Whole genome and biomarker analysis of patients with recurrent glioblastoma on bevacizumab: A subset analysis of the CABARET trial.

The CABARET trial (ACTRN12610000915055) reported no difference in overall survival (OS) between patients with recurrent glioblastoma (GBM) randomized to either bevacizumab monotherapy or bevacizumab plus carboplatin. However, a subset of patients showed durable responses and prolonged survival, with recorded survival times of over 30 months in five of 122 patients (4%). Patient selection for bevacizumab therapy would be enhanced if a predictive biomarker of response or survival could be identified; this biomarker sub-study attempted to identify novel biomarkers. Patients who opted to participate in this sub-study and who had adequate biospecimens for analysis (n = 54) were retrospectively evaluated for the expression of a series of tumor proteins. Immunohistochemistry (IHC) was used to measure the expression of 19 proteins previously implicated in cancer treatment response to bevacizumab. MGMT promoter methylation was also assessed. Tumor DNA from five patients with outlying survival duration ('poor' and 'exceptional' survivors) was subjected to whole genome sequencing (WGS). No single protein expression level, including VEGF-A, predicted OS in the cohort. WGS of poor and exceptional survivors identified a gain in Chromosome 19 that was exclusive to the exceptional survivors. Validation of this finding requires examination of a larger independent cohort.

Comparison between site and central radiological assessments for patients with recurrent glioblastoma on a clinical trial.

AIM: Assessment of magnetic resonance imaging (MRI) in glioblastoma can be challenging. For patients with recurrent glioblastoma managed on the CABARET trial, we compared disease status assessed at hospitals and subsequent blinded central expert radiological review. METHODS: MRI results and clinical status at specified time points were used for site and central assessment of disease status. Clinical status was determined by the site. Response Assessment in Neuro-Oncology (RANO) criteria were used for both assessments. Site and central assessments of progression-free survival (PFS) and response rates were compared. Inter-rater variability for central review progression dates was assessed. RESULTS: Central review resulted in shorter PFS in 45% of 89 evaluable patients (n = 40). Median PFS was 3.6 (central) versus 3.9 months (site) (hazard ratio 1.5, 95% confidence interval 1.3-1.8, P < 0.001). Responses were documented more frequently by sites (n = 16, 18%) than centrally (n = 11, 12%). Seven of 120 patients continued on trial without site-determined progression for more than 6 months beyond the central review determination of progression. Of scans reviewed by all three central reviewers, 33% were fully concordant for progression date. CONCLUSION: While the difference between site and central PFS dates was statistically significant, the 0.3-month median difference is small. The variability within central review is consistent with previous studies, highlighting the challenges in MRI interpretation in this context. A small proportion of patients benefited from treatment well beyond the centrally determined progression date, reinforcing that clinical status together with radiology results are important determinants of whether a therapy is effective for an individual.

The role of early magnetic resonance imaging in predicting survival on bevacizumab for recurrent glioblastoma: Results from a prospective clinical trial (CABARET).

BACKGROUND: Bevacizumab has been associated with prolonged progression-free survival for patients with recurrent glioblastoma; however, not all derive a benefit. An early indicator of efficacy or futility may allow early discontinuation for nonresponders. This study prospectively assessed the role of early magnetic resonance imaging (eMRI) and its correlation with subsequent routine magnetic resonance imaging (MRI) results and survival. METHODS: Patients were part of a randomized phase 2 clinical trial (CABARET) comparing bevacizumab with bevacizumab plus carboplatin for recurrent glioblastoma. eMRI was conducted after 4 weeks in the trial (after 2 treatments with bevacizumab [10 mg/kg every 2 weeks]). The results were compared with the results of the subsequent 8-week MRI standard. RESULTS: For 119 of 122 patients, eMRI was available, and 111 had subsequent MRI for comparison. Thirty-six (30%) had an early radiological response, and 17 (14%) had progressive disease. The concordance between eMRI and 8-week MRI was moderate (κ = 0.56), with most providing the same result (n = 79 [71%]). There was strong evidence that progression-free survival and overall survival were predicted by the eMRI response (both P values < .001). The median survival was 8.6 months for an eMRI response, 6.6 months for stable disease, and 3.7 months for progressive disease; the hazard ratio (progressive disease vs stable disease) was 3.4 (95% confidence interval, 1.9-6.0). Landmark analyses showed that eMRI progression was a strong predictor of mortality independent of other potential baseline predictors. CONCLUSIONS: In this study, early progression on MRI appears to be a robust marker of a poor prognosis for patients on bevacizumab. Cancer 2017;123:3576-82. © 2017 American Cancer Society.

