Emerging role of tyrosine kinase inhibitors in the treatment of advanced renal cell cancer: a review

Small Bowel Perforation Due to Renal Carcinoma Metastasis: A Comprehensive Case Study and Literature Review

This case report presents a unique instance of small bowel perforation caused by solitary metastasis from renal cell carcinoma (RCC), a rare and complex clinical scenario. The patient, a 59-year-old male with a history of RCC treated with nephrectomy four years prior, presented with acute abdomen symptoms. Emergency diagnostic procedures identified a significant lesion in the small intestine. Surgical intervention revealed a perforated jejunal segment due to metastatic RCC. Postoperatively, the patient developed complications, including pneumonia and multi-organ failure, leading to death 10 days after surgery. Histopathological analysis confirmed the metastatic nature of the lesion. This case underscores the unpredictable nature of RCC metastasis and highlights the need for vigilance in post-nephrectomy patients. The rarity of small bowel involvement by RCC metastasis, particularly presenting as perforation, makes this case a significant contribution to medical literature, emphasizing the challenges in the diagnosis and management of such atypical presentations.

MFN2 suppresses clear cell renal cell carcinoma progression by modulating mitochondria-dependent dephosphorylation of EGFR

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the most lethal renal cancer. An overwhelming increase of patients experience tumor progression and unfavorable prognosis. However, the molecular events underlying ccRCC tumorigenesis and metastasis remain unclear. Therefore, uncovering the underlying mechanisms will pave the way for developing novel therapeutic targets for ccRCC. In this study, we sought to investigate the role of mitofusin-2 (MFN2) in supressing ccRCC tumorigenesis and metastasis.

METHODS

The expression pattern and clinical significance of MFN2 in ccRCC were analyzed by using the Cancer Genome Atlas datasets and samples from our independent ccRCC cohort. Both in vitro and in vivo experiments, including cell proliferation, xenograft mouse models and transgenic mouse model, were used to determine the role of MFN2 in regulating the malignant behaviors of ccRCC. RNA-sequencing, mass spectrum analysis, co-immunoprecipitation, bio-layer interferometry and immunofluorescence were employed to elucidate the molecular mechanisms for the tumor-supressing role of MFN2.

RESULTS

we reported a tumor-suppressing pathway in ccRCC, characterized by mitochondria-dependent inactivation of epidermal growth factor receptor (EGFR) signaling. This process was mediated by the outer mitochondrial membrane (OMM) protein MFN2. MFN2 was down-regulated in ccRCC and associated with favorable prognosis of ccRCC patients. in vivo and in vitro assays demonstrated that MFN2 inhibited ccRCC tumor growth and metastasis by suppressing the EGFR signaling pathway. In a kidney-specific knockout mouse model, loss of MFN2 led to EGFR pathway activation and malignant lesions in kidney. Mechanistically, MFN2 preferably binded small GTPase Rab21 in its GTP-loading form, which was colocalized with endocytosed EGFR in ccRCC cells. Through this EGFR-Rab21-MFN2 interaction, endocytosed EGFR was docked to mitochondria and subsequently dephosphorylated by the OMM-residing tyrosine-protein phosphatase receptor type J (PTPRJ).

CONCLUSIONS

Our findings uncover an important non-canonical mitochondria-dependent pathway regulating EGFR signaling by the Rab21-MFN2-PTPRJ axis, which contributes to the development of novel therapeutic strategies for ccRCC.

Patient-reported outcomes in metastatic renal cell carcinoma trials using combinations versus sunitinib as first-line treatment

Over the past 5 years, several new immunotherapy treatments have been tested for metastatic renal cell carcinoma (mRCC). Clinical trials assessing combinations of different immunotherapies, or of an immunotherapy with a tyrosine kinase inhibitor (TKI), have reported improved clinical outcomes compared with the standard of care - that is, treatments using TKIs alone. However, to understand the holistic impact of new treatments on patients, physicians must also consider effects on health-related quality of life (HRQoL). As patient-reported outcome measures (PROMs) on HRQoL are often treated as a secondary outcome in clinical trials, their collection and reporting are non-standardized and, therefore, difficult to compare and interpret. However, results from six clinical trials indicate that two immunotherapy treatments overwhelmingly outperform sunitinib in HRQoL measurements: nivolumab plus cabozantinib (CheckMate 9ER) and atezolizumab plus bevacizumab (IMmotion151). An additional two treatments generally outperform sunitinib: nivolumab plus ipilimumab (CheckMate 214) and lenvatinib plus pembrolizumab (CLEAR). Of three studies that reported no difference from sunitinib, two suffered design flaws that might have obscured HRQoL benefits (JAVELIN Renal 101 and KEYNOTE-426). To ensure future HRQoL data are of the highest quality and comparable across trials, future studies should adopt best practices for the design, analysis and reporting of PROMs.

Inhibition of EZH2 exerts antitumorigenic effects in renal cell carcinoma via LATS1

The most common type of kidney cancer in adults is renal cell carcinoma (RCC), which accounts for approximately 90% of cases. RCC is a variant disease with numerous subtypes; the most common subtype is clear cell RCC (ccRCC, 75%), followed by papillary RCC (pRCC, 10%) and chromophobe RCC (chRCC, 5%). To identify a genetic target for all subtypes, we analyzed The Cancer Genome Atlas (TCGA) databases of ccRCC, pRCC, and chromophobe RCC. Enhancer of zeste homolog 2 (EZH2), which encodes a methyltransferase, was observed to be significantly upregulated in tumors. The EZH2 inhibitor tazemetostat induced anticancer effects in RCC cells. TCGA analysis revealed that large tumor suppressor kinase 1 (LATS1), a key tumor suppressor of the Hippo pathway, was significantly downregulated in tumors; the expression of LATS1 was increased by tazemetostat. Through additional experiments, we confirmed that LATS1 plays a crucial role in EZH2 inhibition and has a negative association with EZH2. Therefore, we suggest that epigenetic control could be a novel therapeutic strategy for three subtypes of RCC.

Discovery of novel VEGFR2-TK inhibitors by phthalimide pharmacophore based virtual screening, molecular docking, MD simulation and DFT

Currently, numerous potent chemotherapeutic agents are available in the market but most of them show poor pharmacokinetics, lethal effects and drug resistance during their enduring use. The increased cancer cases, deaths and need of better treatment stimulates us to give newer lifesaving anticancer drugs. The phthalimide derivatives are structurally diverse and exert potential anticancer activity. In this regard, the 3D QSAR Pharmacophore model was developed and validated using fifty-eight phthalimide derivatives. The validation parameters corroborated the reliability and statistical robustness of CEASER Hypo 1. Three databases-NCI Open, Drug Bank, and Asinex were submitted to ADMET and drug-like filtering; 117893 drug-like compounds were mapped on CEASER Hypo 1; and 362 hits with IC50 <1 µM were discovered. These hits were docked on VEGFR2-TK, and in the form of results fifteen hits exhibited greater affinity than sorafenib. The top lead ASN 03206926 was subjected for MD simulation (100 ns) and RMSD, Rg, RMSF, number of hydrogen bonds, and SASA verified that the complex was stable, rigid and highly compact. Results demonstrated GLU885, PHE918, CYS919, LYS920, HIS1026, CYS1045, ASP1046 are the essential residues for favourable interactions. The binding free energy calculations support the affinity and stability revealed by docking and MD simulation. The DFT calculations, negative binding energy and lower HOMO-LUMO band gap revealed that the process is spontaneous and ASN 03206926 is very reactive. Following extensive analysis we suggest that the ASN 03206926 might be employed as a new VEGFR2-TK inhibitor for the treatment of breast and VEGFR2-TK associated cancers.Communicated by Ramaswamy H. Sarma.

