Influence of two anti-tumor drugs, pazopanib, and axitinib, on the development and thyroid-axis of zebrafish (Danio rerio) embryos/larvae

Introduction

In recent years, the potential toxicities of different pharmaceuticals toward the thyroid system have received increasing attention. In this study, we aim to evaluate the toxic effects of pazopanib and axitinib, two anti-tumor drugs with widespread clinical use, on thyroid function in the zebrafish model.

Methods

We measured levels of thyroid-related hormones using the commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. Whole-mount in situ hybridization (WISH) analysis was employed to detect target gene expression changes. Morphology of the thyroid were evaluated by using transgenic Tg (tg: EGFP) fish line under a confocal microscope. The relative mRNA expression of key genes was verified through quantitative real-time polymerase chain reaction (RT‒qPCR). The size and number of the follicles was quantified whereby Hematoxylin-Eosin (H & E) staining under a light microscope.

Results

The results revealed that fertilized zebrafish embryos were incubated in pazopanib or axitinib for 96 hours, development and survival were significantly affected, which was accompanied by significant disturbances in thyroid endocrine system (e.g., increased thyroid-stimulating hormone (TSH) content and decreased triiodothyronine (T3) and thyroxine (T4) content, as well as transcription changes of genes associated with the hypothalamus-pituitary-thyroid (HPT) axis. Moreover, based on whole-mount in situ hybridization staining of tg and histopathological examination of zebrafish embryos treated with pazopanib and axitinib, we observed a significantly abnormal development of thyroid follicles in the Tg (tg: EGFP) zebrafish transgenic line.

Conclusion

Collectively, these findings indicate that pazopanib and axitinib may have toxic effects on thyroid development and function, at least partially, by influencing the regulation of the HPT axis. Thus, we believe that the potential thyroid toxicities of pazopanib and axitinib in their clinical applications should receive greater attention.

Thyroid dysfunction with atezolizumab plus bevacizumab after lenvatinib in hepatocellular carcinoma: A case series

Atezolizumab plus bevacizumab is the recommended first-line treatment for unresectable hepatocellular carcinoma, based on guidelines from the Barcelona Clinic Liver Cancer prognosis and treatment strategy. However, atezolizumab plus bevacizumab may be used after administration of lenvatinib. Here, we present four patients who developed thyroid dysfunction after second-line treatment with atezolizumab plus bevacizumab, but not after lenvatinib alone. The patients were treated with lenvatinib and/or atezolizumab plus bevacizumab for unresectable hepatocellular carcinoma at Showa University Northern Yokohama Hospital. Of patients treated with only lenvatinib or atezolizumab plus bevacizumab, 2/18 (11%) and 4/15 (27%) developed thyroid dysfunction, respectively. All four patients treated with atezolizumab plus bevacizumab after lenvatinib developed hypothyroidism after 2–14 doses of atezolizumab plus bevacizumab. Three patients developed Grade 2 symptoms and were treated with levothyroxine sodium. In patients with hepatocellular carcinoma, the incidence of thyroid dysfunction may be higher among patients treated with atezolizumab plus bevacizumab after lenvatinib than those treated with lenvatinib or atezolizumab plus bevacizumab alone.

The variants in PTPRB, TRAF3IP3, and DISC1 genes were associated with Graves' disease in the Chinese population

Previously, a case series study was conducted on our part in which 5 patients with Graves' disease (GD) were collected from a 3-generation family to screen for susceptibility genes responsible for GD. The single nucleotide variants of Microtubule-associated protein 7 domain containing 2 c. 452C > T, p. Ala151Val, Solute carrier family 1 member 7 c. 1204C > T, p. Arg402Cys, tumor necrosis factor receptor-associated factor 3 interacting protein 3 (TRAF3IP3) c. 209A > T, p. Asn70Ile, protein tyrosine phosphatase receptor type B (PTPRB) c. 3472A > G, p. Ser1158Gly, Phosphoinositide-3-kinase regulatory subunit 3 c. 121C > T, p. Pro41Ser, disrupted in schizophrenia 1 (DISC1), c. 1591G > C p. Gly531Arg were associated with the familial GD. We then further confirmed these variants and investigated whether other mutations render susceptibility to GD. The case-control study collected patients with sporadic GD or no GD family history. A snapshot program was used for genotyping the selected SNPs in 235 GD patients (GD group 1) and 284 healthy patients (control group). Furthermore, another 184 GD patients were recruited (GD group 2) to sequence the specified exons of these genes. The sequenced data was compared with Chinese Millionome Database (CMDB). Several variants of PTPRB, phosphoinositide-3-kinase regulatory subunit 3, TRAF3IP3, and DISC1 were found in GD group 2 but not in CMDB. Moreover, the allele frequency of SNP rs2076150 (TRAF3IP3) and rs2492367 DISC1 in GD group 2 was significantly higher than that of in CMDB (all P < .05). When the control group or CMDB was set as a reference group, a significantly higher frequency in alter allele C of SNP rs186466118 PTPRB was observed in GD group 1 and GD group (constituted by GD group 1 and GD group 2). Equally importantly, there was a correlation between the allele C of SNP rs186466118 and the increased risk of GD susceptibility (all P < .05). PTPRB, TRAF3IP3, and DISC1 may be susceptibility genes for GD, and more variants of PTPRB, TRAF3IP3, and DISC1 were found in GD patients.

