Axitinib for the treatment of advanced renal cell carcinoma

Approved Small-Molecule ATP-Competitive Kinases Drugs Containing Indole/Azaindole/Oxindole Scaffolds: R&D and Binding Patterns Profiling

Kinases are among the most important families of biomolecules and play an essential role in the regulation of cell proliferation, apoptosis, metabolism, and other critical physiological processes. The dysregulation and gene mutation of kinases are linked to the occurrence and development of various human diseases, especially cancer. As a result, a growing number of small-molecule drugs based on kinase targets are being successfully developed and approved for the treatment of many diseases. The indole/azaindole/oxindole moieties are important key pharmacophores of many bioactive compounds and are generally used as excellent scaffolds for drug discovery in medicinal chemistry. To date, 30 ATP-competitive kinase inhibitors bearing the indole/azaindole/oxindole scaffold have been approved for the treatment of diseases. Herein, we summarize their research and development (R&D) process and describe their binding models to the ATP-binding sites of the target kinases. Moreover, we discuss the significant role of the indole/azaindole/oxindole skeletons in the interaction of their parent drug and target kinases, providing new medicinal chemistry inspiration and ideas for the subsequent development and optimization of kinase inhibitors.

Avelumab: search for combinations of immune checkpoint inhibition with chemotherapy

INTRODUCTION

Immune checkpoint inhibition (ICI) has proved successful for selected tumors and a subpopulation of patients. The human monoclonal IgG1 antibody (mAB) avelumab capable of mediating antibody-dependent cytotoxicity (ADCC) lysis is directed to programmed death ligand-1 (PD-L1) of tumor cells and is tested in trials aiming to improve ICI in combination with chemotherapeutic drugs.

AREAS COVERED

This article presents an overview of the current trials to enhance ICI regimens using avelumab in combination with chemotherapeutics, antiangiogenetic drugs, and immunomodulators. Predictive factors for this kind of immunochemotherapy are discussed.

EXPERT OPINION

Clinical data demonstrate that avelumab shows efficacy in cancer patients against Merkel cell carcinoma (MCC), renal cell carcinoma (RCC), and urothelial cancers as single agent. Furthermore, avelumab in combination with axitinib in RCC increases survival and exhibits activity in combination with docetaxel in urothelial carcinoma. However, several other immunochemotherapy trials for ovarian cancer, gastric cancer, and non-small lung cancer (NSCLC) showed no activity due to factors disfavoring administration of immunotherapy combos.

Immunotherapy in Renal Cell Carcinoma: The Future Is Now

Renal cell carcinoma is the third type of urologic cancer and has a poor prognosis with 30% of metastatic patients at diagnosis. The antiangiogenics and targeted immunotherapies led to treatment remodeling emphasizing the role of the tumour microenvironment. However, long-term responses are rare with a high rate of resistance. New strategies are emerging to improve the efficacy and the emerging drugs are under evaluation in ongoing trials. With the different treatment options, there is an urgent need to identify biomarkers in order to predict the efficacy of drugs and to better stratify patients. Owing to the limitations of programmed death-ligand 1 (PD-L1), the most studied immunohistochemistry biomarkers, and of the tumor mutational burden, the identification of more reliable markers is an unmet need. New technologies could help in this purpose.

Preclinical assessment of the VEGFR inhibitor axitinib as a therapeutic agent for epithelial ovarian cancer

Axitinib, small molecule tyrosine kinase inhibitor, demonstrates anti-cancer activity for various solid tumors. We investigated anti-cancer effect of axitinib in epithelial ovarian cancer (EOC). We treated EOC cells (A2780, HeyA8, RMG1, and HeyA8-MDR) with axitinib to evaluate its effects on cell viabilty, apoptosis and migration. Western blots were performed to assess VEGFR2, ERK, and AKT levels, and ELISA and FACS to evaluate apoptosis according to axitinib treatment. In addition, in vivo experiments in xenografts using A2780, RMG1, and HeyA8-MDR cell lines were performed. We repeated the experiment with patient-derived xenograft models (PDX) of EOC. Axitinib significantly inhibited cell survival and migration, and increased apoptosis in EOC cells. The expression of VEGFR2 and phosphorylation of AKT and ERK in A2780, RMG1, and HeyA8 were decreased with axitinib treatment in dose-dependent manner, but not in HeyA8-MDR. In in vivo experiments, axitinib significantly decreased tumor weight in xenograft models of drug-sensitive (A2780), and clear cell carcinoma (RMG1) and PDX models for platinum sensitive EOC compared to control, but was not effective in drug-resistant cell line (HeyA8-MDR) or heavily pretreated refractory PDX model. Axitinib showed significant anti-cancer effects in drug-sensitive or clear cell EOC cells via inhibition of VEGFR signals associated with cell proliferation, apoptosis and migration, but not in drug-resistant cells.

