VEGF kinase inhibitors: how do they cause hypertension?

Preclinical Pharmacology Characterization of Sovleplenib (HMPL-523), an Orally Available Syk Inhibitor

Spleen tyrosine kinase (Syk) is an intracellular tyrosine kinase involved in the signal transduction in immune cells mainly. Its aberrant regulation is associated with diversified allergic disorders, autoimmune diseases and B cell malignancies. Therefore, inhibition of Syk is considered a reasonable approach to treat autoimmune/inflammatory diseases and B cell malignancies. Here we described the preclinical characterization of sovleplenib, a novel, highly potent and selective, oral Syk inhibitor, in several rodent autoimmune disease models. Sovleplenib potently inhibited Syk activity in a recombinant enzymatic assay and Syk-dependent cellular functions in various immune cell lines and human whole blood in vitro. Furthermore, sovleplenib, by oral administration, demonstrated strong in vivo efficacies in murine models of immune thrombocytopenia (ITP), autoimmune hemolytic anemia (AIHA), and chronic graft-versus-host disease (cGVHD), and a rat model of collagen induced arthritis (CIA) respectively, in a dose-dependent manner. Collectively, these results clearly supported sovleplenib as a therapeutic agent in the treatment of autoimmune diseases. Sovleplenib is being globally developed for ITP (Phase III, NCT05029635, Phase Ib/II, NCT03951623), wAIHA (Phase II/III, NCT05535933) and B-cell lymphoma (Phase I, NCT02857998, NCT03779113). SIGNIFICANCE STATEMENT: Syk is a key mediator of signaling pathways downstream of a wide array of receptors important for immune functions, including the B cell receptor, immunoglobulin receptors bearing Fc receptors. Inhibition of Syk could provide a novel therapeutic approach for autoimmune diseases and hematologic malignancies. The manuscript describes the preclinical pharmacology characterization of sovleplenib, a novel Syk inhibitor, in enzymatic and cellular assays in vitro and several murine autoimmune disease models in vivo.

Comparison of antihypertensive drugs amlodipine and perindopril on blood pressure variability after long-term treatment of hypertension induced by apatinib and bevacizumab

The purpose of this study was to elucidate the therapeutic effect of different antihypertensive drugs (amlodipine and perindopril) on hypertension induced by apatinib and bevacizumab. Sixty patients with hypertension treated with apatinib or bevacizumab were selected and divided into two groups: one group was treated with amlodipine and the other group was treated with perindopril. Before and after treatment, the dynamic blood pressure (BP) measurement (systolic BP [SBP] and diastolic BP [DBP]), echocardiography (left ventricular end-diastolic diameter, interventricular septal thickness [IVST], left ventricular posterior wall thickness [LVPWT], and left atrial diameter [LAD]), and detection of nitric oxide (NO) content in venous blood were performed. In the amlodipine group, the 24hSBP, 24hSSD, 24hSCV, daytime mean SBP (dSBP), daytime mean SSD (dSSD), daytime mean SBP CV, night mean SBP (nSBP), night mean SSD, 24hDBP, 24hDSD, 24 h DBP CV, daytime mean DBP (dDBP), daytime mean DSD (dDSD), daytime mean DBP CV, night mean DBP (nDBP), LAD, and LAD index (LADi) after treatment were all lower than before treatment, while NO was higher than before treatment (all P < 0.05). In the perindopril group, the 24hSBP, dSBP, nSBP, 24hDBP, dDBP, nDBP, LAD, LADi, IVST, LVPWT, and left ventricular mass index (LVMI) after treatment were lower than before treatment, and NO level after treatment was higher than before treatment (all P < 0.05). After treatment, the 24hSBP, 24hSSD, dSBP, dSSD, nSBP, 24hDBP, 24hDSD, dDBP, dDSD, nDBP, night mean DSD, and NO were all lower while the LAD, LADi, IVST, LVPWT, and LVMI were higher in the amlodipine group than those in the perindopril group (all P < 0.05). Our study suggests that the SBP and DBP variability of amlodipine in the treatment of hypertension induced by apatinib and bevacizumab is slightly better than that of perindopril, but the effect of perindopril in improving endothelial function indices NO and echocardiographic data is better than that of amlodipine.

Clinical pharmacology and drug-drug interactions of lenvatinib in thyroid cancer

Lenvatinib is a non-selective tyrosine kinase inhibitor (TKI) with high in vitro potency against vascular endothelial growth factor receptors. Although this drug is used to treat several cancer types, it is the most effective TKI used in patients with thyroid cancer. Lenvatinib is well tolerated and the most common adverse drug reactions can be adequately managed by dose adjustment. Particularly, blood pressure and cardiac function monitoring, as well as antihypertensive treatment optimization, may be required in patients treated with lenvatinib. Dose reduction should be taken into account in patients with body weight <60 kg or severe hepatic failure. No significant change in lenvatinib pharmacokinetics has been observed with other patient-related factors and very few data are available on lenvatinib pharmacogenetics. Lenvatinib can be administered orally regardless of food and no clinically relevant drug-drug interactions have been reported.

Polyprenol-Based Lipofecting Agents for In Vivo Delivery of Therapeutic DNA to Treat Hypertensive Rats

Development of efficient vectors for transfection is one of the major challenges in genetic engineering. Previous research demonstrated that cationic derivatives of polyisoprenoids (PTAI) may serve as carriers of nucleic acids. In the present study, the effectiveness of two PTAI-based formulations (PTAI-6–8 and 10–14) was investigated and compared to the commercial reagents. The purpose of applied gene therapy was to enhance the expression of vascular endothelial growth factor (VEGF-A) in the renal medulla of spontaneously hypertensive rats (SHR) and to test its potential as a novel antihypertensive intervention. In the first part of the study (in vitro), we confirmed that PTAI-based lipoplexes efficiently transfect XC rat sarcoma cells and are stable in 37 °C for 7 days. In the in vivo experiments, we administered selected lipoplexes directly to the kidneys of conscious SHR (via osmotic pumps). There were no blood pressure changes and VEGF-A level in renal medulla was significantly higher only for PTAI-10–14-based formulation. In conclusion, despite the promising results, we were not able to achieve VEGF-A expression level high enough to verify VEGF-A gene therapy usefulness in SHR. However, results of our study give important indications for the future development of PTAI-based DNA carriers and kidney-targeted gene delivery.

