Does axitinib (AG-01376) have a future role in metastatic renal cell carcinoma and other malignancies?

Recent advances of anti-angiogenic inhibitors targeting VEGF/VEGFR axis

Vascular endothelial growth factors (VEGF), Vascular endothelial growth factor receptors (VEGFR) and their downstream signaling pathways are promising targets in anti-angiogenic therapy. They constitute a crucial system to regulate physiological and pathological angiogenesis. In the last 20 years, many anti-angiogenic drugs have been developed based on VEGF/VEGFR system to treat diverse cancers and retinopathies, and new drugs with improved properties continue to emerge at a fast rate. They consist of different molecular structures and characteristics, which enable them to inhibit the interaction of VEGF/VEGFR, to inhibit the activity of VEGFR tyrosine kinase (TK), or to inhibit VEGFR downstream signaling. In this paper, we reviewed the development of marketed anti-angiogenic drugs involved in the VEGF/VEGFR axis, as well as some important drug candidates in clinical trials. We discuss their mode of action, their clinical benefits, and the current challenges that will need to be addressed by the next-generation of anti-angiogenic drugs. We focus on the molecular structures and characteristics of each drug, including those approved only in China.

An Overview of Systemic Targeted Therapy in Renal Cell Carcinoma, with a Focus on Metastatic Renal Cell Carcinoma and Brain Metastases

The most commonly diagnosed malignancy of the urinary system is represented by renal cell carcinoma. Various subvariants of RCC were described, with a clear-cell type prevailing in about 85% of all RCC tumors. Patients with metastases from renal cell carcinoma did not have many effective therapies until the end of the 1980s, as long as hormonal therapy and chemotherapy were the only options available. The outcomes were unsatisfactory due to the poor effectiveness of the available therapeutic options, but then interferon-alpha and interleukin-2 showed treatment effectiveness, providing benefits but only for less than half of the patients. However, it was not until 2004 that targeted therapies emerged, prolonging the survival rate. Currently, new technologies and strategies are being developed to improve the actual efficacy of available treatments and their prognostic aspects. This article summarizes the mechanisms of action, importance, benefits, adverse events of special interest, and efficacy of immunotherapy in metastatic renal cell carcinoma, with a focus on brain metastases.

Avelumab and axitinib in the treatment of renal cell carcinoma: safety and efficacy

Introduction: The incidence of advanced renal cell carcinoma (RCC) is increasing. Over the last 10 years targeted therapies have led to improved efficacy outcomes for renal carcinoma, including longer survival. However, the majority of patients develop disease progression within a year of initiation of first-line therapy. Recently a number of new regimens have been investigated including the combination of immune checkpoint inhibitors with VEGF inhibitors.Areas covered: In this review, we assess the efficacy and safety of avelumab/axitinib in treatment-naïve patients with metastatic RCC and compare this combination to other current and emerging treatment regimens. In the Javelin 101 phase III registration trial, avelumab/axitinib demonstrated superior response rates and progression-free survival compared to sunitinib. However, after follow-up of 11.6 months, there was no significant difference in overall survival (OS). Avelumab/axitinib showed a tolerable safety profile. Adverse events were manageable and were in line with expected toxicities from the single agents.Expert Opinion: Avelumab/axitinib has shown impressive efficacy and a tolerable safety profile in metastatic RCC. The future role of this treatment combination in the rapidly evolving landscape of novel combinations in this disease will have to be defined.

