Maintenance therapy after oxaliplatin withdrawal is useful in patients with metastatic colorectal cancer (mCRC). This study aimed to investigate the timing of discontinuation or reintroduction of oxaliplatin and the optimal maintenance therapy regimen for survival.

PubMed and conference abstracts were searched to select phase II and III trials of first-line oxaliplatin-containing therapy with or without bevacizumab using maintenance therapy for mCRC. Correlations of median overall survival (OS) with induction therapy regimens, induction therapy duration, maintenance therapy regimens (fluoropyrimidine plus bevacizumab [FP+Bev], FP/Bev alone, and no treatment), and oxaliplatin reintroduction were investigated using correlation and weighted multivariate regression analyses.

Twenty-two treatment arms were analyzed, including 2,581 patients. The maintenance therapy regimen FP+Bev showed the strongest correlation with a prolonged OS (Spearman's partial correlation coefficient=0.42), and the other three variables correlated weakly with the OS. The maintenance therapy regimen significantly interacted with the induction chemotherapy duration (p=0.019). The predicted OS for FP+Bev crossed the lines of FP/Bev alone at 18 weeks of induction therapy, and of no treatment at 23 weeks. The corresponding OS at 12 and 27 weeks of induction therapies were 28.6 and 24.2 months for FP+Bev, 25.9 and 28.8 months for FP/Bev alone, and 20.5 and 27.5 months for no treatment.

The optimal maintenance therapy regimen for the OS is a continuous induction therapy as long as possible followed by FP/Bev alone and switching to FP+Bev within approximately 4 months if induction therapy is discontinued.

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr, President, Oncology Pharmacy Services, Inc, 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net. The information presented in this review is based on published data and clinical expertise and includes information not included in the product labeling. Incorporation of such published data provides a more robust assessment of the drugs and assists pharmacists in evaluation of orders for off-label use of these agents.

Colorectal cancer (CRC) is a significant cause of cancer-related morbidity and mortality all over the world. Improvements of cytotoxic and biologic agents have prolonged the survival in metastatic CRC (mCRC), with a median overall survival of approximately 2 years and more in the past two decades. The biologic agents that have proven clinical benefits in mCRC mainly target vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR). In particular, bevacizumab targeting VEGF and cetuximab and panitumumab targeting EGFR have demonstrated significant survival benefits in combination with cytotoxic chemotherapy in the first-line, second-line, or salvage setting. Aflibercept, ramucirumab, and regorafenib are also used in second-line or salvage therapy. Recent retrospective analyses have shown that KRAS or NRAS mutations were negative predictive markers for anti-EGFR therapy. Based on the evidence from large randomized clinical trials, personalized therapy is necessary for patients with mCRC according to their tumor biology and characteristics. The aim of this paper was to summarize the results of the major randomized clinical trials and highlight the benefits of the molecular targeted agents in patients with mCRC.

Recently, anti-vascular endothelial growth factor (anti-VEGF) agents have been described in the literature as a valid treatment option for symptomatic liver hemangiomas, but only limited evidence supports this notion. The purpose of this study was to elucidate whether or not the administration of anti-VEGF agents can reliably achieve a size reduction in liver hemangiomas. We examined patients with incidental hemangiomas who received anti-angiogenic agents for the treatment of other malignancies. Our study population consisted of 17 colorectal cancer patients and one lung cancer patient carrying 21 hemangiomas who received bevacizumab, and seven renal cell carcinoma patients carrying nine hepatic hemangiomas who received sunitinib. We have measured the liver hemangioma volume on both the pre-treatment and post-treatment computed tomography images and then calculated the volume alteration rates. No statistically significant difference (P = 0.365) in the volume of the liver hemangiomas was observed before (1.1-168.8 cm(3); mean ± SD 19.8 ± 39.7 cm(3)) or after (1.2-163.6 cm(3); 19.3 ± 38.0 cm(3)) bevacizumab treatment. The volume reduction rate ranged from -35.0 to 11.2 % (mean ± SD -1.3 ± 10.8 %). The sunitinib treatment group also showed no statistically significant difference (P = 0.889) in hemangioma volume before (1.2-6.5 cm(3); 3.0 ± 1.8 cm(3)) or after (1.2-6.0 cm(3); 3.0-1.7 cm(3)) treatment. The volume reduction rate ranged from -13.3 to 7.7 % (median: mean ± SD -2.5 ± 6.6 %). We did not observe liver hemangioma shrinkage after bevacizumab or sunitinib treatment. Our data do not support the application of anti-VEGF agents for the treatment of hepatic hemangiomas.

The aim of this study was to evaluate the association between the efficacy of first-line cytotoxic chemotherapy plus bevacizumab and single-nucleotide polymorphisms (SNPs) of angiogenic genes in patients with advanced colorectal cancer (CRC).

DNA was extracted from blood samples of 125 patients, and 12 SNPs were evaluated for association with the objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

The vascular endothelial growth factor A (VEGFA) rs833061 T/T was associated with superior ORR compared to its alternative genotypes (75.9 vs. 50.8%; p = 0.008), and the interleukin 8 rs4073 A/A genotype tended to be associated with poor ORR (45.0 vs. 66.0%; p = 0.067). The median PFS and OS were superior in patients with the fms-related tyrosine kinase 1 (FLT1) rs9513070 A/A genotype (8.7 vs. 6.6 months; p = 0.001 and 26.4 vs. 16.1 months; p = 0.038, respectively). The kinase insert domain receptor rs1531289 G/G genotype tended to be associated with improved PFS (8.0 vs. 7.1 months; p = 0.069). In haplotype analysis, the FLT1 rs9513070/rs9554320/rs9582036 GCA haplotype was associated with inferior PFS and OS (p = 0.004 and p = 0.041, respectively).

The VEGFA rs833061 SNP is associated with the ORR, and the FLT1 rs9513070 SNP and FLT1 GCA haplotypes are associated with PFS and OS in advanced CRC patients treated with cytotoxic chemotherapy plus bevacizumab.