Systems Pharmacology-Based Strategy to Investigate Pharmacological Mechanisms of Radix Puerariae for Treatment of Hypertension

Hypertension is a clinical cardiovascular syndrome characterized by elevated systemic arterial pressure with or without multiple cardiovascular risk factors. Radix Pueraria (RP) has the effects of anti-myocardial ischemia, anti-arrhythmia, vasodilatation, blood pressure reduction, anti-inflammation, and attenuating insulin resistance. Although RP can be effective for the treatment of hypertension, its active compounds, drug targets, and exact molecular mechanism are still unclear. In this study, systems pharmacology was used to analyze the active compounds, drug target genes, and key pathways of RP in the treatment of hypertension. Thirteen active compounds and related information on RP were obtained from the TCMSP database, and 140 overlapping genes related to hypertension and drugs were obtained from the GeneCards and OMIM databases. A PPI network and a traditional Chinese medicine (TCM) comprehensive network (Drug-Compounds-Genes-Disease network) were constructed, and 2,246 GO terms and 157 pathways were obtained by GO enrichment analysis and KEGG pathway enrichment analysis. Some important active compounds and targets were evaluated by in vitro experiments. This study shows that RP probably acts by influencing the proliferation module, apoptosis module, inflammation module, and others when treating hypertension. This study provides novel insights for researchers to systematically explore the mechanism of action of TCM.

Adaptation of Human iPSC-Derived Cardiomyocytes to Tyrosine Kinase Inhibitors Reduces Acute Cardiotoxicity via Metabolic Reprogramming

Tyrosine kinase inhibitors (TKIs) are widely used to treat solid tumors but can be cardiotoxic. The molecular basis for this toxicity and its relationship to therapeutic mechanisms remain unclear; we therefore undertook a systems-level analysis of human cardiomyocytes (CMs) exposed to four TKIs. CMs differentiated from human induced pluripotent stem cells (hiPSCs) were exposed to sunitinib, sorafenib, lapatinib, or erlotinib, and responses were assessed by functional assays, microscopy, RNA sequencing, and mass spectrometry (GEO: GSE114686; PRIDE: PXD012043). TKIs have diverse effects on hiPSC-CMs distinct from inhibition of tyrosine-kinase-mediated signal transduction; cardiac metabolism is particularly sensitive. Following sorafenib treatment, oxidative phosphorylation is downregulated, resulting in a profound defect in mitochondrial energetics. Cells adapt by upregulating aerobic glycolysis. Adaptation makes cells less acutely sensitive to sorafenib but may have long-term negative consequences. Thus, CMs exhibit adaptive responses to anti-cancer drugs conceptually similar to those previously shown in tumors to mediate drug resistance.

Hypertension as a predictive biomarker in patients with advanced non-small-cell lung cancer treated with apatinib

Background

Hypertension (HTN) is a common adverse event of the vascular endothelial growth factor pathway inhibitor apatinib. This study was conducted to evaluate the association of apatinib-induced HTN with clinical outcomes in patients with advanced non-small-cell lung cancer (NSCLC).

Methods

We retrospectively analyzed 110 consecutive patients with advanced NSCLC who were treated with apatinib from August 2014 to January 2018. All patients were classified as normotensive or hypertensive based on blood pressure measurements after initiating therapy. Therapeutic response, progression-free survival (PFS), and overall survival (OS) were evaluated. Univariate and multivariate analyses were performed using the Cox proportional hazards method.

Results

A total of 46 patients (42%) were diagnosed with HTN. The median PFS for the hypertensive and normotensive groups were 5.6 months and 4.2 months, respectively (P=0.0027). The median OS times for the hypertensive and normotensive groups were 9.9 months and 7.8 months, respectively (P=0.005). Thirty percent of patients who experienced HTN showed partial response to apatinib as compared with 6.3% of non-hypertensive patients (P=0.002). HTN was independently associated with improved PFS and OS on both univariate and multivariate analyses.

Conclusion

Apatinib-induced HTN may be an inexpensive, valid, and easily measurable biomarker for apatinib antitumor efficacy in patients with advanced NSCLC.

VEGF Signaling in Neurological Disorders

Vascular endothelial growth factor (VEGF) is a potent growth factor playing diverse roles in vasculogenesis and angiogenesis. In the brain, VEGF mediates angiogenesis, neural migration and neuroprotection. As a permeability factor, excessive VEGF disrupts intracellular barriers, increases leakage of the choroid plexus endothelia, evokes edema, and activates the inflammatory pathway. Recently, we discovered that a heparin binding epidermal growth factor like growth factor (HB-EGF)—a class of EGF receptor (EGFR) family ligands—contributes to the development of hydrocephalus with subarachnoid hemorrhage through activation of VEGF signaling. The objective of this review is to entail a recent update on causes of death due to neurological disorders involving cerebrovascular and age-related neurological conditions and to understand the mechanism by which angiogenesis-dependent pathological events can be treated with VEGF antagonisms. The Global Burden of Disease study indicates that cancer and cardiovascular disease including ischemic and hemorrhagic stroke are two leading causes of death worldwide. The literature suggests that VEGF signaling in ischemic brains highlights the importance of concentration, timing, and alternate route of modulating VEGF signaling pathway. Molecular targets distinguishing two distinct pathways of VEGF signaling may provide novel therapies for the treatment of neurological disorders and for maintaining lower mortality due to these conditions.

Hypertension Caused by Lenvatinib and Everolimus in the Treatment of Metastatic Renal Cell Carcinoma

Multikinase inhibitors (MKI) and mammalian target of rapamycin (mTOR) inhibitors prolong progression-free (PFS) and overall survival (OS) in the treatment of metastatic renal cell carcinoma (mRCC) by reducing angiogenesis and tumor growth. In this regard, the MKI lenvatinib and the mTOR inhibitor everolimus proved effective when applied alone, but more effective when they were administered combined. Recently, both drugs were included in clinical trials, resulting in international clinical guidelines for the treatment of mRCC. In May 2016, lenvatinib was approved by the American Food and Drug Administration (FDA) for the use in combination with everolimus, as treatment of advanced renal cell carcinoma following one prior antiangiogenic therapy. A major problem of treating mRCC with lenvatinib and everolimus is the serious adverse event (AE) of arterial hypertension. During the treatment with everolimus and lenvatinib combined, 42% of the patients developed hypertension, while 10% of the patients treated with everolimus alone and 48% of the of the lenvatinib only treated patients developed hypertension. Lenvatinib carries warnings and precautions for hypertension, cardiac failure, and other adverse events. Therefore, careful monitoring of the patients is necessary.

