Axitinib induces paradoxical erythropoietin synthesis in metastatic renal cell carcinoma

Progressive erythrocytosis under lenvatinib treatment in patients with advanced hepatocellular carcinoma

PURPOSE

This manuscript reports on the occurrence of early and frequent erythrocytosis in advanced hepatocellular carcinoma (HCC) patients treated with lenvatinib.

METHODS

A cohort of 23 patients with advanced HCC, treated with this antiangiogenic drug for at least one month, was retrospectively analyzed.

RESULTS

These patients (82.7% men, median age 58.3, cirrhosis in 60.8%) were treated between October 2019 and September 2020 with lenvatinib, as first-line systemic therapy for 82.6% of them. For 20 patients (87%), an early and significant increase in hemoglobin (Hb) level, up to 1.41 g/dL (p < 0.001) was reported and remained elevated. Ten patients (43.5%), all men, reached erythrocytosis (Hb > 16.5 g/dL), 7 were treated with low-dose aspirin for primary thromboprophylaxis and 2 needed phlebotomy. None underwent thromboembolic complications. A significant Hb decrease was observed after treatment discontinuation (p < 0.05). Erythropoietin (EPO) serum levels also increased, which was attributed to HCC after immunostaining for EPO in liver biopsies. The Naranjo adverse drug reaction probability scale documented the relationship between erythrocytosis and lenvatinib and regression at treatment discontinuation. Erythrocytosis was hypothesized to be a class effect of anti-VEGF therapies, the magnitude of which might depend on the IC50 value of each molecule.

CONCLUSION

This report documents the frequent occurrence of erythrocytosis during lenvatinib treatment for advanced HCC, likely secondary to EPO secretion by tumor cells through the antiangiogenic activity levatinib. An early and close monitoring of hematologic parameters is, thus, recommended, together with thromboprophylaxis by low-dose aspirin and phlebotomy in case of symptomatic erythrocytosis.

Pazopanib-related secondary polycythemia in metastatic myxofibrosarcoma: A case report and review of the literature

INTRODUCTION

Pazopanib, a tyrosine kinase inhibitor (TKI), is a standard treatment for various tumours, including metastatic non-adipocytic soft-tissue sarcomas. In literature, erythrocytosis has been described as a TKI-related condition.

CASE REPORT

A 59-year-old man underwent surgical removal of a sub-scapular mass consistent with myxofibrosarcoma. After distant relapse, he first started chemotherapy, and then Pazopanib. He was found to have increased levels of hemoglobin (Hb) and hematocrit (Hct). He was asymphtomatic, with no history of pulmonary disease nor smoking habit. Erythropoietin (EPO) level was higher than normal. A polycythemia vera was ruled out.Management & outcome: The patient started a prophylactic therapy with lysine acetylsalicylate, and we observed a reduction of Hb, but not Hct. Due to disease progression, we interrupted Pazopanib. After a week from drug discontinuation, Hb levels got back to the normal range, Hct was lowering. We decided not to perform phlebotomy, considering the declining trend in Hb and Hct values and the absence of symptoms.

DISCUSSION

We postulated a Pazopanib-related secondary erythrocytosis, since Hb and Hct levels increased from baseline during treatment, then normalized when Pazopanib was discontinued. We used the Naranjo Nomogram to assess the correlation between the adverse effect and Pazopanib, the correlation was "Probable", a score of 5. To the best of our knowledge, this is the first case report of Pazopanib-related secondary polycythemia in a patient with sarcoma. It is important to pay attention to blood count and to any symptoms potentially related to erythrocytosis in patients treated with TKIs.

Optimizing treatment of renal cell carcinoma with VEGFR-TKIs: a comparison of clinical pharmacology and drug-drug interactions of anti-angiogenic drugs

Anti-angiogenic treatment is an important option that has changed the therapeutic landscape in various tumors, particularly in patients affected by renal cell carcinoma (RCC). Agents that block signaling pathways governing tumor angiogenesis have raised high expectations among clinicians. Vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKIs) comprise a heterogeneous class of drugs with distinct pharmacological profiles, including potency, selectivity, pharmacokinetics and drug-drug interactions. Among them, tivozanib is one of the last TKIs introduced in the clinical practice; this drug selectively targets VEGFRs, it is characterized by a favorable pharmacokinetics and safety profile and has been approved as first-line treatment for patients with metastatic RCC (mRCC). In this article, we describe the clinical pharmacology of selected VEGFR-TKIs used for the treatment of mRCC, highlighting the relevant differences; moreover we aim to define the main pharmacologic characteristics of these drug.

