Plasma-Based Measurements of Tumor Heterogeneity Correlate with Clinical Outcomes in Metastatic Colorectal Cancer.

Sequencing circulating tumor DNA (ctDNA) from liquid biopsies may better assess tumor heterogeneity than limited sampling of tumor tissue. Here, we explore ctDNA-based heterogeneity and its correlation with treatment outcome in STEAM, which assessed efficacy and safety of concurrent and sequential FOLFOXIRI-bevacizumab (BEV) vs. FOLFOX-BEV for first-line treatment of metastatic colorectal cancer. We sequenced 146 pre-induction and 89 post-induction patient plasmas with a 198-kilobase capture-based assay, and applied Mutant-Allele Tumor Heterogeneity (MATH), a traditionally tissue-based calculation of allele frequency distribution, on somatic mutations detected in plasma. Higher levels of MATH, particularly in the post-induction sample, were associated with shorter progression-free survival (PFS). Patients with high MATH vs. low MATH in post-induction plasma had shorter PFS (7.2 vs. 11.7 months; hazard ratio, 3.23; 95% confidence interval, 1.85−5.63; log-rank p < 0.0001). These results suggest ctDNA-based tumor heterogeneity may have potential prognostic value in metastatic cancers.

Characterization of response to atezolizumab + bevacizumab versus sorafenib for hepatocellular carcinoma: Results from the IMbrave150 trial.

BACKGROUND: IMbrave150 is a phase III trial that assessed atezolizumab + bevacizumab (ATEZO/BEV) versus sorafenib (SOR) in patients with unresectable hepatocellular carcinoma (HCC) and demonstrated a significant improvement in clinical outcomes. Exploratory analyses characterized objective response rate (ORR), depth (DpR), and duration of response (DoR), and patients with a complete response (CR). METHODS: Patients were randomized 2:1 to intravenous ATEZO (1200 mg) + BEV (15 mg/kg) every 3 weeks or oral SOR (400 mg) twice daily. Tumors were evaluated using Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) and HCC-modified RECIST (mRECIST). ORR by prior treatment and largest baseline liver lesion size, DoR, time to response (TTR), and complete response (TTCR) were analyzed. RESULTS: For both criteria, responses favored ATEZO/BEV versus SOR regardless of prior treatment and in patients with lesions ≥3 cm. Median TTR was 2.8 months per RECIST 1.1 (range: 1.2-12.3 months) and 2.8 months per mRECIST (range: 1.1-12.3 months) with ATEZO/BEV. Patients receiving ATEZO/BEV had a greater DpR, per both criteria, across baseline liver lesion sizes. Characteristics of complete responders were similar to those of the intent-to-treat population. In complete responders receiving ATEZO/BEV per mRECIST versus RECIST 1.1, respectively, median TTCR was shorter (5.5 vs. 7.0 months), mean baseline sum of lesion diameter was longer (5.0 [SD, 5.1] vs. 2.6 [SD, 1.4] cm), and mean largest liver lesion size was larger (4.8 [SD, 4.2] vs. 2.3 [SD, 1.0] cm). CONCLUSIONS: These data highlight the improved ORR, DpR, and CR rates with ATEZO/BEV in unresectable HCC.

Disease Monitoring Using Post-induction Circulating Tumor DNA Analysis Following First-Line Therapy in Patients with Metastatic Colorectal Cancer.