Small Molecule EGFR Inhibitors as Anti-Cancer Agents: Discovery, Mechanisms of Action, and Opportunities

Epidermal growth factor receptors (EGFRs) are a class of receptor tyrosine kinase that are also called ErbB1 and HER1. EGFR tyrosine kinase activity inhibition is considered a promising therapeutic strategy for the treatment of cancer. Many small-molecule inhibitors of EGFR tyrosine kinase (EGFR-TK), from medicinally privileged molecules to commercial drugs, have been overviewed. Particular attention has been paid to the structure of the molecule and its mechanism of action if reported. Subsequent classification of the molecules under discussion has been carried out. Both natural and synthetic and reversible and irreversible EGFR-tyrosine kinase inhibitors have been discussed. Various types of cancers that are caused by overexpression of the EGFR gene, their possible molecular origins, and their natures have also been counted in this article. Because the EGFR signaling pathway controls the proliferation, growth, survival, and differentiation of cells, and the mutated EGFR gene overproduces EGFR protein, which ultimately causes several types of cancer, proper understanding of the molecular dynamics between the protein structure and its inhibitors will lead to more effective and selective EGFR-TKIs, which in turn will be able to save more lives in the battle against cancer.

Recent advances in ocular drug delivery systems and targeting VEGF receptors for management of ocular angiogenesis: A comprehensive review

Background

Angiogenic ocular diseases address the main source of vision impairment or irreversible vision loss. The angiogenesis process depends on the balance between the pro-angiogenic and anti-angiogenic factors. An imbalance between these factors leads to pathological conditions in the body. The vascular endothelial growth factor is the main cause of pathological conditions in the ocular region. Intravitreal injections of anti-angiogenic drugs are selective, safe, specific and revolutionized treatment for ocular angiogenesis. But intravitreal injections are invasive techniques with other severe complications. The area of targeting vascular endothelial growth factor receptors progresses with novel approaches and therapeutically based hope for best clinical outcomes for patients through the developments in anti-angiogenic therapy.

Main text

The present review article gathers prior knowledge about the vascular endothelial growth factor and associated receptors with other angiogenic and anti-angiogenic factors involved in ocular angiogenesis. A focus on the brief mechanism of vascular endothelial growth factor inhibitors in the treatment of ocular angiogenesis is elaborated. The review also covers various recent novel approaches available for ocular drug delivery by comprising a substantial amount of research works. Besides this, we have also discussed in detail the adoption of nanotechnology-based drug delivery systems in ocular angiogenesis by comprising literature having recent advancements. The clinical applications of nanotechnology in terms of ocular drug delivery, risk analysis and future perspectives relating to the treatment approaches for ocular angiogenesis have also been presented.

Conclusion

The novel ocular drug delivery systems involving nanotechnologies are of great importance in the ophthalmological sector to overcome traditional treatments with many drawbacks. This article gives a detailed insight into the various approaches that are currently available to be a road map for future research in the field of ocular angiogenesis disease management.

Evaluation of anti-EGFR potential of quinazoline derivatives using molecular docking: An in silico approach

Overexpression of epidermal growth factor receptor (EGFR) is commonly reported in epithelial malignancies such as oral squamous cell carcinoma. Inhibition of EGFR is, therefore, considered a potential therapeutic strategy. Among various anti-EGFR drugs, quinazoline-based tyrosine kinase inhibitors (TKIs) have gained increasing attention. Present study focused to investigate anti-EGFR potential of quinazoline-based compounds using in silico approach. Two widely used docking programs GOLD and AutoDock Vina were used for the study. Four drugs were docked on the X-ray crystallographic EGFR structure (1XKK). GOLD and AutoDock Vina produced results in terms of fitness score and binding affinity, respectively. GOLD prioritized varlitinib and AutoDock Vina preferred imatinib over other drugs. To reach the consensus from both software, all four drugs coupled with EGFR were studied rigorously. GOLD demonstrated varlitinib to be the best inhibitor with highest fitness score of 109, whereas AutoDock Vina revealed imatinib as the potent ligand with least binding energy of -10.9 kcal/mol. Most stable hydrogen bonds observed by GOLD and maximum number of hydrophobic contacts along with strong ionic interaction exhibited by varlitinib through both software have led us to conclude varlitinib as the most potent EGFR inhibitor in the studied group.

PHGDH as a mechanism for resistance in metabolically-driven cancers

At the forefront of cancer research is the rapidly evolving understanding of metabolic reprogramming within cancer cells. The expeditious adaptation to metabolic inhibition allows cells to evolve and acquire resistance to targeted treatments, which makes therapeutic exploitation complex but achievable. 3-phosphoglycerate dehydrogenase (PHGDH) is the rate-limiting enzyme of de novo serine biosynthesis and is highly expressed in a variety of cancers, including breast cancer, melanoma, and Ewing’s sarcoma. This review will investigate the role of PHGDH in normal biological processes, leading to the role of PHGDH in the progression of cancer. With an understanding of the molecular mechanisms by which PHGDH expression advances cancer growth, we will highlight the known mechanisms of resistance to cancer therapeutics facilitated by PHGDH biology and identify avenues for combatting PHGDH-driven resistance with inhibitors of PHGDH to allow for the development of effective metabolic therapies.

Molecular biology and targeted therapy in metastatic renal cell carcinoma

The treatment of metastatic renal cell carcinoma is challenging as it has proven to be relatively resistant to conventional oncological treatments. An improved understanding of the molecular biology of renal cell carcinoma has led to the development of a number of targeted therapies in metastatic renal cell carcinoma. This includes vascular endothelial growth factor inhibitors, tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors and most recently immune checkpoint inhibitors. This article will review the mechanisms of development and progression of renal cell carcinoma as well as the mechanisms of current approved treatments in metastatic disease.

Level of evidence: Not applicable for this multicentre audit.

Protocol development for discovery of angiogenesis inhibitors via automated methods using zebrafish

Their optical clarity as larvae and embryos, small size, and high fecundity make zebrafish ideal for whole animal high throughput screening. A high-throughput drug discovery platform (HTP) has been built to perform fully automated screens of compound libraries with zebrafish embryos. A Tg(kdrl:EGFP) line, marking endothelial cell cytoplasm, was used in this work to help develop protocols and functional algorithms for the system, with the intent of screening for angiogenesis inhibitors. Indirubin 3’ Monoxime (I3M), a known angiogenesis inhibitor, was used at various concentrations to validate the protocols. Consistent with previous studies, a dose dependant inhibitory effect of I3M on angiogenesis was confirmed. The methods and protocols developed here could significantly increase the throughput of drug screens, while limiting human errors. These methods are expected to facilitate the discovery of novel anti-angiogenesis compounds and can be adapted for many other applications in which samples have a good fluorescent signal.

