The combination of bevacizumab/temsirolimus after first-line anti-VEGF therapy in advanced renal-cell carcinoma: a clinical and biomarker study

BACKGROUND

Vascular endothelial growth factor (VEGF) targeting represents the standard first-line therapy for metastatic renal-cell carcinoma (mRCC), while blocking the mammalian target of rapamycin (mTOR) is effective in relapsed disease. Since continuing blockade of VEGF may be of value, we studied the combination of bevacizumab with temsirolimus in mRCC patients relapsing after first-line treatment.

METHODS

A prospective, phase II study of the combination of bevacizumab (10 mg/kg, every 2 weeks) with temsirolimus (25 mg weekly) in patients with mRCC who failed first-line anti-VEGF treatment. 6-month progression-free survival (PFS) rate was the primary end point. The association of VEGFa, VEGFR2, fibroblast growth factor (FGF) b, platelet-derived growth factor receptor (PDGFR) a and PDGFRb with prognostic factors and outcomes were also studied.

RESULTS

39 patients were enrolled. First-line therapy included: sunitinib (n = 16), bevacizumab/interferon (n = 12), pazopanib (n = 10), sorafenib (n = 1). After a median follow-up of 37 months, 6-month PFS rate was 50.9% [95% confidence interval (CI) 33.8-65.7], median time to progression 6.8 months (95% CI 5.5-9.2) and median overall survival (OS) 18.2 months (95% CI 12.9-27.2). Objective response rate was 27%. The most common AEs were metabolic (33%), renal (8%) and gastrointestinal (GI) (7%). The most common grade 3-5 AEs were GI (18%), infections (14%) and metabolic (25%). Toxicity was the most frequent cause of treatment discontinuation (40%). FGFb levels were associated with OS.

CONCLUSIONS

In concert with recent data, our study confirms the efficacy of anti-VEGF/anti-mTOR combination in mRCC relapsing after anti-VEGF therapy. Toxicity was considerable leading to high rate of treatment discontinuations.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01264341.

A simple prognostic model for overall survival in metastatic renal cell carcinoma

INTRODUCTION

The primary purpose of this study was to develop a simpler prognostic model to predict overall survival for patients treated for metastatic renal cell carcinoma (mRCC) by examining variables shown in the literature to be associated with survival.

METHODS

We conducted a retrospective analysis of patients treated for mRCC at two Canadian centres. All patients who started first-line treatment were included in the analysis. A multivariate Cox proportional hazards regression model was constructed using a stepwise procedure. Patients were assigned to risk groups depending on how many of the three risk factors from the final multivariate model they had.

RESULTS

There were three risk factors in the final multivariate model: hemoglobin, prior nephrectomy, and time from diagnosis to treatment. Patients in the high-risk group (two or three risk factors) had a median survival of 5.9 months, while those in the intermediate-risk group (one risk factor) had a median survival of 16.2 months, and those in the low-risk group (no risk factors) had a median survival of 50.6 months.

CONCLUSIONS

In multivariate analysis, shorter survival times were associated with hemoglobin below the lower limit of normal, absence of prior nephrectomy, and initiation of treatment within one year of diagnosis.

Consensus on the utility of bone markers in the malignant bone disease setting

Biochemical markers of bone turnover provide insight into ongoing rates of skeletal metabolism and tumor-bone interactions in patients with malignant bone disease. This article reviews the available recent evidence assessing the potential of bone markers for detecting and monitoring malignant bone lesions in patients with advanced cancers, and for assessing overall skeletal health and response to antiresorptive therapies in patients at all stages of cancer progression. Most data thus far are for urinary N-terminal cross-linked telopeptide of type I collagen (NTX) in predicting risks of skeletal morbidity and death and monitoring response to zoledronic acid in patients with bone metastases. Ongoing studies are evaluating such correlations for other markers and therapies. Emerging evidence suggests that bone markers may help identify patients at high risk for bone metastasis or bone lesion progression, thereby allowing improved follow-up. Results from ongoing clinical trials evaluating such potential applications of bone markers are awaited.

Glycolytic enzyme inhibitors in cancer treatment

BACKGROUND

The radio- and chemotherapeutics currently used for the treatment of cancer are widely known to be characterized by a low therapeutic index. An interesting approach to overcoming some of the limits of these techniques is the exploitation of the so-called Warburg effect, which typically characterizes neoplastic cells. Interestingly, this feature has already been utilized with good results, but only for diagnostic purposes (PET and SPECT). From a pharmacological point of view, drugs able to perturb cancer cell metabolism, specifically at the level of glycolysis, may display interesting therapeutic activities in cancer.

OBJECTIVE

The pharmacological actions of these glycolytic enzyme inhibitors, based primarily on ATP depletion, could include: i) amelioration of drug selectivity by exploiting the particular glycolysis addiction of cancer cell; ii) inhibition of energetic and anabolic processes; iii) reduction of hypoxia-linked cancer-cell resistance; iv) reduction of ATP-dependent multi-drug resistance; and v) cytotoxic synergism with conventional cancer treatments.

CONCLUSION

Several glycolytic inhibitors are currently in preclinical and clinical development. Their clinical value as anticancer agents, above all in terms of therapeutic index, strictly depends on a careful reevaluation of the pathophyiological role of the unique metabolism of cancer cells in general and of Warburg effect in particular.