Clinical pharmacology of axitinib

Axitinib is a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors 1, 2, and 3 that is approved in the US and several other countries for treatment of patients with advanced renal cell carcinoma after failure of one prior systemic therapy. The recommended clinical starting dose of axitinib is 5 mg twice daily, taken with or without food. Dose increase (up to a maximum of 10 mg twice daily) or reduction is permitted based on individual tolerability. Axitinib pharmacokinetics are dose-proportional within 1-20 mg twice daily, which includes the clinical dose range. Axitinib has a short effective plasma half-life (range 2.5-6.1 h), and the plasma accumulation of axitinib is in agreement with what is expected based on the plasma half-life of the drug. Axitinib is absorbed relatively rapidly, reaching maximum observed plasma concentrations (C max) within 4 h of oral administration. The mean absolute bioavailability of axitinib is 58 %. Axitinib is highly (>99 %) bound to human plasma proteins with preferential binding to albumin and moderate binding to α1-acid glycoprotein. In patients with advanced renal cell carcinoma, at the 5-mg twice-daily dose in the fed state, the geometric mean (% coefficient of variation) C max and area under the plasma concentration-time curve (AUC) from time 0-24 h (AUC24) were 27.8 ng/mL (79 %) and 265 ng·h/mL (77 %), respectively. Axitinib is metabolized primarily in the liver by cytochrome P450 (CYP) 3A4/5 and, to a lesser extent (<10 % each), by CYP1A2, CYP2C19, and uridine diphosphate glucuronosyltransferase (UGT) 1A1. The two major human plasma metabolites, M12 (sulfoxide product) and M7 (glucuronide product), are considered pharmacologically inactive. Axitinib is eliminated via hepatobiliary excretion with negligible urinary excretion. Although mild hepatic impairment does not affect axitinib plasma exposures compared with subjects with normal hepatic function, there was a 2-fold increase in AUC from time zero to infinity (AUC∞) following a single 5-mg dose in subjects with moderate hepatic impairment. In the presence of ketoconazole, a strong CYP3A4/5 inhibitor, axitinib C max and AUC∞ increased by 1.5- and 2-fold, respectively, whereas co-administration of rifampin, a strong CYP3A4/5 inducer, resulted in a 71 and 79 % decrease in the C max and AUC∞, respectively. Axitinib does not inhibit CYP3A4/5, CYP1A2, CYP2C8, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, or UGT1A1 at concentrations obtained with the clinical doses and is not expected to have major interactions with drugs that are metabolized by these enzymes. Axitinib is an inhibitor of the efflux transporter P-glycoprotein (P-gp) in vitro, but is not expected to inhibit P-gp at therapeutic plasma concentrations. A two-compartment population pharmacokinetic model with first-order absorption and lag time was used to describe axitinib pharmacokinetics. No clinically relevant effects of age, sex, body weight, race, renal function, UGT1A1 genotype, or CYP2C19 inferred phenotype on the clearance of axitinib were identified.

Presurgical therapy with axitinib for advanced renal cell carcinoma: a case report

Background

Targeted therapy with tyrosine kinase inhibitors has been shown to reduce tumor volumes and prolong the survival of patients with metastatic renal cell carcinoma. Tyrosine kinase inhibitors, particularly sunitinib, have recently been used in neoadjuvant and presurgical settings. Axitinib is a promising second-line therapy option for advanced or metastatic renal cell carcinoma. Herein, we report a patient with advanced renal cell carcinoma who received presurgical treatment with axitinib.

Case presentation

A 73-year-old man was transported by ambulance to a community hospital with chief complaints of high fever and a gait disorder. Computed tomography screening revealed a hypervascular tumor (size, 9 × 8.5 cm) in the lower pole of the left kidney. Upon admission to our hospital, his general condition was poor and his performance status was judged as 3, based on the Eastern Cooperative Oncology Group performance status criteria. After biopsy for the renal tumor, he received 5 mg of axitinib twice daily for 3 months. No serious adverse events were reported during this treatment. The tumor diameter shrank by 56%. Left radical nephrectomy was performed, and there were no intraoperative or postoperative complications. Pathological examination indicated a pT3aN0M0, Furman grade 3, clear cell renal cell carcinoma with necrosis, hyaline degeneration, and hemosiderosis. The patient was asymptomatic and disease-free at 1 year post-diagnosis.

Conclusion

This case study demonstrate that presurgical therapy with axitinib is feasible and might have several potential advantages for patients with advanced renal cell carcinoma.

Efficacy and safety of axitinib versus sorafenib in metastatic renal cell carcinoma: subgroup analysis of Japanese patients from the global randomized Phase 3 AXIS trial

OBJECTIVE

Axitinib is a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors 1, 2 and 3. The efficacy and safety of axitinib in Japanese patients with metastatic renal cell carcinoma were evaluated.