Autoimmune Myasthenia, Primary Adrenal Insufficiency, and Progressive Hypothyroidism Due to Pembrolizumab and Axitinib Combination Regimen

Immune checkpoint inhibitors (ICI) and tyrosine kinase inhibitors (TKI) have been among the increasingly used antineoplastic agents for advanced cancers including renal cell carcinoma (RCC). Although these antineoplastic agents have broad range of efficacy, rare adverse events - mild and fatal, acute and chronic, immune and non-immune mediated - have been reported. We report a case of a 73-year-old Caucasian male patient with stage IV right-sided clear cell RCC who was treated with a pembrolizumab-axitinib combination regimen and suffered life-threatening, acute onset immune-related myasthenia gravis (MG), subsequently progressive hypothyroidism, and primary adrenal insufficiency.

Effects of tyrosine kinase inhibitors on thyroid function and thyroid hormone metabolism

The increasing knowledge of the molecular mechanisms in the cell signaling pathways of malignant cells, has recently led to the discovery of several tyrosine kinases (TKs), mainly TK receptors (TKR), which play a major role in the pathogenesis of many types of cancer. These receptors, physiologically involved in cell growth and angiogenesis, may harbor mutations or be overexpressed in malignant cells, and represent a target for anticancer therapy. Indeed, several therapeutic agents targeting specific altered pathways such as RET, BRAF, RAS, EGFR and VEGFR, have been identified. Tyrosine kinase inhibitors (TKIs) affect TK dependent oncogenic pathways by competing with ATP binding sites of the TK domain, thus blocking the activity of the enzyme, and thereby inhibiting the growth and spread of several cancers. Although the therapeutic action may be very effective, these molecules, due to their mechanism of multitargeted inhibition, may produce adverse events involving several biological systems. Both hypothyroidism and thyrotoxicosis have been reported during treatment with TKI, as well as an effect on the activity of enzymes involved in thyroid hormone metabolism. The pathogenic mechanisms leading to thyroid dysfunction and changes in serum thyroid function tests occurring in patients on TKI are reviewed and discussed in this manuscript.

Current evidence on thyroid related adverse events in patients treated with protein tyrosine kinase inhibitors

Tyrosine kinase inhibitors (TKI) are gaining more ground in oncology, they are widely used in the treatment of multiple types of cancers; still important side effects limit their efficacy. The aim of this study is to evaluate the existing medical literature on TKI induced thyroid dysfunction, to assess the adverse effects of targeted therapy on thyroid function in oncological patients and to evaluate the effects of thyroid dysfunction on disease prognosis. We included in this review 22 original studies published between 2010 and 2019. We used the PubMed database to search for articles upon the development of hypothyroidism and hyperthyroidism in TKI treated patients. After a careful review of the existing literature, we selected the relevant studies and cross-referenced the bibliography of each paper. A number of 1641 patients were included in our review. We found that thyroid dysfunction is not a rare side effect of TKI treatment, approximately 33% of the total number of patients presented clinical hypothyroidism. We also studied the necessity of thyroid hormone substitution treatment, a quarter of evaluated patients needed substitution therapy. Multiple studies showed that there is a link between a patient developing hypothyroidism and progression free survival. Hypothyroidism is a frequent side effect of TKI treatment, which affects the quality of life, sometimes even determines physicians to stop TKI treatment altogether. Our study underlines the necessity of TSH baseline testing and monitoring in patients treated with TKI agents.