Long-lasting response with polycythemia to third-line axitinib treatment in metastatic renal cell carcinoma: Very rare case presentation

INTRODUCTION

Clear cell renal cell carcinoma is characterized by mutation or inactivation of Von Hippel-Lindau suppressor gene. The mutation of Von Hippel-Lindau mechanism is associated with the upregulation of the hypoxia-inducible factor protein, inducing the overexpression of proteins including erythropoietin and vascular endothelial growth factor. Vascular endothelial growth factor receptor-targeted tyrosine kinase inhibitors are widely used in treatment of metastatic renal cell carcinoma. In paradoxical hematological effect with tyrosine kinase inhibitor therapies, hemoglobin level may be increased, but polycythemia requiring phlebotomy is very rare.

CASE DESCRIPTION

We present here a case of renal cell carcinoma who received successive treatment with sunitinib, everolimus, and axitinib. While he had a normal hemoglobin level with prior sunitinib treatment, on the sixth week of axitinib treatment, he developed polycythemia and treatment response was seen after axitinib-associated polycythemia.

CONCLUSION

Progression-free survival (PFS) was 30 months in our case with third-line treatment axitinib. Higher hemoglobin levels may be associated with longer survival. Polycythemia was the first response to treatment of axitinib in our patient. It may be an indicator of persistent treatment response.

Case: Secondary polycythemia due to pazopanib in patients with metastatic renal cell carcinoma

Clear-cell renal cell carcinoma (RCC) is the most common primary malignant renal neoplasm. Up to 30% of patients have metastatic disease at the time of initial diagnosis.1 Small molecule inhibitors of vascular endothelial growth factor receptor tyrosine kinase (VEGFR TKIs) are used as first-line treatment for most patients with incurable RCC. Pazopanib is a TKI inhibiting VEGFR,1-3 as well as plateletderived growth factor receptors (PDGFRs) α and β and stem cell receptor c-kit. The most common side effects of pazopanib are diarrhea, hypertension, changes in hair colour, anorexia, nausea, and vomiting. Severe hepatic toxicity is the adverse effect of greatest concern,but is uncommon. Myelosuppressive effects are also noted, such as anemia, thrombocytopenia, and leukopenia, and are presumably mediated through c-kit inhibition. Erythrocytosis is a wellrecognized paraneoplastic syndrome associated with RCC; however, erythrocytosis due to pazopanib therapy has only recently been described. We report two cases and review of the literature related to this phenomenon.

Haemoglobin level increase as an efficacy biomarker during axitinib treatment for metastatic renal cell carcinoma: a retrospective study

Background

Axitinib is used after failure of first line treatment for metastatic renal cell carcinoma (mRCC). A known side effect is the increase of haemoglobin level (HbL) during treatment with a suspected correlation with better outcome. Our objective was to examine whether HbL increase during the first three months of axitinib treatment is associated with better prognosis.

Methods

Retrospective multicentre analysis including patients with mRCC treated with axitinib for at least three months from 2012 to 2014. Progression-free survival (PFS) was analysed by a Cox model according to gender, International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) prognostic score, high blood pressure (hBP), and maximum increase in HbL within the first three months of treatment.

Results

Ninety-eight patients were analysed (71% men; median age at treatment initiation: 62 years; IMDC: 24%, 50%, and 26% in the favourable, intermediate, and poor-risk group, respectively). Patients received axitinib for a median of 8 months. During the first three months, the median increase of HbL was +2.3 g/dL (−1.1; 7.2). Fifty-six (57%) patients developed hBP.

In multivariate analysis, after adjustment for performance status (P < 0.0001) and gender (P = 0.0041), the combination of HbL increase ≥2.3 g/dL and any grade hBP was significantly associated with longer PFS (HR = 0.40, 95%CI [0.24; 0.68]).

Conclusions

Early HbL increase during axitinib treatment combined with hBP is an independent predictive factor of PFS. These results require validation in a prospective setting.

Is Change in Hemoglobin Level a Predictive Biomarker of Tyrosine Kinase Efficacy in Metastatic Renal Cell Carcinoma? A Turkish Oncology Group Study

BACKGROUND

There are insufficient predictive markers for renal cell carcinoma (RCC).

METHODS

A total of 308 metastatic RCC patients were analyzed retrospectively.