PURPOSE: We assessed plasma circulating tumor DNA (ctDNA) level as a prognostic marker for progression-free survival (PFS) following first-line metastatic colorectal cancer (mCRC) therapy. EXPERIMENTAL DESIGN: The Sequencing Triplet With Avastin and Maintenance (STEAM) was a randomized, phase II trial investigating efficacy of bevacizumab (BEV) plus 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX) and 5-fluorouracil/leucovorin/irinotecan (FOLFIRI), administered concurrently or sequentially, versus FOLFOX-BEV in first-line mCRC. Evaluation of biomarkers associated with treatment outcomes was an exploratory endpoint. Patients in the biomarker-evaluable population (BEP) had 1 tissue sample, 1 pre-induction plasma sample, and 1 post-induction plasma sample collected ≤60 days of induction from last drug date. RESULTS: Among the 280 patients enrolled in STEAM, 183 had sequenced and evaluable tumor tissue, 118 had matched pre-induction plasma, and 54 (BEP) had ctDNA-evaluable sequencing data for pre- and post-induction plasma. The most common somatic variants in tumor tissue and pre-induction plasma were TP53, APC, and KRAS. Patients with lower-than-median versus higher-than-median post-induction mean allele fraction (mAF) levels had longer median PFS (17.7 vs. 7.5 months, HR, 0.33; 95% confidence interval, 0.17-0.63). Higher levels of post-induction mAF and post-induction mean mutant molecules per milliliter (mMMPM), and changes in ctDNA (stratified by a 10-fold or 100-fold reduction in mAF between pre- and post-induction plasma), were associated with shorter PFS. Post-induction mAF and mMMPM generally correlated with each other (ρ = 0.987, P < 0.0001). CONCLUSIONS: ctDNA quantification in post-induction plasma may serve as a prognostic biomarker for mCRC post-treatment outcomes.

Bevacizumab at first recurrence after standard radio-chemotherapy is associated with improved overall survival in glioblastoma patients with large tumor burden.

BACKGROUND: Since its approval for use in recurrent glioblastoma (GBM), the survival benefit of bevacizumab (Bev) remains to be demonstrated. To address this issue, we retrospectively examined survival from first recurrence in patients treated with Bev, lomustine (CCNU), or Bev/CCNU. METHODS: We identified 168 primary GBM patients diagnosed at UCLA and Kaiser Permanente LA who received upfront radio-chemotherapy, followed by Bev and/or CCNU at first recurrence. Three patient groups, contemporaneously diagnosed from 2009 through 2015, were identified: (1) patients treated with Bev alone (n = 49), (2) CCNU alone (CCNU 09-15) (n = 36), and (3) Bev/CCNU (n = 53). Another CCNU control group (n = 30) diagnosed from 2001 through 2004 (CCNU 01-04) was also derived. We measured tumor size at first recurrence treatment initiation, using bidimensional (2D) and volumetric (3D) techniques, and analyzed overall survival (OS) from first recurrence. RESULTS: Among the entire cohort, larger tumor size at first recurrence was associated with poorer survival. The CCNU 01-04 group had similar tumor size as the Bev arms and low Bev crossover (7%). Treatment with Bev was associated with improved survival in patients with large tumor 2D measurements: Median OS for Bev and Bev/CCNU groups were 6.71 mo (n = 27) and 6.97 mo (n = 36) vs 4.03 mo (n = 10) in CCNU 01-04. Analysis by 3D measurement yielded similar results. Interestingly, the CCNU 09-15 group showed the highest survival, likely due to smaller tumor size and crossover to Bev (69%). CONCLUSION: Survival advantage from Bev treatment was observed only among patients with large tumor burden as determined by either 2D or 3D measurement.

Single-institution retrospective review of patients with recurrent glioblastoma treated with bevacizumab in clinical practice.