Tyrosine kinase inhibitors and immune checkpoint inhibitors-induced thyroid disorders

Recently, tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICPIs) have emerged as new classes of anticancer therapies. Although generally considered less toxic than cytotoxic chemotherapy, these new drugs can cause significant unanticipated side effects including thyroid dysfunction. This review provides a literature assessment of thyroid dysfunctions induced by TKI and ICPIs. We intend to define for these two classes the frequency of thyroid involvement, the potential mechanisms that result in this toxicity, the clinical-biological impact and the therapeutic management. Detection of thyroid dysfunction requires monitoring of TSH, in combination with free T4 if needed and, depending on the clinical impact and the kinetics of biological abnormalities, starting symptomatic treatment of hyperthyroidism and/or correcting hypothyroidism.

Sorafenib-Induced Changes in Thyroid Hormone Levels in Patients Treated for Hepatocellular Carcinoma

CONTEXT

The pathogenesis of tyrosine kinase inhibitor-induced thyroid hormone (TH) alterations are still a matter of debate.

OBJECTIVE

The objective of this study was to determine the effects of sorafenib on TH levels in patients with hepatocellular carcinoma (HCC) and to evaluate possible mechanisms.

DESIGN

We performed a prospective cohort study between 2009 and 2016.

SETTING

This study was conducted at a tertiary referral center.

PATIENTS

This study included 57 consecutive patients with HCC who were treated with sorafenib.

MAIN OUTCOME MEASURE

Thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels were measured every 6 weeks, and extensive thyroid function tests (TFTs) were measured before treatment (t0), after 6 weeks (t6), and at the end of therapy. The effect of sorafenib on TH transport by monocarboxylate transporter (MCT)8 or MCT10 was tested in transfected COS1 cells.

RESULTS

Four patients (7%) developed thyroiditis. Among the other patients, 30% had elevation of TSH or FT4 above the normal range. Overall, between t0 and t6, mean TSH increased from 1.28 to 1.57 mU/L (P < 0.001) and mean FT4 from 18.4 to 21.2 pmol/L (P < 0.001). Simultaneously, the serum triiodothyronine (T3)/reverse triiodothyronine ratio and the (T3/thyroxine) ×100 ratio decreased. Sorafenib decreased cellular T3 uptake by MCT8 and to a lesser extent by MCT10.

CONCLUSIONS

These in vivo data suggest that sorafenib affects TFTs on multiple levels. Our in vitro experiments suggest a possible role of sorafenib-induced inhibition of T3 transport into the cell by MCT8 and MCT10.

Case of pazopanib-induced thyrotoxicosis in a patient with metastatic renal cell carcinoma

Pazopanib is an oral multi-targeted tyrosine kinase inhibitor and has been approved for metastatic renal cell carcinoma and advanced soft tissue sarcoma. To the best of our knowledge, pazopanib-induced thyrotoxicosis has never been reported. The patient was a 68-year-old woman with renal cell carcinoma and multiple metastases. Three weeks after pazopanib medication, she felt fatigue and palpitation. She was admitted because of liver chemistry abnormalities [AST 723 IU/L (normal range 7-37 IU/L); ALT 953 IU/L (normal range 3-33 IU/L)]. She showed abnormal thyroid function tests with suppressed TSH of 0.0585 μIU/mL, and elevated fT4 of 3.38 ng/dL. Ten days after admission, tachycardia appeared and fT3 and fT4 were elevated (fT3 27.85 pg/mL, fT4 2.58 ng/dL), and TSH was suppressed (0.0414 μIU/mL). Her thyroid ultrasound showed hypervascular thyroid gland without nodules. We diagnosed pazopanib-induced thyrotoxicosis. Because the fT3/fT4 ratio was high (10.8) and the thyroid was enlarged, we thought that her thyrotoxicosis might get worse. She was treated with medication of beta-blockers, hydrocortisone, and potassium iodide and thyrotoxicosis resolved. This report highlights that Pazopanib could induce thyrotoxicosis, and therefore, periodic surveillance of thyroid function is required during pazopanib therapy.

Auto-immune thyroid dysfunction induced by tyrosine kinase inhibitors in a patient with recurrent chordoma

Background

While hypothyroidism has frequently been reported with the use of TKIs, the thyroid-stimulating hormone (TSH) suppressing effect of TKIs is rare, except for thyroiditis. We describe a case with progressive recurrent chordoma who initially became hyperthyroid in a context of autoimmunity under sorafenib treatment and later under imatinib treatment.