RESULTS

The increased hemoglobin (Hb) group had significantly higher progression-free survival and overall survival (OS) compared with the decreased Hb group at 11.5 versus 6.35 months (p < .001) and 21.0 versus 11.36 months (p < .001) respectively. The 1- and 3-year OS rates were higher in the Hb increased group, i.e., 84% versus 64% and 52% versus 35% respectively.

CONCLUSIONS

The present study showed that increased Hb levels after tyrosine kinase inhibitor therapy could be a predictive marker of RCC.

The DART Study: Results from the Dose-Escalation and Expansion Cohorts Evaluating the Combination of Dalantercept plus Axitinib in Advanced Renal Cell Carcinoma

Purpose: Activin receptor-like kinase 1 (ALK1) is a novel target in angiogenesis. Concurrent targeting of ALK1 and VEGF signaling results in augmented inhibition of tumor growth in renal cell carcinoma (RCC) xenograft models. Dalantercept is an ALK1-receptor fusion protein that acts as a ligand trap for bone morphogenetic proteins 9 and 10. The DART Study evaluated the safety, tolerability, pharmacokinetics, pharmacodynamics, and antitumor activity of dalantercept plus axitinib in patients with advanced RCC and determined the optimal dose for further testing.Experimental Design: Patients received dalantercept 0.6, 0.9, or 1.2 mg/kg subcutaneously every 3 weeks plus axitinib 5 mg by mouth twice daily until disease progression or intolerance.Results: Twenty-nine patients were enrolled in the dose escalation (n = 15) and expansion (n = 14) cohorts. There were no dose-limiting toxicities or grade 4/5 treatment-related adverse events. In addition to common VEGFR tyrosine kinase inhibitor effects, such as fatigue and diarrhea, commonly seen treatment-related adverse events were peripheral edema, epistaxis, pericardial effusion, and telangiectasia. The objective response rate by RECIST v1.1 was 25% with responses seen at all dose levels. The overall median progression-free survival was 8.3 months.Conclusions: The combination of dalantercept plus axitinib is well tolerated and associated with clinical activity. On the basis of safety and efficacy results, the 0.9 mg/kg dose level was chosen for further study in a randomized phase II trial of dalantercept plus axitinib versus placebo plus axitinib. Clin Cancer Res; 23(14); 3557-65. ©2016 AACR.

Prognostic Significance of Increases in Hemoglobin in Renal Cell Carcinoma Patients During Treatment With VEGF-directed Therapy

BACKGROUND

Increases in hemoglobin have been reported in renal cell carcinoma (RCC) patients treated with vascular endothelial growth factor (VEGF) pathway-targeted therapies and have been associated with increased progression-free survival (PFS). We retrospectively evaluated its significance as a predictive biomarker of clinical response in RCC.

PATIENTS AND METHODS

Patients with advanced RCC treated with VEGF receptor tyrosine kinase inhibitors (TKIs) or bevacizumab as a first-line therapy were identified. Hemoglobin levels were retrieved at baseline and then at monthly intervals for 6 months. Absolute and percentage increases over baseline were evaluated as predictors of objective response rate, PFS, time to treatment failure, and overall survival. Cox regression was used to estimate change status hazard ratios (HR) in univariate and multivariable models.

RESULTS

Among the 71 eligible patients, elevations in hemoglobin were observed in 83%, with a median time to increase of 2.4 weeks since treatment initiation. Changes in hemoglobin at time of response were not associated with objective response rate. Landmark analysis at 3 months showed that increases in hemoglobin were associated with worse PFS (8.0 vs. 19.4 months; HR = 2.29; 95% confidence interval, 1.01-5.16; P = .05) and time to treatment failure (6.4 vs. 18.1 months; HR = 2.14; 95% confidence interval, 0.99-4.60, P = .05). Patients with greater increases (15% or more) had significantly shorter PFS (5.5 vs. 13.6 months) and overall survival (20.8 vs. 30.4 months) compared to those with lesser degree of elevations.

CONCLUSION

Contrary to prior reports, elevation in hemoglobin on VEGF-directed therapy was associated with worse clinical outcomes, and the greater the degree of elevation, the poorer the prognosis.

