Sunitinib for treatment of advanced renal cell cancer: primary tumor response

Quantitative parametric perfusion images using 15O-labeled water and a clinical PET/CT scanner: test-retest variability in lung cancer

Quantification of tumor perfusion using radioactive water (H(2)(15)O) and PET is a promising method for monitoring treatment with antiangiogenic agents. However, use of dynamic H(2)(15)O scans together with a fully 3-dimensional clinical PET/CT scanner needs to be validated. The purpose of the present study was to assess validity and reproducibility of dynamic H(2)(15)O PET/CT scans for measuring tumor perfusion and validate the quantitative accuracy of parametric perfusion images.

METHODS

Eleven patients with non-small cell lung cancer were included in this study. Patients underwent 2 dynamic H(2)(15)O (370 MBq) PET scans on the same day. During the first scan, arterial blood was withdrawn continuously. Input functions were derived from blood sampler data and the ascending aorta as seen in the images themselves (image-derived input function [IDIF]). Parametric perfusion images were computed using a basis function implementation of the standard single-tissue-compartment model. Volumes of interest (VOIs) were delineated on low-dose CT (LD-CT) and parametric perfusion images.

RESULTS

VOIs could be accurately delineated on both LD-CT and parametric perfusion images. These parametric perfusion images had excellent image quality and quantitative accuracy when compared with perfusion values determined by nonlinear regression. Good correlation between perfusion values derived from the blood sampler input function and IDIF was found (Pearson correlation coefficient, r = 0.964; P < 0.001). Test-retest variability of tumor perfusion was 16% and 20% when delineated on LD-CT and parametric perfusion images, respectively.

CONCLUSION

The use of ascending aorta IDIFs is an accurate alternative to arterial blood sampling for quantification of tumor perfusion. Image quality obtained with a clinical PET/CT scanner enables generation of accurate parametric perfusion images. VOIs delineated on LD-CT have the highest reproducibility, and changes of more than 16% in tumor perfusion are likely to represent treatment effects.

Progression of intramedullary metastasis during perioperative cessation of sunitinib

BACKGROUND

A 57-year-old woman presented with metastatic renal cell carcinoma (RCC). She was enrolled in a clinical study, in which she received two cycles of neoadjuvant sunitinib therapy followed by cytoreductive nephrectomy. Her primary tumor and rib metastasis showed a good response to neoadjuvant therapy; however, after surgery, the patient developed neurologic symptoms, including flaccid paraparesis with paresthesia and hypoesthesia. MRI of the brain and spine revealed a leptomeningeal lesion at the T12-L1 space, which was presumed to have progressed during the 3-week treatment-free perioperative period. The patient underwent radiation therapy for the intramedullary lesion 1 month later, and sunitinib therapy was subsequently reinstated. After 6 months, her extracranial lesions remained stable and the intramedullary lesion was undetectable on MRI.

INVESTIGATIONS

CT of the chest and abdomen, bone scan, kidney and liver function tests, measurement of serum levels of calcium, electrolytes and lactate dehydrogenase, CBC, MRI of the brain and spine.

DIAGNOSIS

Progression of a central nervous system metastasis linked to the interruption of neoadjuvant sunitinib therapy.

MANAGEMENT

Neoadjuvant sunitinib therapy followed by cytoreductive nephrectomy for the primary RCC; radiation therapy for the intramedullary lesion, followed by reinstatement of sunitinib therapy owing to a good clinical response observed in the extracranial lesions.

Prospective clinical trial of preoperative sunitinib in patients with renal cell carcinoma

PURPOSE

Sunitinib is an approved treatment for metastatic renal cell carcinoma. We performed a prospective clinical trial to evaluate the safety and clinical response to sunitinib administered before nephrectomy in patients with localized or metastatic clear cell renal cell carcinoma.

MATERIALS AND METHODS

Patients with biopsy proven clear cell renal cell carcinoma were enrolled in the study and treated with 37.5 mg sunitinib malate daily for 3 months before nephrectomy. The primary end point was safety.

RESULTS

In an 18-month period 20 patients were enrolled. The most common toxicities were gastrointestinal symptoms and hematological effects. Grade 3 toxicity developed in 6 patients (30%). No surgical complications were attributable to sunitinib treatment. Of the 20 patients 17 (85%) experienced reduced tumor diameter (mean change -11.8%, range -27% to 11%) and cross-sectional area (mean change -27.9%, range -43% to 23%). Enhancement on contrast enhanced computerized tomography decreased in 15 patients (mean HU change -22%, range -74% to 29%). After tumor reduction 8 patients with cT1b disease underwent laparoscopic partial nephrectomy. Surgical parameters, such as blood loss, transfusion rate, operative time and complications, were similar to those in patients who underwent surgery during the study period and were not enrolled in the trial.

