Phase I study to determine the safety and pharmacokinetics of the novel Raf kinase and VEGFR inhibitor BAY 43-9006, administered for 28 days on/7 days off in patients with advanced, refractory solid tumors

Efficacy and safety of sorafenib for treatment of Japanese metastatic renal cell carcinoma patients undergoing hemodialysis

BACKGROUND

Little information has been published on the use of tyrosine kinase inhibitors for treatment of patients undergoing hemodialysis (HD). We investigated the efficacy and safety of sorafenib for metastatic renal cell carcinoma (mRCC) patients undergoing HD.

METHODS

Twenty patients undergoing HD were treated with sorafenib as first-line therapy for mRCC at our hospital between April 2008 and August 2014. Patient medical records were retrospectively reviewed to evaluate the response to sorafenib and treatment-related toxicity.

RESULTS

Fifteen and 5 patients were classified in the intermediate and poor risk groups, respectively, of the Memorial Sloan-Kettering Cancer Center risk model. Eighteen patients had 3 or more metastatic lesions, and 7 patients had metastases in 2 or more organs. Of 16 patients who had previously undergone nephrectomy, 8 were pathologically diagnosed with non-clear-cell carcinoma. The median duration of sorafenib therapy was 4.7 months. Sorafenib was discontinued owing to progressing disease for 15 patients and because of serious adverse events (AE) (≥grade 3) for 4 patients, i.e. subarachnoid hemorrhage, cerebral hemorrhage, sepsis, and syncope for 1 patient each. Median time to progression was 6.3 months, and median overall survival was 14.2 months.

CONCLUSIONS

In this study, many patients had unfavorable clinical features, for example poor risk classification and metastases in multiple organs. Although sorafenib treatment of HD patients seems feasible, careful monitoring is needed because of the tendency for a high incidence of serious AE, even when a reduced dose is administered.

The discovery and development of sorafenib for the treatment of thyroid cancer

INTRODUCTION

Although the prognosis for most differentiated thyroid cancers (DTCs) remains excellent, recurrence and insensitivity to radioactive iodine (RAI) lead to therapeutic challenges and poorer outcomes. In defining the pathogenesis of DTC, multiple genetic alterations have been identified in key pathways focused around receptor tyrosine kinases (RTKs) and the MAPK cascade. Sorafenib was specifically developed to target rapidly accelerated fibrosarcoma (RAF) kinase in the MAPK pathway. It has been shown, however, to have potent inhibition of several key RTKs, RAF kinase and the V600E BRAF mutation, gaining FDA approval in November 2013 for advanced RAI-refractory DTC.

AREAS COVERED

The authors provide a review of the targeted RAF kinase discovery strategy as well as the preclinical and clinical development of sorafenib, leading to FDA approval of DTC. The authors also provide some insight into the clinical use of sorafenib and look at important considerations for treatment.

EXPERT OPINION

Sorafenib significantly improves progression-free survival in metastatic DTC patients who are RAI-refractory. However, the overall survival benefit is still unproven and requires additional follow up. Despite its cost and significant side-effect profile, which results in dose reductions in the majority of DTC patients, sorafenib should be considered for the treatment of RAI-refractory advanced DTC patients following evaluation of their individual risk-benefit stratification.

Dual-drug delivery by porous silicon nanoparticles for improved cellular uptake, sustained release, and combination therapy

Dual-drug delivery of antiangiogenic and chemotherapeutic drugs can enhance the therapeutic effect for cancer therapy. Conjugation of methotrexate (MTX) to porous silicon (PSi) nanoparticles (MTX-PSi) with positively charged surface can improve the cellular uptake of MTX and inhibit the proliferation of cancer cells. Herein, MTX-PSi conjugates sustained the release of MTX up to 96 h, and the released fragments including MTX were confirmed by mass spectrometry. The intracellular distribution of the MTX-PSi nanoparticles was confirmed by transmission electron microscopy. Compared to pure MTX, the MTX-PSi achieved similar inhibition of cell proliferation in folate receptor (FR) over-expressing U87 MG cancer cells, and a higher effect in low FR-expressing EA.hy926 cells. Nuclear fragmentation analysis demonstrated programmed cell apoptosis of MTX-PSi in the high/low FR-expressing cancer cells, whereas PSi alone at the same dose had a minor effect on cell apoptosis. Finally, the porous structure of MTX-PSi enabled a successful concomitant loading of another anti-angiogenic hydrophobic drug, sorafenib, and considerably enhanced the dissolution rate of sorafenib. Overall, the MTX-PSi nanoparticles can be used as a platform for combination chemotherapy by simultaneously enhancing the dissolution rate of a hydrophobic drug and sustaining the release of a conjugated chemotherapeutic drug.

Sorafenib: a review of its use in patients with radioactive iodine-refractory, metastatic differentiated thyroid carcinoma

Sorafenib (Nexavar®) is the first tyrosine kinase inhibitor to be approved for the treatment of radioactive iodine (RAI)-refractory differentiated thyroid carcinoma (DTC). In the pivotal phase III DECISION trial in patients with RAI-refractory, locally advanced or metastatic DTC, oral sorafenib 400 mg twice daily significantly prolonged median progression-free survival (PFS) relative to placebo. The PFS benefit of sorafenib over placebo was evident in all pre-specified clinical and genetic biomarker subgroups, and neither BRAF nor RAS mutation status was predictive of sorafenib benefit for PFS. The objective response rate was significantly higher in patients receiving sorafenib than in those receiving placebo; all objective responses were partial responses. The overall survival benefit of sorafenib is as yet unclear, with no significant benefit observed at the time of primary analysis or at 9 months following the primary analysis. Overall survival was possibly confounded by the crossover of patients in the placebo group to sorafenib upon disease progression. The adverse events associated with sorafenib in the DECISION trial were consistent with the known tolerability profile of the drug, with hand-foot skin reaction, diarrhea, and alopecia reported most commonly. Most treatment-emergent adverse events were grade 1 or 2 in severity and occurred early in treatment. However, a high proportion of patients discontinued sorafenib therapy or required dose reductions or interruptions because of toxicity. Although final overall survival data are awaited, current evidence suggests that sorafenib is a promising new treatment option for patients with RAI-refractory, metastatic DTC.