Case presentation

A 57-year-old man with lumbar chordoma began daily treatment of 800 mg sorafenib. He did not have any other medication or recent iodinated-contrast exposure and his family history was negative for thyroid and autoimmune disease. There was no history of neck pain, irradiation or trauma, recent fever or viral illness. Pre-treatment TSH was normal. After 18 weeks of treatment, the patient presented hyperthyroidism with positive anti-TSH receptor antibodies. More surprisingly, Graves’ disease recurred during treatment with imatinib.

Conclusion

The fact that Graves’ disease occurred after two different TKIs suggests that it could be a rare but important class effect. Anti-TSH receptor antibodies should be systematically measured when TSH decreases in order to avoid the erroneous diagnosis of transient hyperthyroidism due to thyroiditis.

Safety of available treatment options for renal cell carcinoma

INTRODUCTION

For many years, cytokines (high-dose interleukin (IL)-2 and interferon (IFN)) have been the unique available treatment options for metastatic renal cell carcinoma (mRCC) and they provided durable but modest responses at the cost of significant toxicities. To date, targeted therapies have replaced cytokine therapy due to higher response rates and more favorable toxicity profiles. The major classes of targeted therapy for mRCC include tyrosine kinase inhibitors, monoclonal antibody against vascular endothelial grow factors and inhibitors of the mammalian target of rapamycin. Thanks to these new strategies, the prognosis for the mRCC is shifting toward a chronic disease and the new challenges are the adequate treatment of adverse events (AEs) and the care for quality of life, which is crucial. Emerging immunotherapies targeting the programmed death-1 (PD-1) receptor and the programmed death ligand-1 (PD-L1) ligand have shown promising results in both efficacy and safety profiles.

AREAS COVERED

Safety data published on available treatment options for renal cell carcinoma RCC are reviewed.

EXPERT OPINION

Various toxicities are associated with targeted agents; these toxicities are generally well tolerated but careful monitoring and appropriate management are needed to optimize the use of these strategies.

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.

Thyroid Hormones as Renal Cell Cancer Regulators

It is known that thyroid hormone is an important regulator of cancer development and metastasis. What is more, changes across the genome, as well as alternative splicing, may affect the activity of the thyroid hormone receptors. Mechanism of action of the thyroid hormone is different in every cancer; therefore in this review thyroid hormone and its receptor are presented as a regulator of renal cell carcinoma.

Hypothyroidism Side Effect in Patients Treated with Sunitinib or Sorafenib: Clinical and Structural Analyses

Tyrosine kinase inhibitors (TKIs) provide more effective targeted treatments for cancer, but are subject to a variety of adverse effects, such as hypothyroidism. TKI-induced hypothyroidism is a highly complicated issue, because of not only the unrealized toxicological mechanisms, but also different incidences of individual TKI drugs. While sunitinib is suspected for causing thyroid dysfunction more often than other TKIs, sorafenib is believed to be less risky. Here we integrated clinical data and in silico drug-protein interactions to examine the pharmacological distinction between sunitinib and sorafenib. Statistical analysis on the FDA Adverse Event Reporting System (FAERS) confirmed that sunitinib is more concurrent with hypothyroidism than sorafenib, which was observed in both female and male patients. Then, we used docking method and identified 3 proteins specifically binding to sunitinib but not sorafenib, i.e., retinoid X receptor alpha, retinoic acid receptors beta and gamma. As potential off-targets of sunitinib, these proteins are well known to assemble with thyroid hormone receptors, which can explain the profound impact of sunitinib on thyroid function. Taken together, we established a strategy of integrated analysis on clinical records and drug off-targets, which can be applied to explore the molecular basis of various adverse drug reactions.

Thyroid Dysfunction in Patients with Metastatic Carcinoma Treated with Sunitinib: Is Thyroid Autoimmunity Involved?

BACKGROUND

Sunitinib is a tyrosine kinase inhibitor (TKI) inducing thyroid dysfunction, but the precise mechanism(s) involved remains to be explained, including the role of thyroid autoimmunity. The objective of this study was to evaluate thyroid function, parameters of autoimmunity, and thyroid ultrasound findings in patients with metastatic cancer and normal thyroid function/autoimmunity before the initiation of sunitinib therapy. This was a prospective, observational cohort study.