CONCLUSIONS

Preoperative treatment with sunitinib is safe. Sunitinib decreased the size of primary renal cell carcinoma in 17 of 20 patients. Future trials can be considered to evaluate neoadjuvant sunitinib to maximize nephron sparing and decrease the recurrence of high risk, localized renal cell carcinoma.

Targeted therapies in renal cell cancer: recent developments in imaging

Targeted therapy has significantly improved the perspectives of patients with metastatic renal cell cancer (mRCC). Frequently, these new molecules cause disease stabilization rather than substantial tumor regression. As treatment options expand with the growing number of targeted agents, there is an increasing need for surrogate markers to early assess tumor response. Here, we review the currently available imaging techniques and response evaluation criteria for the assessment of tumor response in mRCC patients. For computed tomography (CT), different criteria are discussed including the Response Evaluation Criteria in Solid Tumors (RECIST), the Choi criteria, the modified Choi criteria, and the size and attenuation CT (SACT) criteria. Functional imaging modalities are discussed, such as dynamic contrast-enhanced CT (DCE-CT), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), dynamic contrast-enhanced ultrasonography (DCE-US), and positron emission tomography (PET).

[Is the cytoreductive nephrectomy still necessary in case of metastases?]

Cytoredutive nephrectomy is a component of metastatic renal cell carcinoma management. This procedure can induce a spontaneous regression of metastases in a small number of cases. It increases the overall survival of correctly selected patients treated with immunotherapy. However, we still do not know if this benefit remains for patient treated with targeted therapies. In the three main prospective randomized studies evaluating targeted therapies, the majority of included patients have had prior nephrectomy. However, this surgical procedure is not without risk and could delay initiation of medical treatment. Age of patient, comorbidities, histologic pattern and surgical difficulties should be taken into account. Until results of prospective studies, the cytoreductive nephrectomy should be still considered as component of the treatment of metastatic renal cell carcinoma.

Choi response criteria for early prediction of clinical outcome in patients with metastatic renal cell cancer treated with sunitinib

Background:

Because sunitinib can induce extensive necrosis in metastatic renal cell cancer (mRCC), we examined whether criteria defined by Choi might be valuable to predict early sunitinib efficacy.

Methods:

Computed tomography was used for measurement of tumour lesions in mm and lesion attenuation in Hounsfield units (HUs). According to Choi criteria partial response (PR) was defined as ⩾10% decrease in size or ⩾15% decrease in attenuation.

Results:

A total of 55 mRCC patients treated with sunitinib were included. At first evaluation, according to the Response Evaluation Criteria in Solid Tumours (RECIST) 7 patients had PR, 38 stable disease (SD), and 10 progressive disease (PD), whereas according to Choi criteria 36 patients had PR, 6 SD and 13 PD. Median tumour attenuation decreased from 66 to 47 HUs (P⩽0.001). In patients with PR, Choi criteria had a significantly better predictive value for progression-free survival and overall survival (both Ps<0.001) than RECIST (P=0.685 and 0.191 respectively). The predictive value for RECIST increased (P=0.001 and <0.001 respectively), when best response during treatment was taken into account.

Conclusion:

Choi criteria could be helpful to define early mRCC patients who benefit from sunitinib, but the use of these criteria will not change the management of these patients.

Molecular diagnosis and therapy of kidney cancer

Kidney cancer is not a single disease; it is made up of a number of cancers that occur in the kidney, each having a different histology, following a different clinical course, responding differently to therapy, and caused by a different gene. Study of the genes underlying kidney cancer has revealed that it is fundamentally a metabolic disorder. Understanding the genetic basis of cancer of the kidney has significant implications for diagnosis and management of this disease. VHL is the gene for clear cell kidney cancer. The VHL protein forms a complex that targets the hypoxia-inducible factors for ubiquitin-mediated degradation. Knowledge of this pathway provided the foundation for the development of novel therapeutic approaches now approved for treatment of this disease. MET is the gene for the hereditary form of type 1 papillary renal carcinoma and is mutated in a subset of sporadic type 1 papillary kidney cancers. Clinical trials are currently ongoing with agents targeting the tyrosine kinase domain of MET in sporadic and hereditary forms of papillary kidney cancer. BHD is the gene for the hereditary type of chromophobe kidney cancer. It is thought to be involved in energy and/or nutrient sensing through the AMPK and mTOR signaling pathways. Hereditary leiomyomatosis renal cell carcinoma, a hereditary form of type 2 papillary renal carcinoma, is caused by inactivation of a Krebs cycle enzyme due to mutation. Knowledge of these kidney cancer gene pathways has enabled new approaches in the management of this disease and has provided the foundation for the development of targeted therapeutics.