Sorafenib and thyroid cancer

The emergence of serine-threonine small molecule, multi-targeted kinase inhibitors over the past decade is greatly impacting the therapeutic armamentarium for numerous malignancies, especially thyroid carcinoma. Chief among them are a class of agents referred to as vascular endothelial growth factor signal pathway inhibitors. Sorafenib is a lead compound that has been recently approved by the US FDA for radioactive iodine-refractory differentiated thyroid cancer (DTC). Sorafenib clearly is altering the natural history of DTC. In the largest randomized Phase III study ever conducted in DTC, sorafenib significantly improved progression-free survival compared to placebo (10.8 vs 5.8 months) and had an acceptable and manageable safety profile, though commonly attributed side effects of hand-foot skin reaction, diarrhea and hypertension were more frequent than in other settings. This agent represents a new treatment option for patients with progressive radioactive iodine-refractory DTC.

Novel approach of MALDI drug imaging, immunohistochemistry, and digital image analysis for drug distribution studies in tissues

Drug efficacy strongly depends on the presence of the drug substance at the target site. As vascularization is an important factor for the distribution of drugs in tissues, we analyzed drug distribution as a function of blood vessel localization in tumor tissue. To explore distribution of the anticancer drugs afatinib, erlotinib, and sorafenib, a combined approach of matrix-assisted laser desorption/ionization (MALDI) drug imaging and immunohistochemical vessel staining was applied and examined by digital image analysis. The following two xenograft models were investigated: (1) mice carrying squamous cell carcinoma (FaDu) xenografts (ntumor = 13) were treated with afatinib or erlotinib, and (2) sarcoma (A673) xenograft bearing mice (ntumor = 8) received sorafenib treatment. MALDI drug imaging revealed a heterogeneous distribution of all anticancer drugs. The tumor regions containing high drug levels were associated with a higher degree of vascularization than the regions without drug signals (p < 0.05). When correlating the impact of blood vessel size to drug abundance in the sarcoma model, a higher amount of small vessels was detected in the tumor regions with high drug levels compared to the tumor regions with low drug levels (p < 0.05). With the analysis of coregistered MALDI imaging and CD31 immunohistochemical data by digital image analysis, we demonstrate for the first time the potential of correlating MALDI drug imaging and immunohistochemistry. Here we describe a specific and precise approach for correlating histological features and pharmacokinetic properties of drugs at microscopic level, which will provide information for the improvement of drug design, administration formula or treatment schemes.

Emerging antiangiogenics for renal cancer

INTRODUCTION

Antiangiogenic therapy is considered to be the backbone of treatment strategy in metastatic renal cell carcinoma (mRCC). New, more focused, targeted drugs are emerging, while other targeted drugs oriented toward resistance or alternative mechanisms are under development.

AREAS COVERED

Antiangiogenic agents include two types of agents: the monoclonal antibody, targeting vascular endothelial growth factor (VEGF), bevacizumab and the tyrosine kinase inhibitors (TKIs). Data regarding efficacy and safety of these agents are reported. Differences between the first generation of TKIs, sunitinib, sorafenib, and the new generation, pazopanib, axitinib and tivozanib are also detailed. Most of these agents have been approved in the treatment of kidney cancer in specific settings of the disease.

EXPERT OPINION

The class of antiangiogenic drugs for treatment of mRCC is already relatively full. After 'me-too' drugs, more targeted drugs against VEGFR have been developed but have to demonstrate a benefit in first-line treatment. Another option for the development is to combine a known drug with an antiangiogenic inhibition profile and at least one additional target involved in resistance to an antiangiogenic or in an alternative pathway. The cost of approach with targeted drugs, including antiangiogenics, has led to a tremendous increase in the cost of care in mRCC.

The study of a novel sorafenib derivative HLC-080 as an antitumor agent

In this study, our objective is to evaluate the potential of a novel Sorafenib derivative, named HLC-080, as a new anticancer agent for colon cancer. We firstly carried out MTT assay, colony formation assay, flow cytometry analysis and transwell invasion assay to determine effect of our compound HLC-080 on cell viability, anti-proliferation activity, cell cycle arrest and the intervention on cell invasion, respectively. On the other hand, in vivo antitumor activity of HLC-080 was also tested using H22 xenograft model and the angiogenesis effect of HLC-080 was measured by EA.hy926 tube formation assay. The expression levels of various proteins in HLC-080 treated with HT-29 cell lines were examined using Western blot and ELISA experiments. The results showed that HLC-080 could dramatically inhibit the growth and colony formation of various tumor cells, therefore exhibited remarkable antitumor activity. HLC-080 can induce cell cycle arrest at G1 phase in HT-29 cells and subsequently inhibit the invasive potential of colon cancer cells. HLC-080 also exhibits anti-angiogenesis effect in EA.hy926 model. Additionally, the in vivo study showed that HLC-080 was able to reduced the tumor weight with the rate of 35.81%. And at the concentration of 0.352±0.034 µM, HLC-080 is able to reduce half of the regular protein level of p-c-Raf (Ser259), consequently block Raf/MEK/ERK signaling in HT-29 cell lines. In conclusion, our study suggests that Sorafenib derivative HLC-080 has the potential to inhibit cell proliferation and angiogenesis, Since, HLC-080 is particularly active against human colon cancer cells, our study highlights that HLC-080 and its related analogues may serve as a new anti-cancer drug, particularly against colon cancer.

Efficacy and tolerability of different starting doses of sorafenib in patients with differentiated thyroid cancer

Sorafenib has proven efficacy in advanced differentiated thyroid cancer (DTC), but many patients must reduce the dose or discontinue treatment because of toxicity. The tolerability and efficacy of lower starting doses of sorafenib for DTC remain largely unstudied. Methods. We retrospectively examined overall survival, time to treatment failure, time to progression, discontinuation rates, and dose-reduction and interruption rates in patients with metastatic DTC treated with first-line sorafenib outside of a clinical trial. Two patient groups were compared; group 1 received the standard starting dose of 800 mg/day, and group 2 received any dose lower than 800 mg/day. Results. We included 75 adult patients, with 51 in group 1 and 24 in group 2. Mean age at diagnosis was 54 years, and 56% were male. The most common histologies included 43% papillary thyroid cancer of the conventional type, 15% papillary thyroid cancer of the follicular variant, and 15% Hürthle cell carcinoma. Time to treatment failure was 10 months (95% confidence interval [CI]: 5.6-14.3) in group 1 and 8 months (95% CI: 3.4-12.5) in group 2 (p = .56). Median overall survival was 56 months (95% CI: 30.6-81.3) in group 1 and 30 months (95% CI: 16.1-43.8) in group 2 (p = .08). Rates of discontinuation due to disease progression were 79% in group 1 and 91% in group 2, and 21% in group 1 and 9% in group 2 (p = .304) stopped treatment because of toxicity. Dose-reduction rates were 59% and 43% (p = .29), and interruption rates were 65% and 67% (p = .908) in group 1 and group 2, respectively. Conclusion. Efficacy and tolerability of sorafenib in treatment-naïve DTC patients does not appear to be negatively influenced by lower starting daily doses.