METHODS

Twenty-seven patients with metastatic carcinomas at comparable tumor stages were evaluated over 12-18 months after initiating therapy with sunitinib given at a daily oral dose of 50 mg for four weeks (ON), followed by one to two weeks off therapy (OFF). Serum thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), and antithyroglobulin (TgAb), and antithyroid peroxidase (TPOAb) autoantibodies were measured in all cases. Thyroid morphology and volume were evaluated by echo-color Doppler ultrasound.

RESULTS

A total of 16/27 patients (60%) became hypothyroid (TSH range 7-114 mIU/L) within 30-120 days of therapy. The thyroid volume decreased in 24/27 (89%) patients (from M = 14.6 mL, SD = 6.4 mL to M = 3.8 mL, SD = 2.6 mL after 12 months; p < 0.001), together with the appearance of mild to severe hypoechogenicity. TPOAb (40-3000 IU/mL) became detectable in 7/27 (25%) patients, and TPOAb-positive patients displayed a higher degree of hypothyroidism and volume reduction. The progression-free survival (PFS) was significantly longer in patients developing TPOAb (10.8 months) than in the other group of patients (5.8 months).

CONCLUSIONS

These data confirm the thyroid inhibitory effect of sunitinib, in keeping with the key role of kinases in controlling thyroid function and growth. However, the novel appearance of TPOAb in a subgroup of patients with more severe hypothyroidism and longer survival indicates that sunitinib may also trigger/exacerbate thyroid autoimmunity contributing to thyroid failure. The development of TPOAb was associated with a longer PFS.

[Dysthyroidism with anti-VEGF treatment, a class effect? about one case report]

Tyrosine-kinase inhibitors are recent therapy used in different neoplastic diseases. Dysthyroidism seems to be a class effect of these drugs with a potentially cross cumulative effect. We describe here the case of a man who first developed dysthyroidism with sunitinib, then a deep and permanent hypothyroidism when axitinib was introduced.

Cabozantinib-induced thyroid dysfunction: a review of two ongoing trials for metastatic bladder cancer and sarcoma

BACKGROUND

Thyroid dysfunction is a common adverse event associated with tyrosine kinase inhibitors (TKI), but its underlying pathophysiology is unclear. Cabozantinib is a novel TKI currently Food and Drug Administration approved for advanced medullary thyroid cancer and tested in clinical trials on solid tumors including prostate, liver, bladder, breast, and ovarian cancer.

METHODS

We analyzed the thyroid function of patients enrolled in two phase 2 clinical trials using cabozantinib at the National Institutes of Health Clinical Center. Two cases of thyroiditis associated with cabozantinib therapy are presented in detail, and a systematic review of the literature on TKI-associated thyroid dysfunction is also discussed.

RESULTS

Between September 2012 and September 2013, 33 patients were treated with cabozantinib, and follow-up thyroid function tests were available for 31 (20 males, 11 females; age 59±1 years). Thyroid dysfunction was recorded in the majority of patients (93.1%), with a predominance of subclinical hypothyroidism. Two cases showed a biphasic pattern of thyroid dysfunction characterized by a transient thyrotoxicosis followed by hypothyroidism. Color Doppler demonstrated an increase in vascularization during the thyrotoxic phase, but no uptake was visualized on nuclear medicine imaging. A systematic review of the literature resulted in the identification of 40 original manuscripts, of which 13 were case series and 6 were case reports describing TKI-associated thyroid dysfunction.

CONCLUSION

TKI therapy often results in clinically significant thyroid dysfunction. Cabozantinib treatment commonly results in thyroid dysfunction varying from subclinical hypothyroidism to symptomatic thyrotoxicosis. Early detection and characterization of cabozantinib-associated thyroid dysfunction and close follow-up are essential to provide adequate management of this common adverse event.

Thyroid dysfunctions induced by tyrosine kinase inhibitors

INTRODUCTION

Recently, tyrosine kinase inhibitors (TKIs) have emerged as a new class of anticancer therapy. Although generally considered less toxic than cytotoxic chemotherapy, TKIs do cause significant side effects including fatigue and hypertension. In addition, thyroid dysfunction is a well-known adverse effect of TKI.