Phase II presurgical feasibility study of bevacizumab in untreated patients with metastatic renal cell carcinoma

PURPOSE

To assess safety and efficacy of presurgical bevacizumab in patients with metastatic renal cell carcinoma (mRCC), and to explore the hypothesis that pretreatment of patients with antiangiogenic therapy will select patients who benefit most from cytoreductive nephrectomy.

PATIENTS AND METHODS

Patients with newly diagnosed, clear cell mRCC whose primary tumors were considered resectable were enrolled. In this single-arm, phase II trial, patients received bevacizumab plus erlotinib (first patients, n = 23) or bevacizumab alone (n = 27 patients) for 8 weeks followed by restaging. If patients demonstrated progressive disease and had declining performance statuses after 8 weeks, nephrectomy procedures were deferred. Postoperatively, patients continued on the study drug or drugs if disease stabilization or regression had occurred.

RESULTS

Between March 2005 and March 2008, 52 patients were enrolled on study, and 50 were included in the analysis. By Memorial Sloan-Kettering Cancer Center criteria, 82% of patients had intermediate-risk, and 18% had poor-risk, features. Forty-two patients underwent nephrectomy. Median progression-free survival was 11.0 months (95% CI, 5.5 to 15.6 months). Median overall survival was 25.4 months (95% CI, 11.4 months to not estimable). Two perioperative deaths occurred; neither was attributable to study drug. Wound dehiscence resulted in treatment discontinuation for three patients and treatment delay for two others.

CONCLUSION

Presurgical treatment with bevacizumab therapy yields clinical outcomes comparable to post-surgical treatment with antiangiogenic therapy in patients with mRCC, but it may result in wound-healing delays. Prospective, randomized trials to test the use of presurgical therapy as a method to select appropriate patients for cytoreductive nephrectomy are warranted.

In vivo antitumor and antimetastatic activity of sunitinib in preclinical neuroblastoma mouse model

Neuroblastoma (NB) is one of the most common pediatric solid tumors originating from the neural crest lineage. Despite intensive treatment protocols including megatherapy with hematopoietic stem cell transplantation, the prognosis of NB patients remains poor. More effective therapeutics are required. High vascularity has been described as a feature of aggressive, widely disseminated NB. Our previous work demonstrated the overexpression of vascular endothelial growth factor (VEGF) in NB, and we showed that an anti-VEGF receptor (VEGFR-2) antibody could induce sustained NB tumor suppression and regression. Sunitinib is a kinase inhibitor targeting platelet-derived growth factor receptors and VEGFRs and, therefore, a promising antiangiogenic agent. In this study, we investigated the antitumor activity of sunitinib and its synergistic cytotoxicity with conventional (cyclophosphamide) and novel (rapamycin) therapies. Both NB cell lines and tumor-initiating cells from patient tumor samples were used in our in vitro and in vivo models for these drug testing. We show that sunitinib inhibits tumor cell proliferation and phosphorylation of VEGFRs. It also inhibits tumor growth, angiogenesis, and metastasis in tumor xenograft models. Low-dose sunitinib (20 mg/kg) demonstrates synergistic cytotoxicity with an mTOR inhibitor, rapamycin, which is more effective than the traditional chemotherapeutic drug, cyclophosphamide. These preclinical studies provide the evidence of antitumor activity of sunitinib both in the early stage of tumor formation and in the progressive metastatic disease. These studies also provide the framework for clinical trial of sunitinib, alone and in combination with conventional and novel therapies to increase efficacy and improve patient outcome in NB.

Neoadjuvant (presurgical) therapy for renal cell carcinoma: a new treatment paradigm for locally advanced and metastatic disease

BACKGROUND

Although upfront cytoreductive nephrectomy followed by systemic therapy remains the standard of care for metastatic renal cell carcinoma, the addition of novel targeted therapy has prompted a reevaluation of this treatment paradigm. The authors reviewed their experience with neoadjuvant systemic therapy administered before cytoreductive surgery for metastatic, locally recurrent, or regionally advanced renal cell carcinoma.

METHODS

The authors compared patients treated with presurgical targeted therapy (with sunitinib, sorafenib, or bevacizumab) with a contemporary group that underwent up-front cytoreductive surgery.