Clinical pharmacokinetics of tyrosine kinase inhibitors: implications for therapeutic drug monitoring

The treatment of many malignancies has been improved in recent years by the introduction of molecular targeted therapies. These drugs interact preferentially with specific targets that are mutated and/or overexpressed in malignant cells. A group of such targets are the tyrosine kinases, against which a number of inhibitors (tyrosine kinase inhibitors, TKIs) have been developed. Imatinib, a TKI with targets that include the breakpoint cluster region-Abelson (bcr-abl) fusion protein kinase and mast/stem cell growth factor receptor kinase (c-Kit), was the first clinically successful drug of this type and revolutionized the treatment and prognosis of chronic myeloid leukemia and gastrointestinal stromal tumors. This success paved the way for the development of other TKIs for the treatment of a range of hematological malignancies and solid tumors. To date, 14 TKIs have been approved for clinical use and many more are under investigation. All these agents are given orally and are substrates of a range of drug transporters and metabolizing enzymes. In addition, some TKIs are capable of inhibiting their own transporters and metabolizing enzymes, making their disposition and metabolism at steady-state unpredictable. A given dose can therefore give rise to markedly different plasma concentrations in different patients, favoring the selection of resistant clones in the case of subtherapeutic exposure, and increasing the risk of toxicity if dosage is excessive. The aim of this review was to summarize current knowledge of the clinical pharmacokinetics and known adverse effects of the TKIs that are available for clinical use and to provide practical guidance on the implications of these data in patient management, in particular with respect to therapeutic drug monitoring.

Sorafenib cardiotoxicity increases mortality after myocardial infarction

RATIONALE

Sorafenib is an effective treatment for renal cell carcinoma, but recent clinical reports have documented its cardiotoxicity through an unknown mechanism.

OBJECTIVE

Determining the mechanism of sorafenib-mediated cardiotoxicity.

METHODS AND RESULTS

Mice treated with sorafenib or vehicle for 3 weeks underwent induced myocardial infarction (MI) after 1 week of treatment. Sorafenib markedly decreased 2-week survival relative to vehicle-treated controls, but echocardiography at 1 and 2 weeks post MI detected no differences in cardiac function. Sorafenib-treated hearts had significantly smaller diastolic and systolic volumes and reduced heart weights. High doses of sorafenib induced necrotic death of isolated myocytes in vitro, but lower doses did not induce myocyte death or affect inotropy. Histological analysis documented increased myocyte cross-sectional area despite smaller heart sizes after sorafenib treatment, further suggesting myocyte loss. Sorafenib caused apoptotic cell death of cardiac- and bone-derived c-kit+ stem cells in vitro and decreased the number of BrdU+ (5-bromo-2'-deoxyuridine+) myocytes detected at the infarct border zone in fixed tissues. Sorafenib had no effect on infarct size, fibrosis, or post-MI neovascularization. When sorafenib-treated animals received metoprolol treatment post MI, the sorafenib-induced increase in post-MI mortality was eliminated, cardiac function was improved, and myocyte loss was ameliorated.

CONCLUSIONS

Sorafenib cardiotoxicity results from myocyte necrosis rather than from any direct effect on myocyte function. Surviving myocytes undergo pathological hypertrophy. Inhibition of c-kit+ stem cell proliferation by inducing apoptosis exacerbates damage by decreasing endogenous cardiac repair. In the setting of MI, which also causes large-scale cell loss, sorafenib cardiotoxicity dramatically increases mortality.

Is intra-patient sorafenib dose re-escalation safe and tolerable in patients with advanced hepatocellular carcinoma?

BACKGROUND

Although sorafenib improves survival in patients with hepatocellular carcinoma (HCC), doses have to be reduced in quite a few patients because of adverse events. We investigated whether intra-patient sorafenib dose re-escalations were safe and tolerable in patients with advanced HCC.

METHODS

Of the 73 advanced HCC patients treated with sorafenib, 42 achieved a tolerable dose with a dose reduction. We evaluated safety and tolerability in patients who attempted intra-patient dose re-escalations from the reduced dose.

RESULTS

Thirteen of 42 patients increased the sorafenib dose from the reduced dose. Ten patients had a tolerable dose of 400 mg on alternate days, and 3 patients had a tolerable dose of 400 mg daily. Dose-limiting toxicity (DLT), defined as toxicity resulting in a dose reduction, was observed in 8 of 13 patients as a hand-foot skin reaction (HFSR), and DLT was noted in 2 of 13 patients as an increase in alanine aminotransferase/aspartate aminotransferase levels. Seven of 13 patients did not exhibit DLT after dose re-escalations. Although 6 patients exhibited DLT, the cause of the adverse event was HFSR in all cases. The median escalation dose ratio, which was calculated as the ratio of the real cumulative dose to the cumulative dose when continued at the tolerable dose after dose re-escalation, was 1.84.

CONCLUSIONS

The results of the present study indicated that intra-patient sorafenib dose re-escalations were safe and tolerable. Further prospective analyses are needed to determine in more detail the safety and efficacy of intra-patient sorafenib dose re-escalations.

Clinical pharmacology of tyrosine kinase inhibitors becoming generic drugs: the regulatory perspective

Over the last decades, billions have been spent and huge efforts have been taken in basic and clinical cancer research [CA Cancer J Clin63:11-30]. About a decade ago, the arms race between drugs and cancer cells reached a new level by introduction of tyrosine kinase inhibitors (TKI) into pharmacological anti-cancer therapy. According to their molecular mechanism of action, TKI in contrast to so-called "classic" or "conventional" cytostatics belong to the group of targeted cancer medicines, characterized by accurately fitting with biological structures (i.e. active centers of kinases). Numerous (partly orphan) indications are covered by this new class of substances. Approximately ten years after the first substances of this class of medicines were authorized, patent protection will end within the next years. The following article covers clinical meaning and regulatory status of anti-cancer TKI and gives an outlook to what is expected from the introduction of generic anti-cancer TKI.

Tivozanib for the treatment of metastatic renal cancer

Tyrosine kinase inhibitors have revolutionized the treatment of metastatic renal cell carcinoma (RCC). Drugs such as sorafenib, sunitinib and pazopanib act on the VEGF receptor pathway, but they can also inhibit other kinases, resulting in off-target toxicities. Tivozanib was developed due to its potency and selectivity against VEGF receptors 1-3. It has a favorable pharmacokinetic profile after oral administration and a long plasma half-life. In the Phase III TIVO-1 trial, it demonstrated a higher response rate and longer progression-free survival than sorafenib with a better side-effect profile. It is currently awaiting approval to be used in the first-line treatment of metastatic RCC. An early-phase trial has also shown its tolerability at full dose when given with the mTOR inhibitor temsirolimus, suggesting its potential in combination treatment. This article examines tivozanib from its laboratory to clinical development, as well as its relevance and future role in the treatment of RCC in the era of the tyrosine kinase inhibitors.