Targeting the PD-1/PD-L1 Pathway in Renal Cell Carcinoma

Renal cell carcinoma encompass distinct diseases with different pathologic features and distinct molecular pathways. Immune checkpoint inhibitors targeting the programmed death receptor ligand 1 (PD-L1)/programmed death receptor 1 (PD-1) pathway alone or in combination have greatly changed clinical management of metastatic renal cell carcinoma, now competing with antiangiogenic drugs in monotherapy for first-line treatment. However, long-term response rates are low, and biomarkers are needed to predict treatment response. Quantification of PD-L1 expression by immunohistochemistry was developed as a promising biomarker in clinical trials, but with many limitations (different antibodies, tumour heterogeneity, specimens, and different thresholds of positivity). Other biomarkers, including tumour mutational burden and molecular signatures, are also developed and discussed in this review.

Rectovaginal fistula during treatment with axitinib in a patient with renal cell carcinoma: a case report and review of the literature

Renal cell carcinoma (RCC) is one of the most frequent malignancies of the adults. Its incidence has been increasing steadily by 2-4% each year. Up to 30% of patients present with metastases at diagnosis. It is a highly vascularized cancer because of the hypoxia-induced factor stabilization as a consequence of von Hippel-Lindau inactivation. Hypoxia-induced factor accumulation leads to transactivation of molecules involved in angiogenesis including vascular endothelial growth factor (VEGF) and platelet-derived growth factor. Sunitinib is an oral tyrosine kinase inhibitor that interacts with several angiogenesis receptors including platelet-derived growth factor receptors and VEGF receptors, and is approved for the first-line treatment in metastatic RCC. In terms of tolerability, patients treated with sunitinib showed a higher incidence of diarrhea, vomiting, hypertension, hand-foot syndrome, and neutropenia, a safety profile consistent with what had been observed in earlier phase studies. Axitnib is a potent and selective tyrosine kinase inhibitor of VEGF receptors 1, 2, and 3, and is approved in the second-line setting for patients with metastatic RCC. The tolerability profile of axitinib is favorable. The most commonly reported treatment-related adverse events are diarrhea, hypertension, fatigue, nausea, and dysphonia. Bowel toxicity, especially pneumatosis intestinalis and bowel perforation, is very uncommon. In particular, the incidence of intestinal perforation or fistulae is not well known for sunitinib or axitinib. Here, for the first time, we report the incidence of rectovaginal fistula in a 57-year-old White woman, with RCC, following treatment with sunitinib and axitinib.

Axitinib in metastatic renal cell carcinoma: single center experience

Aim of the study

Due to the emergence of new therapeutic opportunities in the second-line treatment of metastatic renal cell carcinoma, the choice of the appropriate medication requires consideration. Making the selection one should take into account the likelihood of response, the probability of toxicity, properties of the drug and the clinical characteristics of the patient. Aim of the work was to confirm antitumor efficacy of axitinib in patients with metastatic clear-cell renal-cell carcinoma in the second line treatment remaining under the care of our institution. The primary objective was to determine antitumor activity, secondary – to evaluate progression free survival, safety of the treatment and to analyse clinical characteristics of treated population.

Results

Treatment records of 27 patients (9 females, 18 males) treated from October 2014 to the present (July 2016) were reviewed. The median duration of treatment which corresponds to the time to disease progression in observed population was 6 months (range: under 1 month – 16 months). 1 patient (3.7%) had got objective response (PR, partial remission). Clinical benefit rate (PR + SD (stable disease) was 66%. 9 patients (33.33%) experienced treatment toxicity only in the first degree of CTCAE (common toxicity criteria for adverse events), 11 patients (40.74%) presented the second degree toxicity and 5 patients (18.5%) – third degree. The most commonly reported treatment related adverse events were diarrhea (47%), fatigue (26%), hand-foot syndrome (26%), deterioration of blood pressure control (22.2%), abnormal liver function tests (18.5%), mucositis (11.1%). We observed 3 cases of unacceptable toxicity.

Conclusions

Axitinib confirms its effectiveness also in situation outside clinical trials, however, it is characterized by significant toxicity. Therefore, qualification for treatment should take into account the clinical patient characteristics. Effective diagnosis and treatment of side effects and dose optimization are the key skills of the attending physician.

Axitinib in the treatment of renal cell carcinoma: patient selection and perspectives

BACKGROUND

Axitinib is a next-generation, selective tyrosine kinase inhibitor targeting the vascular endothelial growth factor receptors. It is approved for the treatment of metastatic renal cell carcinoma (mRCC) based on a demonstrated progression-free survival advantage over sorafenib in the second-line treatment setting. However, given the variety of available targeted therapies for mRCC, appropriate patient selection for the available therapies remains a significant clinical challenge.