Effects of vascular endothelial growth factor signaling inhibition on human erythropoiesis

Inhibition of vascular endothelial growth factor (VEGF) signaling increases red blood cell (RBC) counts, and erythropoiesis markers have been proposed to guide antiangiogenic therapy in humans. We analyzed RBC measurements in patients enrolled in three studies: a phase II trial of axitinib in thyroid cancer; a study of sorafenib in advanced solid tumors; and a randomized trial of fluorouracil, hydroxyurea, and radiation with and without bevacizumab for head and neck cancer. In the sorafenib trial, plasma erythropoietin concentrations were measured at baseline, day 8, and day 35. Over the first 84 days of treatment, RBC counts increased for each day on sorafenib (2.7 M/μL [95% confidence interval (CI), 1.5-3.9]) and axitinib (4.3 M/μL [95% CI, 2.2-6.5]). RBCs declined over the first 68 days of cytotoxic chemoradiotherapy alone (-12.8 M/μL per day [95% CI, -15.7 to -9.8]) but less so with added bevacizumab (-7.2 M/μL per day [95% CI, -9.5 to -4.9]). Erythropoietin levels increased, on average, by 9.5 mIU/mL between day 8 and day 35 of sorafenib exposure. No significant relationships between elevations in RBCs and changes in volume status or blood pressure or between elevations in erythropoietin and smoking status were found. VEGF signaling inhibition is associated with increased RBC and erythropoietin production in humans. The effects of these changes are subtle at physiologic doses and are unlikely to be clinically useful biomarkers for guiding the administration of or predicting treatment responses to VEGF pathway inhibitors.

Maintenance bevacizumab is associated with increased hemoglobin in patients with advanced, nonsquamous, non-small cell lung cancer

We retrospectively analyzed hematologic parameters in 22 patients with advanced, nonsquamous, NSCLC undergoing VEGF inhibition on a phase II clinical trial of bevacizumab, carboplatin, and gemcitabine. We also examined TTP in relation to hemoglobin changes. Median hemoglobin increased significantly from a 12.9 g/dL pretreatment to 13.8 g/dL (p =.01) after the second cycle of maintenance bevacizumab until the first off cycle measurement. There was no difference in TTP in patients who achieved a rise in hemoglobin compared with patients who did not (median 238 days vs. 268 days, p =.38.) Maintenance bevacizumab is associated with increased hemoglobin in advanced, nonsquamous, NSCLC patients.

Antiangiogenic therapy for advanced renal cell carcinoma: management of treatment-related toxicities

Treatment of metastatic renal cell carcinoma (mRCC) has evolved rapidly over the last two decades as major pathways involved in pathogenesis have been elucidated. These include the vascular endothelial growth factor (VEGF) axis and mammalian target of rapamycin (mTOR). Therapies targeting the VEGF pathway include bevacizumab, sorafenib, sunitinib, pazopanib, and axitinib, whereas temsirolimus and everolimus inhibit the mTOR pathway. All of these novel therapies—VEGF and mTOR inhibitors—are associated with a variety of unique toxicities, some of which may necessitate expert medical management, treatment interruption, or dose reduction. Common adverse events with newer drugs include hypertension, skin reactions, gastrointestinal disturbances, thyroid dysfunction, and fatigue. Skilled management of these toxicities is vital to ensure optimal therapeutic dosing and maximize patient outcomes, including improved survival and quality of life. This review describes and compares the toxicity profiles of novel molecularly targeted agents used in the treatment of mRCC and presents guidance on how best to prevent and manage treatment-related toxicities. Particular attention is given to axitinib, the newest agent to enter the armamentarium. Axitinib is a second-generation receptor tyrosine kinase inhibitor with potent VEGF receptor inhibition that provides durable responses and superior progression-free survival in advanced RCC compared with sorafenib.

Comparative effectiveness of axitinib versus sorafenib in advanced renal cell carcinoma (AXIS): a randomised phase 3 trial

BACKGROUND

The treatment of advanced renal cell carcinoma has been revolutionised by targeted therapy with drugs that block angiogenesis. So far, no phase 3 randomised trials comparing the effectiveness of one targeted agent against another have been reported. We did a randomised phase 3 study comparing axitinib, a potent and selective second-generation inhibitor of vascular endothelial growth factor (VEGF) receptors, with sorafenib, an approved VEGF receptor inhibitor, as second-line therapy in patients with metastatic renal cell cancer.

METHODS

We included patients coming from 175 sites (hospitals and outpatient clinics) in 22 countries aged 18 years or older with confirmed renal clear-cell carcinoma who progressed despite first-line therapy containing sunitinib, bevacizumab plus interferon-alfa, temsirolimus, or cytokines. Patients were stratified according to Eastern Cooperative Oncology Group performance status and type of previous treatment and then randomly assigned (1:1) to either axitinib (5 mg twice daily) or sorafenib (400 mg twice daily). Axitinib dose increases to 7 mg and then to 10 mg, twice daily, were allowed for those patients without hypertension or adverse reactions above grade 2. Participants were not masked to study treatment. The primary endpoint was progression-free survival (PFS) and was assessed by a masked, independent radiology review and analysed by intention to treat. This trial was registered on ClinicalTrials.gov, number NCT00678392.