Sorafenib for the treatment of hepatocellular carcinoma across geographic regions

Sorafenib is an oral multikinase inhibitor targeting Raf, VEGF receptor, PDGF receptor, c-kit, Flt-3 and rearranged during transfection (RET). Two randomized, placebo-controlled trials for Western and Asian patients, respectively, demonstrated that sorafenib significantly prolongs overall survival and time to progression in patients with advanced hepatocellular carcinoma (HCC). These have become the reference treatment for future clinical trials of advanced HCC. Sorafenib is well tolerated in patients with Child-Pugh liver function class A, but limited data are available in Child-Pugh class B and C patients. Clinical trials are ongoing to test the efficacy of sorafenib-based combination therapy and sorafenib adjuvant therapy for HCC.

Sorafenib: targeting multiple tyrosine kinases in cancer

Sorafenib (BAY 43-9006, Nexavar®) is an oral multiple tyrosine kinase inhibitor. Main targets are receptor tyrosine kinase pathways frequently deregulated in cancer such as the Raf-Ras pathway, vascular endothelial growth factor (VEGF) pathway, and FMS-like tyrosine kinase 3 (FLT3). Sorafenib was approved by the FDA in fast track for advanced renal cell cancer and hepatocellular cancer and shows good clinical activity in thyroid cancer. Multiple clinical trials are undertaken to further investigate the role of sorafenib alone or in combination for the treatment of various tumor entities.

Fractionation of daily dose increases the predicted risk of severe sorafenib-induced hand-foot syndrome (HFS)

OBJECTIVES

The objective was to quantify the risk dynamics for the sorafenib-induced hand-foot syndrome (HFS) and to explore by simulations the dose-toxicity relationships according to different dosing regimens.

PATIENTS AND METHODS

Eighty-nine patients treated with sorafenib were considered: Treatment duration and regimen, and number and frequency of HFS observations were highly variable. A nonlinear mixed-effect model was built to link sorafenib administrations to the risk of each HFS score, through a latent variable model. Model evaluation was driven by goodness-of-fit and simulation-based diagnostics. Impact of sorafenib regimen on HFS dynamics was evaluated by simulations. A surrogate measure of benefit-to-risk ratio was calculated by using the concept of utility function, accounting for efficacy on tumor growth inhibition and severe HFS risk.

RESULTS AND DISCUSSION

An original pharmacokinetic-pharmacodynamic model for sorafenib-induced HFS, including the kinetics of a latent variable model, relating sorafenib administrations, per se its exposure, to HFS dynamics is proposed. From the model simulations, it appears that the more the daily dose is fractioned, the more the patients are at risk of HFS. Interestingly, the number of daily occasions was found more influential than the dose itself. Taking into account tumor growth inhibition in the utility function, the twice-daily administration schedule is favored for daily doses >600 mg. This approach illustrates how understanding the dynamic relationship between drug administrations and a limiting adverse event may help to control toxicity and adequately adjust treatment modalities.

Sorafenib overcomes irinotecan resistance in colorectal cancer by inhibiting the ABCG2 drug-efflux pump

Despite recent advances in the treatment of colorectal cancer (CRC), tumor resistance is a frequent cause of chemotherapy failure. Therefore, new treatment options are needed to improve survival of patients with irinotecan-refractory CRCs, particularly those bearing KRAS mutations that preclude the use of anti-EGFR therapies. In this study, we investigated whether sorafenib could reverse irinotecan resistance, thereby enhancing the therapeutic efficacy of routinely used irinotecan-based chemotherapy. We used both in vitro (the HCT116, SW48, SW620, and HT29 colon adenocarcinoma cell lines and four SN-38-resistant HCT-116 and SW48 clones) and in vivo models (nude mice xenografted with SN-38-resistant HCT116 cells) to test the efficacy of sorafenib alone or in combination with irinotecan or its active metabolite, SN-38. We have shown that sorafenib improved the antitumoral activity of irinotecan in vitro, in both parental and SN-38-resistant colon adenocarcinoma cell lines independently of their KRAS status, as well as in vivo, in xenografted mice. By inhibiting the drug-efflux pump ABCG2, sorafenib favors irinotecan intracellular accumulation and enhances its toxicity. Moreover, we found that sorafenib improved the efficacy of irinotecan by inhibiting the irinotecan-mediated p38 and ERK activation. In conclusion, our results show that sorafenib can suppress resistance to irinotecan and suggest that sorafenib could be used to overcome resistance to irinotecan-based chemotherapies in CRC, particularly in KRAS-mutated tumors.

Targeting tyrosine-kinases in ovarian cancer

INTRODUCTION

Epithelial ovarian cancer (EOC) is the leading cause of gynaecologic cancer death. Although in some cases initial treatment is effective, most of the women diagnosed with EOC will probably need medical treatment for their disease. There is a critical need to develop effective new strategies for the management of patients with advanced or recurrent EOC, and targeted therapy with tyrosine kinase inhibitors (TKIs) has continued to be an area of active research and development in this setting.

AREAS COVERED

This review summarises the available evidence on the use of TKIs in the clinical management of women with EOC. This article consists of material obtained via Medline, PubMed and EMBASE literature searches up to March 2013.

EXPERT OPINION

Several Phase I/II and III trials evaluated TKIs in EOC; however, it is difficult to draw conclusions on the efficacy of TKI regimens in these patients. TKIs seem to be better tolerated than conventional chemotherapy with a different toxicity profile. A better understanding of the signalling pathways, the toxicity profiles, the potential pharmacokinetic interactions as well as the identification of predictive biomarkers are needed to better identify a targeted patient population before these agents become part of routine treatment.

Ras and Ras mutations in cancer

Ras genes are pre-eminent genes that are frequently linked with cancer biology. The functional loss of ras protein caused by various point mutations within the gene, is established as a prognostic factor for the genesis of a constitutively active Ras-MAPK pathway leading to cancer. Ras signaling circuit follows a complex pathway, which connects many signaling molecules and cells. Several strategies have come up for targeting mutant ras proteins for cancer therapy, however, the clinical benefits remain insignificant. Targeting the Ras-MAPK pathway is extremely complicated due its intricate networks involving several upstream and downstream regulators. Blocking oncogenic Ras is still in latent stage and requires alternative approaches to screen the genes involved in Ras transformation. Understanding the mechanism of Ras induced tumorigenesis in diverse cancers and signaling networks will open a path for drug development and other therapeutic approaches.