PURPOSE

This review summarizes the available evidence on the clinical, toxicity, and pharmacologic considerations for determining appropriate patient selection for axitinib therapy. In addition, it describes recent data on the use of predictive biomarkers to guide clinical management. This paper consists of material obtained via PubMed and Medline literature searches through October 2015.

CONCLUSION

Axitinib has a well-established role in the management of mRCC. Consistent clinical efficacy has been demonstrated across prognostic risk groups and prior therapeutic exposures. Although axitinib is generally well tolerated, appropriate toxicity management is critical to maximizing drug delivery and optimizing treatment outcomes. Although incident hypertension has been associated with improved clinical outcomes on axitinib, there are currently no validated clinical or genetic predictive biomarkers to guide patient selection.

Cost-effectiveness analysis of axitinib through a probabilistic decision model

INTRODUCTION

The Oncology field is characterised by a steady increase in demand and a consistent launching of innovative and expensive products. Therefore, cost-effectiveness analysis can contribute as a significant decision-making tool by elucidating the most economically efficient ways to satisfy compelling health needs.

AREAS COVERED

The scope of this study is to estimate the cost-effectiveness of axitinib versus sorafenib, for the second-line treatment of renal cell carcinoma. A literature review for evidence synthesis was performed and a probabilistic Markov Model was employed to simulate disease progression. This study will also assess Value of Information.

EXPERT OPINION

Compared to sorafenib, axitinib resulted in an incremental cost of 87,936 euro per quality adjusted life year. The probability of axitinib to being cost-effective at the willingness-to-pay threshold of 60,000 euro was 13%, while the corresponding probability of being cost-effective at the highest recommended willingness-to-pay threshold of 100,000 euro was 69.9%. Uncertainty was primarily attributed to the price of the product, the utility values, the progression-free survival and to a lesser degree to the overall survival. Axitinib can be considered as a cost-effective therapeutic option for second-line treatment of renal cell carcinoma.

Axitinib plasma pharmacokinetics and ethnic differences

Axitinib, a potent and selective tyrosine kinase inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, showed improved progression-free survival over sorafenib in patients previously treated for advanced renal cell carcinoma in the AXIS trial. Although a few studies had established the efficacy and safety of axitinib in Asian patients, additional evaluation was necessary to obtain regulatory approval in several Asian countries, especially in light of ethnic differences that are known to exist in genetic polymorphisms for metabolizing enzymes such as cytochrome P450 (CYP) 3A5, CYP2C19 and uridine diphosphate glucuronosyltransferase (UGT) 1A1, which are involved in axitinib metabolism. Axitinib plasma pharmacokinetics following single or multiple administration of oral axitinib in Asian (Japanese or Chinese) healthy subjects as well as Asian patients with advanced solid tumors was compared with that obtained in Caucasians. Upon review, the data demonstrated that axitinib can be characterized as not sensitive to ethnic factors based on its pharmacokinetic and pharmacodynamic properties. Axitinib exhibited similar pharmacokinetics in Asian and non-Asian subjects. A pooled population pharmacokinetic analysis indicated lack of a clinically meaningful effect of ethnicity on axitinib disposition. Therefore, dose adjustment for axitinib on the basis of ethnicity is not currently warranted.

Overall survival and final efficacy and safety results from a Japanese phase II study of axitinib in cytokine-refractory metastatic renal cell carcinoma

In an open-label, multicenter phase II study of Japanese patients with cytokine-refractory metastatic renal cell carcinoma, axitinib showed substantial antitumor activity with an acceptable safety profile. Here, we report overall survival and updated efficacy and safety results. Sixty-four Japanese patients with metastatic renal cell carcinoma following prior therapy with cytokines were treated with axitinib at a starting dose of 5 mg b.i.d. Following median treatment duration of 14.2 months, median overall survival was 37.3 months (95% CI, 28.6-49.9). The objective response rate, the primary endpoint of the study, was 51.6% (95% CI, 38.7-64.2); the median duration of response, 11.1 months (95% CI, 8.2-13.7); and the median progression-free survival was 11.0 months (95% CI, 9.2-12.0), assessed by the independent review committee. Common treatment-related all-grade adverse events were hypertension (88%), hand-foot syndrome (75%), diarrhea (66%), proteinuria (63%), fatigue (55%) and dysphonia (53%). In an exploratory analysis, median overall survival was found to be significantly longer in patients who had greater decreases in plasma levels of soluble vascular endothelial growth factor receptor-2 during the first cycle of treatment. In conclusion, the present study showed axitinib to be effective, and toxicities with long-term treatment were generally controllable with axitinib dose modification and/or standard medications in these Japanese patients. Some frequently reported adverse events warrant close monitoring and management. Changes in the plasma levels of soluble vascular endothelial growth factor receptor-2 may be used as a prognostic factor for overall survival in metastatic renal cell carcinoma following axitinib treatment. This study is registered at ClinicalTrial.gov (identifier NCT00569946).