Axitinib for the treatment of metastatic renal cell carcinoma: recommendations for therapy management to optimize outcomes

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.

Management of Immune-Related Adverse Events from Immune-Checkpoint Inhibitors in Advanced or Metastatic Renal Cell Carcinoma

Immune checkpoint inhibitors (ICI) are now, among other cancers, routinely used for the treatment of advanced or metastatic renal cell carcinoma (mRCC). In mRCC various combinations of ICIs and inhibitors of the vascular epidermal growth factor receptor tyrosine kinase (VEGFR-TKIs) as well as dual checkpoint inhibition (nivolumab + ipilimumab), the latter for patients with intermediate and poor risk according to IMDC only (international metastatic renal cell carcinoma database consortium), are now standard of care in the first line setting. Therefore, a profound understanding of immune-related adverse events (irAE) and the differential diagnosis of adverse reactions caused by other therapeutic agents in combination therapies is of paramount importance. Here we describe prevention, early diagnosis and clinical management of the most relevant irAE derived from ICI treatment focusing on the new VEGFR-TKI/ICI combinations.

Risk Stratification and Treatment Algorithm of Metastatic Renal Cell Carcinoma

Systemic therapy for metastatic renal cell carcinoma has continuously evolved over the last two decades. Significant improvements in overall survival and quality of life of patients with advanced disease have been observed. With the approval of combination therapies with PD(L)-1 immune checkpoint inhibitors (ICI) as first-line therapy in 2019, the previous standard VEGFR-TKI monotherapy has been replaced as the primary treatment option. In addition to immunotherapy with nivolumab and ipilimumab, three VEGFR-TKI/ICI combinations are now approved. Therapy selection should be preceded by risk stratification using defined criteria from the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC). Clinical parameters, as well as detailed patient counseling on differences in the efficacy profile (response rate, long-term progression-free survival), potential side effects, and impact on quality of life, are of key importance in the individual treatment decision.

[Side effects of immune checkpoint inhibitor treatment of urological tumors]

Immune checkpoint inhibitors (ICI) are currently routinely used for the treatment of advanced or metastatic urothelial and renal cell carcinomas. Furthermore, several clinical trials are currently investigating their role in adjuvant and neoadjuvant settings as well as in high-risk non-muscle-invasive bladder cancer. As a result, urologists are increasingly confronted with patients who are currently receiving, have recently received or will receive ICI treatment. Care is often interdisciplinary, with urologists playing a central role. Therefore, a profound understanding of immune-mediated adverse events and their differential diagnoses with respect to side effects of other medications in combination treatment are therefore extremely important. This article focusses on the prevention, early diagnosis and clinical management of the most relevant immune-related side effects derived from the new VEGFR-TKI/ICI combinations.

Isolated temporalis muscle metastasis of renal cell carcinoma

Isolated head and neck metastasis of renal cell carcinoma (RCC) is relatively rare and metastasis to the temple area is very rare. Here, we present the case of a 51-year-old man who was diagnosed with RCC 2 years earlier and had a contralateral metastatic temple area lesion. The patient who was diagnosed with renal cell cancer and underwent a nephrectomy 2 years ago was referred to the plastic surgery department for a temple mass on the contralateral side. In the operative field, the mass was located in the temporalis muscle with a red-to-purple protruding shape. Biopsy of the mass revealed a metastatic RCC lesion. Computed tomography imaging showed a lobulated, contoured enhancing lesion. Positron emission tomography/computed tomography imaging showed high-fluorodeoxyglucose uptake in the right temporalis muscle. The patient underwent wide excision of the metastatic RCC including the temporalis muscle at the plastic surgery department. Skeletal muscle metastasis of head and neck lesions is extremely rare in RCC. Isolated contralateral temporalis muscle metastasis in RCC has not been previously reported in the literature. If a patient has a history of malignant cancer, plastic surgeons should always consider metastatic lesions of head and neck tumors. Because of its high metastatic ability and poor prognosis, it is very important to keep this case in mind.