Off-label use of cetuximab plus sorafenib and panitumumab plus regorafenib to personalize therapy for a patient with V600E BRAF-mutant metastatic colon cancer

Sorafenib, the first agent developed to target BRAF mutant melanoma, is a multi-kinase inhibitor that was approved by the FDA for therapy of kidney and subsequently liver cancer, and is currently in clinical trials for thyroid, lung and brain cancer. Colorectal cancer with V600E BRAF mutation has shown relative resistance to standard chemotherapy regimens, as well as lack of efficacy to vemurafenib in clinical trials. New treatments are needed for BRAF-mutant colorectal cancer. We report a case of a patient with BRAF-mutant metastatic colon cancer whose disease had progressed on FOLFOX plus bevacizumab and subsequent FOLFIRI plus cetuximab. Based on preclinical data published in Nature in 2012 suggesting that successful therapeutic targeting of BRAF in colorectal cancer may require concomitant targeting of the EGFR, we offered this patient without other attractive options the combination of sorafenib plus cetuximab, in off-label use with informed consent. Sorafenib and cetuximab therapy led to a mixed radiographic response with some areas showing dramatic improvement and other areas showing stable disease over a 7-month period which is a notably long period of progression-free survival for V600E BRAF mutated colon cancer. The cetuximab plus sorafenib therapy was very well-tolerated by the patient who remained on it long enough until another therapy option, regorafenib, was approved in September 2012. The patient was offered single agent regorafenib at the time of progression. At the time of progression on single agent regorafenib, panitumumab was combined with regorafenib and this was also well-tolerated and appeared to slow disease progression. Further study of these approaches in the clinic as personalized treatment of BRAF-mutant advanced colorectal cancer is warranted.

Safety of liver resection for hepatocellular carcinoma after sorafenib therapy: a multicenter case-matched study

BACKGROUND

Liver resection can be considered in some hepatocellular carcinoma (HCC) patients who received sorafenib. The lack of clinical data about safety of resection after sorafenib treatment led us to assess its potential impact on perioperative course in a multicentric study.

METHODS

From 2008 to 2011, a total of 23 HCC patients who underwent liver resection after treatment with sorafenib (sorafenib group) were compared with 46 HCC patients (control group) matched for age, gender, underlying liver disease, tumor characteristics and type of resection. Patients received sorafenib for a median duration of 1 (range 0.2-11) months and drug was interrupted at least 7 days before surgery. End points were intraoperative (operative time, vascular clamping, blood loss and transfusion), and postoperative outcomes focusing on recovery of liver function.

RESULTS

In the sorafenib group, HCC was developed on F4 cirrhosis in 48 % and the rate of major resection was 44 %. Surgical procedure duration (280 vs. 240 min), transfusion rate (26 vs. 15 %), blood loss (400 vs. 300 mL) and vascular clamping (70 vs. 74 %) were similar in the two groups. Mortality was zero in the sorafenib group and one (2.1 %) in the control group (p = 1.000). The incidence of postoperative complications was 44 % in the sorafenib group and 59 % in the control group (p = 0.307). Recovery of liver function was similar in the two groups in terms of prothrombin time (90 vs. 81 %, p = 0.429) and bilirubin level (16 vs. 24 μmol/L, p = 102) at postoperative day 5.

CONCLUSIONS

No adverse effect of preoperative administration of sorafenib was observed during and immediately after liver resection for HCC.

Targeted therapies in the treatment of advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common liver cancer and the third leading cause of cancer death. It has been a major worldwide health problem with more new cases being diagnosed each year. The current available therapies for patients with advanced HCC are extremely limited. Therefore, it is of great clinical interests to develop more effective therapies for systemic treatment of advanced HCC. Several promising target-based drugs have been tested in a number of clinical trials. One breakthrough of these efforts is the approved clinical use of sorafenib in patients with advanced HCC. Targeted therapies are becoming an attractive option for the treatment of advanced HCC. In this review, we summarize the most recent progress in clinical targeted treatments of advanced HCC.

Phase I trial and pharmacokinetic study of sorafenib in children with neurofibromatosis type I and plexiform neurofibromas

BACKGROUND

Sorafenib targets multiple pathways thought to be crucial in growth of plexiform neurofibroma (PN) in children with neurofibromatosis type 1 (NF1). Sorafenib has been tolerated with manageable toxicities in adults and children with refractory cancer. We conducted a separate study in this population. Monitoring long-term toxicities such as effects on growth and obtaining additional pharmacokinetic data were of importance due to the young age and long duration of therapy seen in previous phase I trials in children with NF1.

PROCEDURE

Children ≥3 and ≤18-year-old with NF1 and inoperable PN were eligible. Sorafenib was administered orally twice daily for consecutive 28-day cycles. Maximum tolerated dose (MTD) was determined from toxicities observed during the first three cycles.

RESULTS

Nine children enrolled, median age 8 (6-12) years. At the starting 115 mg/m(2) /dose (n = 5), two experienced dose-limiting grade 3 pain in their PN. At the de-escalated 80 mg/m(2) /dose (n = 4), approximately 40% of the pediatric solid tumor MTD, two had dose-limiting toxicity (grade 3 rash and grade 4 mood alteration), exceeding the MTD. At 80 mg/m(2) /dose, the median AUC(0-12 hours) at steady-state was 39.5 µg hours/ml. Toxicities appeared to correspond with decreases in quality of life (QOL). No tumor shrinkage was observed.

CONCLUSIONS

Children with NF1 and PN did not tolerate sorafenib at doses substantially lower than the MTD in children and adults with malignant solid tumors. Future trials with targeted agents for children with NF1 may require a more conservative starting dose and separate definitions of dose limiting toxicities (DLT) than children with cancer.

In vivo RAF signal transduction as a potential biomarker for sorafenib efficacy in patients with neuroendocrine tumours

BACKGROUND

Targeted therapies elicit anticancer activity by exerting pharmacodynamic effects on specific molecular targets. Currently, there is limited use of pharmacodynamic assessment to guide drug administration in the routine oncology setting.

METHODS

We developed a phosphoshift (pShift) flow cytometry-based test that measures RAF signal transduction capacity in peripheral blood cells, and evaluated it in a phase II clinical trial of oral sorafenib plus low-dose cyclophosphamide in patients with advanced neuroendocrine tumours (NETs), in order to predict clinical course and/or guide individual dose-titration.

