Federico Innocenti

PURPOSE: Severe toxicity is commonly observed in cancer patients receiving irinotecan. UDP-glucuronosyltransferase 1A1 (UGT1A1) catalyzes the glucuronidation of the active metabolite SN-38. This study prospectively evaluated the association between the prevalence of severe toxicity and UGT1A1 genetic variation. PATIENTS AND METHODS: Sixty-six cancer patients with advanced disease refractory to other treatments received irinotecan 350 mg/m(2) every 3 weeks. Toxicity and pharmacokinetic data were measured during cycle 1. UGT1A1 variants (-3279G>T, -3156G>A, promoter TA indel, 211G>A, 686C>A) were genotyped. RESULTS: The prevalence of grade 4 neutropenia was 9.5%. Grade 4 neutropenia was much more common in patients with the TA indel 7/7 genotype (3 of 6 patients; 50%) compared with 6/7 (3 of 24 patients; 12.5%) and 6/6 (0 of 29 patients; 0%) (P =.001). The TA indel genotype was significantly associated with the absolute neutrophil count nadir (7/7 < 6/7 < 6/6, P =.02). The relative risk of grade 4 neutropenia was 9.3 (95% CI, 2.4 to 36.4) for the 7/7 patients versus the rest of the patients. Pretreatment total bilirubin levels (mean +/- standard deviation) were significantly higher in patients with grade 4 neutropenia (0.83 +/- 0.08 mg/dL) compared to those without grade 4 neutropenia (0.47 +/- 0.03 mg/dL; P <.001). The -3156G>A variant seemed to distinguish different phenotypes of total bilirubin within the TA indel genotypes. The -3156 genotype and the SN-38 area under the concentration versus time curve were significant predictors of ln(absolute neutrophil count nadir; r(2) = 0.51). CONCLUSION: UGT1A1 genotype and total bilirubin levels are strongly associated with severe neutropenia, and could be used to identify cancer patients predisposed to the severe toxicity of irinotecan. The hypothesis that the -3156G>A variant is a better predictor of UGT1A1 status than the previously reported TA indel requires further testing.

Importance: Combining biologic monoclonal antibodies with chemotherapeutic cytotoxic drugs provides clinical benefit to patients with advanced or metastatic colorectal cancer, but the optimal choice of the initial biologic therapy in previously untreated patients is unknown. Objective: To determine if the addition of cetuximab vs bevacizumab to the combination of leucovorin, fluorouracil, and oxaliplatin (mFOLFOX6) regimen or the combination of leucovorin, fluorouracil, and irinotecan (FOLFIRI) regimen is superior as first-line therapy in advanced or metastatic KRAS wild-type (wt) colorectal cancer. Design, Setting, and Participants: Patients (≥18 years) enrolled at community and academic centers throughout the National Clinical Trials Network in the United States and Canada (November 2005-March 2012) with previously untreated advanced or metastatic colorectal cancer whose tumors were KRAS wt chose to take either the mFOLFOX6 regimen or the FOLFIRI regimen as chemotherapy and were randomized to receive either cetuximab (n = 578) or bevacizumab (n = 559). The last date of follow-up was December 15, 2015. Interventions: Cetuximab vs bevacizumab combined with either mFOLFOX6 or FOLFIRI chemotherapy regimen chosen by the treating physician and patient. Main Outcomes and Measures: The primary end point was overall survival. Secondary objectives included progression-free survival and overall response rate, site-reported confirmed or unconfirmed complete or partial response. Results: Among 1137 patients (median age, 59 years; 440 [39%] women), 1074 (94%) of patients met eligibility criteria. As of December 15, 2015, median follow-up for 263 surviving patients was 47.4 months (range, 0-110.7 months), and 82% of patients (938 of 1137) experienced disease progression. The median overall survival was 30.0 months in the cetuximab-chemotherapy group and 29.0 months in the bevacizumab-chemotherapy group with a stratified hazard ratio (HR) of 0.88 (95% CI, 0.77-1.01; P = .08). The median progression-free survival was 10.5 months in the cetuximab-chemotherapy group and 10.6 months in the bevacizumab-chemotherapy group with a stratified HR of 0.95 (95% CI, 0.84-1.08; P = .45). Response rates were not significantly different, 59.6% vs 55.2% for cetuximab and bevacizumab, respectively (difference, 4.4%, 95% CI, 1.0%-9.0%, P = .13). Conclusions and Relevance: Among patients with KRAS wt untreated advanced or metastatic colorectal cancer, there was no significant difference in overall survival between the addition of cetuximab vs bevacizumab to chemotherapy as initial biologic treatment. Trial Registration: clinicaltrials.gov identifier: NCT00265850.