BACKGROUND AND AIMS: This retrospective review of patients with recurrent glioblastoma treated at the Preston Robert Tisch Brain Tumor Center investigated treatment patterns, survival, and safety with bevacizumab in a real-world setting. METHODS: Adult patients with glioblastoma who initiated bevacizumab at disease progression between January 1, 2009, and May 14, 2012, were included. A Kaplan-Meier estimator was used to describe overall survival (OS), progression-free survival (PFS), and time to greater than or equal to 20% reduction in Karnofsky Performance Status (KPS). The effect of baseline demographic and clinical factors on survival was examined using a Cox proportional hazards model. Adverse event (AE) data were collected. RESULTS: Seventy-four patients, with a median age of 59 years, were included in this cohort. Between bevacizumab initiation and first failure, defined as the first disease progression after bevacizumab initiation, biweekly bevacizumab and bevacizumab/irinotecan were the most frequently prescribed regimens. Median duration of bevacizumab treatment until failure was 6.4 months (range, 0.5-58.7). Median OS and PFS from bevacizumab initiation were 11.1 months (95% confidence interval [CI], 7.3-13.4) and 6.4 months (95% CI, 3.9-8.5), respectively. Median time to greater than or equal to 20% reduction in KPS was 29.3 months (95% CI, 13.8-∞). Lack of corticosteroid usage at the start of bevacizumab therapy was associated with both longer OS and PFS, with a median OS of 13.2 months (95% CI, 8.6-16.6) in patients who did not initially require corticosteroids versus 7.2 months (95% CI, 4.8-12.5) in those who did (P = 0.0382, log-rank), while median PFS values were 8.6 months (95% CI, 4.6-9.7) and 3.7 months (95% CI, 2.7-6.6), respectively (P = 0.0243, log-rank). Treatment failure occurred in 70 patients; 47 of whom received salvage therapy, and most frequently bevacizumab/carboplatin (7/47; 14.9%). Thirteen patients (18%) experienced a grade 3 AE of special interest for bevacizumab. CONCLUSIONS: Treatment patterns and outcomes for patients with recurrent glioblastoma receiving bevacizumab in a real-world setting were comparable with those reported in prospective clinical trials.

Treatment Patterns and Outcomes in Patients with KRAS Wild-Type Metastatic Colorectal Cancer Treated in First Line with Bevacizumab- or Cetuximab-Containing Regimens.

PURPOSE: Patients with Kirsten rat sarcoma viral oncogene wild-type (KRAS WT) metastatic colorectal cancer (mCRC) treated in first line with bevacizumab (B) or cetuximab (C) plus standard chemo backbones had comparable outcomes in phase III Cancer and Leukemia Group B (CALGB) 80405. We examined comparative effectiveness of B and C regimens in real-world community settings. METHODS: This retrospective study examined progression-free survival (PFS) and OS in a US community sample of KRAS WT mCRC patients treated with first-line B (n = 254) or C (n = 146) regimens. Medical records from the Vector Oncology Data Warehouse were used. Disease progression was determined from patient charts. OS was measured from the start of first-line treatment until death. RESULTS: There were no significant difference in either PFS or OS respectively between B-treated compared to C-treated patients (HR = 1.324, 95% CI 0.901, 1.947; HR = 1.080, 95% CI 0.721, 1.617). More B patients received oxaliplatin backbones (74.8 vs. 36.3%), and more C patients received irinotecan backbones (51.4 vs. 20.1%), ps < 0.001. Multivariate survival analyses showed a significant difference indicating a greater risk for death among C-treated patients with right-sided tumors vs. left-sided tumors (HR = 2.263, 95% CI 1.394, 3.673, p = 0.0009), but not for B-treated patients (HR = 1.209, 95% CI 0.825, 1.771, p = 0.3297). CONCLUSIONS: Consistent with CALGB 80405, median PFS and OS for these community oncology KRAS WT mCRC patients treated with first-line B or C regimens did not differ significantly.

Progression-Free Survival in Patients Receiving Chemotherapy Alone (C) or Chemotherapy with Bevacizumab (CB) for First-Line Treatment of KRAS Mutant Metastatic Colorectal Cancer in Community Oncology Settings.

PURPOSE: Bevacizumab is a standard first-line (L1) treatment for metastatic colorectal cancer (mCRC) patients regardless of RAS status. This retrospective study examined treatment patterns and outcomes in a community oncology sample of KRAS mutant mCRC patients treated with chemotherapy (C) or C plus bevacizumab (CB) in L1. METHODS: This study used medical records from the Vector Oncology Data Warehouse. Eligible patients were confirmed KRAS mutant mCRC and received L1 C or CB. Kaplan-Meier analysis assessed L1 progression-free survival (PFS) and overall survival (OS). Cox regression models examined the interaction of tumor location (R/L) with treatment. RESULTS: CB (n = 264) compared to C (n = 109) patients were younger, less likely performance status (PS) impaired, and more likely with liver metastases. Median unadjusted PFS was 10.41 months (95% CI 9.0-11.3) in CB and 7.66 months (95% CI 6.5-9.1) in C patients (p = 0.174). Median unadjusted OS was 26.91 months (95% CI 24.3-29.3) in CB and 23.33 months (95% CI 19.7-29.2) in C patients (p = 0.571). For patients with right- vs. left-sided tumors, C (but not CB)-treated patients had higher adjusted risk for progression (HR = 1.715, 95% CI 1.108, 2.653; p = 0.015). CONCLUSIONS: CB- vs. C-treated KRAS mutant mCRC patients may have a meaningful PFS benefit. Patients with right-sided tumors treated with C were at higher risk for disease progression than patients with left-sided tumors. Tumor location had no significant effect on outcomes in the CB cohort.