Health-related quality of life outcomes from CABARET: a randomized phase 2 trial of carboplatin and bevacizumab in recurrent glioblastoma.

In recurrent glioblastoma, health-related quality of life (HRQL) is a crucial trial endpoint. We examined HRQL outcomes as a secondary endpoint for patients in the CABARET randomized phase 2 trial. 122 patients were randomly allocated to bevacizumab monotherapy or bevacizumab plus carboplatin. We calculated change scores from baseline for each HRQL measure on the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and the Brain Cancer Module (QLQ-BN20), together with time to deterioration in HRQL, and the proportion of participants with clinically meaningful improvements in specific disease-related symptoms. At baseline, 117 of 122 randomized patients (96%) attempted questionnaires. Questionnaire participation rates were >90% for patients continuing on treatment, however at the end-of-treatment visit only 72 (64% of eligible participants) returned a form. There were no differences between arms in change scores over the treatment period. Time to ≥10 point deterioration in scores from baseline was also similar between arms. HRQL deterioration occurred largely before progression for the domains tested, but scores in HRQL domains specifically relevant to symptoms of recurrent glioblastoma also improved for about 50% of patients with symptoms at baseline. Neither detrimental nor beneficial effects on HRQL were seen with carboplatin added to bevacizumab, with a proportion of patients on both arms experiencing symptomatic benefit. Given the reduced questionnaire completion at end of treatment, time to HRQL deterioration is a feasible and robust clinical trial endpoint in this patient population. Clinical trials registration number: ACTRN12610000915055.

Continuing or ceasing bevacizumab beyond progression in recurrent glioblastoma: an exploratory randomized phase II trial.

BACKGROUND: In patients with recurrent glioblastoma, the benefit of bevacizumab beyond progression remains uncertain. We prospectively evaluated continuing or ceasing bevacizumab in patients who progressed while on bevacizumab. METHODS: CABARET, a phase II study, initially randomized patients to bevacizumab with or without carboplatin (Part 1). At progression, eligible patients underwent a second randomization to continue or cease bevacizumab (Part 2). They could also receive additional chemotherapy regimens (carboplatin, temozolomide, or etoposide) or supportive care. RESULTS: Of 120 patients treated in Part 1, 48 (80% of the anticipated 60-patient sample size) continued to Part 2. Despite randomization, there were some imbalances in patient characteristics. The best response was stable disease in 7 (30%) patients who continued bevacizumab and 2 (8%) patients who stopped receiving bevacizumab. There were no radiological responses. Median progression-free survival was 1.8 vs 2.0 months (bevacizumab vs no bevacizumab; hazard ratio [HR], 1.08; 95% CI, .59-1.96; P = .81). Median overall survival was 3.4 vs 3.0 months (HR, .84; 95% CI, .47-1.50; P = .56 and HR .70; 95% CI .38-1.29; P = .25 after adjustment for baseline factors). Quality-of-life scores did not significantly differ between arms. While the maximum daily steroid dose was lower in the continuation arm, the difference was not statistically significant. CONCLUSIONS: Patients who continued bevacizumab beyond disease progression did not have clear survival improvements, although the study was not powered to detect other than very large differences. While these data provide the only randomized evidence related to continuing bevacizumab beyond progression in recurrent glioblastoma, the small sample size precludes definitive conclusions and suggests this remains an open question.