[Risk-adapted therapy for metastatic renal cell carcinoma]

Current pivotal phase 3 studies have permanently changed the first-line treatment landscape in metastatic renal cell carcinoma. These studies showed that immune checkpoint combinations were more efficacious than sunitinib, a previous standard of care. Nivolumab plus ipilimumab is characterized by a survival advantage, a high rate of complete response and durable remission in patients with intermediate and unfavorable prognosis. Despite frequent immune-mediated side effects, fewer symptoms and a better quality of life were observed compared to sunitinib. Pembrolizumab or avelumab plus axitinib were characterized by an improved PFS and a high response rate with a low rate of intrinsic resistance. In addition, a significant survival benefit was achieved with pembrolizumab plus axitinib. The side effect profile is driven by the "chronic" toxicity of axitinib, but there is additional risk of immune-mediated side effects of the PD-1/PD-L1 immune checkpoint inhibitors. The quality-of-life data published so far do not suggest any improvement compared to the previous standard sunitinib. The PD-1/PD-L1 immune-check-point inhibitors thus form the "backbone" of the first-line therapy of metastatic renal cell carcinoma. Monotherapy with VEGFR-TKI remains an option in cases with contraindications and possibly for subgroups with favorable prognosis.

New First Line Treatment Options of Clear Cell Renal Cell Cancer Patients with PD-1 or PD-L1 Immune-Checkpoint Inhibitor-Based Combination Therapies

In metastatic renal cell carcinoma (mRCC) the PD-1 immune-checkpoint inhibitor (ICI) Nivolumab became a standard second line treatment option in 2015 based on a significant improvement of overall survival compared to Everolimus. Current pivotal phase 3 studies showed that PD-1 ICI-based combinations were more efficacious than the VEGFR-TKI Sunitinib, a previous standard of care, leading to approval of three new regimens as guideline-recommended first-line treatment. Nivolumab plus Ipilimumab is characterized by a survival advantage, a high rate of complete response and durable remissions in intermediate and poor prognosis patients. Despite frequent immune-mediated side effects, fewer symptoms and a better quality of life were observed compared to Sunitinib. Pembrolizumab or Avelumab plus Axitinib were characterized by an improved progression-free-survival and a high response rate with a low rate of intrinsic resistance. In addition, Pembrolizumab plus Axitinib reached a significant survival benefit. The side effect profile is driven by the chronic toxicity of Axitinib, but there is additional risk of immune-mediated side effects of the PD-1/PD-L1 ICIs. The quality of life data published so far do not suggest any improvement regarding patient-reported outcomes compared to the previous standard Sunitinib. The PD-1/PD-L1 ICIs thus form the backbone of the first-line therapy of mRCC.

Individualized dosing with axitinib: rationale and practical guidance

Axitinib is a potent, selective, vascular endothelial growth factor receptor inhibitor with demonstrated efficacy as second-line treatment for metastatic renal cell carcinoma. Analyses of axitinib drug exposures have demonstrated high interpatient variability in patients receiving the 5 mg twice-daily (b.i.d.) starting dose. Clinical criteria can be used to assess whether individual patients may benefit further from dose modifications, based on their safety and tolerability data. This review provides practical guidance on the 'flexible dosing' method, to help physicians identify who would benefit from dose escalations, dose reductions or continuation with manageable toxicity at the 5 mg b.i.d. dose. This flexible approach allows patients to achieve the best possible outcomes without compromising safety.

Axitinib in metastatic renal cell carcinoma: beyond the second-line setting

Treatment options for advanced and metastatic renal cell carcinoma have advanced considerably in the past decade with the approval of several targeted agents, including axitinib. Axitinib is a potent and selective inhibitor of VEGFRs 1-3, and is well established as second-line treatment. This article summarizes factors to be considered when administering axitinib, such as individualized dose titration and axitinib-associated adverse events, in order to retain patients longer on treatment, which would likely lead to improved efficacy outcomes. In addition, potential clinical perspectives for axitinib beyond the second-line setting, including its role in the first-line setting, sequential therapy, neoadjuvant and adjuvant therapies, and combination therapy with immunotherapy, in particular, immune checkpoint inhibitors, are discussed.

