Phase I dose-escalation study to determine the safety, pharmacokinetics and pharmacodynamics of brivanib alaninate in combination with full-dose cetuximab in patients with advanced gastrointestinal malignancies who have failed prior therapy

Pharmacological boosting of cGAS activation sensitizes chemotherapy by enhancing antitumor immunity

Enhancing chemosensitivity is one of the largest unmet medical needs in cancer therapy. Cyclic GMP-AMP synthase (cGAS) connects genome instability caused by platinum-based chemotherapeutics to type I interferon (IFN) response. Here, by using a high-throughput small-molecule microarray-based screening of cGAS interacting compounds, we identify brivanib, known as a dual inhibitor of vascular endothelial growth factor receptor and fibroblast growth factor receptor, as a cGAS modulator. Brivanib markedly enhances cGAS-mediated type I IFN response in tumor cells treated with platinum. Mechanistically, brivanib directly targets cGAS and enhances its DNA binding affinity. Importantly, brivanib synergizes with cisplatin in tumor control by boosting CD8⁺ T cell response in a tumor-intrinsic cGAS-dependent manner, which is further validated by a patient-derived tumor-like cell clusters model. Taken together, our findings identify cGAS as an unprecedented target of brivanib and provide a rationale for the combination of brivanib with platinum-based chemotherapeutics in cancer treatment.

Identification of Potent Small-Molecule PCSK9 Inhibitors Based on Quantitative Structure-Activity Relationship, Pharmacophore Modeling, and Molecular Docking Procedure

The leading cause of atherosclerotic cardiovascular disease (ASCVD) is elevated low-density lipoprotein cholesterol (LDL-C). Proprotein convertase subtilisin/kexin type 9 (PCSK9) attaches to the domain of LDL receptor (LDLR), diminishing LDL-C influx and LDLR cell surface presentation in hepatocytes, resulting in higher circulating LDL-C levels. PCSK9 dysfunction has been linked to lower levels of plasma LDLC and a decreased risk of coronary heart disease (CHD). Herein, using virtual screening tools, we aimed to identify a potent small-molecule PCSK9 inhibitor in compounds that are currently being studied in clinical trials. We first performed chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) filtering of 9800 clinical trial compounds obtained from the ZINC 15 database using Lipinski's rule of 5 and achieved 3853 compounds. Two-dimensional (2D) quantitative structure-activity relationship (QSAR) was initiated by computing molecular descriptors and selecting important descriptors of 23 PCSK9 inhibitors. Multivariate calibration was performed with the partial least square regression (PLS) method with 18 compounds for training to design the QSAR model and 5 compounds for the test set to assess the model. The best latent variables (LV) (LV=6) with the lowest value of Root-Mean-Square Error of Cross-Validation (RMSECV) of 0.48 and leave-one-out cross-validation correlation coefficient (R²CV) = 0.83 were obtained for the QSAR model. The low RMSEC (0.21) with high R²cal (0.966) indicates the probability of fit between the experimental data and the calibration model. Using QSAR analysis of 3853 compounds, 2635 had a pIC₅₀<1 and were considered for pharmacophore screening. The PHASE module (a complete package for pharmacophore modeling) designed the pharmacophore hypothesis through multiple ligands. The top 14 compounds (pIC₅₀>1) were defined as active, whereas 9 (pIC₅₀<1) were considered as an inactive set. Three five-point pharmacophore hypotheses achieved the highest score: DHHRR1, DHHRR2, and DHRRR1. The highest and best model with survival scores (5.365) was DHHRR1, comprising 1 hydrogen donor (D), 2 hydrophobic groups (H), and 2 rings of aromatic (R) features. We selected the molecules with a higher 1.5 fitness score (257 compounds) in pharmacophore screening (DHHRR1) for molecular docking screening. Molecular docking indicates that ZINC000051951669, with a binding affinity: of -13.2 kcal/mol and 2 H-bonds, has the highest binding to the PCSK9 protein. ZINC000011726230 with energy binding: -11.4 kcal/mol and 3 H-bonds, ZINC000068248147 with binding affinity: -10.7 kcal/mol and 1 H-bond, ZINC000029134440 with a binding affinity: -10.6 kcal/mol and 4 H-bonds were ranked next, respectively. To conclude, the archived molecules identified as inhibitory PCSK9 candidates, and especially ZINC000051951669 may therefore significantly inhibit PCSK9 and should be considered in the newly designed trials.

A review of harmonization strategies for quantitative PET

PET can reveal in vivo biological processes at the molecular level. PET-derived quantitative values have been used as a surrogate marker for clinical decision-making in numerous clinical studies and trials. However, quantitative values in PET are variable depending on technical, biological, and physical factors. The variability may have a significant impact on a study outcome. Appropriate scanner calibration and quality control, standardization of imaging protocols, and any necessary harmonization strategies are essential to make use of PET as a biomarker with low bias and variability. This review summarizes benefits, limitations, and remaining challenges for harmonization of quantitative PET, including whole-body PET in oncology, brain PET in neurology, PET/MR, and non-¹⁸F PET imaging. This review is expected to facilitate harmonization of quantitative PET and to promote the contribution of PET-derived biomarkers to research and development in medicine.