Early perfusion MRI predicts survival outcome in patients with recurrent glioblastoma treated with bevacizumab and carboplatin.

Bevacizumab, an anti-angiogenic agent, is FDA-approved for use in patients with recurrent glioblastoma multiforme (rGBM). The radiologic evaluation of tumor response to bevacizumab is complex and there is no validated method of monitoring tumor vascularity during therapy. We evaluated perfusion-weighted MR imaging (PWI) in our cohort of patients enrolled in the CABARET trial, which examined the effectiveness of bevacizumab with or without carboplatin in patients with rGBM. Pre-treatment and early follow-up (4- and 8-week) PWI were used to calculate relative cerebral blood volume (rCBV) histogram statistics of the contrast-enhancing and FLAIR hyperintense tumor volumes. A novel rCBV measurement (load) was developed to estimate the total volume of perfused tumor blood vessels. Changes in all rCBV measures were examined for correlations with progression-free (PFS) and overall survival (OS). All of our 15 patients enrolled in the CABARET trial were included. Median PFS and OS were 23 and 45 weeks respectively. Kaplan-Meier analysis of pre-treatment PWI revealed an 18 week reduction in median OS in patients with high tumor rCBV (p = 0.031). Changes in rCBV measures, especially load, correlated significantly with PFS and OS at both follow-up time-points. Patients with the greatest reduction in rCBVload by 8-weeks of therapy had a significantly increased median OS (30 weeks; p = 0.013). PWI may be of significant clinical utility in managing patients with rGBM, particularly those treated with anti-angiogenic agents such as bevacizumab. These findings need to be confirmed prospectively in larger studies.

Primary Tumor Resection and Overall Survival in Patients With Metastatic Colorectal Cancer Treated With Palliative Intent.

BACKGROUND: The survival impact of primary tumor resection in patients with metastatic colorectal cancer (mCRC) treated with palliative intent remains uncertain. In the absence of randomized data, the objectives of the present study were to examine the effect of primary tumor resection (PTR) and major prognostic variables on overall survival (OS) of patients with de novo mCRC. PATIENTS AND METHODS: Consecutive patients from the Australian 'Treatment of Recurrent and Advanced Colorectal Cancer' registry were examined from June 2009 to March 2015. Univariate and multivariate Cox proportional hazards regression analyses were used to identify associations between multiple patient or clinical variables and OS. Patients with metachronous mCRC were excluded from the analyses. RESULTS: A total of 690 patients de novo and 373 metachronous mCRC patients treated with palliative intent were identified. The median follow-up period was 30 months. The median age of de novo patients was 66 years; 57% were male; 77% had an Eastern Cooperative Oncology Group performance status of 0 to 1; and 76% had a colon primary. A total of 216 de novo mCRC patients treated with palliative intent underwent PTR at diagnosis and were more likely to have a colon primary (odds ratio [OR], 15.4), a lower carcinoembryonic antigen level (OR, 2.08), and peritoneal involvement (OR, 2.58; P < .001). On multivariate analysis, PTR at diagnosis in de novo patients was not associated with significantly improved OS (hazard ratio [HR], 0.82; 99% confidence interval [CI], 0.62-1.09; P = .068). PTR at diagnosis did not correlate with outcome in de novo patients with a colon primary (HR, 0.74; 99% CI, 0.54-1.01; P = .014) or a rectal primary (HR, 0.81; 99% CI, 0.27-2.44; P = .621). CONCLUSION: For de novo mCRC patients treated with palliative intent, PTR at diagnosis does not significantly improve OS when adjusting for known major prognostic factors. The outcomes of randomized trials examining the survival impact of PTR are awaited.

