT) during cycle 1 was hematologic, dermatologic, and cardiovascular. The RP2D was identified at 3 mg/m2 weekly for vinblastine with 230 mg/m2 BID for nilotinib (estimated probability of DLT = 18%; 95% credibility interval, 7-29%). Fifteen patients completed the 12 cycles; 2 stopped therapy prematurely due to toxicity and 18 due to disease progression. Three patients achieved a partial response leading to an objective response rate of 8.8% (95% confidence interval [CI], 1.9-23.7), and the disease control rate was 85.3% (95% CI, 68.9-95.1). The 12-month progression-free survival was 37.1% (95% CI, 23.2-53.67). CONCLUSIONS: Vinblastine and nilotinib combination was mostly limited by myelosuppression and dermatologic toxicity. The efficacy of the combination at the RP2D is currently evaluated in a randomized phase II trial comparing this regimen to vinblastine alone.

How to design a dose-finding study on combined agents: Choice of design and development of R functions.

BACKGROUND: In oncology, the aim of dose-finding phase I studies is to find the maximum tolerated dose for further studies. The use of combinations of two or more agents is increasing. Several dose-finding designs have been proposed for this situation. Numerous publications have however pointed out the complexity of evaluating therapies in combination due to difficulties in choosing between different designs for an actual trial, as well as complications related to their implementation and application in practice. METHODS: In this work, we propose R functions for Wang and Ivanova's approach. These functions compute the dose for the next patients enrolled and provide a simulation study in order to calibrate the design before it is applied and to assess the performance of the design in different scenarios of dose-toxicity relationships. This choice of the method was supported by a simulation study which the aim was to compare two designs in the context of an actual phase I trial: i) in 2005, Wang and Ivanova developed an empirical three-parameter model-based method in Bayesian inference, ii) in 2008, Yuan and Yin proposed a simple, adaptive two-dimensional dose-finding design. In particular, they converted the two-dimensional dose-finding trial to a series of one-dimensional dose-finding sub-trials by setting the dose of one drug at a fixed level. The performance assessment of Wang's design was then compared with those of designs presented in the paper by Hirakawa et al. (2015) in their simulation context. RESULTS AND CONCLUSION: It is recommended to assess the performances of the designs in the context of the clinical trial before beginning the trial. The two-dimensional dose-finding design proposed by Wang and Ivanova is a comprehensive approach that yields good performances. The two R functions that we propose can facilitate the use of this design in practice.

The ongoing French metastatic breast cancer (MBC) cohort: the example-based methodology of the Epidemiological Strategy and Medical Economics (ESME).

PURPOSE: The currently ongoing Epidemiological Strategy and Medical Economics (ESME) research programme aims at centralising real-life data on oncology care for epidemiological research purposes. We draw on results from the metastatic breast cancer (MBC) cohort to illustrate the methodology used for data collection in the ESME research programme. PARTICIPANTS: All consecutive ≥18 years patients with MBC treatment initiated between 2008 and 2014 in one of the 18 French Comprehensive Cancer Centres were selected. Diagnostic, therapeutic and follow-up data (demographics, primary tumour, metastatic disease, treatment patterns and vital status) were collected through the course of the disease. Data collection is updated annually. FINDING TO DATE: With a recruitment target of 30 000 patients with MBC by 2019, we currently screened a total of 45 329 patients, and >16 700 patients with a metastatic disease treatment initiated after 2008 have been selected. 20.7% of patients had an hormone receptor (HR)-negative MBC, 73.7% had a HER2-negative MBC and 13.9% were classified as triple-negative BC (ie, HER2 and HR status both negative). Median follow-up duration from MBC diagnosis was 48.55 months for the whole cohort. FUTURE PLANS: These real-world data will help standardise the management of MBC and improve patient care. A dozen of ancillary research projects have been conducted and some of them are already accepted for publication or ready to be issued. The ESME research programme is expanding to ovarian cancer and advanced/metastatic lung cancer. Our ultimate goal is to achieve a continuous link to the data of the cohort to the French national Health Data System for centralising data on healthcare reimbursement (drugs, medical procedures), inpatient/outpatient stays and visits in primary/secondary care settings. TRIAL REGISTRATION NUMBER: NCT03275311; Pre-results.

Time trends of overall survival among metastatic breast cancer patients in the real-life ESME cohort.