RESULTS

Twenty-two patients were enrolled. Median progression-free survival (PFS) was 3 months (95% CI 2-10.7), and one patient had a partial response. PFS was longer among five patients who demonstrated an increase in pShift after 7 days of sorafenib compared with those who did not (14.9 months vs 2.8 months; P=0.047). However, pShift did not add value to toxicity-based dose-titration.

CONCLUSION

The pharmacodynamic assessment of RAF transduction may identify selected patients with advanced NETs most likely to benefit from the combination of sorafenib plus cyclophosphamide. Further investigation of this test as a potential biomarker is warranted.

Comprehensive overview of the efficacy and safety of sorafenib in advanced or metastatic renal cell carcinoma after a first tyrosine kinase inhibitor

We performed a literature search that shed light on the signaling pathways involved in the sorafenib activity as first- or subsequent-line treatment, taking into account its toxicity profile. Sorafenib appears to have better tolerability when compared with other agents in the same indication. Cross-resistance between tyrosine kinase inhibitors (TKIs) may be limited, even after failure with a previous VEGFR inhibitor, but the optimal sequence with TKIs remains to be determined. Randomized trials of second-line treatment options have showed either modest or no differences in terms of progression-free and overall survival (OS). Direct comparison between sorafenib and axitinib demonstrated differences in terms of PFS in favor of axitinib, but not in terms of OS as second-line treatment. In contrast, a phase III study showed a benefit in OS, favoring sorafenib when compared with temsirolimus. In conclusion, after using other VEGF inhibitor such as sunitinib, sorafenib is active and safe for the treatment of patients with advanced or metastatic RCC.

NABTT 0502: a phase II and pharmacokinetic study of erlotinib and sorafenib for patients with progressive or recurrent glioblastoma multiforme

BACKGROUND

The signal transduction pathways of epidermal growth factor receptor and Ras are both important in the growth of glioblastoma multiforme (GBM). We hypothesized that inhibition of both pathways would improve the survival time of patients with recurrent GBM.

METHODS

Patients with recurrent/progressive GBM with 0-2 prior chemotherapy regimens received erlotinib 150 mg once daily and sorafenib 400 mg twice daily until progression. The primary endpoint was overall survival. Pharmacokinetic sampling was performed during cycle 1.

RESULTS

The median overall survival was 5.7 months. Progression-free survival at 6 months was 14%. Toxicity was manageable. Clearance of erlotinib was markedly enhanced by sorafenib.

CONCLUSION

The study did not meet its objective of a 30% increase in overall survival time compared with historical controls. Erlotinib and sorafenib have significant pharmacokinetic interactions that may negatively impact the efficacy of the combination regimen.

Experience with sorafenib in the treatment of advanced renal cell carcinoma

The molecular-targeted agent sorafenib is the first anticancer agent able to slow the progression of advanced/metastatic renal cell carcinoma, a tumor that was formerly refractory to conventional therapy. Experience from everyday clinical practice and investigations exploring the suitability of this agent for patients with harmful pathological conditions has extended the use of sorafenib to other settings of renal cell carcinoma and to particular risk populations. The aim of this review is to provide evidence on the most effective and safe use of sorafenib. The review pays particular attention to patients who have several comorbidities, such as impaired renal and cardiac function, and older patients whose frailty due to impaired organ function necessitates the most careful administration of targeted antineoplastic agents.

Safety and Efficacy of Sorafenib in Renal Cell Carcinoma

This article reviews data on sorafenib use in renal cell carcinoma. Mechanisms of actions and pharmacokinetics are briefly described. Major clinical trials are presented, summarizing efficacy and safety of sorafenib. Its place in current treatment of renal cell carcinoma is discussed. Sorafenib is likely to remain one of the mainstays of RCC treatment in coming years.

Long-term exposure to sorafenib of liver cancer cells induces resistance with epithelial-to-mesenchymal transition, increased invasion and risk of rebound growth

Sorafenib leads to a survival benefit in patients with advanced hepatocellular carcinoma but its use is hampered by the occurrence of drug resistance. To investigate the molecular mechanisms involved we developed five resistant human liver cell lines in which we studied morphology, gene expression and invasive potential. The cells changed their appearance, lost E-cadherin and KRT19 and showed high expression of vimentin, indicating epithelial-to-mesenchymal transition. Resistant cells showed reduced adherent growth, became more invasive and lost liver-specific gene expression. Furthermore, following withdrawal of sorafenib, the resistant cells showed rebound growth, a phenomenon also found in patients. This cell model was further used to investigate strategies for restoration of sensitivity to sorafenib.

Phase I trial of axitinib combined with platinum doublets in patients with advanced non-small cell lung cancer and other solid tumours

Background:

This phase I dose-finding trial evaluated safety, efficacy and pharmacokinetics of axitinib, a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors, combined with platinum doublets in patients with advanced non-small cell lung cancer (NSCLC) and other solid tumours.

Methods:

In all, 49 patients received axitinib 5 mg twice daily (b.i.d.) with paclitaxel/carboplatin or gemcitabine/cisplatin in 3-week cycles. Following determination of the maximum tolerated dose, a squamous cell NSCLC expansion cohort was enroled and received axitinib 5 mg b.i.d. with paclitaxel/carboplatin.

Results:

Two patients experienced dose-limiting toxicities: febrile neutropenia (n=1) in the paclitaxel/carboplatin cohort and fatigue (n=1) in the gemcitabine/cisplatin cohort. Common nonhaematologic treatment-related adverse events were hypertension (36.7%), diarrhoea (34.7%) and fatigue (28.6%). No grade⩾3 haemoptysis occurred among 12 patients with squamous cell NSCLC. The objective response rate was 37.0% for patients receiving axitinib/paclitaxel/carboplatin (n=27) and 23.8% for patients receiving axitinib/gemcitabine/cisplatin (n=21). Pharmacokinetics of axitinib and chemotherapeutic agents were similar when administered alone or in combination.

Conclusion:

Axitinib 5 mg b.i.d. may be combined with standard paclitaxel/carboplatin or gemcitabine/cisplatin regimens without evidence of overt drug–drug interactions. Both combinations demonstrated clinical efficacy and were well tolerated.

A phase I trial and pharmacokinetic study of sorafenib in children with refractory solid tumors or leukemias: a Children's Oncology Group Phase I Consortium report

PURPOSE

To determine the dose-limiting toxicities (DLT), maximum tolerated dose (MTD), pharmacokinetics, and pharmacodynamics of sorafenib in children with refractory extracranial solid tumors and evaluate the tolerability of the solid tumor MTD in children with refractory leukemias.