Renal Cell Cancer and Sorafenib: Skin Toxicity and Treatment Outcome

We describe the case of a young man with refractory renal cell carcinoma who achieved an objective response in a metastatic lesion after biotherapy with the multikinase inhibitor sorafenib and also developed a severe skin reaction. The patient had been previously treated with various combinations of immunochemotherapy without any clinical benefit. We performed a brief review of the literature where similar cases were documented with the use of various anti-EGFR agents. The hypothesis of the correlation of skin toxicity with disease response is not new, but in the absence of any strong evidence remains controversial.

Non-coding RNA 886 promotes renal cell carcinoma growth and metastasis through the Janus kinase 2/signal transducer and activator of transcription 3 signaling pathway

Non-coding RNA 886 (nc886) has been suggested to serve tumor-suppressing roles in several cancer cells. However, the expression pattern of nc886 and its function in renal cell carcinoma (RCC) has not been reported until now. The present study aimed to examine the expression of nc886 in human RCC tissues and to investigate the role of nc886 in RCC cell proliferation, apoptosis and invasion in vitro. Furthermore, whether nc886 exerts its function on RCC via Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling was investigated. It was demonstrated that nc886 is overexpressed in human RCC tissues compared with normal tissues, as determined by reverse transcription-quantitative polymerase chain reaction analysis. The nc886 mimic and inhibitor were transfected into the A‑498 cells to overexpress or knock down nc886 expression. Cell proliferation, cell apoptosis rate and cell invasion ability were determined by MTT, flow cytometry and Transwell‑Matrigel invasion assays. The results demonstrated that nc886 overexpression promotes A‑498 cell proliferation and invasion, and inhibits cell apoptosis, while nc886 knockdown resulted in the opposite effects. Furthermore, nc886 could activate the JAK2/STAT3 signaling pathway in A‑498 cells. AG490, an inhibitor of JAK2, could attenuate the effects of nc886 on cell proliferation, apoptosis and invasion. In conclusion, to the best of our knowledge, the present study for the first time revealed the expression profile and the tumor‑promoting role of nc886 in RCC. nc886 affects RCC cell proliferation, apoptosis and invasion at least partially via the activation of JAK2/STAT3 signaling. This study may provide a useful therapeutic target for RCC.

Radio-Immunotherapy-Induced Immunogenic Cancer Cells as Basis for Induction of Systemic Anti-Tumor Immune Responses - Pre-Clinical Evidence and Ongoing Clinical Applications

Radiotherapy (RT) primarily aims to locally destroy the tumor via the induction of DNA damage in the tumor cells. However, the so-called abscopal, namely systemic and immune–mediated, effects of RT move over more and more in the focus of scientists and clinicians since combinations of local irradiation with immune therapy have been demonstrated to induce anti-tumor immunity. We here summarize changes of the phenotype and microenvironment of tumor cells after exposure to irradiation, chemotherapeutic agents, and immune modulating agents rendering the tumor more immunogenic. The impact of therapy-modified tumor cells and damage-associated molecular patterns on local and systemic control of the primary tumor, recurrent tumors, and metastases will be outlined. Finally, clinical studies affirming the bench-side findings of interactions and synergies of radiation therapy and immunotherapy will be discussed. Focus is set on combination of radio(chemo)therapy (RCT) with immune checkpoint inhibitors, growth factor inhibitors, and chimeric antigen receptor T-cell therapy. Well-deliberated combination of RCT with selected immune therapies and growth factor inhibitors bear the great potential to further improve anti-cancer therapies.

Assessment of early therapeutic response to sorafenib in renal cell carcinoma xenografts by dynamic contrast-enhanced and diffusion-weighted MR imaging

OBJECTIVE

To investigate the feasibility of dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted MRI (DWI) in monitoring early therapeutic response to sorafenib in renal cell carcinoma (RCC) xenograft models.

METHODS

Sorafenib (40 mg kg(-1)) was administered orally to BALB/c nude mice (n = 9) bearing subcutaneous tumours of human RCC ACHN xenografts. DCE-MRI and DWI were obtained 0, 1, 3 and 7 days after therapy, and DCE-MRI parameters (K(trans) and ve) and apparent diffusion coefficient (ADC) values were calculated. Tumour size and volume changes were correlated with changes in DCE-MRI parameters or ADC values after therapy.

RESULTS

Following therapy, K(trans) showed a significant decrease over time (p = 0.005), whereas ve did not demonstrate significant changes between time points (p = 0.97). ADC values showed a progressive increase over time (p = 0.004). Compared with pre-therapy, K(trans) showed a significant decrease after 3 days of therapy (p = 0.039), and ADC values increased significantly after 7 days (p = 0.039). Tumour size and volume did not show significant changes during 7 days. Tumour size and volume changes were not associated with changes in DCE-MRI parameters or ADC values.

CONCLUSION

DCE-MRI and DWI may show early physiological changes within 1 week after initiating sorafenib treatment on human RCC xenografts.

ADVANCES IN KNOWLEDGE

The quantitative parameters of DCE-MRI and DWI may offer the potential for assessing early therapeutic response to sorafenib in clinical trials.

The androgen receptor as an emerging target in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the male-dominant liver diseases with poor prognosis, although treatments for HCC have been progressing in the past decades. Androgen receptor (AR) is a member of the nuclear receptor superfamily. Previous studies reported that AR was expressed in human HCC and non-HCC tissues. AR is activated both ligand-dependently and ligand-independently. The latter is associated with a mitogen-activated protein kinase–, v-akt murine thymoma viral oncogene homolog 1–, or signal-transducer and activator of transcription–signaling pathway, which has been implicated in the development of HCC. It has been reported that more than 200 RNA expression levels are altered by androgen treatment. In the liver, androgen-responsive genes are cytochrome P450s, transforming growth factor β, vascular endothelial growth factor, and glucose-regulated protein 78 kDa, which are also associated with human hepatocarcinogenesis. Recent studies also revealed that AR plays a role in cell migration and metastasis. It is possible that cross-talk among AR-signaling, endoplasmic reticulum stress, and innate immune response is important for human hepatocarcinogenesis and HCC development. This review shows that AR could play a potential role in human HCC and represent one of the important target molecules for the treatment of HCC.

Effects of preset sequential administrations of sunitinib and everolimus on tumour differentiation in Caki-1 renal cell carcinoma

BACKGROUND

Sunitinib (VEGFR/PDGFR inhibitor) and everolimus (mTOR inhibitor) are both approved for advanced renal cell carcinoma (RCC) as first-line and second-line therapy, respectively. In the clinics, sunitinib treatment is limited by the emergence of acquired resistance, leading to a switch to second-line treatment at progression, often based on everolimus. No data have been yet generated on programmed alternating sequential strategies combining alternative use of sunitinib and everolimus before progression. Such strategy is expected to delay the emergence of acquired resistance and improve tumour control. The aim of our study was to assess the changes in tumours induced by three different sequences administration of sunitinib and everolimus.