Tyrosine kinase inhibitor sunitinib therapy is effective in the treatment of bone metastasis from cancer of unknown primary: Identification of clinical and immunohistochemical biomarkers predicting survival

Bone metastasis from cancer of unknown primary (BMCUP) brings poor survival prognosis and its management remains controversial. Sunitinib (SUTENT) proved effective in many sorts of solid tumors but has never been applied for patients with occult primary cancers, and there is no study to identify sensitive or resistant biomarkers for sunitinib therapy in CUP patients. An analysis was carried out to investigate the efficacy of sunitinib by multivariate survival analysis of 286 patients with BMCUP. We further carried out multivariate analysis to identify histological and clinical biomarkers that could predict sensitivity or resistance for sunitinib therapy. Of the 286 patients included from January 2011 to March 2016, sunitinib therapy proved effective to prolong survival in patients with BMCUP. Sensitive and resistant biomarkers were identified in histological specimen of patients receiving sunitinib therapy. Clinical factors were also identified that predict poor survival prognosis for sunitinib therapy. Sunitinib therapy proved effective to prolong survival in patients with BMCUP. Sensitive markers for sunitinib therapy include KDR positivity and early-developed treatment-induced hypertension. Resistance factors for sunitinib include VEGF positivity, CAIX positivity and squamous cell carcinoma pathology type. Prolonged symptom time and severe weight loss before therapy seemed to be associated with poor survival prognosis for sunitinib therapy.

Dickkopf-3 Upregulates VEGF in Cultured Human Endothelial Cells by Activating Activin Receptor-Like Kinase 1 (ALK1) Pathway

Dkk-3 is a member of the dickkopf protein family of secreted inhibitors of the Wnt pathway, which has been shown to enhance angiogenesis. The mechanism underlying this effect is currently unknown. Here, we used cultured HUVECs to study the involvement of the TGF-β and VEGF on the angiogenic effect of Dkk-3. Addition of hrDkk-3 peptide (1 or 10 ng/ml) to HUVECs for 6 or 12 h enhanced the intracellular and extracellular VEGF protein levels, as assessed by RTPCR, immunoblotting, immunocytochemistry and ELISA. The increase in the extracellular VEGF levels was associated to the VEGFR2 activation. Pharmacological blockade of VEGFR2 abrogated Dkk-3-induced endothelial cell tubes formation, indicating that VEGF is a molecular player of the angiogenic effects of Dkk-3. Moreover, Dkk-3 enhanced Smad1/5/8 phosphorylation and recruited Smad4 to the VEGF gene promoter, suggesting that Dkk-3 activated ALK1 receptor leading to a transcriptional activation of VEGF. This mechanism was instrumental to the increased VEGF expression and endothelial cell tubes formation mediated by Dkk-3, because both effects were abolished by siRNA-mediated ALK1 knockdown. In summary, we have found that Dkk-3 activates ALK1 to stimulate VEGF production and induce angiogenesis in HUVECs.

Effects of Toceranib Phosphate on Systolic Blood Pressure and Proteinuria in Dogs

Background

Systemic hypertension and proteinuria are established adverse effects of tyrosine kinase inhibitor treatment in people.

Objective

The objective of this study was to investigate changes in systolic blood pressure and the incidence of proteinuria secondary to treatment with toceranib phosphate in dogs with cancer.

Animals

Twenty‐six control dogs and 30 dogs with cancer were evaluated for the first part of the study (baseline characteristics). For the second part (effect of toceranib phosphate treatment), 48 client‐owned dogs were evaluated, including 20 control dogs and 28 dogs with various types of neoplasia.

Methods

Prospective cohort study. Client‐owned healthy control dogs and dogs with cancer were enrolled. Blood pressure and urine protein:creatinine ratios were measured before treatment and 2 weeks after initiation of toceranib phosphate treatment.

Results

Systolic blood pressure was significantly (P = 0.0013) higher in previously normotensive treatment dogs after initiation of treatment with toceranib phosphate (152 mmHg ± 19) compared to baseline (136 mmHg ± 14). 37% of treated dogs developed SBP ≥ 160 mmHg. The prevalence of systemic hypertension (37%) and proteinuria (21%) at baseline in treatment dogs did not differ from that of age‐matched healthy controls (15% [P = 0.13] and 0% [P = 0.069], respectively).

Conclusions and Clinical Importance

Toceranib phosphate treatment might result in increased systolic blood pressures in dogs. Systemic hypertension should be considered a potential adverse effect of this drug in dogs. Systemic hypertension and proteinuria were detected at clinically relevant frequencies in the dogs with cancer before antineoplastic therapies suggesting that monitoring of these variables might be warranted in this population.

Hypertension in cancer patients treated with anti-angiogenic based regimens

New anti-cancer drugs that inhibit the vascular endothelial growth factor (VEGF) signaling pathway are highly effective in the treatment of solid tumors, however concerns remain regarding their cardiovascular safety. The most common side effect of VEGF signaling pathway (VSP) inhibition is the development of systemic hypertension. We review the incidence, possible mechanisms, significance and management of hypertension in patients treated with VSP inhibitors.

Toxicology Strategies for Drug Discovery: Present and Future

Attrition due to nonclinical safety represents a major issue for the productivity of pharmaceutical research and development (R&D) organizations, especially during the compound optimization stages of drug discovery and the early stages of clinical development. Focusing on decreasing nonclinical safety-related attrition is not a new concept, and various approaches have been experimented with over the last two decades. Front-loading testing funnels in Discovery with in vitro toxicity assays designed to rapidly identify unfavorable molecules was the approach adopted by most pharmaceutical R&D organizations a few years ago. However, this approach has also a non-negligible opportunity cost. Hence, significant refinements to the "fail early, fail often" paradigm have been proposed recently to reflect the complexity of accurately categorizing compounds with early data points without taking into account other important contextual aspects, in particular efficacious systemic and tissue exposures. This review provides an overview of toxicology approaches and models that can be used in pharmaceutical Discovery at the series/lead identification and lead optimization stages to guide and inform chemistry efforts, as well as a personal view on how to best use them to meet nonclinical safety-related attrition objectives consistent with a sustainable pharmaceutical R&D model. The scope of this review is limited to small molecules, as large molecules are associated with challenges that are quite different. Finally, a perspective on how several emerging technologies may impact toxicity evaluation is also provided.

Population pharmacokinetic-pharmacodynamic modelling of 24-h diastolic ambulatory blood pressure changes mediated by axitinib in patients with metastatic renal cell carcinoma

BACKGROUND

Increased blood pressure (BP) is commonly observed in patients treated with vascular endothelial growth factor pathway inhibitors, including axitinib. Ambulatory BP monitoring (ABPM) and pharmacokinetic data were collected in a randomised, double-blind phase II study of axitinib with or without dose titration in previously untreated patients with metastatic renal cell carcinoma.