Advances in the Lung Cancer Immunotherapy Approaches

Despite the progress in the comprehension of LC progression, risk, immunologic control, and treatment choices, it is still the primary cause of cancer-related death. LC cells possess a very low and heterogeneous antigenicity, which allows them to passively evade the anticancer defense of the immune system by educating cytotoxic lymphocytes (CTLs), tumor-infiltrating lymphocytes (TILs), regulatory T cells (Treg), immune checkpoint inhibitors (ICIs), and myeloid-derived suppressor cells (MDSCs). Though ICIs are an important candidate in first-line therapy, consolidation therapy, adjuvant therapy, and other combination therapies involving traditional therapies, the need for new predictive immunotherapy biomarkers remains. Furthermore, ICI-induced resistance after an initial response makes it vital to seek and exploit new targets to benefit greatly from immunotherapy. As ICIs, tumor mutation burden (TMB), and microsatellite instability (MSI) are not ideal LC predictive markers, a multi-parameter analysis of the immune system considering tumor, stroma, and beyond can be the future-oriented predictive marker. The optimal patient selection with a proper adjuvant agent in immunotherapy approaches needs to be still revised. Here, we summarize advances in LC immunotherapy approaches with their clinical and preclinical trials considering cancer models and vaccines and the potential of employing immunology to predict immunotherapy effectiveness in cancer patients and address the viewpoints on future directions. We conclude that the field of lung cancer therapeutics can benefit from the use of combination strategies but with comprehension of their limitations and improvements.

Comparison of Various Phase I Combination Therapy Designs in Oncology for Evaluation of Early Tumor Shrinkage Using Simulations

There is still a lack of efficient designs for identifying the dose response in oncology combination therapies in early clinical trials. The concentration response relationship can be identified using the early tumor shrinkage time course, which has been shown to be a good early response marker of clinical efficacy. The performance of various designs using an exposure–tumor growth inhibition model was explored using simulations. Different combination effects of new drug M and cetuximab (reference therapy) were explored first assuming no effect of M on cetuximab (to investigate the type I error (α)), and subsequently assuming additivity or synergy between cetuximab and M. One‐arm, two‐arm, and four‐arm designs were evaluated. In the one‐arm design, 60 patients received cetuximab + M. In the two‐arm design, 30 patients received cetuximab and 30 received cetuximab + M. In the four‐arm design, in addition to cetuximab and cetuximab + M as standard doses, combination arms with lower doses of cetuximab were evaluated (15 patients/arm). Model‐based predictions or “simulated observations” of early tumor shrinkage at week 8 (ETS8) were compared between the different arms. With the same number of individuals, the one‐arm design showed better statistical power than other designs but led to strong inflation of α in case of misestimated reference for ETS8 value. The two‐arm design protected against this misestimation and, with the same total number of subjects, would provide higher statistical power than a four‐arm design. However, a four‐arm design would be helpful for exploring more doses of cetuximab in combination with M to better understand the interaction.

Clinical significance of various growth factors in patients with different gastric neoplasms

Growth factors represent a family of important biological molecules that can also be critical in the pathogenesis of various gastrointestinal cancers. In this study, we conducted a comprehensive analysis of the systemic levels of selected growth factors - hepatocyte, vascular-endothelial, fibroblast, and insulin-like 1 growth factors (HGF, VEGF, FGF, and IGF-1, respectively), as well as granulocyte-colony stimulating factor (G-CSF) in 75 patients with different gastric neoplasms (carcinomas, gastrointestinal stromal tumors - GISTs, neuroendocrine neoplasms - NENs, and lymphomas) and 40 healthy volunteers. Patients with gastric carcinoma or other types of gastric neoplasms had higher HGF and IGF-1 levels than healthy individuals (P < 0.05 in all cases). In comparison to healthy control subjects, systemic VEGF concentrations were elevated in patients with gastric carcinoma (P < 0.05), but not in individuals with other types of gastric malignancies. No statistically significant differences were observed between the analyzed groups in terms of FGF and G-CSF levels. When patients with gastric carcinoma were subdivided according to the Japanese classification system, significantly elevated levels of HGF, VEGF, and IGF-1 concentrations were observed in patients with advanced gastric carcinoma (extending beyond the submucosal layer of the stomach). Only the systemic levels of HGF were associated with tumor node metastasis - TNM staging, the absolute numbers of bone marrow-derived mesenchymal cells, and very small embryonic/epiblast-like stem cells circulating in patients with gastric carcinoma. ROC curves analyses demonstrated that AUC values of systemic levels of examined growth factors ranged from 0.40-0.65 (P > 0.06 in all cases). In conclusion, patients with gastric malignancies showed a systemic biochemical imbalance in multiple growth factors, which appears to be associated with clinical presentation of these neoplasms in humans. However, none of the growth factors examined here seem to be suitable diagnostic biomarkers for detecting or differentiating different types of gastric malignancies in humans.

