Improving outcomes in metastatic clear cell renal cell carcinoma by sequencing therapy

Sunitinib Rechallenge After Other Targeted Therapies in Metastatic Renal Cell Carcinoma Patients: A Single-Center, Retrospective Study

BACKGROUND

Sunitinib is still one of the standard therapies in metastatic renal cell carcinoma (mRCC). Despite the benefit of sunitinib resistance will develop in the majority of patients. Most of them receive multiple sequential therapies during the course of disease.

OBJECTIVES

To retrospectively investigate the efficacy and safety of rechallenged sunitinib in third or later line settings.

PATIENTS AND METHODS

Twenty-one mRCC patients were identified who received rechallenged sunitinib between March 2010 and April 2018. Patients received sunitinib in first or second line, then other tyrosine kinase and/or mTOR inhibitors were applied, then sunitinib was rechallenged. Patients' characteristics, tolerability, treatment modalities, and treatment outcomes were recorded. The primary end-point was progression-free survival (PFS) of rechallenged sunitinib.

RESULTS

Median age of patients was 62 years at the start of sunitinib rechallenge. Sixty-seven percent of patients were male. All patients had prior nephrectomy. Upon rechallenge 4 patients achieved partial response and 12 stable disease. The median PFS of first sunitinib treatment was 22 (95% CI 17-26) months and for rechallenged sunitinib 14 (95% CI 6-20) months. No increased severity of prior toxicity or new adverse events was reported during rechallenged sunitinib. The median overall survival (OS) from the start of first sunitinib was 67 (95% CI 46-76) months. Multivariate Cox regression analysis revealed that younger age (< 57 years) at start of first sunitinib (HR = 0.24; 95% CI 0.07-0.79; p = 0.019) and longer (> 2 years) first sunitinib treatment (HR = 0.28; 95% CI 0.09-0.93; p = 0.038) were independent markers of longer OS.

CONCLUSION

Sunitinib rechallenge is a feasible and tolerable option with clinical benefit in selected mRCC patients.

Time on Therapy for at Least Three Months Correlates with Overall Survival in Metastatic Renal Cell Carcinoma

With 15 drugs currently approved for the treatment of metastatic renal cell carcinoma (mRCC) and even more combination regimens with immunotherapy on the horizon, there remains a distinct lack of molecular biomarkers for therapeutic efficacy. Our study reports on real-world clinical outcomes of mRCC patients from a tertiary academic medical center treated with empirically selected standard-of-care therapy. We utilized the Stanford Renal Cell Carcinoma Database (RCCD) to report on various outcome measures, including overall survival (OS) and the median number of lines of targeted therapies received from the time of metastatic diagnosis. We found that most metastatic patients did not survive long enough to attempt even half of the available targeted therapies. We also noted that patients who failed to receive a clinical benefit within the first two lines of therapy could still go on to experience clinical benefit in later lines of therapy. The term, “clinical benefit” was assigned to a line of therapy if a patient remained on drug treatment for three months or longer. Moreover, patients with clinical benefit in at least one line of therapy experienced significantly longer OS compared to those who did not have clinical benefit in at least one line of therapy. Developing biomarkers that identify patients who will receive clinical benefit in individual lines of therapy is one potential strategy for achieving rational drug sequencing in mRCC.

Sunitinib does not impair natural killer cell function in patients with renal cell carcinoma

Although the available treatment options have expanded, the survival of patients with metastatic renal cell carcinoma (RCC) remains poor. As patients with RCC lack responsiveness to chemotherapy or radiation, therapeutic options predominantly include surgical interventions and immunomodulatory approaches, including the administration of tyrosine kinase inhibitors (TKIs) such as sunitinib. Natural killer (NK) cells have been reported to be key players in TKI-mediated off-target effects on the immune system. However, only limited information is available regarding the possible impact of sunitinib on the function of NK cells of individual patients. The present study reports on the immunomonitoring results of three patients with metastatic RCC who underwent sunitinib treatment. These results were compared with age-matched, healthy controls in terms of the immune status of T, B and NK cells, focusing on functional in vitro analyses of NK cells. In all three patients, NK cell number, subset distribution and function, as measured by cluster of differentiation 107a degranulation, did not exhibit any significant alterations as a result of sunitinib treatment. These results indicate that sunitinib does not negatively affect NK cell function, which supports the pursuit of therapeutic modalities that combine immunomodulation and NK cell-stimulating approaches.

Pediatric Patient With Renal Cell Carcinoma Treated by Successive Antiangiogenics Drugs: A Case Report and Review of the Literature

Antiangiogenic drugs are currently standard of care in adults with renal cell carcinoma (RCC), including translocation RCC. Although antitumor activity and toxicity profile are well known in adults, few data have been reported in children. Here we present the case of a patient diagnosed at 2 years old with a metastatic translocation RCC, consecutively treated with 5 tyrosine kinase inhibitors during 6 years. The antitumor activity and toxic effects are described, and a brief review of the literature is presented.