FINDINGS

A total of 723 patients were enrolled and randomly assigned to receive axitinib (n=361) or sorafenib (n=362). The median PFS was 6·7 months with axitinib compared to 4·7 months with sorafenib (hazard ratio 0·665; 95% CI 0·544-0·812; one-sided p<0·0001). Treatment was discontinued because of toxic effects in 14 (4%) of 359 patients treated with axitinib and 29 (8%) of 355 patients treated with sorafenib. The most common adverse events were diarrhoea, hypertension, and fatigue in the axitinib arm, and diarrhoea, palmar-plantar erythrodysaesthesia, and alopecia in the sorafenib arm.

INTERPRETATION

Axitinib resulted in significantly longer PFS compared with sorafenib. Axitinib is a treatment option for second-line therapy of advanced renal cell carcinoma.

FUNDING

Pfizer Inc.

Anti-vascular endothelial growth factor antibody bevacizumab reduced the risk of anemia associated with chemotherapy-A meta-analysis

INTRODUCTION

Vascular endothelial growth factor (VEGF) may play a role in erythropoiesis. We performed a meta-analysis of randomized controlled trials (RCT) to determine the effect of the anti-VEGF antibody bevacizumab on anemia in cancer patients treated with chemotherapy.

METHODS

Databases from PUBMED, the Web of Science, Embase, the Cochrane Library, and abstracts presented at the American Society of Clinical Oncology (ASCO) conferences until May 2010 were searched to identify relevant studies. Eligible studies included prospective RCTs in which the combination of bevacizumab and chemotherapy was compared with chemotherapy alone. Summary incidence rate, relative risk (RR), and 95% confidence interval (CI) were calculated.

RESULTS

A total of 6439 patients with a variety of solid tumors were included for analysis from 11 RCTs. Among those patients receiving bevacizumab and chemotherapy, the incidences of all-grade and high-grade (grade 3 and above) anemia were 17.8% (95% CI: 11.1-27.1%) and 2.8% (95% CI: 1.6-5.0%) respectively. In comparison with chemotherapy alone, bevacizumab significantly reduced all-grade (RR, 0.79; 95% CI: 0.66-1.0, p = 0.007) and high-grade anemia (RR, 0.72; 95% CI: 0.57-0.90, p = 0.005). The effect did not vary significantly among bevacizumab doses (p = 0.88), tumor types (p = 0.75) or chemotherapy regimens (p = 0.98).

DISCUSSION

Bevacizumab may significantly reduce the risk of anemia with chemotherapy in cancer patients.

Management of axitinib (AG-013736)-induced fatigue and thyroid dysfunction, and predictive biomarkers of axitinib exposure: results from phase I studies in Japanese patients

Background Axitinib is an oral, potent and selective inhibitor of vascular endothelial growth factor receptors (VEGFRs) 1, 2 and 3. We report on data obtained from 18 Japanese patients with advanced solid tumors in two phase I trials that evaluated the safety, pharmacokinetics and antitumor activity of axitinib and also examined potential biomarkers. Methods Six patients received a single 5-mg dose of axitinib followed by 5 mg twice daily (BID), and an additional six patients received axitinib 5 mg BID only. Another six patients received axitinib at 5-mg, 7-mg and 10-mg single doses followed by 5 mg BID. Results Plasma pharmacokinetics following single doses of axitinib was generally linear. Common treatment-related adverse events were fatigue (83%), anorexia (72%), diarrhea (67%), hand–foot syndrome (67%) and hypertension (61%). Sixteen patients (89%) experienced thyroid-stimulating hormone (TSH) elevation. Grade 3/4 toxicities included hypertension (33%) and fatigue (28%). No grade 3/4 fatigue occurred in patients who started thyroid hormone replacement therapy when TSH was elevated. Thyroglobulin elevation was observed in all patients who continued treatment with axitinib for ≥3 months. Abnormal TSH correlated with exposure to axitinib (r = 0.72). Decrease in soluble (s) VEGFR-2 levels significantly correlated with exposure to axitinib (r = –0.94). Axitinib showed antitumor activity across multiple tumor types. Conclusions Axitinib-related thyroid dysfunction could be due to a direct effect on the thyroid gland. Grade 3/4 fatigue and hypothyroidism appear to be controllable with use of thyroid hormone replacement therapy. sVEGFR-2 and TSH may act as biomarkers of axitinib plasma exposure.