PURPOSE: The combination of gemcitabine plus bevacizumab produced a 21% response rate and a median survival of 8.8 months in a multicenter phase II trial in patients with metastatic pancreatic cancer. These encouraging data led Cancer and Leukemia Group B (CALGB) to conduct a double-blind, placebo-controlled, randomized phase III trial of gemcitabine/bevacizumab versus gemcitabine/placebo in advanced pancreatic cancer patients. PATIENTS AND METHODS: Eligible patients had no prior therapy for advanced disease, Eastern Cooperative Oncology Group (ECOG) performance status 0 to 2, no tumor invasion of adjacent organs, and no increased bleeding risk. The primary end point was overall survival. Patients were stratified by performance status, extent of disease, and prior radiotherapy. Patients received gemcitabine at 1,000 mg/m(2) over 30 minutes on days 1, 8, and 15 every 28 days and bevacizumab at 10 mg/kg or placebo on days 1 and 15 every 28 days. RESULTS: Between June 2004 and April 2006, 602 patients were enrolled onto the study and 535 were treated. Median overall survival was 5.8 months for gemcitabine/bevacizumab and 5.9 months for gemcitabine/placebo (P = .95). Median progression-free survival was 3.8 and 2.9 months, respectively (P = .07). Overall response rates were 13% and 10%, respectively. Patients with a performance status of 0, 1, and 2 survived a median of 7.9, 4.8, and 2.4 months, respectively. The only statistically significant differences in grades 3 and 4 toxicity occurred for hypertension (10% v 3%; P < .001) and proteinuria (5% v 1%; P = .002); venous thrombosis grade > or = 3 was equivalent in both arms (14% and 15%, respectively). CONCLUSION: The addition of bevacizumab to gemcitabine does not improve survival in advanced pancreatic cancer patients.

LBA3 Background: Irinotecan/5-FU/leucovorin (FOLFIRI) or oxaliplatin/5-FU/leucovorin (mFOLFOX6), combined with bevacizumab (BV) or cetuximab (CET), are first-line treatments for metastatic adenocarcinoma of the colon or rectum (MCRC). The optimal antibody combination is unknown. Methods: Patients (pts) with KRAS wild-type (wt)(codons 12 and 13) MCRC and performance status 0-1 received FOLFIRI or mFOLFOX6 (MD/pt choice at enrollment) and randomized to either CET 400 mg/m 2 X 1, then 250 mg/m 2 qw or BV 5 mg/kg q2w. The original study included unselected MCRC pts receiving FOLFIRI or mFOLFOX6 and randomized to CET, BV, or both. After 1,420 pts accrued the study amended as follows: only pts with KRAS wt tumors (codon 12 and 13) were included and the combination CET + BV arm was deleted. Rx continued until progression, death, unacceptable toxicity, curative surgery; treatment holidays of 4 wks permitted. Subsequent Rx not mandated. Accrual goal was 1,142 pts. One° endpoint was overall survival (OS). Results: Between November 2005 and March 2012, 3,058 unselected pts enrolled, 2,334 KRAS wt pts randomized; final N =1137 (333 pre-amend eligible retrospective KRAS test, 804 post-amend), median f/u = 24 mos; Median age – 59 y; 61% male. Chemo/BV – 559; chemo/CET – 578. FOLFIRI = 26.6%, mFOLFOX6 = 73.4%. OS analysis planned at 849 events; efficacy futility boundary crossed at 10 th interim analysis on 1/29/14. OS - chemo/BV v. chemo/CET = 29.04 (25.66 - 31.21) v. 29.93 (27.56 - 31.21) mos; HR = 0.92 (0.78, 1.09) (p value = 0.34). PFS (by investigator): chemo/BV v. chemo/CET: 10.84 (9.86 - 11.4) v. 10.45 (9.66 - 11.33) mos. There were 94 pts free of disease following surgery, median f/u 40 mos (range 8.0 - 86.0). Outcomes similar by gender. On-study toxicity and deaths as expected. Analyses underway: Expanded RAS, FOLFOX v. FOLFIRI, subsequent therapies, long-term survivors, correlates. Conclusions: Chemo/CET and chemo/BV equivalent in OS in pts KRAS wt (codons 12 + 13) MCRC; either is appropriate in first line. Overall OS of 29 + mos and 8% long-term survivors confirms progress in MCRC. The preference for FOLFOX limits chemotherapy comparison. Expanded RAS and other molecular and clinical analyses may identify subsets of pts who get more or less benefit from specific regimens. Clinical trial information: NCT00265850.

An increasing number of studies are describing potential uses of circulating tumour DNA (ctDNA) in the care of patients with colorectal cancer. Owing to this rapidly developing area of research, the Colon and Rectal-Anal Task Forces of the United States National Cancer Institute convened a panel of multidisciplinary experts to summarize current data on the utility of ctDNA in the management of colorectal cancer and to provide guidance in promoting the efficient development and integration of this technology into clinical care. The panel focused on four key areas in which ctDNA has the potential to change clinical practice, including the detection of minimal residual disease, the management of patients with rectal cancer, monitoring responses to therapy, and tracking clonal dynamics in response to targeted therapies and other systemic treatments. The panel also provides general guidelines with relevance for ctDNA-related research efforts, irrespective of indication.