A phase II evaluation of brivanib in the treatment of persistent or recurrent carcinoma of the cervix: An NRG Oncology/Gynecologic Oncology Group study

BACKGROUND

Brivanib is an oral, tyrosine kinase inhibitor against vascular endothelial growth factor (VEGF) and fibroblast growth factor receptor (FGFR). We studied its efficacy and tolerability in persistent or recurrent cervical cancer patients.

METHODS

Eligible patients had at least one prior cytotoxic regimen for recurrence and with measurable disease. Brivanib 800mg was administered orally every day (1cycle=28days) until disease progression or prohibitive toxicity. Primary endpoints were progression-free survival (PFS) >6months and objective tumor response.

RESULTS

Of 28 eligible and evaluable women enrolled, 11 (39%) had primary surgery and 25 (89%) had prior radiation. Eighteen (64%) received one prior cytotoxic treatment and 10 (36%) had 2 prior regimens. Twelve (43%) had >2cycles of brivanib with 4 (14%) receiving >10cycles (range: 1-20). Seven (25%) patients had PFS >6months (90% CI: 7.3%-33.9%). Two (7%) (90% CI: 1.3%-20.8%) patients had partial tumor response with duration of 8 and 22months and 12 (43%) had stable disease. The median PFS was 3.2months (90% CI: 2.1-4.4). The median overall survival was 7.9months (90% CI: 6.1-11.7). More common grade 3 adverse events were hypertension, anemia, hyponatremia, hyperglycemia, elevated liver enzymes, nausea, headache, and colon hemorrhage. Grade 4 adverse events included sepsis and hypertension.

CONCLUSIONS

Based on early results of this phase II trial, brivanib was well tolerated and demonstrated sufficient activity after first stage but trial was stopped due to lack of drug availability.

Targeted therapies for the treatment of non-small-cell lung cancer: Monoclonal antibodies and biological inhibitors

The usual treatments for patients with non-small-cell lung cancer (NSCLC), such as advanced lung adenocarcinoma, are unspecific and aggressive, and include lung resection, radiotherapy and chemotherapy. Recently, treatment with monoclonal antibodies and biological inhibitors has emerged as an effective alternative, generating effective results with few side effects. In recent years, several clinical trials using monoclonal antibodies presented potential benefits to NSCLC, and 4 of them are already approved for the treatment of NSCLC, such as cetuximab, bevacizumab, nivolumab and pembrolizumab. Also, biological inhibitors are attractive tolls for biological applications. Among the approved inhibitors are crizotinib, erlotinib, afatinib and gefitinib, and side effects are usually mild to intense. Nevertheless, biological molecule treatments are under development, and several new monoclonal antibodies and biological inhibitors are in trial to treat NSCLC. Also under trial study are as follows: anti-epidermal growth factor receptor (EGFR) antibodies (nimotuzumab and ficlatuzumab), anti-IGF 1 receptor (IGF-1R) monoclonal antibody (figitumumab), anti-NR-LU-10 monoclonal antibody (nofetumomab) as well as antibodies directly affecting the cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) molecule (ipilimumab and tremelimumab), to receptor activator of nuclear factor-kappa B ligand (RANKL) (denosumab) or to polymerase enzyme (veliparib and olaparib). Among new inhibitors under investigation are poly-ADP ribose polymerase (PARP) inhibitors (veliparib and olaparib) and phosphatidylinositol 3-kinase (PI3K) inhibitor (buparlisib). However, the success of immunotherapies still requires extensive research and additional controlled trials to evaluate the long-term benefits and side effects.

Pharmacokinetic Aspects of Vascular Endothelial Growth Factor Tyrosine Kinase Inhibitors

Scientists have identified the impact of angiogenesis on tumor growth and survival. Among other efficient drugs, several small-molecule tyrosine kinase inhibitors (TKIs) targeting the vascular endothelial growth factor receptor (VEGFR) have been developed and have already been integrated into the treatment of various advanced malignancies. This review provides a compilation of current knowledge on the pharmacokinetic aspects of all VEGFR-TKIs already approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) and of those still under investigation. Additional information on substance metabolism, potential for drug-drug interactions (DDIs), and the need for dose adaptation in patients with predominant renal and/or hepatic impairment has been included. All TKIs introduced in this review were administered orally, allowing for easy drug handling for healthcare professionals and patients. For almost all substances, the maximum plasma concentrations were reached within a short period of time. The majority of the substances showed a high plasma protein binding and their excretion occurred via the feces and, to a lesser extent, via the urine. In most cases, dose adaptation in patients with mild to moderate renal or hepatic impairment is not recommended. Cytochrome P450 (CYP) 3A4 was found to play a crucial role in the drug metabolic processes of many compounds. In order to prevent unwanted DDIs, co-administration of VEGFR TKIs together with CYP3A4 inhibitors or inducers should be avoided. Throughout all TKIs, the data indicate high inter-individual variability. The causes of this are still unclear and require further research to allow for individualization of treatment regimens.

