Everolimus in metastatic renal cell carcinoma after failure of initial vascular endothelial growth factor receptor-tyrosine kinase inhibitor (VEGFr-TKI) therapy: results of an interim analysis of a non-interventional study

Everolimus in metastatic renal cell carcinoma after failure of initial anti-VEGF therapy: final results of a noninterventional study

BACKGROUND

Data are limited regarding routine use of everolimus after initial vascular endothelial growth factor (VEGF)-targeted therapy. The aim of this prospective, noninterventional, observational study was to assess efficacy and safety of everolimus after initial VEGF-targeted treatment in patients with metastatic renal cell carcinoma (mRCC) in routine clinical settings.

METHODS

Everolimus was administered per routine clinical practice. Patients with mRCC of any histology from 116 active sites in Germany were included. The main objective was to determine everolimus efficacy in time to progression (TTP). Progression-free survival (PFS), treatment duration, tumor response, adherence to everolimus regimen, treatment after everolimus, and safety were also assessed.

RESULTS

In the total population (N = 334), median follow-up was 5.2 months (range, 0-32 months). Median treatment duration (safety population, n = 318) was 6.5 months (95% confidence interval [CI], 5-8 months). Median TTP and median PFS were similar in populations investigated. In patients who received everolimus as second-line treatment (n = 211), median (95% CI) TTP was 7.1 months (5-9 months) and median PFS was 6.9 months (5-9 months). Commonly reported adverse events (safety population, n = 318) were dyspnea (17%), anemia (15%), and fatigue (12%). Limitations of the noninterventional design should be considered.

CONCLUSIONS

This study reflects routine clinical use of everolimus in a large sample of patients with mRCC. Favorable efficacy and safety were seen for everolimus after previous therapy with one VEGF-targeted agent. Results of this study confirm everolimus as one of the standard options in second-line therapy for patients with mRCC. Novartis study code, CRAD001LD27: VFA registry for noninterventional studies ( http://www.vfa.de/de/forschung/nisdb/).

Future perspectives for mTOR inhibitors in renal cell cancer treatment

ABSTRACT 

Everolimus is a mTOR inhibitor that demonstrates antitumor and antiangiogenic activities. In a randomized Phase III trial, patients with metastatic renal cell carcinoma who progressed on sunitinib/sorafenib were treated with everolimus and showed significant improvement in progression-free survival compared with best supportive care. Novel approaches in treatment are expected to ensure less toxic therapies and increase efficacy of everolimus. To provide a new perspective for mTOR inhibitor research and therapy, we discuss renal cell carcinoma cancer stem cells as a potential target for mTOR inhibitors and present new concepts on emerging antiangiogenic therapies. Finally, we point why systems biology approach with reverse molecular engineering may also contribute to the field of drug discovery in renal cell carcinoma.

Everolimus as second-line therapy for metastatic renal cell carcinoma: a 'real-life' study

AIMS

This study, conducted in a 'field-practice' scenario, investigates the effectiveness and safety of everolimus in the second-line treatment of metastatic renal cell carcinoma (mRCC) patients.

PATIENTS & METHODS

mRCC patients, who started everolimus 10 mg/day after failure of first-line VEGF receptor-targeted tyrosine kinase inhibitor, were included in this study. Study end points were treatment response, progression-free survival and tolerability.

RESULTS

In total, 100 patients were assessed; the median duration of everolimus treatment was 7.1 months (95% CI: 5.7-8.5). A total of 19% of patients experienced a partial response and 62% of patients reached a stable disease. Median progression-free survival was 8 months (95% CI: 6.7-9.3). A total of 75% of patients experienced adverse events; no grade 4 adverse events were reported.

CONCLUSION

These findings, obtained in a 'field-practice' scenario, support the use of everolimus for mRCC patients who failed one VEGF receptor-targeted tyrosine kinase inhibitor.

Controversies in renal cell carcinoma: treatment choice after progression on vascular endothelial growth factor-targeted therapy

The mammalian target of rapamycin inhibitor (mTORI) everolimus and the tyrosine kinase inhibitor (TKI) axitinib are the only two post-first-line treatment options for metastatic renal cell carcinoma (mRCC) licensed at present. Extrapolation of robust phase III studies suggests that median progression-free survival (PFS) is similar between agents. This presents a dilemma for the physician planning treatment for their patients with mRCC: should they be treated with a TKI-mTORI or a TKI-TKI sequence? The lack of direct comparison between axitinib and everolimus leaves the clinician without clear guidance on the optimal choice in second-line therapy. In phase III studies, both post first-line everolimus and axitinib have been shown to delay disease progression; however, cumulative toxicity with sequential use of TKIs may result in more treatment interruptions or dose reductions or increased likelihood of adverse events. While everolimus exerts a tolerability advantage, axitinib is associated with higher response rate and a similar PFS benefit. Proven superiority cannot be used to guide treatment sequence selection in mRCC. Instead, therapeutic planning requires us to take a long-term view of our patient's treatment that includes quality of life and a balance between symptom control, adverse event management and avoidance of unnecessary drug interruptions or dose reductions. In the absence of curative therapies, sustaining a patient's quality of life is a major goal throughout the course of treatment and choosing a second-line agent that is able to adequately achieve this by limiting adverse events should be a priority.