OBJECTIVE

Aims of these analyses were to (1) develop a population pharmacokinetic-pharmacodynamic model for describing the relationship between axitinib exposure and changes in diastolic BP (dBP) and (2) simulate changes in dBP with different axitinib dosing regimens.

METHODS

We employed a three-stage modelling approach, which included development of (1) a baseline 24-h ABPM model, (2) a pharmacokinetic model from serial and sparse pharmacokinetic data, and (3) an indirect-response, maximum-effect (Emax) model to evaluate the exposure-driven effect of axitinib on dBP. Simulations (N = 1,000) were performed using the final pharmacokinetic-pharmacodynamic model to evaluate dBP changes on days 4 and 15 of treatment with different axitinib doses.

RESULTS

Baseline ABPM data from 62 patients were best described by 24-h mean dBP and two cosine terms. The final indirect-response Emax model showed good agreement between observed 24-h ABPM data and population and individual predictions. The maximum increase in dBP was 20.8 %, and the axitinib concentration at which 50 % of the maximal increase in dBP was reached was 12.4 ng/mL.

CONCLUSION

Our model adequately describes the relationship between axitinib exposure and dBP increases. Results from these analyses may potentially be applied to infer dBP changes in patients administered axitinib at nonstandard doses.

In vitro pharmacological profiling of R406 identifies molecular targets underlying the clinical effects of fostamatinib

Off-target pharmacology may contribute to both adverse and beneficial effects of a new drug. In vitro pharmacological profiling is often applied early in drug discovery; there are fewer reports addressing the relevance of broad profiles to clinical adverse effects. Here, we have characterized the pharmacological profile of the active metabolite of fostamatinib, R406, linking an understanding of drug selectivity to the increase in blood pressure observed in clinical studies. R406 was profiled in a broad range of in vitro assays to generate a comprehensive pharmacological profile and key targets were further investigated using functional and cellular assay systems. A combination of traditional literature searches and text-mining approaches established potential mechanistic links between the profile of R406 and clinical side effects. R406 was selective outside the kinase domain, with only antagonist activity at the adenosine A3 receptor in the range relevant to clinical effects. R406 was less selective in the kinase domain, having activity at many protein kinases at therapeutically relevant concentrations when tested in multiple in vitro systems. Systematic literature analyses identified KDR as the probable target underlying the blood pressure increase observed in patients. While the in vitro pharmacological profile of R406 suggests a lack of selectivity among kinases, a combination of classical searching and text-mining approaches rationalized the complex profile establishing linkage between off-target pharmacology and clinically observed effects. These results demonstrate the utility of in vitro pharmacological profiling for a compound in late-stage clinical development.

Prevention of fostamatinib-induced blood pressure elevation by antihypertensive agents

Fostamatinib is a tyrosine kinase inhibitor with activity against spleen tyrosine kinase which has completed clinical trials for patients with rheumatoid arthritis. In clinical studies fostamatinib treatment was associated with a small elevation of systemic arterial blood pressure (BP), a similar finding to that seen with other kinase inhibitors, especially those that inhibit VEGFR2 signaling. We have investigated the link between fostamatinib-induced blood pressure elevation and plasma levels of the fostamatinib-active metabolite R940406 in conscious rats and found the time course of the BP effect correlated closely with changes in R940406 plasma concentration, indicating a direct pharmacological relationship. Free plasma levels of R940406 produced in these studies (up to 346 nmol/L) span the clinically observed mean peak free plasma concentration of 49 nmol/L. We have demonstrated that the blood pressure elevation induced by fostamatinib dosing can be successfully controlled by a variety of methods, notably simple drug withdrawal or codosing with a range of standard antihypertensive agents such as atenolol, captopril, and nifedipine. These findings support potential methods of maintaining patient safety while on fostamatinib therapy. Furthermore, we have demonstrated, using nifedipine as an example agent, that this blood pressure control was not achieved by reduction in plasma exposure of R940406, suggesting that potential benefits from the pharmacology of the investigational drug can be maintained while blood pressure control is managed by use of standard comedications.

Targeted therapies for treatment of renal cell carcinoma: recent advances and future perspectives

PURPOSE

A wide variety of targeted therapies are available for the treatment of renal cancer that has progressed beyond the point at which surgery is a viable option. In addition, there are many more that are in the different stages of clinical trials. Here, we provide a methodical discussion of the efficacy and safety of targeted therapies for the treatment of advanced renal cell carcinoma.

METHODS

We conducted a systematic literature employing the search terms: renal cell carcinoma targets, tyrosine kinase inhibitors, mammalian target of rapamycin inhibitors, and each of the drugs discussed within these papers.

RESULTS

The identified targeted therapies work by disrupting specific signalling pathways involved in tumour progression, such as those responsible for angiogenesis and cell proliferation. Tyrosine kinase inhibitors and mammalian target of rapamycin inhibitors are now established classes of drugs used in the treatment of renal cancer, with a total of six having received regulatory approval to date (sorafenib, sunitinib, pazopanib, axitinib, temsirolimus, and everolimus). Ongoing trials are likely to result in addition to these in the near future, for example, tivozanib, dovitinib, and cediranib. Furthermore, in addition to these small molecule drugs, immunotherapies involving monoclonal antibodies against signalling molecules such as vascular endothelial growth factor (bevacizumab) or programmed death-1 (nivolumab) are receiving increasing attention.

CONCLUSIONS

Targeted therapies have great potential for disrupting tumour progression by inhibiting certain signalling pathways. As our understanding of the biochemical pathways involved in cancer progresses, additional targets are certain to become apparent, expanding treatment options even further.

The contribution of VEGF signalling to fostamatinib-induced blood pressure elevation

BACKGROUND AND PURPOSE

Fostamatinib is an inhibitor of spleen tyrosine kinase (TK). In patients, fostamatinib treatment was associated with increased BP. Some TK inhibitors cause BP elevation, by inhibiting the VEGF receptor 2 (VEGFR2). Here, we have assessed the mechanistic link between fostamatinib-induced BP elevation and inhibition of VEGF signalling.

EXPERIMENTAL APPROACH

We used conscious rats with automated blood sampling and radio telemetry and anaesthetized rats to measure cardiovascular changes. Rat isolated aorta and isolated hearts, and human resistance vessels in vitro were also used. NO production by human microvascular endothelial cells was measured with the NO-dependent probe, DAF-FM and VEGFR2 phosphorylation was determined in mouse lung, ex vivo.