Novel anti-angiogenic therapeutic strategies in colorectal cancer

INTRODUCTION

Anti-angiogenetic agents are currently the standard of care in metastatic CRC patients. Bevacizumab, aflibercept, regorafenib and recently ramucirumab have significantly improved both progression-free and overall survival in different lines of treatment. Since bevacizumab's approval, a number of novel anti-VEGF agents have been tested in preclinical and clinical models.

AREAS COVERED

This review is focused on the most recent clinical results of novel agents targeting VEGF and its receptors with a major focus on those investigated recently in clinical trials.

EXPERT OPINION

In the last 15 years, a number of new anti-angiogenetic agents have been tested. Unfortunately, most of them have demonstrated unacceptable toxicities or failed to show activity. When tested as single agents, encouraging preliminary results were reported with fruquintinib, famitinib, and nintedanib. Interesting novel mechanisms of action are also being explored: VGX-100 is a monoclonal antibody (mAb) which binds to VEGF-C, inhibiting activation of VEGFR-2 and VEGFR-3 when combined with bevacizumab; tanibirumab is a mAb which binds to VEGFR-2 and vanucizumab is a bispecific mAb binding both to VEGF-A and Angiopoietin-2. Data about the combination of these agents with chemotherapy are very encouraging, even though preliminary. However, the definition of specific predictive biomarkers remains a priority.

Signaling mechanisms of resistance to EGFR- and Anti-Angiogenic Inhibitors cancer

Colorectal cancer is among four most common malignancies and the second leading cause of cancer death in the western world. Epidermal Growth Factor Receptor (EGFR) and Vascular Endothelial Growth Factor (VEGF) are often overexpressed in colorectal cancer and are associated with inferior outcomes. More recently, further improvements in survival have occurred due to the use of novel targeted therapies such EGFR Tyrosine Kinase Inibitors (EGFR-TKIs), EGFR monoclonal antibodies (EGFR-mAb), and VEGF antibodies. Despite the initial clinical efficacy of these inhibitors in such cancer, resistance invariably develops, typically within 1 to 2 years. Over the past several years, multiple molecular mechanisms of resistance have been identified, and some common themes have emerged. One is the development of resistance mutations in the drug target and another it is activation of alternative signaling of key downstream pathways despite sustained inhibition of the original drug target. In this mini-review, we summarize the concepts underlying EGFR- and VEGF-mediated resistance, the specific examples known to date, and the challenges of applying this knowledge to develop improved therapeutic strategies to prevent or overcome resistance.

Repeatability of metabolically active tumor volume measurements with FDG PET/CT in advanced gastrointestinal malignancies: a multicenter study

PURPOSE

To evaluate the feasibility and repeatability of various metabolically active tumor volume ( MATV metabolically active tumor volume ) quantification methods in fluorine 18 fluorodeoxyglucose ( FDG fluorine 18 fluorodeoxyglucose ) positron emission tomography (PET)/computed tomography (CT) in a multicenter setting and propose the optimal MATV metabolically active tumor volume method together with the minimal threshold for future response evaluation studies.

MATERIALS AND METHODS

The study was approved by the institutional review board of all four participating centers, and patients provided written informed consent. Thirty-four patients with advanced gastrointestinal malignancies underwent two FDG fluorine 18 fluorodeoxyglucose PET/CT examinations within 1 week. MATV metabolically active tumor volume s were defined semiautomatically with 27 variations of tumor delineation methods with different reference values. Feasibility was determined as the percentage of successful tumor segmentations per MATV metabolically active tumor volume method. Repeatability was determined with intraclass correlation coefficients, Bland-Altman plots, and limits of agreement ( LOA limit of agreement s) of the percentage difference between the test and repeat test measurements. In addition, LOA limit of agreement variability per center was investigated.

RESULTS

In total, 136 lesions were identified. Feasibility of tumor segmentation ranged from 54% to 100% (74-136 of 136 lesions); repeatability was evaluated for 19 MATV metabolically active tumor volume methods with feasibility of greater than 95%. The median MATV metabolically active tumor volume derived with 50% threshold of mean standardized uptake value ( SUV standardized uptake value ) of a sphere of 12-mm diameter with highest local intensity ( SUVhp mean SUV of a sphere of 12-mm diameter with highest local intensity ), which may not include the voxel with highest SUV standardized uptake value corrected for local background, was 5.7 and 6.1 mL for test and retest scans, respectively, with a relative LOA limit of agreement of 36.1%. Comparable repeatability was found between centers. A difference in uptake time between scan 1 and 2 of 15 minutes or longer had a minor negative influence on repeatability.