METHODS

A subgroup analysis was conducted in Japanese patients enrolled in the randomized Phase III trial of axitinib versus sorafenib after failure of one prior systemic therapy for metastatic renal cell carcinoma.

RESULTS

Twenty-five (of 361) and 29 (of 362) patients randomized to the axitinib and sorafenib arms, respectively, were Japanese and included in this analysis. Median progression-free survival in Japanese patients was 12.1 months (95% confidence interval 8.6 to not estimable) for axitinib and 4.9 months (95% confidence interval 2.8-6.6) for sorafenib (hazard ratio 0.390; 95% confidence interval 0.130-1.173; stratified one-sided P = 0.0401). The objective response rate was 52.0% for axitinib and 3.4% for sorafenib (P = 0.0001). The common all-causality adverse events (all grades) in Japanese patients were dysphonia (68%), hypertension (64%), hand-foot syndrome (64%) and diarrhea (56%) for axitinib, and hand-foot syndrome (86%), hypertension (62%) and diarrhea (52%) for sorafenib. The safety profiles of axitinib and sorafenib in Japanese patients were generally similar to those observed in the overall population, with the exceptions of higher incidences of hypertension, dysphonia, hand-foot syndrome, hypothyroidism and stomatitis.

CONCLUSIONS

Axitinib is efficacious and well tolerated in Japanese patients with previously treated metastatic renal cell carcinoma, consistent with the results in the overall population, providing a new targeted therapy for these Japanese patients.

Vascular endothelial growth factor-targeted therapy for the treatment of renal cell carcinoma

Vascular endothelial growth factor (VEGF)-targeted agents have rapidly been adopted into standard-of-care treatment for renal cell carcinoma (RCC). However, a substantial proportion of patients fail to respond to these agents or experience considerable toxicity. This article reviews the benefits and limitations of currently approved anti-VEGF agents in advanced and metastatic RCC, and the role for newly approved and developmental agents. Sunitinib and bevacizumab plus interferon (IFN)-α have demonstrated significant improvements in progression-free survival (PFS) compared with IFNα in treatment-naïve patients. A PFS benefit has also been shown with sorafenib versus placebo second-line to cytokine therapy. However, no anti-VEGF agent has shown a significant overall survival benefit. Anti-VEGF therapy is generally well tolerated, but a number of key adverse events, including dermatological, mucosal and constitutional symptoms, may limit treatment compliance and success. Pazopanib is a recently approved, highly selective anti-VEGF agent that shows benefit in PFS over IFNα, with low rates of treatment-related adverse events and, therefore, may be better tolerated than other currently approved agents. The advent of VEGF-targeted therapy for RCC has greatly improved prospects for patients with advanced or metastatic disease, but more efficacious agents are required that demonstrate a clear survival advantage. Ongoing trials evaluating novel anti-VEGF therapies could establish whether the increased potency and selectivity of these agents results in improved efficacy and tolerability in RCC patients, further improving their prognosis.

Novelties of treatment in advanced renal-cell cancer

Therapeutic options in advanced renal-cell cancer have expanded through better understanding of molecular patho­logy and development of novel targeted therapeutics. Vascular endothelial growth factor, the key ligand of angioge­nesis, has a major role in the progression of vascularized kidney tumors and this is the target molecule of modern medications. The three types of the mechanism of action of current therapies are: monoclonal antibodies blocking directly vascular endothelial growth factor ligand (bevacizumab), tyrosine-kinase inhibitors blocking vascular endothelial growth factor receptors (sorafenib, sunitinib, pazopanib) and inhibitors of the intracellular mTOR-kinase (temsirolimus, everolimus). Based on randomized studies, sunitinib, pazopanib or interferon-α-bevacizumab combination should be the first-line therapy in patients with good/moderate prognosis, while temsirolimus is recommended in those with poor prognosis. Following an ineffective cytokine therapy sorafenib or pazopanib are the se­cond-line treatment. In case of tyrosine-kinase inhibitor inefficacy, current evidence favors everolimus. Patient outcome can further be improved by the involvement of more modern and effective target products. Orv. Hetil., 2011, 152, 655–662.