METHODS

In human Caki-1 RCC xenograft model, sunitinib was alternated with everolimus every week, every 2 weeks, or every 3 weeks. Effects on necrosis, hypoxia, angiogenesis, and EMT status were assessed by immunohisochemistry and immunofluorescence.

RESULTS

Sunitinib and everolimus programmed sequential regimens before progression yielded longer median time to tumour progression than sunitinib and everolimus monotherapies. In each group of treatment, tumour growth control was associated with inhibition of mTOR pathway and changes from a mesenchymal towards an epithelial phenotype, with a decrease in vimentin and an increase in E-cadherin expression. The sequential combinations of these two agents in a RCC mouse clinical trial induced antiangiogenic effects, leading to tumour necrosis.

CONCLUSIONS

In summary, our study showed that alternate sequence of sunitinib and everolimus mitigated the development of mesenchymal phenotype compared with sunitinib as single agent.

Thyroid dysfunction and tyrosine kinase inhibitors in renal cell carcinoma

The most recent World Health Organization classification of renal neoplasms encompassed nearly 50 distinctive renal neoplasms. Different histological subtypes have different clinical outcomes and show different responses to therapy. Overall, the incidence of kidney cancer has increased worldwide in the last years. Although the most common type of kidney cancer is localized renal cell carcinoma (RCC), with a 5-year survival rate of 85%, about one third of patients present advanced or metastatic disease at diagnosis, with a 5-year survival rate of only 10%. Multi-targeted receptor tyrosine kinase inhibitors (TKIs, sunitinib and sorafenib), the anti-VEGF MAB bevacizumab in association with interferon-α, and the mTOR inhibitors are now approved for the treatment of mRCC. Recently, the novel agents pazopanib and axitinib have also demonstrated efficacy in mRCC patients. Several recent retrospective and prospective trials have suggested that some of their adverse events, such as hypertension, hypothyroidism, and hand foot syndrome (HFS) may act as potential biomarkers of response and efficacy of treatment. In this review, we analyzed the studies that have suggested a relationship between hypothyroidism onset and a better outcome of mRCC patients treated with TKIs. The biological mechanisms suggesting and explaining this correlation are not well known and different speculative theories have been considered in order to investigate the clinical link between hypothyroidism occurrence and the prolonged therapy with TKIs in solid tumors. Furthermore, the management of this unexplained side effect is very important to maximize the efficacy of therapy in mRCC patients because there is a clear and consistent relationship between drug dose and efficacy of treatment. Certainly, other studies are needed to clarify whether a better outcome is associated with hypothyroidism induced to TKIs in patients with mRCC.

Update on in vitro cytotoxicity assays for drug development

BACKGROUND

in vitro cytotoxicity testing provides a crucial means of ranking compounds for consideration in drug discovery. The choice of using a particular viability or cytotoxicity assay technology may be influenced by specific research goals.

OBJECTIVE

Although the high-throughput screening (HTS) utility is typically dependent upon sensitivity and scalability, it is also impacted by signal robustness and resiliency to assay interferences. Further consideration should be given to data quality, ease-of-use, reagent stability, and matters of cost-effectiveness.

METHODS

Here we focus on three main classes of assays that are at present the most popular, useful, and practical for HTS drug discovery efforts. These methods measure: i) viability by metabolism reductase activities; ii) viability by bioluminescent ATP assays; or iii) cytotoxicity by enzymes 'released' into culture medium. Multi-parametric technologies are also briefly discussed.

RESULTS/CONCLUSION

Each of these methods has its relative merits and detractions; however multi-parametric methods using both viability and cytotoxicity markers may mitigate the inherent shortcomings of single parameter measures.

FDG-PET as a pharmacodynamic biomarker for early assessment of treatment response to linifanib (ABT-869) in a non-small cell lung cancer xenograft model

Linifanib (ABT-869) is a multitargeted receptor tyrosine kinase inhibitor. This work aims to evaluate F-fluorodeoxyglucose-positron emission tomography (FDG-PET) as a pharmacodynamic (PD) biomarker for linifanib treatment utilizing the Calu-6 model of human non-small cell lung (NSCLC) cancer in SCID-beige mice. Animals received either vehicle or 12.5 mg/kg linifanib orally twice a day for the duration of the study. Imaging was performed at -1, 1, 3, and 7 days after beginning treatment (n = 12-14 per group). Linifanib inhibited tumor growth and suppressed tumor metabolic activity. Changes in tumor FDG uptake were observed as early as 1 day after beginning linifanib treatment and were sustained for the duration of the study. This study confirms that linifanib is efficacious in this xenograft model of human NSCLC and confirms FDG-PET is a potential PD biomarker strategy for linifanib therapy.

Unique angiogenic and vasculogenic properties of renal cell carcinoma in a xenograft model of bone metastasis are associated with high levels of vegf-a and decreased ang-1 expression

Management of various tumor metastases to bone has dramatically improved, but this is not so for renal cell carcinoma (RCC), which is a difficult surgical problem due to its great vascularity. Furthermore, the unique mechanisms that mediate RCC vasculogenesis in bone remain unknown. To understand this process we developed a xenograft model that recapitulates highly vascular RCC versus less vascular tumors that metastasize to bone. Human tumor cell lines of RCC (786-O), prostate cancer (PC3), lung cancer (A549), breast cancer (MDA-MB231), and melanoma (A375) were transduced with firefly luciferase (Luc), injected into the tibiae of nude mice, and differences in growth, osteolysis, and vascularity were assessed by longitudinal bioluminescent imaging, micro-CT for measurement of calcified tissues and vascularity and histology. The results showed that while RCC-Luc has reduced growth and osteolytic potential versus the other tumor lines, it displayed a significant increase in vascular volume (p < 0.05). This expansion was due to 3- and 5-fold increases in small and large vessel numbers respectively. In vitro gene expression profiling revealed that RCC-Luc expresses significantly (p < 0.05) more vegf-a (10-fold) and 20- to 30-fold less ang-1 versus the other lines. These data demonstrate the utility of this model to study the unique vasculogenic properties of RCC bone metastases.

Cutaneous lupus erythematosus after treatment with paclitaxel and bevacizumab for metastatic breast cancer: a case report

Introduction

The monoclonal anti-vascular endothelial growth factor antibody bevacizumab is increasingly used in the treatment of several malignant tumors. The usual side effects of this drug are hypertension and proteinuria. Paclitaxel is widely used in the treatment of breast cancer and head and neck carcinomas. Neither of these two drugs typically causes skin disorders. Paclitaxel-related cutaneous lupus erythematosus has been described before, but in earlier cases patients had a history of autoimmune disease.

Case presentation

We report a case of a 65-year-old Caucasian woman who presented with cutaneous lupus erythematosus after receiving paclitaxel-bevacizumab combination treatment as first-line therapy for metastatic breast cancer. Her cutaneous symptoms and increased serum anti-SSA and anti-SSB antibodies disappeared shortly after the discontinuation of therapy.