CONCLUSION

MATV metabolically active tumor volume measured with 50% of SUVhp mean SUV of a sphere of 12-mm diameter with highest local intensity corrected for local background is recommended in multicenter FDG fluorine 18 fluorodeoxyglucose PET/CT studies on the basis of a high feasibility (96%) and repeatability ( LOA limit of agreement of 36.1%).

What could Nintedanib (BIBF 1120), a triple inhibitor of VEGFR, PDGFR, and FGFR, add to the current treatment options for patients with metastatic colorectal cancer?

Increasing knowledge of the pro-angiogenic processes involved in the progression of metastatic colorectal cancer (mCRC) has resulted in the clinical development of several anti-angiogenic agents, with bevacizumab currently being the only approved agent for mCRC. Nintedanib (BIBF 1120) has been shown to block the vascular endothelial growth factor receptor (VEGFR), the platelet-derived growth factor receptor (PDGFR), and the fibroblast growth factor receptor (FGFR). By targeting FGFR signaling, nintedanib may overcome resistance to previous anti-VEGF treatments, and may represent a better approach in patients with high basal levels of circulating FGFs. In this article, the angiogenic mechanisms implicated in mCRC are reviewed (focusing on the signaling pathways activated by VEGFR, PDGFR, and FGFR), along with the clinical data for nintedanib in the context of other anti-angiogenic tyrosine kinase inhibitors under clinical development for mCRC. Biomarkers that could predict response to nintedanib are also discussed.

Effects of reusing baseline volumes of interest by applying (non-)rigid image registration on positron emission tomography response assessments

Objectives

Reusing baseline volumes of interest (VOI) by applying non-rigid and to some extent (local) rigid image registration showed good test-retest variability similar to delineating VOI on both scans individually. The aim of the present study was to compare response assessments and classifications based on various types of image registration with those based on (semi)-automatic tumour delineation.

Methods

Baseline (n = 13), early (n = 12) and late (n = 9) response (after one and three cycles of treatment, respectively) whole body [¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (PET/CT) scans were acquired in subjects with advanced gastrointestinal malignancies. Lesions were identified for early and late response scans. VOI were drawn independently on all scans using an adaptive 50% threshold method (A50). In addition, various types of (non-)rigid image registration were applied to PET and/or CT images, after which baseline VOI were projected onto response scans. Response was classified using PET Response Criteria in Solid Tumors for maximum standardized uptake value (SUV_max), average SUV (SUV_mean), peak SUV (SUV_peak), metabolically active tumour volume (MATV), total lesion glycolysis (TLG) and the area under a cumulative SUV-volume histogram curve (AUC).

Results

Non-rigid PET-based registration and non-rigid CT-based registration followed by non-rigid PET-based registration (CTPET) did not show differences in response classifications compared to A50 for SUV_max and SUV_peak,, however, differences were observed for MATV, SUV_mean, TLG and AUC. For the latter, these registrations demonstrated a poorer performance for small lung lesions (<2.8 ml), whereas A50 showed a poorer performance when another area with high uptake was close to the target lesion. All methods were affected by lesions with very heterogeneous tracer uptake.

Conclusions

Non-rigid PET- and CTPET-based image registrations may be used to classify response based on SUV_max and SUV_peak. For other quantitative measures future studies should assess which method is valid for response evaluations by correlating with survival data.

Anti-angiogenic therapies for metastatic colorectal cancer: Current and future perspectives

Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer and the second leading cause of cancer death in both men and women in the United States, with about 142820 new cases and 50830 deaths expected in 2013. Metastatic disease (mCRC) remains a challenge for oncologists worldwide due to its potential comorbidities. Recently, chemotherapy regimens containing 5-fluorouracil, leucovorin, oxaliplatin and irinotecan combinations are a standard of care in the metastatic disease. Currently, biological therapies involving vascular endothelial growth factor and epidermal growth factor receptor pathways, such as bevacizumab and cetuximab, have emerged as good option for improving mCRC patient survival. Now, aflibercept plus standard chemotherapy has also been approved in second line regimen for mCRC patients. Our review will discuss novel biological drugs and their indications for mCRC patients and will bring future perspectives in this regard.

Regorafenib: from bench to bedside in colorectal cancer

Colorectal cancer (CRC) remains the third cause of cancer-related mortality in the USA. Despite the advances in screening, many patients present with incurable metastatic disease. Chemotherapy forms the basis of treatment for patients with advanced disease. Angiogenesis is an important step in developing metastases and, therefore, blocking the VEGF pathway seems promising. The development of bevacizumab as a monoclonal antibody targeting the VEGF pathway improved progression-free survival and overall survival in the metastatic settings, with no improvement in disease-free or overall survival in the adjuvant settings. Small molecules such as tyrosine-kinase inhibitors have been long evaluated in metastatic CRC with disappointing results in improving outcome. Most recently, the CORRECT study has resulted in improved outcome in patients with metastatic CRC who were heavily pretreated when they received regorafenib.