AIM: Real-life analysis of overall survival (OS) trends among metastatic breast cancer (MBC) patients may help define medical needs and evaluate the impact of public health investments. The present study aimed to evaluate the independent impact of the year of MBC diagnosis on OS in the Epidemio-Strategy-Medical-Economical (ESME)-MBC cohort. METHODS: ESME-MBC (NCT03275311) is a French, national, multicentre, observational cohort including 16,702 consecutive newly diagnosed MBC patients (01 January 2008-31 December 2014). Of 16,680 eligible patients, 15,085 had full immunohistochemistry data, allowing classification as hormone receptor-positive and HER2-negative (HR+/HER2-, N = 9907), HER2-positive (HER2+, N = 2861) or triple-negative (HR-/HER2-, N = 2317) subcohorts. Multivariate analyses of OS were conducted among the full ESME cohort and subcohorts. RESULTS: Median OS of the whole cohort was 37.22 months (95% confidence interval [CI], 36.3-38.04). Year of diagnosis was an independent predictor of OS (hazard ratio 0.98 [95% CI, 0.97-1.00], P = .01) together with age, subtype, disease-free interval, visceral metastases and number of organs involved. Median OS of HR+/HER2-, HER2+ and HR-/HER2- subcohorts was, respectively, 42.12 (95% CI, 40.90-43.10), 44.91 (95% CI, 42.51-47.90) and 14.52 (95% CI, 13.70-15.24) months. Year of diagnosis was a strong independent predictor of OS in HER2+ subcohort (hazard ratio 0.91 [95% CI, 0.88-0.94], P < .001), but not in HR+/HER2- nor HR-/HER2- subcohorts (hazard ratio 1.00 [95% CI, 0.98-1.01], P = .80 and 1.00 [95% CI, 0.97-1.02], P = .90, respectively). CONCLUSIONS: The OS of MBC patients has slightly improved over the past decade. However, this effect is confined to HER2+ cases, highlighting the need of new strategies in the other subtypes.

A Bayesian dose-finding design incorporating toxicity data from multiple treatment cycles.

Phase I oncology trials are designed to identify a safe dose with an acceptable toxicity profile. The dose is typically determined based on the probability of severe toxicity observed during the first treatment cycle, although patients continue to receive treatment for multiple cycles. In addition, the toxicity data from multiple types and grades are typically summarized into a single binary outcome of dose-limiting toxicity. A novel endpoint, the total toxicity profile, was previously developed to account for the multiple toxicity types and grades. In this work, we propose to account for longitudinal repeated measures of total toxicity profile over multiple treatment cycles, accounting for cumulative toxicity during dosing-finding. A linear mixed model was utilized in the Bayesian framework, with addition of Bayesian risk functions for decision-making in dose assignment. The performance of this design is evaluated using simulation studies and compared with the previously proposed quasi-likelihood continual reassessment method (QLCRM) design. Twelve clinical scenarios incorporating four different locations of maximum tolerated dose and three different time trends (decreasing, increasing, and no effect) were investigated. The proposed repeated measures design was comparable with the QLCRM when only cycle 1 data were utilized in dose-finding; however, it demonstrated an improvement over the QLCRM when data from multiple cycles were used across all scenarios. Copyright © 2016 John Wiley & Sons, Ltd.

Dose finding with longitudinal data: simpler models, richer outcomes.

Phase I oncology clinical trials are designed to identify the optimal dose that will be recommended for phase II trials. This dose is typically defined as the dose associated with a certain probability of severe toxicity at cycle 1, although toxicity is repeatedly measured over cycles on an ordinal scale. Recently, a proportional odds mixed-effect model for ordinal outcomes has been proposed to (i) identify the optimal dose accounting for repeated events and (ii) to provide some framework to explore time trend. We compare this approach to a method based on repeated binary variables and to a method based on an under-parameterized model of the dose-time toxicity relationship. We show that repeated binary and ordinal outcomes both improve the accuracy of dose-finding trials in the same proportion; ordinal outcomes are, however, superior to detect time trend even in the presence of nonproportional odds models. Moreover, less parameterized models led to the best operating characteristics. These approaches are illustrated on two dose-finding phase I trials. Integration of repeated measurements is appealing in phase I dose-finding trials.

[The role of the expansion cohort in phase I trials in oncology: guidelines of the phase I HUB]. / Le rôle des cohortes d'expansion dans les essais de phase I en cancérologie : des recommandations du HUB phase I.