Conclusion

We conclude that cutaneous lupus erythematosus can also be seen in patients without earlier anamnesis of autoimmune disorders and that, furthermore, bevacizumab might cause atypical cutaneous side effects.

Disturbed expression of splicing factors in renal cancer affects alternative splicing of apoptosis regulators, oncogenes, and tumor suppressors

Background

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cancer. One of the processes disturbed in this cancer type is alternative splicing, although phenomena underlying these disturbances remain unknown. Alternative splicing consists of selective removal of introns and joining of residual exons of the primary transcript, to produce mRNA molecules of different sequence. Splicing aberrations may lead to tumoral transformation due to synthesis of impaired splice variants with oncogenic potential. In this paper we hypothesized that disturbed alternative splicing in ccRCC may result from improper expression of splicing factors, mediators of splicing reactions.

Methodology/Principal Findings

Using real-time PCR and Western-blot analysis we analyzed expression of seven splicing factors belonging to SR proteins family (SF2/ASF, SC35, SRp20, SRp75, SRp40, SRp55 and 9G8), and one non-SR factor, hnRNP A1 (heterogeneous nuclear ribonucleoprotein A1) in 38 pairs of tumor-control ccRCC samples. Moreover, we analyzed splicing patterns of five genes involved in carcinogenesis and partially regulated by analyzed splicing factors: RON, CEACAM1, Rac1, Caspase-9, and GLI1.

Conclusions/Significance

We found that the mRNA expression of splicing factors was disturbed in tumors when compared to paired controls, similarly as levels of SF2/ASF and hnRNP A1 proteins. The correlation coefficients between expression levels of specific splicing factors were increased in tumor samples. Moreover, alternative splicing of five analyzed genes was also disturbed in ccRCC samples and splicing pattern of two of them, Caspase-9 and CEACAM1 correlated with expression of SF2/ASF in tumors. We conclude that disturbed expression of splicing factors in ccRCC may possibly lead to impaired alternative splicing of genes regulating tumor growth and this way contribute to the process of carcinogenesis.

Sunitinib in combination with docetaxel in patients with advanced solid tumors: a phase I dose-escalation study

Purpose

Sunitinib in combination with docetaxel enhances antitumor activity in xenograft models of human breast and non-small cell lung cancer. We assessed the maximum tolerated doses (MTDs), safety, pharmacokinetic profiles, and preliminary efficacy of sunitinib plus docetaxel in patients with advanced solid tumors.

Methods

In this phase I study, successive patient cohorts received sunitinib 25, 37.5, or 50 mg/day for 4 weeks of a 6-week cycle (Schedule 4/2, 4 weeks on, 2 weeks off) or for 2 weeks of a 3-week cycle (Schedule 2/1, 2 weeks on, 1 week off) with docetaxel 60 or 75 mg/m² IV q21d to determine the MTDs of this treatment combination.

Results

Fifty patients enrolled: 10 on Schedule 4/2 and 40 on Schedule 2/1. MTDs were established as sunitinib 25 mg on Schedule 4/2 with docetaxel 60 mg/m² q21d, and as sunitinib 37.5 mg on Schedule 2/1 with docetaxel 75 mg/m² q21d. On Schedule 2/1, the most frequent dose-limiting toxicity was neutropenia (±fever; grade [G]3/4, n = 5) and the most common G3/4 non-hematologic adverse event (AE) was fatigue (G3, n = 8). Hematologic AEs were managed with growth factor support in 11 of 23 (48%) patients treated at Schedule 2/1 MTD. Three patients achieved a partial response at the Schedule 2/1 MTD. There were no pharmacokinetic drug–drug interactions with either schedule.

Conclusions

Oral sunitinib 37.5 mg/day on Schedule 2/1 with docetaxel 75 mg/m² IV q21d is a clinically feasible regimen with a manageable safety profile, no pharmacokinetic drug–drug interactions, and shows antitumor activity in patients with advanced solid tumors.

Calcineurin inhibitors activate the proto-oncogene Ras and promote protumorigenic signals in renal cancer cells

The development of cancer is a major problem in immunosuppressed patients, particularly after solid organ transplantation. We have recently shown that calcineurin inhibitors (CNI) used to treat transplant patients may play a critical role in the rapid progression of renal cancer. To examine the intracellular signaling events for CNI-mediated direct tumorigenic pathway(s), we studied the effect of CNI on the activation of proto-oncogenic Ras in human normal renal epithelial cells (REC) and renal cancer cells (786-0 and Caki-1). We found that CNI treatment significantly increased the level of activated GTP-bound form of Ras in these cells. In addition, CNI induced the association of Ras with one of its effector molecules, Raf, but not with Rho and phosphatidylinositol 3-kinase; CNI treatment also promoted the phosphorylation of the Raf kinase inhibitory protein and the downregulation of carabin, all of which may lead to the activation of the Ras-Raf pathway. Blockade of this pathway through either pharmacologic inhibitors or gene-specific small interfering RNA significantly inhibited CNI-mediated augmented proliferation of renal cancer cells. Finally, it was observed that CNI treatment increased the growth of human renal tumors in vivo, and the Ras-Raf pathway is significantly activated in the tumor tissues of CNI-treated mice. Together, targeting the Ras-Raf pathway may prevent the development/progression of renal cancer in CNI-treated patients.

A phase II study of sunitinib in Japanese patients with metastatic renal cell carcinoma: insights into the treatment, efficacy and safety

OBJECTIVE

This study aims to assess the efficacy and safety of sunitinib in Japanese patients with metastatic renal cell carcinoma (RCC).

METHODS

Fifty-one Japanese patients with prior nephrectomy, 25 treatment-naive patients (first-line group) and 26 cytokine-refractory patients (pretreated group) were enrolled in this phase II trial. Patients received sunitinib 50 mg orally, once daily, in repeated 6-week cycles (4 weeks on treatment, 2 weeks off). The primary endpoint was RECIST-defined objective response rate (ORR) with tumour assessments every 6 weeks via computed tomography or magnetic resonance imaging. Toxicity was assessed regularly. In the primary efficacy analysis of the intent-to-treat (ITT) population, ORR and 95% confidence interval were calculated based on independent review. Secondary time-to-event endpoints, such as progression-free survival (PFS), were estimated using the Kaplan-Meier method.

RESULTS

In the ITT population, ORR was 48.0% in the first-line group (after a median 4 cycles), 46.2% in the pretreated group (5 cycles) and 47.1% overall, with median times to tumour response of 7.1, 10.7 and 10.0 weeks, respectively. Median PFS was 46.0, 33.6 and 46.0 weeks, respectively. The most common treatment-related grade 3/4 adverse events and laboratory abnormalities were fatigue (20%), hand-foot syndrome (14%) and hypertension (12%), decreased platelet count (55%), decreased neutrophil count (51%), increased lipase (39%) and decreased lymphocyte count (33%).