Cabozantinib inhibits tumor growth and metastasis of a patient-derived xenograft model of papillary renal cell carcinoma with MET mutation

MET plays an important role in the development and progression of papillary renal cell carcinoma (pRCC). Evaluation of efficacy of MET inhibitors against pRCC has been hampered by limited preclinical models depicting MET abnormalities. We established a new patient-derived xenograft (PDX) model of pRCC carrying an activating mutation of MET and tested the ability of cabozantinib, an inhibitor of receptor tyrosine kinases including MET, to inhibit tumor growth and metastasis. Precision-cut, thin tissue slices from a pRCC specimen obtained by nephrectomy were implanted under the renal capsule of RAG2^-/-γC^-/- mice to establish first generation TSG-RCC-030. Histologic and genetic fidelity and metastatic potential of this model were characterized by immunohistochemistry, direct DNA sequencing and quantitative polymerase chain reaction (qPCR). The effect of cabozantinib on tumor growth and metastasis was evaluated. Whether measurements of circulating tumor DNA (ctDNA) by allele-specific qPCR could be used as a biomarker of tumor growth and response to therapy was determined. Subrenal and subcutaneous tumor grafts showed high take rates and metastasized to the lung. Both primary tumors and metastases expressed typical markers of pRCC and carried the same activating MET mutation as the parental tumor. Cabozantinib treatment caused striking tumor regression and inhibited lung metastasis in TSG-RCC-030. Plasma ctDNA levels correlated with tumor volume in control mice and changed in response to cabozantinib treatment. TSG-RCC-030 provides a realistic preclinical model to better understand the development and progression of pRCC with MET mutation and accelerate the development of new therapies for pRCC.

Role of mTOR Inhibitors in Kidney Disease

The first compound that inhibited the mammalian target of rapamycin (mTOR), sirolimus (rapamycin) was discovered in the 1970s as a soil bacterium metabolite collected on Easter Island (Rapa Nui). Because sirolimus showed antiproliferative activity, researchers investigated its molecular target and identified the TOR1 and TOR2. The mTOR consists of mTOR complex 1 (mTORC1) and mTORC2. Rapalogues including sirolimus, everolimus, and temsirolimus exert their effect mainly on mTORC1, whereas their inhibitory effect on mTORC2 is mild. To obtain compounds with more potent antiproliferative effects, ATP-competitive inhibitors of mTOR targeting both mTORC1 and mTORC2 have been developed and tested in clinical trials as anticancer drugs. Currently, mTOR inhibitors are used as anticancer drugs against several solid tumors, and immunosuppressive agents for transplantation of various organs. This review discusses the role of mTOR inhibitors in renal disease with a particular focus on renal cancer, diabetic nephropathy, and kidney transplantation.

Beyond evidence-based data: scientific rationale and tumor behavior to drive sequential and personalized therapeutic strategies for the treatment of metastatic renal cell carcinoma

The recent advances in identification of the molecular mechanisms related to tumorigenesis and angiogenesis, along with the understanding of molecular alterations involved in renal cell carcinoma (RCC) pathogenesis, has allowed the development of several new drugs which have revolutionized the treatment of metastatic renal cell carcinoma (mRCC).This process has resulted in clinically significant improvements in median overall survival and an increasing number of patients undergoes two or even three lines of therapy. Therefore, it is necessary a long-term perspective of the treatment: planning a sequential and personalized therapeutic strategy to improve clinical outcome, the potential to achieve long-term response, and to preserve quality of life (QOL), minimizing treatment-related toxicity and transforming mRCC into a chronically treatable condition.Because of the challenges still encountered to draw an optimal therapeutic sequence, the main focus of this article will be to propose the optimal sequencing of existing, approved, oral targeted agents for the treatment of mRCC using evidence-based data along with the knowledge available on the tumor behavior and mechanisms of resistance to anti-angiogenic treatment to provide complementary information and to help the clinicians to maximize the effectiveness of targeted agents in the treatment of mRCC.

Sequence of treatment in locally advanced and metastatic renal cell carcinoma

The spectrum of drugs that have shown activity in advanced or metastatic renal cell carcinoma (RCC) has led to a debate on the optimal sequence of treatments. There is agreement on recommending targeted agents as the standard of care in this disease. Uncertainty, however, remains on the best first-line drug choice. Physicians and patients may select sunitinib, bevacizumab in combination with interferon-alpha (IFN-α), pazopanib, or-in poor risk patients-temsirolimus. There are also a variety of therapies with proven efficacy on hand in the second-line setting: sorafenib, pazopanib, axitinib, and everolimus. While most randomized RCC trials assessed progression free survival (PFS) as primary endpoint, some agents were shown to improve median overall survival (OS), and given in sequence they have extended the life expectancy of RCC patients from 13 months in the cytokine era to over 30 months. Despite the progress made, there are sobering aspects to the oncologic success story in RCC, as the new treatments do not obtain an objective response or disease stabilization (SD) in all patients. There are also as yet no predictors to select patients who might benefit and those who are primary resistant to specific drugs, and ultimately almost all patients will experience disease progression. Bearing inevitable treatment failure in mind, availability of further drugs and switching therapy while the patient is in a condition to continue pharmacotherapy is essential. Of note, depending on the setting, only 33-59% of patients receive second-line treatment. In this review we present data on first-, second-, and third-line treatment in RCC, and discuss the difficulties in their interpretation in the context of treatment sequence. We summarize biological aspects and discuss mechanisms of resistance to anti-angiogenic therapy and their implications for treatment selection.