RESULTS

The authors found no difference in any perioperative surgical parameters indicative of morbidity or mortality between the 2 groups. Laboratory models of renal cell carcinoma treated with systemic targeted therapy demonstrate specific protein expression profiles that correlate with response to therapy and the development of therapy resistance.

CONCLUSIONS

Neoadjuvant (presurgical) targeted therapy before cytoreductive surgery appears safe in the setting of metastatic renal cell carcinoma. It identifies patients who respond to systemic therapy before surgery, thus avoiding highly morbid surgery in patients destined for a poor outcome. Further studies are needed to identify the molecular endpoints associated with treatment response and the development of the resistant phenotype, which will in turn identify novel transduction pathways worthy of therapeutic development.

Cytoreductive nephrectomy for metastatic RCC in the era of targeted therapy

Metastatic renal cell carcinoma (RCC) has traditionally been associated with a poor prognosis with few effective treatments. In the multimodal treatment of metastatic RCC, cytoreductive nephrectomy (CN) became the standard of care after two randomized trials demonstrated a benefit in overall survival in patients who received CN prior to treatment with interferon. More recently, several agents (sunitinib, sorafenib, temsirolimus, everolimus and bevacizumab) have been developed that target angiogenesis and the cellular growth pathways involved in metastatic RCC. These targeted agents have demonstrated improved outcomes compared to cytokine therapy, and have transformed metastatic RCC treatment. Targeted agents are being used as a first-line systemic treatment in patients with metastatic RCC with unprecedented success, and many studies are now focusing on the role of CN in combination with these agents for patients with metastatic RCC.

Neoadjuvant sunitinib for surgically complex advanced renal cell cancer of doubtful resectability: initial experience with downsizing to reconsider cytoreductive surgery

OBJECTIVE

To evaluate neoadjuvant sunitinib in patients with synchronous metastatic renal cell cancer (mRCC) to downsize surgically complex tumours and reconsider cytoreductive surgery.

PATIENTS AND METHODS

Retrospective analysis of ten consecutive mRCC patients treated with sunitinib in an expanded access program who presented with surgically complex primary tumours or bulky locoregional metastases. Surgery-limiting tumour sites (SLTSs) were defined as primary or retroperitoneal lesions with direct invasion of adjacent organs or encasement of vital structures on imaging. Patients received sunitinib 50 mg/day for 4 weeks on and 2 weeks off to be followed by cytoreductive surgery after downsizing and individual reassessment. Response was measured according to Response Evaluation Criteria in Solid Tumours (RECIST).

RESULTS

Six out of ten SLTSs revealed a reduction of tumour size with a median of 14% according to RECIST. None of the ten SLTSs had a partial response (PR), whilst at distant metastatic sites one complete remission and two PRs occurred. Downsizing of SLTSs appeared most prominent in the first 2-4 months, which resulted in reconsidering cytoreductive nephrectomy in three patients. These three tumours invaded the liver on imaging and were reduced by 11, 18 and 20%.

CONCLUSIONS

In this patient group with mRCC and surgically complex primary tumours or locoregional metastases, downsizing of SLTSs by neoadjuvant sunitinib was limited. Cytoreductive surgery was reconsidered in three patients. Given the overall reduction in tumour burden by sunitinib alone, further investigation to define the role of cytoreductive surgery is warranted.

Cytoreductive nephrectomy in metastatic clear-cell renal cell carcinoma: perspectives in the tyrosine kinase inhibitor era

Cytoreductive nephrectomy in combination with adjuvant immunotherapy is an established treatment option for selected patients with metastatic clear-cell renal cell carcinoma (mCC-RCC). Multitargeted antiangiogenic and mammalian target of rapamycin tyrosine kinase inhibitors (TKIs) are now established treatment paradigms in patients with mCC-RCC. Given that all the recent seminal TKI trials in mCC-RCC provide no evidence base for the use of cytoreductive nephrectomy in the TKI era, it is not presently clear where such a surgical approach fits into the treatment paradigm. This review summarizes the evidence for the management of mCC-RCC and outlines novel approaches to be tested within future trials if the initial proposed phase III trials in this setting, using sunitinib, are successful. Overall, two principal questions need addressing. First, is cytoreductive nephrectomy necessary in the TKI era? Second, if so, what is the most appropriate scheduling of TKI therapy with cytoreductive nephrectomy?

Response of the primary tumor to neoadjuvant sunitinib in patients with advanced renal cell carcinoma

PURPOSE

We assessed the activity of neoadjuvant sunitinib on primary renal tumors in patients with advanced renal cell carcinoma as well as the feasibility and safety of subsequent surgical resection.