Randomized phase 2 study of carboplatin and bevacizumab in recurrent glioblastoma.

BACKGROUND: The optimal use of bevacizumab in recurrent glioblastoma (GBM), including the choice of monotherapy or combination therapy, remains uncertain. The purpose of this study was to compare combination therapy with bevacizumab monotherapy. METHODS: This was a 2-part randomized phase 2 study. Eligibility criteria included recurrent GBM after radiotherapy and temozolomide, no other chemotherapy for GBM, and Eastern Cooperative Oncology Group performance status 0-2. The primary objective (Part 1) was to determine the effect of bevacizumab plus carboplatin versus bevacizumab monotherapy on progression-free survival (PFS) using modified Response Assessment in Neuro-Oncology criteria. Bevacizumab was given every 2 weeks, 10 mg/kg; and carboplatin every 4 weeks, (AUC 5). On progression, patients able to continue were randomized to continue or cease bevacizumab (Part 2). Secondary endpoints included objective radiological response rate (ORR), quality of life, toxicity, and overall survival (OS). RESULTS: One hundred twenty-two patients (median age, 55y) were enrolled to Part 1 from 18 Australian sites. Median follow-up was 32 months, and median on-treatment time was 3.3 months. Median PFS was 3.5 months for each arm (hazard ratio [HR]: 0.92, 95% CI: 0.64-1.33, P = .66). ORR was 14% (combination) versus 6% (monotherapy) (P = .18). Median OS was 6.9 (combination) versus 7.5 months (monotherapy) (HR: 1.18, 95% CI: 0.82-1.69, P = .38). The incidence of bevacizumab-related adverse events was similar to prior literature, with no new toxicity signals. Toxicities were higher in the combination arm. Part 2 data (n = 48) will be reported separately. CONCLUSIONS: Adding carboplatin resulted in more toxicity without additional clinical benefit. Clinical outcomes in patients with recurrent GBM treated with bevacizumab were inferior to those in previously reported studies. CLINICAL TRIALS REGISTRATION NR: ACTRN12610000915055.

Bevacizumab and glioblastoma: scientific review, newly reported updates, and ongoing controversies.

Anti-angiogenic therapy for glioblastoma has been in the spotlight for several years, as researchers and clinicians strive to find agents with meaningful efficacy against glioblastoma. Bevacizumab in particular, in the second half of the last decade, became the most significant breakthrough in anti-glioblastoma therapy since temozolomide. Optimism for bevacizumab has been somewhat challenged given recent clinical trials that have raised questions regarding its clinical effectiveness, the optimal timing of its use and the validity of endpoints, among other issues. In addition, uncertainty has recently arisen regarding the effects of bevacizumab on quality of life and neurocognitive function, two key clinical endpoints of unquestionable significance among glioblastoma patients. In this review, we highlight these controversies and other recent work related to bevacizumab for glioblastoma.

Clinical trial participation and outcome for patients with glioblastoma: multivariate analysis from a comprehensive dataset.

Glioblastoma multiforme (GBM) is the most common malignant brain tumor in adults. Although multiple clinical and tumor-related variables affect survival outcomes, the effect of clinical trial participation has not been explored. The aim of this study was to determine whether clinical trial participation improves outcome for patients with GBM. Data from patients with GBM were accessed from a dataset collected over 12 years (1998-2010) at two institutions. Univariable and multivariate logistic regression analyses were performed to look for relationships between clinical trial participation, other baseline clinical and sociodemographic variables and overall survival (OS). In total, 542 patients were identified and included in the analysis; median age was 62 years. Sixty-one patients (11%) were enrolled in a clinical trial. Clinical trial enrollment was associated with improved median survival (14.5 months compared to 6.3 months, p < 0.001) and this difference remained significant in multivariate analysis (hazard ratio 0.67, p = 0.046). Age, poor performance status and operation type were also independent predictors for OS in multivariate analysis. Disease site, socioeconomic status and co-morbidity did not affect survival outcome. This is the first study in patients with GBM to suggest a survival benefit from clinical trial participation, independent of age and performance status; while also confirming the importance of other previously reported prognostic factors. This should encourage clinicians to offer trial therapies to patients with GBM and encourage patients to participate in available studies.