CONCLUSIONS

In Japanese patients with RCC, sunitinib is consistently effective and tolerable with similar risk/benefit as that in Western patients, though there was a trend toward greater antitumour efficacy and higher incidence of haematological adverse events in Japanese patients.

Efficacy and safety of sorafenib in patients with advanced renal cell carcinoma with and without prior cytokine therapy, a subanalysis of TARGET

Before the development of targeted therapies, administration of cytokines (e.g., interleukin-2, interferon-alpha) was the primary systemic treatment option for advanced renal cell carcinoma. Sorafenib, an oral targeted, multikinase inhibitor, significantly prolonged progression-free survival and overall survival in the Treatment Approaches in Renal Cancer Global Evaluation Trial (TARGET), a large (N = 903) phase III, double-blind, randomised, placebo-controlled study of patients with advanced renal cell carcinoma resistant to standard therapy. This analysis of a patient subgroup from TARGET evaluated the safety and efficacy of sorafenib in patients who had received prior cytokine therapy (sorafenib: n = 374; placebo: n = 368) and in patients who were cytokine-naïve (sorafenib: n = 77; placebo: n = 84). Progression-free survival was significantly prolonged with sorafenib therapy compared with placebo among patients with and without prior cytokine therapy (respectively 5.5 vs. 2.7 months; hazard ratio, 0.54; 95% confidence interval, 0.45-0.64 and 5.8 vs. 2.8 months; hazard ratio, 0.48; 95% confidence interval, 0.32-0.73). Clinical benefit rates for sorafenib-treated patients compared with placebo patients were also higher (cytokine-treated: 83 vs. 54.3%; cytokine-naïve: 85.7 vs. 56.0%). Sorafenib was well tolerated in both subgroups (grade 3/4: 20 and 22%, respectively). Sorafenib demonstrated a consistent, significant clinical benefit against advanced renal cell carcinoma, with a twofold improvement in progression-free survival and disease control rate, with similar toxicities in patients with or without prior cytokine treatment.

Efficacy of targeted therapy in patients with renal cell carcinoma with pre-existing or new bone metastases

INTRODUCTION

This single-centre retrospective analysis of data from three randomised studies and two expanded-access studies compared the effect of interferon (IFN)-alfa, sunitinib, and sorafenib on the occurrence and progression of metastatic bone lesions in patients with renal cell carcinoma (RCC).

METHODS

The analysis included 292 patients: 107 received sunitinib 50 mg/day in 6-week cycles (Schedule 4/2), 147 received sorafenib 800 mg/day, and 38 received placebo or IFN-alfa 9 MU t.i.w.

RESULTS

Pre-existing metastatic bone lesions were reported in 82 patients, of which 30 experienced progression. Twenty-three of 210 patients developed new bone lesions. Overall, sunitinib appeared slightly more effective than sorafenib or IFN-alfa at extending mean time to progression of pre-existing bone lesions (P = 0.057). Compared with sorafenib, sunitinib significantly decreased formation (P = 0.034) and prolonged time to occurrence of new bone lesions (P = 0.047).

CONCLUSION

Further evaluation of the effect of these therapies on bone metastases in RCC is warranted.

Safety and efficacy of sunitinib for metastatic renal-cell carcinoma: an expanded-access trial

BACKGROUND

Results from clinical trials have established sunitinib as a standard of care for first-line treatment of advanced or metastatic renal-cell carcinoma (RCC); however, many patients, particularly those with a poorer prognosis, do not meet inclusion criteria and little is known about the activity of sunitinib in these subgroups. The primary objective of this trial was to provide sunitinib on a compassionate-use basis to trial-ineligible patients with RCC from countries where regulatory approval had not been granted.

METHODS

Previously treated and treatment-naive patients at least 18 years of age with metastatic RCC were eligible. All patients received open-label sunitinib 50 mg orally once daily on schedule 4-2 (4 weeks on treatment, 2 weeks off). Safety was assessed regularly, tumour measurements done per local practice, and survival data collected where possible. Analyses were done in the modified intention-to-treat (ITT) population, which consisted of all patients who received at least one dose of sunitinib. This study is registered with ClinicalTrials.gov, NCT00130897.

FINDINGS

As of December, 2007, 4564 patients were enrolled in 52 countries. 4371 patients were included in the modified ITT population. This population included 321 (7%) patients with brain metastases, 582 (13%) with Eastern Cooperative Oncology Group (ECOG) performance status of 2 or higher, 588 (13%) non-clear-cell RCC, and 1418 (32%) aged 65 years or more. Patients received a median of five treatment cycles (range 1-25). Reasons for discontinuation included lack of efficacy (n=1168 [27%]) and adverse events (n=362 [8%]). The most common treatment-related adverse events were diarrhoea (n=1936 [44%]) and fatigue (n=1606 [37%]). The most common grade 3-4 adverse events were fatigue (n=344 [8%]) and thrombocytopenia (n=338 [8%]) with incidences of grade 3-4 adverse events similar across subgroups. In 3464 evaluable patients, the objective response rate (ORR) was 17% (n=603), with subgroup ORR as follows: brain metastases (26 of 213 [12%]), ECOG performance status 2 or higher (29 of 319 [9%]), non-clear-cell RCC (48 of 437 [11%]) and age 65 years or more (176 of 1056 [17%]). Median progression-free survival was 10.9 months (95% CI 10.3-11.2) and overall survival was 18.4 months (17.4-19.2).

INTERPRETATION

In a broad population of patients with metastatic RCC, the safety profile of sunitinib 50 mg once-daily (initial dose) on schedule 4-2 was manageable and efficacy results were encouraging, particularly in subgroups associated with poor prognosis who are not usually entered into clinical trials.

FUNDING

Pfizer Inc.

Does arterial spin-labeling MR imaging-measured tumor perfusion correlate with renal cell cancer response to antiangiogenic therapy in a mouse model?

PURPOSE

To determine whether arterial spin-labeling (ASL) magnetic resonance (MR) imaging findings at baseline and early during antiangiogenic therapy can predict later resistance to therapy.

MATERIALS AND METHODS

Protocol was approved by an institutional animal care and use committee. Caki-1, A498, and 786-0 human renal cell carcinoma (RCC) xenografts were implanted in 39 nude mice. Animals received 80 mg sorafenib per kilogram of body weight once daily once tumors measured 12 mm. ASL imaging was performed at baseline and day 14, with additional imaging performed for 786-0 and A498 (3 days to 12 weeks). Mean blood flow values and qualitative differences in spatial distribution of blood flow were analyzed and compared with histopathologic findings for viability and microvascular density. t Tests were used to compare differences in mean tumor blood flow. Bonferroni-adjusted P values less than .05 denoted significant differences.