KEY RESULTS

In conscious rats, fostamatinib dose-dependently increased BP. The time course of the BP effect correlated closely with the plasma concentrations of R406 (the active metabolite of fostamatinib). In anaesthetized rats, infusion of R406 increased BP and decreased femoral arterial conductance. Endothelial function was unaffected, as infusion of R406 did not inhibit hyperaemia- or ACh-induced vasodilatation in rats. R406 did not affect contraction of isolated blood vessels. R406 inhibited VEGF-stimulated NO production from human endothelial cells in vitro, and treatment with R406 inhibited VEGFR2 phosphorylation in vivo. R406 inhibited VEGF-induced hypotension in anaesthetized rats.

CONCLUSIONS AND IMPLICATIONS

Increased vascular resistance, secondary to reduced VEGF-induced NO release from endothelium, may contribute to BP increases observed with fostamatanib. This is consistent with the elevated BP induced by other drugs inhibiting VEGF signalling, although the contribution of other mechanisms cannot be excluded.

Low-concentration detergent sclerosants stimulate white blood cells and release proinflammatory and proangiogenic cytokines in vitro

OBJECTIVE

The objective of this study was to investigate the effects of the detergent sclerosants sodium tetradecyl sulfate (STS) and polidocanol (POL) on the release of proinflammatory and angiogenic mediators from circulating blood cells.

METHODS

Whole blood, platelet-rich plasma, platelet-poor plasma, and suspensions of polymorphonuclear cells (PMNCs) and mononuclear cells (MNCs) were incubated with varying concentrations of sclerosants. Enzyme-linked immunosorbent assay was used to detect the release of interferon-γ (IFN-γ); tumor necrosis factor-α (TNF-α); interleukins (IL) 1α, 1β, 6, 8, and 17; vascular endothelial growth factor (VEGF); and basic fibroblast growth factor. Leukocyte activation was assessed by flow cytometry.

RESULTS

IFN-γ and TNF-α were released from STS-stimulated PMNCs at high (387 ng/mL; P < .01) and modest (232 ng/mL; P < .05) quantities, respectively. Both sclerosants induced a weak response in MNCs, releasing minor quantities of IL-1α (STS, 18.2 ng/mL; POL, 14.0 ng/mL), IFN-γ (STS, 41.7 ng/mL; POL, 27.7 ng/mL), and TNF-α (STS, 29.7 ng/mL; POL, 14.0 ng/mL). POL at a wide range of concentrations and in all sample types tested stimulated the release of VEGF, whereas the effect of STS was limited to low concentrations and not detected in MNCs. Both agents stimulated moderate release of IL-8 from PMNCs (STS, 223.3 ng/mL, P < .001; POL, 84.23 ng/mL, P < .05). Neither agent induced a significant rise in basic fibroblast growth factor, IL-6, or IL-17. STS at low concentrations increased the expression of CD11b in both PMNCs and MNCs, suggestive of cellular activation. The activating effect of POL was limited to MNCs.

CONCLUSIONS

STS demonstrated proinflammatory activity mediated primarily by IFN-γ released from PMNCs and MNCs. POL had a weak proinflammatory effect limited to MNCs. Both sclerosants (POL > STS) induced a proangiogenic response mediated by VEGF.

Systematic review of the risk of adverse outcomes associated with vascular endothelial growth factor inhibitors for the treatment of cancer

BACKGROUND

Anti-angiogenic therapy targeted at vascular endothelial growth factor (VEGF) is now used to treat several types of cancer. We did a systematic review of randomized controlled trials (RCTs) to summarize the adverse effects of vascular endothelial growth factor inhibitors (VEGFi), focusing on those with vascular pathogenesis.

METHODS AND FINDINGS

We searched MEDLINE, EMBASE and Cochrane Library until April 19, 2012 to identify parallel RCTs comparing a VEGFi with a control among adults with any cancer. We pooled the risk of mortality, vascular events (myocardial infarction, stroke, heart failure, and thromboembolism), hypertension and new proteinuria using random-effects models and calculated unadjusted relative risk (RR). We also did meta-regression and assessed publication bias. We retrieved 83 comparisons from 72 studies (n = 38,078) on 11 different VEGFi from 7901 identified citations. The risk of mortality was significantly lower among VEGFi recipients than controls (pooled RR 0.96, 95% confidence interval [CI] 0.94 to 0.98, I2 = 0%, tau2 = 0; risk difference 2%). Compared to controls, VEGFi recipients had significantly higher risk of myocardial infarction (MI) (RR 3.54, 95% CI 1.61 to 7.80, I2 = 0%, tau2 = 0), arterial thrombotic events (RR 1.80, 95% CI 1.24 to 2.59, I2 = 0%, tau2 = 0); hypertension (RR 3.46, 95% CI 2.89 to 4.15, I2 = 58%, tau2 = 0.16), and new proteinuria (RR 2.51, 95% CI 1.60 to 3.94, I2 = 87%, tau2 = 0.65). The absolute risk difference was 0.8% for MI, 1% for arterial thrombotic events, 15% for hypertension and 12% for new proteinuria. Meta-regression did not suggest any statistically significant modifiers of the association between VEGFi treatment and any of the vascular events. Limitations include heterogeneity across the trials.

CONCLUSIONS

VEGFi increases the risk of MI, hypertension, arterial thromboembolism and proteinuria. The absolute magnitude of the excess risk appears clinically relevant, as the number needed to harm ranges from 7 to 125. These adverse events must be weighed against the lower mortality associated with VEGFi treatment.

Hypertension among patients with renal cell carcinoma receiving axitinib or sorafenib: analysis from the randomized phase III AXIS trial

Inhibitors of the vascular endothelial growth factor (VEGF) pathway frequently induce hypertension when used to treat patients with advanced renal cell carcinoma (RCC). This analysis characterizes hypertension and hypertension-related events in patients treated with the VEGF pathway inhibitors axitinib or sorafenib in the AXIS trial. AXIS was a randomized phase III study of axitinib versus sorafenib in patients with metastatic RCC following failure of one prior systemic regimen. Patients with uncontrolled hypertension were excluded, but patients with hypertension controlled with antihypertensive medication were allowed to participate. Guidelines for hypertension management included adjustment or addition of antihypertensive medications and/or axitinib or sorafenib dose reductions, interruptions, or discontinuations. Treatment-emergent all-causality hypertension occurred in 145 (40.4 %) axitinib-treated patients (N = 359) and 103 (29.0 %) sorafenib-treated patients (N = 355), with grade 3 hypertension reported in 55 (15.3 %) and 38 (10.7 %) patients, respectively, and grade 4 hypertension reported in one (0.3 %) patient in each arm. Hypertension-related events led to axitinib dose interruptions (n = 46; 12.8 %), dose reductions (n = 16; 4.5 %), or discontinuations (n = 1; 0.3 %). Approximately 50 % of axitinib-treated patients with grade 3 or 4 hypertension continued treatment for ≥ 9 months. Hypertension-related sequelae occurred in <1 % of axitinib-treated patients. Hypertension was more frequently observed during treatment with axitinib than sorafenib in patients with RCC, but axitinib-induced hypertension rarely led to treatment discontinuation or cardiovascular sequelae. Recommendations for monitoring blood pressure and managing hypertension during axitinib therapy are presented.