Part II: Liver function in oncology: towards safer chemotherapy use.

The liver is fundamentally important in drug metabolism. In oncology, the astute clinician must not only understand the meaning and limitations of commonly ordered liver biochemical tests, but also be aware of which anticancer agents might induce liver dysfunction, and of the strategies for appropriate dosing of patients with pre-existing liver dysfunction. In part I of our Review, we highlighted both the importance and inadequacies of identifying serum biochemical liver abnormalities in oncology; we also discussed a lack of routine formal investigation of liver function. We summarised chemotherapy-related hepatotoxicity and other causes of liver toxic effects in patients with cancer. Here in part II, we discuss trials that have specifically assessed chemotherapy dosing strategies in the setting of overt biochemical liver dysfunction and we note their recommendations. Furthermore, we review other assessments of liver metabolic and excretory function, particularly in the setting of chemotherapy drug handling. We discuss the potential use of these metabolic probes in practice.

Part I: Liver function in oncology: biochemistry and beyond.

The liver has a key role in the metabolism (ie, inactivation or activation) of many commonly used anticancer agents-cytotoxics or new biological agents. Therefore, assessment of liver function is a fundamental part of initial work-up and management of patients with cancer. An understanding of the meaning of conventional serum biochemical testing of liver function and status, what variables they are measuring, and usefulness for chemotherapy dosing is essential. Emerging awareness of the drawbacks of conventional serum biochemical testing and further understanding of the intricacies of liver function is leading to the development of alternative strategies for appropriate chemotherapy regimens and dosing. We present an overview of assessment of liver function and chemotherapy dosing. We consider the use of serum liver biochemical testing to predict liver function, potential causes of biochemical abnormalities in patients with cancer, and chemotherapy drugs that are associated with hepatotoxicity. Part II will overview the current knowledge surrounding chemotherapy dosing in the setting of liver dysfunction; as well as alternative tests of hepatic metabolic function that are beginning to be used as strategies for appropriate individualised chemotherapy administration.

Chemotherapy dosing strategies in the obese, elderly, and thin patient: results of a nationwide survey.

PURPOSE: Determining the optimal starting dose of chemotherapy (CHT) presents a considerable challenge when using body-surface area (BSA)-based dosing, particularly in obese, elderly, or thin patients. We sought to document the range of approaches employed when administering CHT to these patients. METHODS: A questionnaire was developed by a panel of oncologists and mailed to all members of the Medical Oncology Group of Australia. RESULTS: From 315 oncologists, 188 responded (response rate 59.7%). BSA-based dosing is standard practice for 176 (97.2%) of the responding oncologists. In the adjuvant disease setting, 23 (12.7%) use ideal rather than actual body weight (BW) to calculate BSA, or choose whichever is less. When treating obese patients, only 6.1% of respondents routinely use actual BW. Of the remainder, 69.5% either cap the dose at 2 m(2) or use ideal BW. In underweight patients, 95% (n = 171) routinely calculate BSA using actual BW. Forty one respondents (22.7%) routinely reduce dose in the fit elderly. CONCLUSION: This analysis of BSA-based CHT dosing methods demonstrates significant variability in practice. Based on evidence from adjuvant studies showing that actual BSA-based dosing is desirable, a substantial number of Australian patients are being underdosed. Further education, together with ongoing research, is required to optimize individualized dosing for efficacy and tolerability.

Chemotherapy treatments for metastatic colorectal cancer: is evidence-based medicine in practice?

Treatment options for colorectal cancer have expanded to include multiple oxaliplatin- and irinotecan-based regimens and more biological/targeted therapies.