RESULTS

Baseline blood flow was 80.1 mL/100 g/min +/- 23.3 (standard deviation) for A498, 75.1 mL/100 g/min +/- 28.6 for 786-0, and 10.2 mL/100 g/min +/- 9.0 for Caki-1. Treated Caki-1 showed no significant change (14.9 mL/100 g/min +/- 7.6) in flow, whereas flow decreased in all treated A498 on day 14 (47.9 mL/100 g/min +/- 21.1) and in 786-0 on day 3 (20.3 mL/100 g/min +/- 8.7) (P = .003 and .03, respectively). For A498, lowest values were measured at 28-42 days of receiving sorafenib. Regions of increased flow occurred on days 35-49, 17-32 days before documented tumor growth and before significant increases in mean flow (day 77). Although 786-0 showed new, progressive regions with signal intensity detected as early as day 5 that correlated to viable tumor at histopathologic examination, no significant changes in mean flow were noted when day 3 was compared with all subsequent days (P > .99).

CONCLUSION

ASL imaging provides clinically relevant information regarding tumor viability in RCC lines that respond to sorafenib.

Sorafenib for older patients with renal cell carcinoma: subset analysis from a randomized trial

Background

The perception that older cancer patients may be at higher risk than younger patients of toxic effects from cancer therapy but may obtain less clinical benefit from it may be based on the underrepresentation of older patients in clinical trials and the known toxic effects of cytotoxic chemotherapy. It is not known how older patients respond to targeted therapy.

Methods

This retrospective subgroup analysis of data from the phase 3, randomized Treatment Approach in Renal Cancer Global Evaluation Trial examined the safety and efficacy of sorafenib in older (age ≥70 years, n = 115) and younger patients (age <70 years, n = 787) who received treatment for advanced renal cell carcinoma. Patient demographics and progression-free survival were recorded. Best tumor response, clinical benefit rate (defined as complete response plus partial response plus stable disease), time to self-reported health status deterioration, and toxic effects were assessed by descriptive statistics. Health-related quality of life was assessed with a Cox proportional hazards model. Kaplan–Meier analyses were used to summarize time-to-event data.

Results

Median progression-free survival was similar in sorafenib-treated younger patients (23.9 weeks; hazard ratio [HR] for progression compared with placebo = 0.55, 95% confidence interval [CI] = 0.47 to 0.66) and older patients (26.3 weeks; HR = 0.43, 95% CI = 0.26 to 0.69). Clinical benefit rates among younger and older sorafenib-treated patients were also similar (83.5% and 84.3%, respectively) and were superior to those of younger and older placebo-treated patients (53.8% and 62.2%, respectively). Adverse events were predictable and manageable regardless of age. Sorafenib treatment delayed the time to self-reported health status deterioration among both older patients (121 days with sorafenib vs 85 days with placebo; HR = 0.66, 95% CI = 0.43 to 1.03) and younger patients (90 days with sorafenib vs 52 days with placebo; HR = 0.69, 95% CI = 0.59 to 0.81) and improved quality of life over that time.

Conclusions

Among patients with advanced renal cell carcinoma receiving sorafenib treatment, outcomes of older (≥70 years) and younger (<70 years) patients were similar.

Thyrotoxicosis during sunitinib treatment for renal cell carcinoma

CONTEXT

Sunitinib malate is an oral tyrosine kinase inhibitor used in the treatment of renal cell carcinoma (RCC) and gastrointestinal stromal tumours. Hypothyroidism has been observed in patients treated with sunitinib, but the mechanism whereby sunitinib induces hypothyroidism is unknown.

OBJECTIVE

To describe a series of six patients who developed thyrotoxicosis while on sunitinib for metastatic RCC.

SETTING

The study was conducted at Austin Health, a tertiary teaching hospital in Melbourne, Australia.

RESULTS

Two patients developed severe thyrotoxicosis within 10 weeks after commencing sunitinib. In contrast, in the four patients who presented with later onset (16-30 weeks) thyrotoxicosis, the thyrotoxicosis was relatively mild, self-limiting and rapidly progressed to hypothyroidism. These patients experienced recurrent episodes of thyrotoxicosis in temporal relation to their cyclical sunitinib treatment. One patient had cytological evidence of lymphocytic thyroiditis.

CONCLUSIONS

These findings suggest that sunitinib-induced hypothyroidism may be a consequence of preceding thyroiditis with associated transient thyrotoxicosis. As predictive factors are currently unknown, we suggest regular monitoring of thyroid function in all patients commenced on sunitinib. Clinicians treating patients with sunitinib or other similar kinase inhibitors should to be alerted to thyroid dysfunction as a potential toxicity of these agents.

The clinical implications of sunitinib-induced hypothyroidism: a prospective evaluation

Sunitinib is approved for the treatment of metastatic renal cell carcinoma (RCC) and imatinib-resistant or -intolerant gastrointestinal stromal tumours (GIST). Several studies have identified unexpected rates of thyroid dysfunction with sunitinib treatment. We performed a prospective observational study with the aim of more accurately defining the incidence and severity of hypothyroidism in RCC or GIST patients receiving sunitinib. Thyroid function was assessed at baseline and on days 1 and 28 of each treatment cycle. Thyroid antibodies were assessed at baseline and during follow-up if abnormal thyroid function tests were recorded. Sixteen patients (27%) developed sub- or clinical hypothyroidism and required hormone replacement and 20 patients (34%) showed at least one elevated thyroid-stimulating hormone not requiring therapeutic intervention. Twenty patients (34%) did not develop any biochemical thyroid abnormality. Thus, sunitinib can induce (sub-) clinical hypothyroidism, warranting close monitoring of thyroid function. We propose a new algorithm for managing this side effect in clinical practise.

Treatment options in renal cell carcinoma: past, present and future

Cytokine therapies have been the standard of care in metastatic renal cell carcinoma (RCC). However, these agents only provide clinical benefit to a small subset of patients and are associated with significant toxicity. A better understanding of the molecular biology of RCC has identified the vascular endothelial growth factor (VEGF) and platelet-derived growth factor signalling pathways as rational targets for anticancer therapy. The multitargeted receptor tyrosine kinase inhibitors sunitinib and sorafenib have both demonstrated improved efficacy as second-line therapy in patients with RCC. Sunitinib has also been shown to be effective in the first-line setting, and has recently received European Union approval as first-line treatment for advanced and/or metastatic RCC. There is also recent evidence that temsirolimus (an inhibitor of the mammalian target of rapamycin) and bevacizumab (a mAb targeted against VEGF) may provide benefits in the first-line treatment setting. These results confirm that inhibiting these tumour targets is a feasible approach to treatment and provides a more positive outlook for the future management of metastatic RCC.

Sorafenib, but not sunitinib, affects function of dendritic cells and induction of primary immune responses

The tyrosine kinase inhibitors sorafenib and sunitinib are approved for the treatment of patients with malignant diseases. To analyze the possible use of these compounds in combination with immunotherapeutic approaches, we analyzed the effects of both inhibitors on the immunostimulatory capacity of human dendritic cells (DCs) and the induction of primary immune responses in vivo. Sorafenib, but not sunitinib, inhibits function of DCs, characterized by reduced secretion of cytokines and expression of CD1a, major histocompatibility complex, and costimulatory molecules in response to TLR ligands as well as by their impaired ability to migrate and stimulate T-cell responses. These inhibitory effects are mediated by inhibition of PI3 and MAP kinases and NFκB signaling. In contrast, sorafenib had no influence on the phenotype and proliferation of T cells. To analyze the effects of both TKIs on cytotoxic T-cell induction in vivo, C57BL/6 mice were pretreated with sorafenib or sunitinib and immunized with OVA257-264 peptide. Sorafenib, but not sunitinib, application significantly reduced the induction of antigen-specific T cells. Numbers of regulatory T cells were reduced in peripheral blood mononuclear cells from mice treated with sunitinib. These results indicate that sunitinib, but not sorafenib, is suitable for combination with immunotherapeutic approaches for treatment of cancer patients.