The effects of exercise on cardiovascular outcomes before, during, and after treatment for breast cancer

Asymptomatic cardiotoxicity following breast cancer treatment is a significant issue for many patients, as these patients typically face an increased risk of cardiovascular disease (CVD). Exercise has well established benefits to improve and maintain cardiovascular function across patients with and without CVD. However, there is a dearth of information on the effects of exercise on cardiovascular outcomes in breast cancer patients. While pre-clinical studies support the use of exercise in mitigating cardiotoxicity, only one human study has specifically investigated cardiac function following an exercise intervention during chemotherapy treatment. No significant differences were observed between groups, which highlights the unidentified role of exercise in altering the risk of cardiotoxicity in breast cancer patients. Issues such as establishing the optimal timing, type, and intensity of an exercise program before, during, or after oncologic treatment for breast cancer are unclear. CVD risk and incidence increase in breast cancer survivors post therapy, and CVD is the number one killer of women in the United States. Thus, there is an increasing need to define the efficacy of exercise as a non-pharmacologic intervention in this growing population.

Immune cells control skin lymphatic electrolyte homeostasis and blood pressure

The skin interstitium sequesters excess Na+ and Cl- in salt-sensitive hypertension. Mononuclear phagocyte system (MPS) cells are recruited to the skin, sense the hypertonic electrolyte accumulation in skin, and activate the tonicity-responsive enhancer-binding protein (TONEBP, also known as NFAT5) to initiate expression and secretion of VEGFC, which enhances electrolyte clearance via cutaneous lymph vessels and increases eNOS expression in blood vessels. It is unclear whether this local MPS response to osmotic stress is important to systemic blood pressure control. Herein, we show that deletion of TonEBP in mouse MPS cells prevents the VEGFC response to a high-salt diet (HSD) and increases blood pressure. Additionally, an antibody that blocks the lymph-endothelial VEGFC receptor, VEGFR3, selectively inhibited MPS-driven increases in cutaneous lymphatic capillary density, led to skin Cl- accumulation, and induced salt-sensitive hypertension. Mice overexpressing soluble VEGFR3 in epidermal keratinocytes exhibited hypoplastic cutaneous lymph capillaries and increased Na+, Cl-, and water retention in skin and salt-sensitive hypertension. Further, we found that HSD elevated skin osmolality above plasma levels. These results suggest that the skin contains a hypertonic interstitial fluid compartment in which MPS cells exert homeostatic and blood pressure-regulatory control by local organization of interstitial electrolyte clearance via TONEBP and VEGFC/VEGFR3-mediated modification of cutaneous lymphatic capillary function.

Cardiovascular safety and hemodynamic considerations in oncology drug development - webinar highlights October 10th 2012

INTRODUCTION

Development of new drugs in oncology may have implications for cardiovascular risk. This report describes some aspects of our growing knowledge in the area of evaluating benefit-risk and may be of direct importance to scientists working in drug discovery and development.

AREAS COVERED

This report of webinar highlights entitled "Trends in CardiOncology: the evolution of blood pressure and electrocardiogram (ECG) Markers" covers the current state of pharmacology of selected drugs which induce blood pressure elevation and best practices in employing the measurement of blood pressure elevation and cardiac safety parameters for drug development in oncology.

EXPERT OPINION

Oncology drug-induced cardiotoxicity has recently been recognised as an important drug development and clinical issue. The recognition of the risks and opportunities has prompted intensive research into mechanisms of chemotherapy-induced cardiotoxicity and potential prevention strategies. Drug-induced blood pressure elevation has emerged as a key area of interest, both as a marker of efficacy of vascular targeted chemotherapies as well as a target for early intervention strategies. While further research is ongoing, current data strongly suggest that early intervention strategies may provide significant short- and long-term clinical benefits to cancer patients undergoing chemotherapy.

Axitinib in Metastatic Renal Cell Carcinoma

Targeted agents have revolutionized the management of metastatic renal cell carcinoma (RCC). Axitinib, an inhibitor of vascular endothelial growth factor receptor (VEGFR), has been an important addition to currently available therapies for advanced RCC. Its ability to inhibit VEGFRs at nanomolar concentrations distinguishes it as a potent tyrosine kinase inhibitor, with increased selectivity for VEGFR-1, 2, and 3 at clinically applicable concentrations. The phase 3 AXIS trial has established its superiority in prolonging progression-free survival (PFS) in previously treated RCC patients (median PFS 6.7 months for axitinib vs. 4.7 months for sorafenib). Common toxicities of axitinib include hypertension, diarrhea, nausea, hand-foot syndrome, fatigue, and hypothyroidism. Axitinib-induced diastolic blood pressure elevation may be associated with improved clinical outcome, likely reflecting the “on-target” effect of axitinib. Dose escalation to achieve therapeutic plasma drug levels is of considerable clinical interest. Although axitinib has established efficacy in patients treated with one previous agent, its use in the frontline setting is currently the subject of ongoing research.

Endostatin lowers blood pressure via nitric oxide and prevents hypertension associated with VEGF inhibition

Antiangiogenesis therapy has become a vital part of the armamentarium against cancer. Hypertension is a dose-limiting toxicity for VEGF inhibitors. Thus, there is a pressing need to address the associated adverse events so these agents can be better used. The hypertension may be mediated by reduced NO bioavailability resulting from VEGF inhibition. We proposed that the hypertension may be prevented by coadministration with endostatin (ES), an endogenous angiogenesis inhibitor with antitumor effects shown to increase endothelial NO production in vitro. We determined that Fc-conjugated ES promoted NO production in endothelial and smooth muscle cells. ES also lowered blood pressure in normotensive mice and prevented hypertension induced by anti-VEGF antibodies. This effect was associated with higher circulating nitrate levels and was absent in eNOS-knockout mice, implicating a NO-mediated mechanism. Retrospective study of patients treated with ES in a clinical trial revealed a small but significant reduction in blood pressure, suggesting that the findings may translate to the clinic. Coadministration of ES with VEGF inhibitors may offer a unique strategy to prevent drug-related hypertension and enhance antiangiogenic tumor suppression.