At the end of the dose escalation step of phase I trials in oncology, it is increasingly frequent to include patients in expansion cohorts. However, the objective of the expansion cohorts, the number of patients included and their justification are insufficiently explained in the protocols. These cohorts are sometimes of considerable size. The aim of this article is to outline the methodology of expansion cohorts in order to provide recommendations for their planning in practice. This work has been undertaken in collaboration with the statisticians of the early phase investigation centers (CLIP(2)), supported by INCA. First, we have outlined the recent articles published on the expansion cohorts in phase I. We then proposed recommendations, in terms of objectives and number of patients to be included, to guide investigators and facilitate the use of these expansion cohorts in practice. Manji et al. have identified 149 phase I clinical trials using expansion cohorts in oncology with a review of the literature between 2006 and 2011 (Manji et al., 2013). Objectives of the expansion cohort were reported in 111 trials (74%). In these trials, safety was the most reported objective (80% of trials), followed by efficacy (45%). According to this review, the number of patients included in these cohorts was insufficiently justified. This result was confirmed by the study of literature that we conducted over the period 2011-2014. We propose to define the number of patients to be included in expansion cohorts in terms of (1) their objectives, (2) the statistical criteria and (3) the clinical context of the trial. The toxicity study remains the primary objective to evaluate in the expansion phase. In some contexts, the activity study is considered as co-primary objective, either for identifying preliminary signs of activity in studies like screening, or for studying the activity when the target population is known. This study is then considered as phase I/II, and experience plans of phase II can be adapted for planning expansion cohorts. Recommendations for the size of expansion cohorts are proposed. Despite the exploratory character of the expansion cohort, a justification of their size based on assumptions statistically defined is recommended in order to provide an interpretable conclusion and to quantify the risk of errors.

Dose-finding designs using a novel quasi-continuous endpoint for multiple toxicities.

The aim of a phase I oncology trial is to identify a dose with an acceptable safety profile. Most phase I designs use the dose-limiting toxicity, a binary endpoint, to assess the unacceptable level of toxicity. The dose-limiting toxicity might be incomplete for investigating molecularly targeted therapies as much useful toxicity information is discarded. In this work, we propose a quasi-continuous toxicity score, the total toxicity profile (TTP), to measure quantitatively and comprehensively the overall severity of multiple toxicities. We define the TTP as the Euclidean norm of the weights of toxicities experienced by a patient, where the weights reflect the relative clinical importance of each grade and toxicity type. We propose a dose-finding design, the quasi-likelihood continual reassessment method (CRM), incorporating the TTP score into the CRM, with a logistic model for the dose-toxicity relationship in a frequentist framework. Using simulations, we compared our design with three existing designs for quasi-continuous toxicity score (the Bayesian quasi-CRM with an empiric model and two nonparametric designs), all using the TTP score, under eight different scenarios. All designs using the TTP score to identify the recommended dose had good performance characteristics for most scenarios, with good overdosing control. For a sample size of 36, the percentage of correct selection for the quasi-likelihood CRM ranged from 80% to 90%, with similar results for the quasi-CRM design. These designs with TTP score present an appealing alternative to the conventional dose-finding designs, especially in the context of molecularly targeted agents.

A pooled exploratory analysis of the effect of tumor size and KRAS mutations on survival benefit from adjuvant platinum-based chemotherapy in node-negative non-small cell lung cancer.

INTRODUCTION: The staging of node-negative non-small-cell lung cancer is modified in the 7th edition TNM classification. Here, we pool data from the National Cancer Institute of Canada Clinical Trials Group JBR.10 trial and the Cancer and Leukemia Group B-9633 trial to explore the prognostic and predictive effects of the new T-size descriptors and KRAS mutation status. METHODS: Node-negative patients were reclassified as T2a (>3-≤5 cm), T2b (>5-≤7 cm), T3 (>7 cm) or T ≤ 3 cm (≤3 cm, but other T2 characteristics). RESULTS: Of 538 eligible patients, 288 (53.5%) were T2a, 111 (21%) T2b, 62 (11.5%) T3, whereas 77 (14%) T≤3 cm were excluded to avoid confounding. KRAS mutations were detected in 104 of 390 patients (27%). T-size was prognostic for disease-free survival (p = 0.03), but borderline for overall survival (OS; p = 0.10), on multivariable analysis. Significant interaction between the prognostic value of KRAS and tumor size was observed for OS (p = 0.01), but not disease-free survival (p = 0.10). There was a nonsignificant trend (p = 0.24) for increased chemotherapy effect on OS with advancing T-size (hazard ratio [HR] T2a 0.90, [0.63-1.30]; T2b 0.69, [0.38-1.24]; and T3 0.57, [0.28-1.17]). The HR for chemotherapy effect on OS in T2a patients with KRAS wild-type tumors was 0.81 (p = 0.36), whereas a trend for detrimental effect was observed in those with mutant tumors (HR 2.11; p = 0.09; interaction p = 0.05). Similar trends were observed in T2b to T3 patients with wild-type (HR 0.86; p = 0.62), and KRAS mutant tumors (HR 1.16; p = 0.74; interaction p = 0.58). CONCLUSION: Chemotherapy effect seems to increase with tumor size. However, this small study could not identify subgroups of patients who did or did not derive significant benefit from adjuvant chemotherapy based on T-size or KRAS status.