Exploratory analysis of early toxicity of sunitinib in advanced hepatocellular carcinoma patients: kinetics and potential biomarker value

PURPOSE

Sunitinib--a multitargeted tyrosine kinase inhibitor--can modulate circulating inflammatory factors in cancer patients that may be relevant for hepatocellular carcinoma (HCC) progression. However, a recent phase III study of sunitinib in HCC was halted due to its toxicity. Here, we studied the early kinetics of adverse events after sunitinib, and explored their association with circulating proteins and clinical outcome in advanced HCC in a single-arm phase II study.

EXPERIMENTAL DESIGN

Toxicity was evaluated every two weeks during the first cycle of therapy. Biomarker changes from baseline were tested after adjusting for multiple comparisons. Correlation between toxicities and overall survival (OS) or time-to-tumor progression (TTP) was evaluated in a Cox model using log-transformed levels or change in biomarkers, after stratifying by stage and adjusting for baseline level.

RESULTS

Myeloid and lymphoid blood cell counts decreased by 20% to 50% after sunitinib treatment (P < 0.05 for all). The extent of the early decrease in neutrophils and monocytes, and the development of nonhematologic toxicities (i.e., skin toxicities), were significantly associated with both OS and TTP (P < 0.05). Changes in circulating cells significantly associated with specific changes in plasma biomarkers (i.e., changes in platelets with changes in VEGF-C and soluble-VEGFR3; changes in neutrophils with changes in IL-8, TNF-α, and soluble-VEGFR2).

CONCLUSIONS

The adverse effects of sunitinib, particularly on the hematopoietic system, may be rapid and appear directly related to its activity in HCC. This exploratory study suggests that early hematopoietic toxicities may potentially predict outcome in advanced HCC after sunitinib treatment.

Effect of axitinib (AG-013736) on fatigue, thyroid-stimulating hormone, and biomarkers: a phase I study in Japanese patients

Axitinib is an oral, potent, and selective inhibitor of vascular endothelial growth factor receptor (VEGFR) 1, 2, and 3. This phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, antitumor activity, and recommended starting dose of axitinib in patients with advanced solid tumors. Twelve patients received single-dose axitinib 5 mg and were monitored for > or =48 h. Continuous 5 mg twice-daily dosing was then initiated. One patient had dose-limiting toxicity (grade 3 proteinuria and fatigue). Common treatment-related adverse events were anorexia, fatigue, and diarrhea. Grade 3 treatment-related adverse events were fatigue and hypertension. Maximum axitinib plasma concentration occurred 1-4 h after steady-state dosing. Eleven patients experienced thyroid-stimulating hormone elevation; time-course change and fatigue onset appeared to be related in some patients. Significant correlation was observed between thyroid-stimulating hormone change and area under the plasma concentration-time curve (AUC; r = 0.80, P = 0.005). Axitinib decreased plasma soluble vascular endothelial growth factor receptor 2 (s-VEGFR2), with significant correlation between change in s-VEGFR2 and AUC (r = -0.92, P < 0.0001). Fluorodeoxyglucose positron emission tomography revealed a substantial decrease in tumor metabolic activity associated with axitinib. Tumor size decreased in nine patients. The time-course of thyroid-stimulating hormone change appeared correlated with fatigue. There were significant correlations between thyroid-stimulating hormone or s-VEGFR2 and axitinib exposure. Axitinib 5 mg twice-daily is the recommended starting dose for Japanese patients. This trial is registered with ClinicalTrials.gov, identifier NCT00447005.

Increased hemoglobin associated with VEGF inhibitors in advanced renal cell carcinoma

We retrospectively analyzed whether increased hemoglobin is a surrogate biomarker of efficacy for vascular endothelial growth factor (VEGF) inhibitors in advanced renal cell carcinoma (RCC) patients. Twelve patients were identified who had received bevacizumab alone or as combination therapy. Eleven patients experienced a rise in hemoglobin. Median change was 1.6 g/dL (0-4.0). Degree of peak increase correlated with longer progression-free survival (PFS) in metastatic patients: increase of < 15% yielded a 3.1-month median PFS compared to 8.2 months with rises > 15%. This study identifies increased hemoglobin as a possible consequence of VEGF inhibitors. The correlation with longer PFS suggests that rise in hemoglobin may be a surrogate biomarker of efficacy.