AREAS COVERED

This review provides a comprehensive assessment of TKI-induced thyroid dysfunctions by sunitinib, sorafenib, pazopanib, imatinib, dasatinib, nilotinib, vandetanib, axitinib, motesanib and tivozanib. Furthermore, the potential mechanisms that result in this toxicity, the clinical impact of thyroid dysfunction in these patients and the controversies regarding treatment with thyroid hormone (TH) therapy are evaluated.

EXPERT OPINION

Detection of TKI-induced thyroid dysfunction requires routine monitoring of thyroid function and may necessitate treatment. Potential benefits in developing thyroid dysfunction and potential harm in treating it necessitate controlled studies. Finally, if treatment is pursued, appropriate dosing and timing of TH replacement will require prospective clinical evaluation.

Targeted therapy with kinase inhibitors in aggressive endocrine tumors

INTRODUCTION

Kinase inhibitors (KIs) are a class of anticancer drugs that inhibit activity of the enzymes protein kinases, which regulate crucial cellular processes and have a demonstrated role in human oncogenesis. Treatment of advanced forms of endocrine cancer which are not responsive to cytotoxic chemotherapies is challenging and use of KIs is gaining a growing role in this field.

AREAS COVERED

The authors summarize the main genetic alterations known to be linked to endocrine tumors, indicating the rationale for utilizing KIs. Furthermore, they present an updated analysis of clinical trials available on PubMed Central, which were pertinent to the activities of KIs in aggressive endocrine cancer. The authors also discuss the adverse effects of KIs and summarize likely involved underlying mechanisms.

EXPERT OPINION

KIs are effective in obtaining a radiological disease control and an improvement of progression-free survival in several forms of endocrine cancer but will never deliver a knockout blow of the disease, due to mechanisms of adaptation to circumvent the specific molecular blockade. The new frontier of KIs treatment is to identify agents that could synergize activity of KIs. The true goal will be to perform an overall genotyping of each tumor, thus predicting the impact of combined targeted therapies in the context of a particular constellation of mutant genes.

Thyroid dysfunction as an unintended side effect of anticancer drugs

BACKGROUND

Several of the currently used anticancer drugs may variably affect thyroid function, with impairment ranging from modified total but not free concentration of thyroid hormones to overt thyroid disease.

SUMMARY

Cytotoxic agents seem to alter thyroid function in a relatively small proportion of adult patients. Anticancer hormone drugs may mainly alter serum levels of thyroid hormone-binding proteins without clinically relevant thyroid dysfunction. Old immunomodulating drugs, such as interferon-α and interleukin-2, are known to induce variably high incidence of autoimmune thyroid dysfunction. Newer immune checkpoint inhibitors, such as anti-CTLA4 monoclonal antibodies, are responsible for a relatively low incidence of thyroiditis and may induce secondary hypothyroidism resulting from hypophysitis. Central hypothyroidism is a well-recognized side effect of bexarotene. Despite their inherent selectivity, tyrosine kinase inhibitors may cause high rates of thyroid dysfunction. Notably, thyroid toxicity seems to be restricted to tyrosine kinase inhibitors targeting key kinase-receptors in angiogenic pathways, but not other kinase-receptors (e.g., epidermal growth factor receptors family or c-KIT). In addition, a number of these agents may also increase the levothyroxine requirement in thyroidectomized patients.

CONCLUSIONS

The pathophysiology of thyroid toxicity induced by many anticancer agents is not fully clarified and for others it remains speculative. Thyroid dysfunction induced by anticancer agents is generally manageable and dose reduction or discontinuation of these agents is not required. The prognostic relevance of thyroid autoimmunity, overt and subclinical hypothyroidism induced by anticancer drugs, the value of thyroid hormone replacement in individuals with abnormal thyrotropin following anticancer systemic therapy, and the correct timing of replacement therapy in cancer patients need to be defined more accurately in well-powered prospective clinical trials.

Patient approach in advanced/metastatic renal cell carcinoma: focus on the elderly population and treatment-related toxicity

Recent therapeutic advances have changed the treatment landscape of metastatic renal cell carcinoma. Unfortunately, the seven agents now available are not based on biomarkers that would indicate which one could provide the best benefit for every patient. We have reviewed the available information concerning the impact of each treatment on comorbidities or status that are frequently seen before commencing treatment for the advanced disease: elderly and patients with cardiovascular complications, metabolic and endocrinology disorders, and infections, as well as impaired organ function (kidney, liver and heart). Additional new drugs will be launched, but no predictive biomarkers are available. Head-to-head studies to evaluate the safety of the different drugs are rare. In this quite complex scenario, we believe that a decision-making approach focused on the patient may represent a suitable strategy.