Therapy management with sunitinib in patients with metastatic renal cell carcinoma: key concepts and the impact of clinical biomarkers

Targeted agents have improved prognosis for patients with metastatic renal cell carcinoma (mRCC), and they are changing therapeutic expectations with respect to long-term clinical outcomes for these patients. However, in order to obtain the maximum clinical benefit from targeted agents, effective therapy management is essential and includes optimization of dosing and treatment duration, as well as adequate side-effect management. Sunitinib has demonstrated efficacy for the treatment of patients with mRCC and is a reference standard of care for first-line therapy. However, in clinical practice, it is difficult to determine the best treatment strategy with targeted agents due to long-term tolerability and the development of resistance. An individualized therapeutic strategy in RCC requires a comprehensive understanding of the biology of response and resistance to targeted therapy. Here we review the clinical data regarding the efficacy and safety for sunitinib and highlight the importance of therapy management, as well as the potential use of clinical biomarkers in order to maximize the clinical benefit from sunitinib treatment in patients with mRCC.

Therapy management of cardiovascular adverse events in the context of targeted therapy for metastatic renal cell carcinoma

Targeted agents have significantly improved outcomes in patients with metastatic renal cell carcinoma, and are changing long-term expectations in these patients. Experience with these agents highlights a distinct safety and tolerability profile, differing from that observed with conventional chemotherapy and radiotherapy. Cardiovascular adverse events have been observed when treating with targeted agents. This is of particular importance for patients with metastatic renal cell carcinoma who are elderly and present with significant comorbidities. A multidisciplinary approach and close collaboration between oncologists and cardiologists is essential for optimal management of cardiovascular adverse events. Strategies for the management of these adverse events include assessment of cardiovascular status at baseline and at regular intervals, patient education, and the use of supportive medication. Effective therapy management allows patients with cardiovascular adverse events to receive and continue targeted therapy with careful monitoring. Implementation of therapy management measures contributes towards maximizing treatment outcomes with targeted agents in patients with metastatic renal cell carcinoma.

Sunitinib-Induced Systemic Vasoconstriction in Swine Is Endothelin Mediated and Does Not Involve Nitric Oxide or Oxidative Stress

Angiogenesis inhibition with agents targeting tyrosine kinases of vascular endothelial growth factor receptors is an established anticancer treatment, but is, unfortunately, frequently accompanied by systemic hypertension and cardiac toxicity. Whether vascular endothelial growth factor receptor antagonism also has adverse effects on the pulmonary and coronary circulations is presently unknown. In chronically instrumented awake swine, the effects of the vascular endothelial growth factor receptor antagonist sunitinib on the systemic, pulmonary, and coronary circulation were studied. One week after sunitinib (50 mg PO daily), mean aortic blood pressure (MABP) had increased from 83±5 mm Hg at baseline to 97±6 mm Hg ( P <0.05) because of a 57±20% increase in systemic vascular resistance as cardiac output decreased. In contrast, sunitinib had no discernible effects on pulmonary and coronary hemodynamics or cardiac function. We subsequently investigated the mechanisms underlying the sunitinib-induced systemic hypertension. Intravenous administration of NO synthase inhibitor N G -nitro- l -arginine increased MABP by 24±1 mm Hg under baseline conditions, whereas it increased MABP even further after sunitinib administration (32±3 mm Hg; P <0.05). Reactive oxygen species scavenging with a mixture of antioxidants lowered MABP by 13±2 mm Hg before but only by 5±2 mm Hg ( P <0.05) after sunitinib administration. However, intravenous administration of the dual endothelin A/endothelin B receptor blocker tezosentan, which did not lower MABP at baseline, completely reversed MABP to presunitinib values. These findings indicate that sunitinib produces vasoconstriction selectively in the systemic vascular bed, without affecting pulmonary or coronary circulations. The sunitinib-mediated systemic hypertension is principally attributed to an increased vasoconstrictor influence of endothelin, with no apparent contributions of a loss of NO bioavailability or increased oxidative stress.

Predicting responses to sunitinib using single nucleotide polymorphisms: Progress and recommendations for future trials

Targeted therapy with tyrosine kinase inhibitors has led to a substantial improvement in the standard of care for patients with advanced or metastatic clear cell renal cell carcinoma. Because the mechanism of action, metabolism and transport of tyrosine kinase inhibitors can affect outcome and toxicity, several investigators have pursued the identification of single nucleotide polymorphisms (SNPs) in genes associated with these actions. We discuss SNPs associated with outcome and toxicity following sunitinib therapy and provide recommendations for future trials to facilitate the use of SNPs in personalized therapy for this disease.

Predictive factors of response to treatment in patients with metastatic renal cell carcinoma: new evidence

Renal cell carcinoma represents approximately 3% of adult malignancies and 90-95% of neoplasms arising from the kidney. Many agents that target angiogenesis (e.g., sunitinib, sorafenib, bevacizumab and pazopanib) and mTOR-targeted therapy (e.g., temsirolimus and everolimus) have been approved as first-line agents. The choice of the most suitable treatment for advanced renal cell carcinoma depends on the definition of risk. In this article, we reviewed the scientific literature identifying predictive factors on the activity/efficacy of a specific therapy.

Association of VEGF and VEGFR2 single nucleotide polymorphisms with hypertension and clinical outcome in metastatic clear cell renal cell carcinoma patients treated with sunitinib

PURPOSE

Biomarkers that predict response or toxicity to antiangiogenic therapy are sought to favorably inform the risk/benefit ratio. This study evaluated the association of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) genetic polymorphisms with the development of hypertension (HTN) and clinical outcome in metastatic clear cell renal cell carcinoma (MCCRCC) patients treated with sunitinib.

PATIENT AND METHODS

Sixty-three MCCRCC patients receiving sunitinib (50 mg 4/2) with available blood pressure (BP) data and germline DNA were retrospectively identified. A panel of candidate VEGF and VEGFR2 single nucleotide polymorphisms (SNPs) were evaluated for associations with the development of hypertension and clinical outcome.

RESULTS

VEGF SNP -634 genotype was associated with the prevalence and duration of sunitinib-induced hypertension (as defined by systolic pressure ≥150 mmHg and/or diastolic pressure ≥90 mmHg) in both univariable analysis (P = .03 and .01, respectively) and multivariable analysis, which adjusted for baseline BP and use of antihypertension medication (P = .05 and .02, respectively). Patients with the GG genotype were estimated to have a greater likelihood of being hypertensive during treatment compared with patients with the CC genotype (odds ratio of 13.62, 95% confidence interval [CI] 3.71-50.04). No single VEGF or VEGFR SNPs were found to correlate with clinical outcome. However, the combination of VEGF SNP 936 and VEGFR2 SNP 889 were associated with overall survival after adjustment for prognostic risk group (P = .03).