Phase 2 study of ABT-510 in patients with previously untreated advanced renal cell carcinoma

PURPOSE

Angiogenesis is a characteristic of renal cell carcinoma. ABT-510 is an angiogenesis inhibitor that mimics the antiangiogenic properties of thrombospondin-1. This study was designed to assess the safety and efficacy of ABT-510 in patients with advanced renal cell carcinoma.

EXPERIMENTAL DESIGN

Patients with previously untreated metastatic or unresectable renal cell carcinoma were randomized to treatment with one of two doses of ABT-510, self-administered s.c. twice daily in 28-day treatment periods without intervening rest periods. End points were progression-free survival (PFS), objective response rate, overall survival, and toxicity.

RESULTS

The objective response rate was 4% in the 10 mg twice daily group, and there were two unconfirmed PRs in the 100 mg twice daily group. Respective median PFS was 4.2 and 3.3 months, with a 6-month PFS of 39% and 32%. Median overall survival was 27.8 months (10 mg twice daily) and 26.1 months (100 mg twice daily). The most frequent adverse events were injection site reactions (84%), fatigue (50%), headache (20%), and nausea (19%). The incidence of treatment-related, grade 3/4 adverse events was low and included three bleeding episodes (gastrointestinal hemorrhage, intracranial hemorrhage, and hemoptysis) and one thrombotic event (deep vein thrombosis). No deaths were attributed to ABT-510.

CONCLUSIONS

There was little evidence of clinical activity for ABT-510, and further evaluation as a single agent for treating advanced renal cell carcinoma is not warranted. The evidence of a favorable safety profile may justify further evaluation in combination therapy.

Targeting mitogen-activated protein kinase/extracellular signal-regulated kinase kinase in the mutant (V600E) B-Raf signaling cascade effectively inhibits melanoma lung metastases

Malignant melanoma has a high propensity for metastatic spread, making it the most deadly form of skin cancer. B-RAF has been identified as the most mutated gene in these invasive cells and therefore an attractive therapeutic target. However, for uncertain reasons, chemotherapy inhibiting B-Raf has not been clinically effective. This has raised questions whether this pathway is important in melanoma metastasis or whether targeting a protein other than B-Raf in the signaling cascade could more effectively inhibit this pathway to reduce lung metastases. Here, we investigated the role played by (V600E)B-Raf in melanoma metastasis and showed that targeting this signaling cascade significantly reduces lung metastases. Small interfering RNA (siRNA)-mediated inhibition was used in mice to reduce expression (activity) of each member of the signaling cascade and effects on metastasis development were measured. Targeting any member of the signaling cascade reduced metastasis but inhibition of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (Mek) 1 and Mek 2 almost completely prevented lung tumor development. Mechanistically, metastatic inhibition was mediated through reduction of melanoma cell extravasation through the endothelium and decreased proliferative capacity. Targeting B-Raf with the pharmacologic inhibitor BAY 43-9006, which was found ineffective in clinical trials and seems to act primarily as an angiogenesis inhibitor, did not decrease metastasis, whereas inhibition of Mek using U0126 decreased cellular proliferative capacity, thereby effectively reducing number and size of lung metastases. In summary, this study provides a mechanistic basis for targeting Mek and not B-Raf in the mutant (V600E)B-Raf signaling cascade to inhibit melanoma metastases.

Sunitinib malate for the treatment of metastatic renal cell carcinoma and gastrointestinal stromal tumors

BACKGROUND

Sunitinib was approved by the US Food and Drug Administration (FDA) on January 26, 2006, for the treatment of metastatic renal cell carcinoma (mRCC) and gastrointestinal stromal tumor (GIST) in patients who have failed to respond to imatinib or were unable to tolerate it.

OBJECTIVE

This article reviews the pharmacology, pharmacokinetics, and pharmacodynamics of sunitinib; potential drug interactions; and the results of clinical trials evaluating its efficacy and tolerability.

METHODS

Pertinent literature was identified by searches of MEDLINE (1966-January 31, 2007), the American Society of Clinical Oncology abstracts database (2000-2007 annual meetings/symposia and previous meetings), and the FDA Web site (October 2006). Search terms included, but were not limited to, sunitinib, SUl1248, renal cell carcinoma, gastrointestinal stromal tumor, pharmacology, pharmacokinetic, adverse events, and clinical trial. Additional publications were found by scanning the reference lists of the identified articles.

RESULTS

Sunitinib is a potent inhibitor of multiple tyrosine kinase receptors. Its Tmax is reached within 6 to 12 hours, and food does not appear to affect its bioavailability. Sunitinib is metabolized by cytochrome P450 (CYP) 3A4 to an active metabolite, SU12662, which is further metabolized by CYP3A4 to an inactive moiety. The parent compound and active metabolite have similar biochemical activity and potency and reach similar plasma concentrations. Sunitinib and SU12662 have a tl/2 of 40 to 60 hours and 80 to 110 hours, respectively. Steady-state concentrations of both active entities are reached after 10 to 14 days of therapy. In a Phase III trial comparing sunitinib with interferon-alfa (IFN-00 as first-line therapy for mRCC, sunitinib was associated with a median progression-free survival of 11 months, compared with 5 months with IFN-cz (P < 0.001). A randomized, double-blind, placebo-controlled trial evaluating sunitinib as second-line therapy for GIST found a median time to progression of 28.9 weeks in the sunitinib arm, compared with 7 weeks in the placebo arm (hazard ratio = 0.28; P < 0.001). In Phase II trials, sunitinib also had anti-tumor activity in patients with breast cancer, neuroendocrine tumors, and non-small cell lung cancer. Further evaluation in these tumors, as well as in patients with acute myelogenous leukemia, may lead to expanded indications. The approved dose of sunitinib is 50 mg/d PO for 4 weeks, followed by a 2-week rest; this pattern is repeated until tumor progression or the occurrence of intolerable adverse effects. The most common clinical toxicities attributable to sunitinib include diarrhea, mucositis/stomatitis, hypertension, rash, skin discoloration, and altered taste, whereas commonly occurring laboratory abnormalities have been seen in association with gastrointestinal toxicity, renal toxicity, and hematologic toxicity. Of grade 3/4 toxicities occurring with sunitinib (which are relatively uncommon [<10%]), those that are clinically important include hypertension, diarrhea, fatigue, and hand-foot syndrome.

CONCLUSIONS

Sunitinib is a multiple tyrosine kinase receptor inhibitor approved for the treatment of mRCC and GIST. Evidence for long-term clinical benefit in renal cell cancer and other tumors awaits the results of ongoing trials.