EXPERIMENTAL DESIGN

Sorafenib was administered orally every 12 hours for consecutive 28-day cycles. Pharmacokinetics (day 1 and steady-state) and pharmacodynamics were conducted during cycle 1.

RESULTS

Of 65 patients enrolled, 60 were eligible. In the solid tumor cohort (n = 49), 4 of 6 patients experienced a DLT [hypertension, pain, rash/urticaria, thrombocytopenia, alanine aminotransferase (ALT)/aspartate aminotransferase (AST)] at the starting dose (150 mg/m(2)/dose) which resulted in de-escalation to 105 mg/m(2)/dose. After eligibility criteria modification and dose re-escalation, the MTD was 200 mg/m(2)/dose for solid tumors and 150 mg/m(2)/dose for leukemias. Sorafenib exposure was highly variable between patients but was within the ranges reported in adults. The apparent sorafenib clearance increased with patient age. Diarrhea, rash, fatigue, and increased ALT/AST were the most common sorafenib-related toxicities. Stable disease for 4 or more cycles was observed in 14 solid tumor patients, and 2 patients with acute myeloid leukemia (AML) and FLT3 internal tandem duplication (FLT3ITD) experienced a decrease in bone marrow blasts to less than 5%.

CONCLUSIONS

The recommended phase II dose of sorafenib administered every 12 hours continuously for children with solid tumors is 200 mg/m(2)/dose and 150 mg/m(2)/dose for children with leukemias. Sorafenib toxicities and distribution in children are similar to adults. The activity of sorafenib in children with AML and FLT3ITD is currently being evaluated, and a phase II study for select solid tumors is ongoing.

Sorafenib in advanced melanoma: a critical role for pharmacokinetics?

BACKGROUND

Inter-patient pharmacokinetic variability can lead to suboptimal drug exposure, and therefore might impact the efficacy of sorafenib. This study reports long-term pharmacokinetic monitoring of patients treated with sorafenib and a retrospective pharmacodynamic/pharmacokinetic analysis in melanoma patients.

PATIENTS AND METHODS

Heavily pretreated patients with stage IV melanoma were started on sorafenib 400 mg twice daily (bid). In the absence of limiting toxicity, dose escalation of 200 mg bid levels was done every 2 weeks. Plasma sorafenib measurement was performed at each visit, allowing a retrospective pharmacodynamic/pharmacokinetic analysis for safety and efficacy.

RESULTS

In all, 19 of 30 patients underwent dose escalation over 400 mg bid, and 28 were evaluable for response. The overall disease control rate was 61% (95% confidence interval (CI): 42.6-78.8), including three confirmed responses (12%). Disease control rate and progression-free survival (PFS) were improved in patients with high vs low exposure (80% vs 32%, P=0.02, and 5.25 vs 2.5 months, P=0.005, hazard ratio (HR)=0.28 (95% CI: 0.11-0.73)). In contrast, drug dosing had no effect on PFS. In multivariate analysis, drug exposure was the only factor associated with PFS (HR=0.36 (95% CI: 0.13-0.99)). Diarrhoea and anorexia were correlated with drug dosing, while hypertension and hand-foot skin reaction were correlated with drug exposure.

CONCLUSIONS

Although sorafenib had modest efficacy in melanoma, these results suggest a correlation between exposure and efficacy of sorafenib. Therefore, dose optimisation in patients with low exposure at standard doses should be evaluated in validated indications.

Sorafenib in locally advanced or metastatic breast cancer

INTRODUCTION

Sorafenib is an oral multikinase inhibitor with anti-angiogenic and anti-proliferative activity that is indicated for use in hepatocellular and renal cell carcinomas. Sorafenib is being developed in a number of solid tumors, including breast cancer (BC).

AREAS COVERED

A series of four randomized, double-blind, placebo-controlled Phase IIb screening Trials were developed to Investigate the Efficacy of Sorafenib (TIES) when added to select chemotherapies for patients with HER2-negative advanced BC with a primary endpoint of progression-free survival (PFS). Results have been varied. SOLTI-0701 reported significant PFS benefit for sorafenib plus capecitabine as first- or second-line treatment, and AC01B07 reported a modest but significant PFS benefit when sorafenib was combined with gemcitabine or capecitabine for patients whose disease had progressed during or after bevacizumab. Sorafenib plus first-line paclitaxel did not significantly improve PFS (NU07B1 study), nor did its addition to first-line docetaxel and/or letrozole (FM-B07-01 study). A Phase III trial of sorafenib plus capecitabine has been initiated.

EXPERT OPINION

Phase IIb data indicate a potential role for sorafenib in combination with select chemotherapies for HER2-negative advanced BC, but Phase III confirmatory trials are necessary. The variability in results across studies with sorafenib may be related to the chemotherapy combination and/or patient population.

The plasma and cerebrospinal fluid pharmacokinetics of sorafenib after intravenous administration in non-human primates

PURPOSE

Sorafenib is a small molecule inhibitor of multiple signaling kinases thought to contribute to the pathogenesis of many tumors including brain tumors. Clinical trials with sorafenib in primary and metastatic brain tumors are ongoing. We evaluated the plasma and cerebrospinal fluid (CSF) pharmacokinetics (PK) of sorafenib after an intravenous (IV) dose in a non-human primate (NHP) model.

METHODS

7.3 mg/kg of sorafenib free base equivalent solubilized in 20% cyclodextrin was administered IV over 1 h to three adult rhesus monkeys. Serial paired plasma and CSF samples were collected over 24 h. Sorafenib was quantified with a validated HPLC/tandem mass spectrometry assay. PK parameters were estimated using non-compartmental methods. CSF penetration was calculated from the AUC(CSF) : AUC(plasma).

RESULTS

Peak plasma concentrations after IV dosing ranged from 3.4 to 7.6 μg/mL. The mean ± standard deviation (SD) area under the plasma concentration from 0 to 24 h was 28 ± 4.3 μg • h/mL, which is comparable to the exposure observed in humans at recommended doses. The mean ± SD clearance was 1.7 ± 0.5 mL/min/kg. The peak CSF concentrations ranged from 0.00045 to 0.00058 μg/mL. The mean ± SD area under the CSF concentration from 0 to 24h was 0.0048 ± 0.0016 μg•h/mL. The mean CSF penetration of sorafenib was 0.02% and 3.4% after correcting for plasma protein binding.

CONCLUSION

Sorafenib is well tolerated in NHP and measurable in CSF after an IV dose. The CSF penetration of sorafenib is limited relative to total and free drug exposure in plasma.