CONCLUSIONS

In MCCRCC patients treated with sunitinib, VEGF SNP -634 is associated with hypertension and a combination of VEGF SNP 936 and VEGFR2 SNP 889 genotypes is associated with overall survival.

Antiangiogenic agents in combination with chemotherapy in patients with advanced non-small cell lung cancer

Most patients with non-small cell lung cancer (NSCLC) present with advanced disease requiring systemic chemotherapy. Treatment with the antiangiogenic agent bevacizumab in combination with standard platinum-based doublet chemotherapy has been shown to improve outcomes in patients with advanced NSCLC. Several multitargeted antiangiogenic tyrosine kinase inhibitors (e.g., sorafenib, sunitinib, cediranib, vandetanib, BIBF 1120, pazopanib, and axitinib) are also being evaluated in combination with standard chemotherapy. Here we review current clinical data with combination therapy involving antiangiogenic agents and cytotoxic chemotherapy in patients with advanced NSCLC.

Contrary effects of the receptor tyrosine kinase inhibitor vandetanib on constitutive and flow-stimulated nitric oxide elaboration in humans

Vascular endothelial growth factor regulates neoplastic angiogenesis through production of endothelium-derived NO. We performed a prospective evaluation of vascular function during treatment with vandetanib, a vascular endothelial growth receptor 2 and 3 receptor tyrosine kinase inhibitor, to determine the effects of vascular endothelial growth receptor signal interruption on endothelial function in humans. Seventeen patients with stage IV breast cancer received dose-escalated vandetanib in combination with low-dose oral chemotherapy. We measured blood pressure, systemic nitrate/nitrite levels, and brachial artery vascular function. In vitro analyses of cultured endothelial cells were performed to determine the effect of vandetanib on NO production, akt(473) phosphorylation, and endothelial NO synthase protein content and membrane localization. Vandetanib treatment for 6 weeks significantly increased blood pressure, decreased resting brachial artery diameter, and decreased plasma systemic nitrate/nitrite levels compared with baseline. Flow-mediated vasodilation was preserved, and no change was noted in nitroglycerin-mediated vasodilation. In vitro, endothelial cell nitrite levels and akt(473) phosphorylation were reduced and vascular endothelial growth receptor 2 levels did not change, but endothelial NO synthase membrane concentration doubled. Vandetanib reduces constitutive NO production and increases blood pressure, yet flow-stimulated NO bioavailability was preserved. Changes in vascular function with tyrosine kinase inhibition are complex and require further study in humans.

Noncardiac vascular toxicities of vascular endothelial growth factor inhibitors in advanced cancer: a review

The introduction of molecularly targeted anticancer therapies has brought the promise of longer survival times for select patients with cancers previously considered untreatable. However, it has also brought new toxicities that require understanding and management, sometimes for long periods of time. Vascular endothelial growth factor inhibitors are associated with a broad range of adverse effects, with vascular toxicity being particularly serious. This review focuses on the current understanding of the pathophysiology and mechanisms of macrovascular toxicities (hypertension, hemorrhage, and thromboembolism), their incidence and severity, the current clinical management, and implications in the advanced cancer setting. Movement of these agents into the early disease setting will alter the impact of these toxicities. Search Strategy and Selection Criteria. Information for this review was collected by searching PubMed/Medline and American Society of Clinical Oncology abstract databases. The medical subject heading terms used included toxicity, hypertension, thromboembolism, hemorrhage, intestinal perforation, risk factors, pharmacokinetics, and metabolism, combined with free text search terms including, but not limited to, VEGF inhibitor*, bevacizumab, sunitinib, and sorafenib. Articles published in English before March 2010 were included, in addition to information from case reports and pharmaceutical agent package inserts.

Bevacizumab in the treatment of patients with advanced breast cancer: where have we landed?

Vast preclinical and clinical evidence has made angiogenesis one of the hallmarks of cancer. In many human tumours, vascular endothelial growth factor (VEGF) has been identified as the crucial mediator of this process. Initial studies suggested that angiogenesis, and VEGF in particular, could be inhibited without the risk of major side effects. After the pivotal data in first-line studies in patients with colorectal cancer, numerous clinical trials have been undertaken in patients with breast cancer. This review attempts to update these investigations and define the role of anti-VEGF antibody treatment in advanced breast cancer.

Vascular endothelial growth factor polymorphisms: role in response and toxicity of tyrosine kinase inhibitors

Angiogenesis is central to the growth of normal tissues and tumors. Inhibiting this pathway has been a strategy for drug development for tumors not responsive to most agents used in chemotherapy. Notably, signaling mediated by vascular endothelial growth factor (VEGF) is a key target because aberrant signaling via this pathway is frequently associated with neoangiogenesis in tumors. The drug-discovery effort to blunt VEGF signaling has led to the approval of bevacizumab and several receptor tyrosine kinase inhibitors (TKIs) that have shown efficacy in the clinical management of breast, colorectal, lung, and kidney cancer. Understanding the genetic variability in VEGF and VEGF receptor has led to identifying genotypic variations (single nucleotide polymorphisms [SNPs]) associated with treatment outcome and toxicity. Notably, identification of SNPs in VEGF associated with angiogenesis inhibitor treatment-induced hypertension and outcome provides exciting opportunities for personalized medicine to improve outcome and reduced toxicity with these novel TKIs.

Phase 1 study of the investigational, oral angiogenesis inhibitor motesanib in Japanese patients with advanced solid tumors

PURPOSE

The aim of this study was to investigate the safety and pharmacokinetics of motesanib (AMG 706), a small-molecule antagonist of vascular endothelial growth factor receptors 1, 2, and 3, platelet-derived growth factor receptor, and c-Kit in Japanese patients with advanced solid tumors.

METHODS

Patients were administered motesanib orally once daily (QD) at doses of 50, 100, and 125 mg QD. The total study duration for each patient consisted of three cycles of 28 days per cycle. The primary endpoints were the incidence of dose-limiting toxicities (DLTs), estimation of the maximum tolerated dose (MTD), and assessment of pharmacokinetic parameters of motesanib.

RESULTS

Fifteen patients were enrolled and received motesanib. No DLTs were observed and, therefore, the MTD was not reached. Motesanib had acceptable toxicity at doses up to 125 mg QD. The pharmacokinetics of motesanib appears to be dose proportional. No objective responses per RECIST were observed. However, all 15 patients achieved stable disease, and five patients had durable (>24 weeks) stable disease.

CONCLUSIONS

The results of this study demonstrate that motesanib is tolerable in Japanese patients at doses up to 125 mg QD.