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.

Hematogenous Renal Cell Carcinoma Metastasis in the Postoperative Temporal Bone

Metastatic renal cell carcinoma (RCC) involving the temporal bone is a rare entity. It is usually asymptomatic and misdiagnosis as acute otitis media, mastoiditis, and Ramsay-Hunt syndrome in early onset is not uncommon. We report a case of RCC metastasis to the postoperative temporal bone in the middle of molecular targeted therapy. A 60-year-old man presented left facial palsy with severe retro-auricular pain and he also underwent left middle ear surgery for cholesteatoma more than 30 years before and had been aware of discontinuous otorrhea; therefore, initially we speculated that facial palsy was derived from recurrent cholesteatoma or Ramsay-Hunt syndrome. Exploratory tympanotomy revealed RCC metastasis and postoperative MR indicated hematogenous metastasis. To the best of our knowledge, no report was obtained on temporal bone metastasis in the middle of chemotherapy or hematogenous metastasis in the postoperative middle ear. Metastasis in the temporal bone is still a possible pathological condition despite the development of present cancer therapy. Besides, this case indicates that hematogenous metastasis can occur in the postoperative state of the temporal bone.

[Side effect management of tyrosine kinase inhibitors in urology : Gastrointestinal side effects]

For approximately one decade, tyrosinkinase inhibitors (TKIs, smart drugs) have dramatically changed and improved the treatment of patients suffering from metastasized renal cell carcinoma. However, the different drugs have substantial side effects. Especially gastrointestinal symptoms may be problematic for patients. These side effects represent a challenge for the physician. On the one hand, dosage modifications and treatment interruption should be avoided to minimize the risk for progression. On the other hand, only mild side effects are tolerable for the patient. Based on a literature review, a clear overview of the incidence of possible side effects for the drugs axitinib, cabozantinib, pazopanib, sorafenib, and sunitinib is provided. Furthermore, we give a practical guide on how to prevent and treat the different gastrointestinal side effects. Finally, it is pointed out when dosage modifications or interruption of treatment are necessary and how to expeditiously re-escalate the treatment after mitigation of side effects.

[Side effect management of tyrosine kinase inhibitors in urology : Fatigue and hypothyroidism]

Not only has the use of tyrosine kinase inhibitors (TKI) for the treatment of metastatic renal cell carcinomas (mRCC) changed the therapeutic options for this disease significantly, but with the occurrence of typical side effects this therapy also poses a challenge for the treating physician. Fatigue und hypothyroidism are two common side effects of TKI therapy that can often appear simultaneously. By reducing the patients' quality of life these side effects often lead to a discontinuation of therapy. With this review we want to give the treating physician an overview of the classification and the specific treatment of TKI-induced fatigue and hypothyroidism in order to maximize patients' compliance and the therapeutic efficacy of TKI therapy.

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.

Targeted treatments in advanced renal cell carcinoma: focus on axitinib

Antiangiogenesis options have evolved rapidly in the last few years, with an increasing number of agents currently approved by the US Food and Drug Administration and European Medicines Agency. Angiogenesis inhibitors have been shown to be very effective for the treatment of metastatic renal cancer cell. Axitinib is a third-generation inhibitor of vascular endothelial growth factor receptor and is currently being developed for the treatment of various malignancies. The pharmacokinetic properties of axitinib may have a selective therapeutic effect, with minimal adverse reactions and enhanced safety. In a large Phase III study of previously treated patients with metastatic renal cell carcinoma, axitinib achieved a longer progression-free survival than sorafenib with an acceptable safety profile and good quality of life. This review focuses on the pharmacology, pharmacokinetics, and clinical activity of axitinib in the current treatment of renal cell carcinoma. The role of axitinib in the adjuvant and/or neoadjuvant setting needs to be evaluated in further clinical trials.