Fibroblast growth factor receptor 2: a therapeutic target in gastric cancer

Gastric cancer remains a leading cause of cancer-related death in the world. FGF receptor 2 (FGFR2) is preferentially amplified and overexpressed in the diffuse type of gastric cancer. This review evaluates the expression and function of FGFR2 in gastric cancer, and analyzes the use of its inhibitors for gastric cancer therapy. This review also discusses the limitations of FGFR2-based therapy, and envisages future developments toward the clinical applications of FGFR2.

Quality of life in patients with K-RAS wild-type colorectal cancer: the CO.20 phase 3 randomized trial

BACKGROUND

The CO.20 trial randomized patients with K-RAS wild-type, chemotherapy-refractory, metastatic colorectal cancer to receive cetuximab (CET) plus brivanib alaninate (BRIV) or CET plus placebo (CET/placebo).

METHODS

Quality of life (QoL) was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 at baseline and at 2, 4, 6, 8, 12, 16, and 24 weeks until disease progression. Predefined coprimary QoL endpoints were time to deterioration (first worsening from baseline of ≥ 10 points) on the Physical Function (PF) and Global (GHS) scales.

RESULTS

Of 750 randomized patients, 721 (358 of whom received CET/BRIV) were assessable for QoL. QoL compliance and baseline PF and GHS scores did not differ by treatment arm. The median time to deterioration was 1.6 months versus 1.1 months for GHS (P =.02) and 5.6 months versus 1.7 months for PF (P <.0001) favoring CET/placebo. Secondary analysis favored CET/placebo for QOL response on the PF, Cognitive Function, Fatigue, Nausea, Appetite, and Diarrhea scales. A greater percentage of patients on the CET/BRIV arm had PF worsening at 6 weeks (31% vs 17%). Clinical adverse events of ≥ grade 3 were more common with CET/BRIV than with CET/placebo, including fatigue (25% vs 11%), hypertension, rash, diarrhea, abdominal pain, dehydration, and anorexia.

CONCLUSIONS

Compared with CET/placebo, the combination of CET/BRIV worsened time to QoL deterioration for patients with K-RAS wild-type, chemotherapy-refractory, metastatic colorectal cancer on the PF and GHS scales of European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30. This result may be due to higher rates of fatigue and gastrointestinal adverse events.

Brivanib in Patients With Advanced Hepatocellular Carcinoma Who Were Intolerant to Sorafenib or for Whom Sorafenib Failed: Results From the Randomized Phase III BRISK-PS Study

Purpose

Brivanib is a selective dual inhibitor of vascular endothelial growth factor and fibroblast growth factor receptors implicated in tumorigenesis and angiogenesis in hepatocellular carcinoma (HCC). An unmet medical need persists for patients with HCC whose tumors do not respond to sorafenib or who cannot tolerate it. This multicenter, double-blind, randomized, placebo-controlled trial assessed brivanib in patients with HCC who had been treated with sorafenib.

Patients and Methods

In all, 395 patients with advanced HCC who progressed on/after or were intolerant to sorafenib were randomly assigned (2:1) to receive brivanib 800 mg orally once per day plus best supportive care (BSC) or placebo plus BSC. The primary end point was overall survival (OS). Secondary end points included time to progression (TTP), objective response rate (ORR), and disease control rate based on modified Response Evaluation Criteria in Solid Tumors (mRECIST) and safety.

Results

Median OS was 9.4 months for brivanib and 8.2 months for placebo (hazard ratio [HR], 0.89; 95.8% CI, 0.69 to 1.15; P = .3307). Adjusting treatment effect for baseline prognostic factors yielded an OS HR of 0.81 (95% CI, 0.63 to 1.04; P = .1044). Exploratory analyses showed a median time to progression of 4.2 months for brivanib and 2.7 months for placebo (HR, 0.56; 95% CI, 0.42 to 0.76; P < .001), and an mRECIST ORR of 10% for brivanib and 2% for placebo (odds ratio, 5.72). Study discontinuation due to treatment-related adverse events (AEs) occurred in 61 brivanib patients (23%) and nine placebo patients (7%). The most frequent treatment-related grade 3 to 4 AEs for brivanib included hypertension (17%), fatigue (13%), hyponatremia (11%), and decreased appetite (10%).

Conclusion

In patients with HCC who had been treated with sorafenib, brivanib did not significantly improve OS. The observed benefit in the secondary outcomes of TTP and ORR warrants further investigation.

Brivanib versus sorafenib as first-line therapy in patients with unresectable, advanced hepatocellular carcinoma: results from the randomized phase III BRISK-FL study

PURPOSE

Brivanib is a dual inhibitor of vascular-endothelial growth factor and fibroblast growth factor receptors that are implicated in the pathogenesis of hepatocellular carcinoma (HCC). Our multinational, randomized, double-blind, phase III trial compared brivanib with sorafenib as first-line treatment for HCC.

PATIENTS AND METHODS

Advanced HCC patients who had no prior systemic therapy were randomly assigned (ratio, 1:1) to receive sorafenib 400 mg twice daily orally (n = 578) or brivanib 800 mg once daily orally (n = 577). Primary end point was overall survival (OS). Secondary end points included time to progression (TTP), objective response rate (ORR), disease control rate (DCR) based on modified Response Evaluation Criteria in Solid Tumors (mRECIST), and safety.