Phase II Randomized Trial of Sequential or Concurrent FOLFOXIRI-Bevacizumab Versus FOLFOX-Bevacizumab for Metastatic Colorectal Cancer (STEAM).

BACKGROUND: First-line treatment for metastatic colorectal cancer (mCRC) typically entails a biologic such as bevacizumab (BEV) with 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX) or 5-fluorouracil/leucovorin/irinotecan (FOLFIRI). STEAM (NCT01765582) assessed the efficacy of BEV plus FOLFOX/FOLFIRI (FOLFOXIRI), administered concurrently (cFOLFOXIRI-BEV) or sequentially (sFOLFOXIRI-BEV, FOLFOX-BEV alternating with FOLFIRI-BEV), versus FOLFOX-BEV for mCRC. PATIENTS AND METHODS: Patients with previously untreated mCRC (n = 280) were randomized 1:1:1 to cFOLFOXIRI-BEV, sFOLFOXIRI-BEV, or FOLFOX-BEV and treated with 4-6-month induction followed by maintenance. Coprimary objectives were overall response rate (ORR; first-line cFOLFOXIRI-BEV vs. FOLFOX-BEV) and progression-free survival (PFS; pooled first-line cFOLFOXIRI-BEV and sFOLFOXIRI-BEV vs. FOLFOX-BEV). Secondary/exploratory objectives included overall survival (OS), liver resection rates, biomarker analyses, and safety. RESULTS: ORR was 72.0%, 72.8%, and 62.1% and median PFS was 11.9, 11.4, and 9.5 months with cFOLFOXIRI-BEV, sFOLFOXIRI-BEV, and FOLFOX-BEV, respectively. OS was similar between arms. ORR between cFOLFOXIRI-BEV and FOLFOX-BEV did not significantly differ (p = .132); thus, the primary ORR endpoint was not met. cFOLFOXIRI-BEV and sFOLFOXIRI-BEV numerically improved ORR and PFS, regardless of RAS status. Median PFS was higher with pooled concurrent and sequential FOLFOXIRI-BEV versus FOLFOX-BEV (11.7 vs. 9.5 months; hazard ratio, 0.7; 90% confidence interval, 0.5-0.9; p < .01). Liver resection rates were 17.2% (cFOLFOXIRI-BEV), 9.8% (sFOLFOXIRI-BEV), and 8.4% (FOLFOX-BEV). Grade ≥ 3 treatment-emergent adverse events (TEAEs) were observed in 91.2% (cFOLFOXIRI-BEV), 86.7% (sFOLFOXIRI-BEV), and 85.6% (FOLFOX-BEV) of patients, with no increase in serious chemotherapy-associated TEAEs. CONCLUSION: cFOLFOXIRI-BEV and sFOLFOXIRI-BEV were well tolerated with numerically improved ORR, PFS, and liver resection rates versus FOLFOX-BEV, supporting triplet chemotherapy plus BEV as a first-line treatment option for mCRC. IMPLICATIONS FOR PRACTICE: The combination of first-line FOLFIRI with FOLFOX and bevacizumab (concurrent FOLFOXIRI-BEV) improves clinical outcomes in patients with metastatic colorectal cancer (mCRC) relative to FOLFIRI-BEV or FOLFOX-BEV, but it is thought to be associated with increased toxicity. Alternating treatment of FOLFOX and FOLFIRI (sequential FOLFOXIRI-BEV) could improve tolerability. In the phase II STEAM trial, which is the largest study of FOLFOXIRI-BEV in patients in the U.S., it was found that both concurrent and sequential FOLFOXIRI-BEV are active and well tolerated in patients with previously untreated mCRC, supporting the use of these regimens as potential first-line treatment options for this population.