Tyrosine kinase inhibitors: their on-target toxicities as potential indicators of efficacy

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of certain forms of cancers, raising hopes for many patients with otherwise unresponsive tumours. While these agents are generally well tolerated, clinical experience with them has highlighted their unexpected association with serious toxic effects on various organs such as the heart, lungs, liver, kidneys, thyroid, skin, blood coagulation, gastrointestinal tract and nervous system. Many of these toxic effects result from downstream inhibition of vascular endothelial growth factor or epidermal growth factor signalling in cells of normal organs. Many of these undesirable effects such as hypertension, hypothyroidism, skin reactions and possibly proteinuria are on-target effects. Since tyrosine kinases are widely distributed with specific functional roles in different organs, this association is not too surprising. Various studies suggest that the development of these on-target effects indicates clinically desirable and effective inhibition of the corresponding ligand-mediated receptor linked with oncogenesis. This is reflected as improved efficacy in the subgroup of patients who develop these on-target adverse effects compared with those who do not. Inevitably, issues arise with respect to the regulatory assessment of efficacy and risk/benefit of the TKIs as well as the clinical approach to managing patients who develop these effects. Routine subgroup analysis of efficacy data from clinical trials (patients with and without on-target toxicity) may enable more effective clinical use of TKIs since (i) discontinuing or reducing the dose of the TKI has a negative impact if the tumour is TKI-responsive; and (ii) it is usually possible to manage these undesirable on-target effects with conventional clinical approaches. Prospective studies are needed to investigate this proposition further.

Axitinib controlled metastatic renal cell carcinoma for 5 years

We present two patients with a long-term response to axitinib for cytokine-refractory metastatic renal cell carcinoma. One patient has had a continuing partial response for 58 months with cytokine-intolerant metastatic renal cell carcinoma and the other patient has had continuing stable disease accompanied by a mixed response for 57 months with cytokine-refractory and intolerant metastatic renal cell carcinoma. The condition of hypertension as an adverse event markedly depended on whether or not axitinib was administered. The patients responded to axitinib with an elevation of diastolic blood pressure to 90 mmHg or higher until 2 weeks after starting axitinib. To get a long-term response to axitinib, it may be important to control well the balance between treatment effect and adverse events while using drug withdrawal.

Inappropriate elevation of serum thyrotropin levels in patients treated with axitinib

BACKGROUND

Although anticancer treatment with the tyrosine kinase inhibitor (TKI) axitinib frequently causes thyroid dysfunction, the associated mechanism and clinical features have not been elucidated.

METHODS

Six patients were treated with axitinib for metastatic renal cell carcinoma at the Hamamatsu University School of Medicine between 2008 and 2010. We reviewed their thyroid function results and compared them to those of patients treated with two other TKIs, sunitinib or sorafenib, and to those of subjects with normal hypothalamic-pituitary-thyroid (HPT) function.

RESULTS

Axitinib-induced thyroid dysfunction was observed in all patients, and two patterns were observed: increased serum thyrotropin (TSH) levels within one month after administration occurred in five patients and transient thyrotoxicosis due to destructive thyroiditis occurred in five patients within 7 months of treatment. Four patients exhibited both. When the relationship between the serum TSH and thyroid hormones was evaluated using plots of TSH versus both free thyroxine and free triiodothyronine, four patients showed an inappropriate elevation of serum TSH during administration of axitinib. Their values apparently shifted against the regression line compared to data from patients with a normal HPT function. A similar tendency, though weaker, was observed in some patients treated with sunitinib or sorafenib.

CONCLUSION

This is the first study to report an inappropriate elevation of serum TSH levels in patients treated with axitinib.

Dramatic response to inhaled dobesilate in a patient with lung squamous cell cancer

The effectiveness of local application, by inhalation, of dobesilate, an inhibitor of fibroblast growth factor signalling, in a patient with squamous cell lung carcinoma is reported. To our knowledge, these are the first published data on the efficacy of dobesilate in the treatment of this disease. The antimitotic, antiangiogenic, proapoptotic and anti-inflammatory activities of dobesilate can be important factors to consider, in explaining the efficacy of the treatment. Dobesilate administration can be a therapeutic option in patients with lung cancer having poor performance status or severe complications.