RESULTS

The primary end point of OS noninferiority for brivanib versus sorafenib in the per-protocol population (n = 1,150) was not met (hazard ratio [HR], 1.06; 95.8% CI, 0.93 to 1.22), based on the prespecified margin (upper CI limit for HR ≤ 1.08). Median OS was 9.9 months for sorafenib and 9.5 months for brivanib. TTP, ORR, and DCR were similar between the study arms. Most frequent grade 3/4 adverse events for sorafenib and brivanib were hyponatremia (9% and 23%, respectively), AST elevation (17% and 14%), fatigue (7% and 15%), hand-foot-skin reaction (15% and 2%), and hypertension (5% and 13%). Discontinuation as a result of adverse events was 33% for sorafenib and 43% for brivanib; rates for dose reduction were 50% and 49%, respectively.

CONCLUSION

Our study did not meet its primary end point of OS noninferiority for brivanib versus sorafenib. However, both agents had similar antitumor activity, based on secondary efficacy end points. Brivanib had an acceptable safety profile, but was less well-tolerated than sorafenib.

Protein kinase inhibitors in metastatic colorectal cancer. Let's pick patients, tumors, and kinase inhibitors to piece the puzzle together!

INTRODUCTION

Increased understanding in intracellular signaling pathways leading to carcinogenesis, proliferation, migration, invasion, angiogenesis, and anti-apoptosis of colorectal cancer cells has been critical for target identification and drug development. Specific protein kinase inhibitors (KIs) have been developed to block activated pathways associated with tumor growth and progression. Although showing promising activity in preclinical models, until now, the majority of KIs were not able to demonstrate clinically meaningful efficacy in Phase II/III trials.

AREAS COVERED

The major pathways altered in colorectal cancer will be highlighted, and molecularly defined targets will be discussed. The mechanisms of action and the proof of principle demonstrated in preclinical models of KIs and the disappointing efficacy in clinical trials will be reviewed.

EXPERT OPINION

Despite recent negative study results, KIs have the potential to be the next class of therapeutics in the treatment of metastatic colorectal cancer. Molecular classification of the individual tumors and identification of molecular escape mechanisms for primary (intrinsic) and secondary resistances to KI treatment is critical to select the patients' most likely to benefit. Appropriate drug combinations based on those mechanisms of resistance have to be tested in selected patient populations to ensure progress and efficacy with the goal to lead to a clinically meaningful prolongation of patients' lives.

Phase III randomized, placebo-controlled study of cetuximab plus brivanib alaninate versus cetuximab plus placebo in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal carcinoma: the NCIC Clinical Trials Group and AGITG CO.20 Trial

PURPOSE

The antiepidermal growth factor receptor monoclonal antibody cetuximab has improved survival in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer. The addition of brivanib, a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor and fibroblast growth factor receptor, to cetuximab has shown encouraging early clinical activity.

PATIENTS AND METHODS

Patients with metastatic colorectal cancer previously treated with combination chemotherapy were randomly assigned 1:1 to receive cetuximab 400 mg/m(2) intravenous loading dose followed by weekly maintenance of 250 mg/m(2) plus either brivanib 800 mg orally daily (arm A) or placebo (arm B). The primary end point was overall survival (OS).

RESULTS

A total of 750 patients were randomly assigned (376 in arm A and 374 in arm B). Median OS in the intent-to-treat population was 8.8 months in arm A and 8.1 months in arm B (hazard ratio [HR], 0.88; 95% CI, 0.74 to 1.03; P = .12). Median progression-free survival (PFS) was 5.0 months in arm A and 3.4 months in arm B (HR, 0.72; 95% CI, 0.62 to 0.84; P < .001). Partial responses observed (13.6% v 7.2%; P = .004) were higher in arm A. Incidence of any grade ≥ 3 adverse events was 78% in arm A and 53% in arm B. Fewer patients received ≥ 90% dose-intensity of both cetuximab (57% v 83%) and brivanib/placebo (48% v 87%) in arm A versus arm B, respectively.

CONCLUSION

Despite positive effects on PFS and objective response, cetuximab plus brivanib increased toxicity and did not significantly improve OS in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer.

Brivanib: a review of development

The development of new agents in oncology has focused on disrupting key pathways in oncogenesis. Both malignant angiogenesis and peptide growth factor signaling have been studied extensively and have been validated for cancer treatment. While antibody-directed therapeutics offer increased specificity, small-molecule tyrosine kinase inhibitors often have the ability to hit multiple targets. Brivanib alaninate (BMS582664) is an oral, potent selective inhibitor of both the FGF and VEGF family of receptors. It is a first-in-class FGF/VEGF inhibitor now in late-phase clinical trials. Besides its antiangiogenic activity from blocking VEGF receptor 1-3, its ability to disrupt FGF receptors 1-3 has been suggested to add additional antiangiogenic activity, overcome resistance from VEGF blockade, and block FGF-dependent tumor proliferation. In this review, we will discuss the preclinical science driving brivanib's development and the clinical data generated to date.