Overall survival in patients with glioblastoma before and after bevacizumab approval.

OBJECTIVE: Glioblastoma (GBM) is an aggressive disease with limited therapeutic options. While bevacizumab was approved in 2009 for the treatment of patients with progressive GBM, its impact on overall survival (OS) remains unclear. Using US population-based cancer registry data (SEER), this study compared OS of patients diagnosed with GBM before and after bevacizumab approval. METHODS: Adult patients from SEER with a GBM diagnosis were divided into two cohorts: patients diagnosed in 2006-2008 (pre-bevacizumab cohort, n = 6,120) and patients diagnosed in 2010-2012 (post-bevacizumab cohort, n = 6,753). Patients were included irrespective of the treatments received. OS post-diagnosis was compared between the study cohorts utilizing Kaplan-Meier analyses and multivariate Cox proportional hazards regression. RESULTS: Among 12,873 patients with GBM, the median age was 62 years, 41% were women, 31% underwent gross total resection, and 75% received radiation therapy. Survival was stable within the 2006-2008 period (median survival = 9 months for each year), but increased after year 2009 (median survival = 10 and 11 months for years 2010/2011 and 2012, respectively). The adjusted hazard of death was significantly lower in the post-bevacizumab approval cohort (hazard ratio = 0.91, p < .01). CONCLUSIONS: The results of this large population-based study suggested an improvement in OS among patients with a GBM diagnosis in 2010-2012 compared to 2006-2008. While the cause of this improvement cannot be proven in a retrospective analysis, the timing of the survival increase coincides with the approval of bevacizumab for the treatment of patients with progressive GBM, indicating a possible benefit of bevacizumab in this population.

Real-world Direct Health Care Costs for Metastatic Colorectal Cancer Patients Treated With Cetuximab or Bevacizumab-containing Regimens in First-line or First-line Through Second-line Therapy.

BACKGROUND: The present study examined real-world direct health care costs for metastatic colorectal cancer (mCRC) patients initiating first-line (1L) bevacizumab (BEV)- or cetuximab (CET)-containing regimen in 1L or 1L-through-second-line (1L-2L) therapy. PATIENTS AND METHODS: Using a large US insurance claims database, patients with mCRC initiating 1L BEV- or 1L CET-containing regimen from January 1, 2008 to September 30, 2014 were identified. The per-patient per-month (PPPM) all-cause health care costs (2014 US dollars) were measured during 1L therapy and, for patients continuing to a 2L biologic-containing regimen, 1L-2L therapy. Multivariable regression analyses were used to compare PPPM total health care costs between patients initiating a 1L BEV- versus 1L CET-containing regimen. RESULTS: A total of 6095 patients initiating a 1L BEV- and 453 initiating a 1L CET-containing regimen were evaluated for 1L costs; 2218 patients initiating a 1L BEV- and 134 initiating a 1L CET-containing regimen were evaluated for 1L-2L costs. In 1L therapy, 1L CET had adjusted PPPM costs that were $3135 (95% confidence interval [CI], $1174-$5040; P < .001) greater on average than 1L BEV. In 1L-2L therapy, 1L BEV-2L CET had adjusted PPPM costs that were $1402 (95% CI, $1365-$1442; P = .010) greater than those for 1L BEV-2L BEV, and 1L CET-2L BEV had adjusted PPPM costs that were $4279 (95% CI, $4167-$4400; P = .001) greater on average than those for 1L BEV-2L BEV. The adjusted PPPM cost differences for 1L BEV-2L other biologic or 1L CET-2L other biologic agent were numerically greater but statistically insignificant. CONCLUSION: PPPM total health care costs for 1L and 2L therapy tended to be greater for patients treated with 1L CET-containing regimens than for 1L BEV-containing regimens. Also, continuing treatment with BEV-containing regimens 1L-2L was less costly than switching between BEV and CET. The cost differences between BEV and CET hold important implications for treatment decisions of mCRC patients in real-world clinical practice.