Use of tyrosine kinase inhibitors in patients with metastatic kidney cancer receiving haemodialysis: a retrospective Italian survey

What's known on the subject? and What does the study add? Sunitinib and sorafenib are orally administered multikinase inhibitors approved for the treatment of advanced RCC. The limited pharmacokinetics data on sunitinib and sorafenib suggest that haemodialysis does not significantly alter plasma concentrations. In this retrospective study we define the safety and efficacy of tyrosine kinase inhibitors in patients with metastatic RCC (mRCC) and end-stage renal disease requiring haemodialysis. Even though the retrospective nature of this survey and the relatively small sample size represent major limitations, these data indicate that treatment with sunitinib and sorafenib in this cohort of patients is feasible with no unexpected toxicity and good efficacy, results similar to those in the general population of patients with mRCC.

OBJECTIVE

To investigate the safety and efficacy of tyrosine kinase inhibitors (TKIs) in patients with metastatic renal cell carcinoma (mRCC) and end-stage renal disease requiring haemodialysis (HD).

PATIENTS AND METHODS

Between July 2006 and December 2010, 24 patients undergoing HD were treated with sunitinib and/or sorafenib for mRCC in 14 Italian institutions. We retrospectively reviewed the medical records of these patients to evaluate the administered doses of TKIs, treatment-related toxicities and the clinical response to therapy.

RESULTS

Sunitinib was administered at 50 mg daily for 4-6 weeks in six patients, 37.5 mg daily for 4-6 weeks in seven patients (one patient subsequently increased the dose to 50 mg daily), 25 mg daily for 4-6 weeks in two patients and 12.5 mg daily for 4-6 weeks in one patient. Among the eight patients treated with sorafenib, four patients received 800 mg daily (400 mg every 12 h), three patients 400 mg daily and one patient 200 mg daily with a continuous schedule. The estimated median progression-free and overall survival periods of this cohort of patients were 10.3 months and 22.6 months, respectively. With regard to tolerability and safety, no unexpected adverse events were registered and no grade 4 haematological or non-haematological toxicities were reported.

CONCLUSIONS

Sunitinib and sorafenib treatment is not contraindicated in patients with mRCC undergoing HD. The outcome of this patient population is similar to that observed in patients with normal renal function treated with TKIs. These results merit further confirmation by a larger prospective trial.

Efficacy and safety of sorafenib in advanced renal cell carcinoma patients: Results from a long-term study

Sorafenib has been confirmed as an effective drug in advanced renal cell carcinoma (RCC). This study aimed to evaluate the long-term efficacy and safety of sorafenib in ethnic Chinese patients with advanced RCC, and to develop optimal treatment strategies for Asian patients. Between May 2006 and August 2011, 30 patients with advanced RCC were treated with sorafenib in the Oncology Center, Tongji Hospital. All 30 patients received continuous treatment with 400 mg of sorafenib orally twice daily until disease progression or intolerable toxicities or mortality occurred. Dose reduction to 600 mg daily or even less was required if toxicities of grade 3 or 4 occurred. Patients were assessed for tumor response, progression-free survival (PFS), overall survival (OS) and drug-related toxicities. The median follow-up time was 58 weeks (range, 12-270). Among the 30 patients, 1 patient had complete remission (CR 3.3%), 4 patients had partial remission (PR 13.3%), 19 patients had stable disease (SD 63.3%) and 6 patients had disease progression (PD 20%). The disease control rate (DCR, CR+PR+SD) was 80%, the median PFS time was 14 months, and the median OS time was 16 months. Only 1 patient discontinued sorafenib treatment permanently due to severe toxicities. Dose reduction or interruption was required in 12 patients (40%) who developed adverse events of grade 3 or 4. Seven of these patients tolerated the dose of 600 mg per day well, and experienced clinical benefit. The Kaplan-Meier method and log-rank test revealed that the Memorial Sloan-Kettering Cancer Center (MSKCC) status was a prognostic factor for PFS and OS in advanced RCC. The long-term efficacy and safety of sorafenib were confirmed in Chinese advanced RCC patients who showed an even greater benefit in PFS. The findings of this study indicate that a dose of 600 mg instead of 400 mg per day may be an optimal choice for Asian patients when a reduction of the initial dose is required.

Phase I trial to investigate the safety, pharmacokinetics and efficacy of sorafenib combined with docetaxel in patients with advanced refractory solid tumours

AIM

The safety, pharmacokinetics and efficacy of sorafenib plus docetaxel in patients with advanced refractory cancer were investigated in a phase I, dose-escalation trial.

METHODS

Twenty-seven patients in four cohorts received docetaxel on day 1 (cohorts 1 and 4: 75 mg/m2; cohorts 2 and 3: 100 mg/m2) plus sorafenib on days 2-19 (cohorts 1 and 2: 200 mg twice-daily (bid); cohorts 3 and 4: 400 mg bid) in 21-day cycles.

RESULTS

Most common adverse events (AEs) (grade 3-5) included neutropenia (89%), leucopaenia (81%), hand-foot skin reaction (30%) and fatigue (30%). The most common drug-related AEs leading to dose reduction/interruption or permanent discontinuation were dermatologic (41%), gastrointestinal (26%) and constitutional (22%). Coadministration of sorafenib altered the pharmacokinetics of docetaxel. On average, docetaxel area under the concentration-time curve (AUC)(0-24) increased by 5% (cohort 1), 54% (cohort 2), 36% (Cohort 3) and 80% (cohort 4) with docetaxel plus sorafenib, while C(max) increased by 16-32%, independent of sorafenib/docetaxel doses. Three of 25 evaluable patients (11%) had partial responses; 14 (52%) had stable disease.

CONCLUSION

Dose-limiting dermatologic AEs were more common than expected for either therapy alone. A starting dose of docetaxel 75 mg/m2 plus sorafenib 400mg bid (with dose reductions for dermatological toxicities) is proposed for phase II.

Vascular endothelial growth factor-targeted therapies in advanced renal cell carcinoma

Vascular endothelial growth factor (VEGF) is, to date, the key element in the pathogenesis of renal cell carcinoma (RCC). VEGF pathway activation is responsible for the recruitment, migration, and expansion of endothelial cells, with this angiogenesis tumor model being characteristic of RCC. Different strategies have been developed for almost a decade to block the VEGF pathway in this setting. Four different compounds were approved for metastatic RCC (mRCC) in the past 6 years: bevacizumab, sunitinib, sorafenib, and pazopanib. Axitinib and tivozanib are also promising compounds under evaluation. The revolution in the management and prognosis of patients with mRCC is ongoing.