Emerging VEGF-receptor inhibitors for colorectal cancer

INTRODUCTION

Targeted agents have dramatically improved and enriched the therapeutical choices for patients with metastatic colorectal cancer (mCRC). By better understanding the role of the angiogenic pathway in colorectal cancer (CRC), new therapies have been developed. Bevacizumab, the first anti-angiogenetic agent approved for the treatment of mCRC provide a proof of concept since it has improved the progression-free survival and overall survival when combined with cytotoxic chemotherapy.

AREAS COVERED

This review is focused on the most recent findings on the VEGF signaling pathway and new therapeutic drugs explored in clinical trials.

EXPERT OPINION

Despite the advantage offered by bevacizumab, the median overall survival of mCRC patient exceeds 21 months; thus, investigational efforts are needed. Several antiangiogenic agents for the treatment of mCRC are being tested in preclinical and clinical Phase I/II trials. Unfortunately a discrete number of Phase III trials produced negative results. Recently aflibercept and regorafenib, two new antiangiogenic drugs, have been approved as the new-targeted agents for the treatment of mCRC, according to the positive findings from the VELOUR and the CORRECT studies. In order to maximize clinical impact it will be important to validate predictive biomarkers and best combination treatments to offer for mCRC patients; further research and intense investigation is still required.

Antiangiogenesis therapy in the treatment of metastatic colorectal cancer

The process of new blood vessel formation, or angiogenesis, has become an important target for therapeutic intervention in many cancers, including metastatic colorectal cancer (mCRC). The growth and metastasis of primary tumors is dependent upon their ability to acquire and maintain an adequate blood supply; however, angiogenesis in tumors is an irregular process leading to chaotic and hyperpermeable vessels that may result in increased intratumoral pressure and poor exchange of macromolecules and oxygen. It has been hypothesized that inhibition of angiogenesis in tumors can both impair the formation of new tumor blood vessels and possibly 'normalize' the existing tumor vasculature, causing a more efficient delivery of cytotoxic chemotherapies (CTs). Over the last decade, therapies that target vascular endothelial growth factor (VEGF) have become a component of treatment for several cancers. In particular, the combination of bevacizumab with established chemotherapeutic regimens for mCRC has been shown to improve overall and progression-free survival, as well as response rates, over CT alone. Agents that target various members of the VEGF family, as well as signaling by the VEGF receptors and their tyrosine kinase components, are currently under development and evaluation in clinical trials. Integration of these new therapies into the treatment of mCRC will ultimately increase the available therapeutic options for patients. Still, many challenges remain, including identifying and validating relevant biomarkers to guide the optimal use of antiangiogenesis agents.

Antiangiogenic drugs for colorectal cancer: exploring new possibilities

Angiogenesis is essential to cancer development and progression, and its inhibition has been shown to benefit patients with several different malignancies. A considerable number of antiangiogenic compounds have been evaluated for the treatment of colorectal cancer, but only bevacizumab and aflibercept were able to demonstrate a survival benefit in phase III trials. In this review, we discuss important aspects of the interrelationship between tumor cells and the microenvironment leading to tumor progression, with a focus on angiogenesis. Clinical data on antiangiogenic therapies for colorectal cancer in the metastatic and adjuvant settings, as well as the potential use of antiangiogenics beyond tumor progression are analyzed. The need to identify surrogate biomarkers towards a more personalized approach in oncology is emphasized as this is becoming increasingly important in drug development.

Novel targets for VEGF-independent anti-angiogenic drugs

INTRODUCTION

In the last decades, the active research in the field of tumor angiogenesis led to the development of a class of agents providing an effective inhibition of neovessels formation through the blockade of VEGF-related pathways. More recently, the identification of several non-VEGF factors such as PDGF, FGF, HGF, angiopoietins, ALK1/endoglin, endothelis and ephrins involved in tumor angiogenesis have emphasized the need to develop agents targeting multiple pro-angiogenic pathways.

AREAS COVERED

This review aimed at summarizing the role of non-VEGF molecular pathways in targeting tumor angiogenesis. Preclinical and clinical data for investigational agents against non-VEGF targets have been reviewed emphasizing the role of combined inhibition strategies.

EXPERT OPINION

Besides the successful development of drugs providing a specific VEGF blockade, novel agents targeting alternative angiogenesis-related pathways are being tested. Although it seems that the potential clinical usefulness of these novel compounds have been not yet fully investigated, sunitinib, sorafenib, pazopanib and other multikinase inhibitors have certainly displayed encouraging results. A more in-depth clarification of anti-angiogenic agents is still needed, in order to design the best clinical setting and schedule for target-based agents and possibly anticipate potential tools to overcome the emerging issue of anti-angiogenic drug resistance.