Patient and physician preferences for anticancer drugs for the treatment of metastatic colorectal cancer: a discrete-choice experiment.

OBJECTIVE: Many publications describe preferences for colorectal cancer (CRC) screening; however, few studies elicited preferences for anticancer-drug treatment for metastatic CRC (mCRC). This study was designed to elicit preferences and risk tolerance among patients and oncologists in the USA for anticancer drugs to treat mCRC. MATERIALS AND METHODS: Patients aged 18 years or older with a self-reported diagnosis of mCRC and board-certified (or equivalent) oncologists who had treated patients with mCRC were recruited by two survey research companies from existing online patient panels in the USA. Additional oncologists were recruited from a list of US physicians. Patients and oncologists completed a discrete-choice experiment (DCE) survey. DCEs offer a systematic method of eliciting preferences and quantifying both the relative importance of treatment attributes and the tradeoffs respondents are willing to make among benefits and risks. Treatment attributes in the DCE were progression-free survival (PFS) and risks of severe papulopustular rash, serious hemorrhage, cardiopulmonary arrest, and gastrointestinal perforation. Patients' and physicians' maximum levels of acceptable treatment-related risks for two prespecified increases in efficacy were estimated. RESULTS: A total of 127 patients and 150 oncologists completed the survey. Relative preferences for the treatment attributes in the study were mostly consistent with the expectation that better clinical outcomes were preferred over worse clinical outcomes. Risk tolerance varied between patients and physicians. On average, physicians were willing to tolerate higher risks than patients, although these differences were mostly not statistically significant. Post hoc latent-class analyses revealed that some patients and physicians were unwilling to forgo any efficacy to avoid toxicities, while others were willing to make such tradeoffs. CONCLUSION: Differences in preferences between patients and physicians suggest that there is the potential for improvement in patients' well-being. Initiating or enhancing discussions about patient tolerance for toxicities, such as skin rash and gastrointestinal perforations, may help prescribe treatments that entail more appropriate benefit-risk tradeoffs.

Phase IB Study of Vemurafenib in Combination with Irinotecan and Cetuximab in Patients with Metastatic Colorectal Cancer with BRAFV600E Mutation.

In vitro, EGFR inhibition, combined with the BRAF inhibitor vemurafenib, causes synergistic cytotoxicity for BRAFV600E metastatic colorectal cancer, further augmented by irinotecan. The safety and efficacy of vemurafenib, irinotecan, and cetuximab in BRAF-mutated malignancies are not defined. In this 3+3 phase I study, patients with BRAFV600E-advanced solid cancers received cetuximab and irinotecan with escalating doses of vemurafenib. Nineteen patients (18 with metastatic colorectal cancer and 1 with appendiceal cancer) were enrolled. Three patients experienced dose-limiting toxicities. The MTD of vemurafenib was 960 mg twice daily. Six of 17 evaluable patients (35%) achieved a radiographic response by Response Evaluation Criteria in Solid Tumors 1.1 criteria, consistent with in vivo models demonstrating tumor regressions with the triplet regimen. Median progression-free survival was 7.7 months. BRAFV600E circulating cell-free DNA (cfDNA) trends correlated with radiographic changes, and acquired mutations from cfDNA in genes reactivating MAPK signaling were observed at progression. SIGNIFICANCE: Vemurafenib, in combination with irinotecan and cetuximab, was well tolerated in patients with refractory, BRAF-mutated metastatic colorectal cancer, and both survival outcomes and response rates exceeded prior reports for vemurafenib and for irinotecan plus cetuximab in BRAFV600E metastatic colorectal cancer. In vivo models demonstrated regressions with the triplet, in contrast with vemurafenib and cetuximab alone. cfDNA predicted radiographic response and identified mutations reactivating the MAPK pathway upon progression. Cancer Discov; 6(12); 1352-65. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 1293.