METHODS

A total of 19 patients with advanced renal cell carcinoma deemed unsuitable for initial nephrectomy due to locally advanced disease or extensive metastatic burden were treated with 50 mg sunitinib daily for 4 weeks on followed by 2 weeks off. Tumor response was assessed by Response Evaluation Criteria in Solid Tumors every 2 cycles and the rate of conversion to resectable status was estimated.

RESULTS

Median patient age was 64 years and initial median radiographic renal tumor size was 10.5 cm. Clinical stage was N+ (10) and M+ (15). No patients experienced a complete response. Partial responses of the primary tumor were noted in 3 patients (16%), 7 (37%) had stable disease and 9 (47%) had disease progression in the primary tumor. Overall tumor response included 2 patients (11%) with partial response, 7 (37%) with stable disease and 10 (53%) with disease progression. At a median followup of 6 months (range 1 to 15) 4 patients (21%) had undergone nephrectomy and 5 died of disease progression. No unexpected surgical morbidity was encountered. Viable tumor was present in all 4 specimens. Sunitinib was associated with grade 3-4 toxicity in 7 patients (37%) and treatment was discontinued in 1 due to toxicity.

CONCLUSIONS

Administration of sunitinib in patients with advanced renal cell carcinoma with the primary tumor in place is feasible and can lead to a reduction in tumor burden that can facilitate subsequent surgical resection.

Pre-surgical targeted molecular therapy in renal cell carcinoma

Pre-surgical systemic therapy with targeted molecular agents is an attractive option as an approach to the treatment of patients with renal cell carcinoma. This treatment strategy offers a rational approach for selecting patients with metastatic disease who are most likely to benefit from cytoreductive nephrectomy, but also allows access to treated tumour tissue to study the molecular mechanisms of response and resistance. In patients with locally advanced disease, this strategy offers the potential for improved resectability and timely delivery of systemic therapy to treat subclinical metastatic disease. Preliminary evidence indicates that the use of targeted therapies before nephrectomy is safe. Reliable therapy-specific prognostic biomarkers are needed for the optimal integration of aggressive surgical intervention and systemic therapy to maximize the oncological benefits for the patient.

Role of the microenvironment in tumor growth and in refractoriness/resistance to anti-angiogenic therapies

Angiogenesis is critical for growth of many tumor types and the development of anti-angiogenic agents opened a new era in cancer therapy. However, similar to other anti-cancer therapies, inherent/acquired resistance to anti-angiogenic drugs may occur in cancer patients leading to disease recurrence. Recent studies in several experimental models suggest that both tumor and non-tumor (stromal) cell types may be involved in the reduced responsiveness to the treatments. The current review focuses on the role of stromal cells in tumor growth and in refractoriness to anti-VEGF treatment.

Conclusion and future directions

Twenty-five years ago treatment for metastatic renal cancer was generally ineffective. Over the intervening period, cytokines such as interferon-alpha and interleukin-2 gained prominence in the treatment of metastatic renal cancer. These agents produced clinical responses in a minority of patients with metastatic renal cancer, albeit with substantial toxicity. Over the last 3 years, there has been a substantial increase in our understanding of kidney cancer at the molecular level. This has led to major breakthroughs in the management of this once untreatable disease. Substantial gains in progression free and overall survival have occurred as a consequence. This issue of The Cancer Journal has been devoted to reviewing clinical progress in the treatment of metastatic renal cancer, with an eye toward current needs and the likely future directions of the field.

Predictive factors for severe toxicity of sunitinib in unselected patients with advanced renal cell cancer

Sunitinib has been registered for the treatment of advanced renal cell cancer (RCC). As patient inclusion was highly selective in previous studies, experience with sunitinib in general oncological practice remains to be reported. We determined the efficacy and safety of sunitinib in patients with advanced RCC included in an expanded access programme. ECOG performance status >1, histology other than clear cell and presence of brain metastases were no exclusion criteria. Eighty-two patients were treated: 23% reached a partial response, 50% had stable disease, 20% progressed and six patients were not evaluable. Median progression-free survival (PFS) was 9 months and median overall survival (OS) was 15 months. Importantly, 47 patients (57%) needed a dose reduction, 35 (43%) because of treatment-related adverse events, 10 (12%) because of continuous dosing, and two because of both. Stomatitis, fatigue, hand-foot syndrome and a combination of grade 1-2 adverse events were the most frequent reasons for dose reduction. In 40 patients (49%), there was severe toxicity, defined as dose reduction or permanent discontinuation, which was highly correlated with low body surface area, high age and female gender. On the basis of age and gender, a model was developed that could predict the probability of severe toxicity.