Therapy of mRCC beyond mTOR-inhibition in clinical practice: results of a retrospective analysis

PURPOSE

Renal cell carcinoma (RCC) is the most common renal tumor and accounts for nearly 3 % of adult cancers. In the recent years, seven new targeted agents have been approved changing the treatment in metastatic RCC dramatically. So far, however, it remains unclear which sequence is best for those patients. This study analyzed retrospectively the outcome of patients treated with everolimus after failure of a vascular endothelial growth factor receptor-directed therapy and which therapies were used after everolimus.

PATIENTS AND METHODS

In a retrospective analysis, patients receiving everolimus after failure of first-line VEGFR-directed therapy have been analyzed in regard to response, duration of treatment and subsequent therapies. In total, the data of 81 patients have been analyzed.

RESULTS

The most observed first-line therapy was sunitinib followed by sorafenib. Thirty-two patients received everolimus as second-line therapy, and 49 as third-line therapy. The median duration of treatment with everolimus was 4.5 months. Seventy-seven of eighty-one patients (95 %) received a further therapy after discontinuation of everolimus. The agents administered beyond were sunitinib (28.6 %), sorafenib (28.6 %) and 42.8 % received other therapies. Twenty-seven patients received an additional sequence of therapy (fourth to fifth line). Fifty-eight percentage of patients have still been alive at time of analysis.

CONCLUSION

The duration of everolimus therapy beyond failure of anti-VEGF-directed therapy and the reported time to progression was in the range of the RECORD-1 trial in daily practice as well. After failure of everolimus, reexposure to tyrosine kinase inhibitors is a common clinical practice and demonstrates a clinical benefit of therapies beyond everolimus.

Using cumulative toxicity to identify the optimal second-line targeted therapy in patients with metastatic renal cell carcinoma: what's new?

The life expectancy in metastatic renal cell carcinoma patients treated with targeted therapies can be influenced by the time spent on treatment, and the current focus of clinical research in this field appears to be on extending the time on treatment while limiting toxicities. It has been proposed that a strategy based on the sequential administration of two tyrosine kinase inhibitors could result in unacceptable cumulative toxicity for many metastatic renal cell carcinoma patients, while switching to a mTOR inhibitor does not. However, a definite consensus on this issue has not been reached. As very little information from head-to-head studies is available, clinicians have to base their treatment decisions on existing evidence, with an obvious preference for high-quality studies. Some recent studies have provided new insights into the issue of cumulative toxicity of second-line targeted therapies in metastatic renal cell carcinoma patients. In this article, we discuss the evidence emerging from the randomized AXIS and RECORD-3 trials.

Temsirolimus for advanced renal cell carcinoma

Renal cell carcinomas (RCCs) represent one of the ten leading cancer entities with an increasing incidence especially in the western world. Unfortunately, about 25% of the patients develop metastatic RCC (mRCC) associated with a most unfavorable prognosis. In the recent years, various new agents targeting VEGF or VEGF receptor (VEGFR) or the mTOR pathway have been approved for the treatment of mRCC with significant prolongation of progression-free survival and, in part, of overall survival (OS). Targeting the mTOR kinase is an interesting option for mRCC. Temsirolimus, one of the available mTOR inhibitors, has been approved as a single agent in poor-risk mRCC patients based on the pivotal Phase III trial showing a significant superiority in OS versus IFN-α or temsirolimus + IFN-α, which has been verified by a pivotal Phase III trial. The benefit has been shown for clear cell carcinoma and papillary RCC as well. For poor prognosis patients, temsirolimus improves median survival by 3.6 months. In second-line treatment compared with sorafenib following first-line treatment with sunitinib temsirolimus showed a relative progression-free survival benefit for patients with nonclear cell RCC with temsirolimus. The median OS for the temsirolimus group was 12.27 and 16.64 months for the sorafenib group. In 2007, the US FDA granted approval for temsirolimus for the treatment of advanced RCC.

eIF4E-Overexpression imparts perillyl alcohol and rapamycin-mediated regulation of telomerase reverse transcriptase

Translation is mediated partly by regulation of free eukaryotic initiation factor 4E (eIF4E) levels through PI3K-Akt-mTOR signaling. Cancer cells treated with the plant-derived perillyl alcohol (POH) or the mechanistic target of rapamycin (mTOR) inhibitor rapamycin dephosphorylate eIF4E-binding protein (4E-BP1) and attenuate cap-dependent translation. We previously showed in cancer cell lines with elevated eIF4E that POH and rapamycin regulate telomerase activity through this pathway. Here, immortalized Chinese hamster ovary (CHO) control cells and CHO cells with forced eIF4E expression (rb4E) were used to elucidate eIF4E's role in telomerase regulation by POH and rapamycin. Despite 5-fold higher eIF4E amounts in rb4E, telomerase activity, telomerase reverse transcriptase (TERT) mRNA, and TERT protein were nearly equivalent in control and rb4E cells. In control cells, telomerase activity, TERT mRNA and protein levels were unaffected by either compound. In contrast, telomerase activity and TERT protein were both attenuated by either agent in rb4E cells, but without corresponding TERT mRNA decreases indicating a translational/post-translational process. S6K, Akt, and 4E-BP1 were modulated by mTOR mediators only in the presence of increased eIF4E. Thus, eIF4E-overexpression in rb4E cells enables inhibitory effects of POH and rapamycin on telomerase and TERT protein. Importantly, eIF4E-overexpression modifies cellular protein synthetic processes and gene regulation.