Phase II trial of thalidomide for therapy of radioiodine-unresponsive and rapidly progressive thyroid carcinomas

A multicenter, open-label, randomized, phase II study of cediranib with or without lenalidomide in iodine 131-refractory differentiated thyroid cancer

BACKGROUND

Multitargeted tyrosine kinase inhibitors (TKIs) of the vascular endothelial growth factor receptor (VEGFR) pathway have activity in differentiated thyroid cancer (DTC). Lenalidomide demonstrated preliminary efficacy in DTC, but its safety and efficacy in combination with VEGFR-targeted TKIs is unknown. We sought to determine the safety and efficacy of cediranib, a VEGFR-targeted TKI, with or without lenalidomide, in the treatment of iodine 131-refractory DTC.

PATIENTS AND METHODS

In this multicenter, open-label, randomized, phase II clinical trial, 110 patients were enrolled and randomized to cediranib alone or cediranib with lenalidomide. The primary endpoint was progression-free survival (PFS). Secondary endpoints included response rate, duration of response, toxicity, and overall survival (OS). Patients (≥18 years of age) with DTC who were refractory to further surgical or radioactive iodine (RAI) therapy as reviewed at a multispecialty tumor board conference, and evidence of disease progression within the previous 12 months and no more than one prior line of systemic therapy were eligible.

RESULTS

Of the 110 patients, 108 started therapy and were assessable for efficacy. The median PFS was 14.8 months [95% confidence interval (CI) 8.5-23.8 months] in the cediranib arm and 11.3 months (95% CI 8.7-18.9 months) in the cediranib with lenalidomide arm (P = 0.36). The 2-year OS was 64.8% (95% CI 43.3% to 86.4%) and 75.3% (95% CI 59.4% to 91.0%), respectively (P = 0.80). The serious adverse event rate was 41% in the cediranib arm and 46% in the cediranib with lenalidomide arm.

CONCLUSIONS

Single-agent therapy with cediranib showed promising efficacy in RAI-refractory DTC similar to other VEGFR-targeted TKIs, while the addition of lenalidomide did not result in clinically meaningful improvements in outcomes.

Significant Amelioration of Tracheal Stenosis following Lenvatinib in a Patient Who Has Anaplastic Thyroid Carcinoma with Bronchomediastinal Infiltration: A Case Report

BACKGROUND

Anaplastic thyroid carcinoma has an extremely poor prognosis, and no known drugs have exhibited acceptable efficacy. In recent years, novel anticancer tyrosine kinase inhibitors have been developed. We encountered a case of tracheal stenosis due to mediastinal and tracheal infiltration of anaplastic carcinoma for which lenvatinib exhibited remarkable effects; owing to this, airway management could be performed, even though the patient's condition was considered critical.

CASE REPORT

A 55-year-old man presented with locally advanced anaplastic thyroid carcinoma that was observed to have mediastinal infiltration. Tracheal stenosis due to infiltration of the trachea occurred, and the condition of the patient rapidly deteriorated. Radiation and chemotherapy consisting of cetuximab, cisplatin, and fluorouracil were ineffective, but his tracheal stenosis was relieved 2 weeks after initiation of lenvatinib, after which the patient could be discharged. However, the lenvatinib was ineffective for his liver, bone, and brain metastatic lesions, and the patient remained in a critical condition.

CONCLUSION

We encountered a case in which lenvatinib was effective for locally advanced anaplastic thyroid carcinoma, leading to an improvement in quality of life and a prolonged life. The drug was effective for the primary lesion, but mixed efficacy was noted for distant metastatic lesions.

Evolving approaches in managing radioactive iodine-refractory differentiated thyroid cancer

OBJECTIVE

To discuss the approach to care of patients with advanced differentiated thyroid cancer (DTC), in particular those with radioactive iodine (RAI)-refractory disease, and the transition to systemic treatment.

METHODS

A PubMed search was conducted using the search terms "radioactive iodine-refractory, differentiated thyroid cancer and treatment" restricted to a 2000-2012 timeframe, English language, and humans. Relevant articles were identified from the bibliographies of selected references. Four patient cases are presented to illustrate the clinical course of RAI-refractory DTC.

RESULTS

The current standard of care for early stage DTC could include surgery, RAI in some cases, and thyroid hormone suppression. For advanced RAI-refractory DTC, clinical practice guidelines established by the National Comprehensive Cancer Network and the American Thyroid Association recommend, as one option, the use of systemic therapy, including kinase inhibitors. Numerous trials are underway to evaluate the clinical benefit of these targeted therapies.

CONCLUSION

Preliminary results are encouraging with respect to the clinical benefit of targeted systemic therapies. However, at present there is no consensus on the criteria that define RAI-refractory disease and the optimal timing for transition to systemic therapy. There remains a need to establish common criteria to enhance patient care and enable better comparison across clinical studies.

Systemic therapeutic approaches to advanced thyroid cancers

Until only recently, few effective systemic therapies were available to treat patients with metastatic thyroid cancers. Recent advances in better understanding the pathogenesis and altered signaling pathways-especially in medullary and differentiated thyroid cancers (MTCs and DTCs)-have begun to change this situation substantially. Vandetanib, an orally bioavailable inhibitor of the RET kinase that is constitutively activated in MTC, has now been approved by the U.S. Food and Drug Administration (FDA) for use in progressive and symptomatic metastatic MTC; it has been shown to delay time to progression relative to placebo in a randomized phase III trial. Further, vascular endothelial growth factor receptor (VEGF-R) inhibitory agents including sorafenib, sunitinib, pazopanib, and axitinib that are already approved in the United States for use in advanced renal cell carcinoma have shown high response rates in treating advanced DTCs in multiple phase II trials, and have become commonly used in progressive radioiodine-refractory metastatic DTC. Yet additional agents are now in development, with several including XL184 (cabozantinib) also showing promise in DTC and MTC. In anaplastic thyroid cancer (ATC), progress has been slower, with the greatest apparent gains resulting more from the application of systemic therapies earlier in the disease course, especially when used in conjunction with initial surgical and radiation therapies. Despite recent progress, additional effective systemic therapeutic approaches remain sorely needed for treating metastatic MTC, DTC, and ATC.

Molecular pathogenesis and targeted therapies in well-differentiated thyroid carcinoma

Four proto-oncogenes commonly associated with well-differentiated thyroid carcinoma, rearranged during transfection (RET)/papillary thyroid cancer, BRAF, RAS, and PAX8/peroxisome proliferator activated receptor-γ, may carry diagnostic and prognostic significance. These oncogenes can be used to improve the diagnosis and management of well-differentiated thyroid carcinoma. Limited therapeutic options are available for patients with metastatic well-differentiated thyroid cancer, necessitating the development of novel therapies. Vascular endothelial growth factor (VEGF)- and RET-directed therapies such as sorafenib, motesanib, and sunitinib have been shown to be the most effective at inducing clinical responses and stabilizing the disease process. Further clinical trials of these therapeutic agents may soon change the management of thyroid cancer.

Medical therapy for advanced forms of thyroid cancer

More options than ever before are currently available for medical therapy in patients who present with advanced thyroid cancer or develop surgically unresectable recurrences or symptomatic or progressive disease. The newer medical therapies have addressed the need to find effective therapies beyond the conventional treatment with radioactive iodine, thyroid stimulating hormone suppression, and palliative cytotoxic chemotherapy for patients with advanced thyroid cancer. Although tumor responses to these medical therapies vary by type of thyroid cancer and type of therapy selected, they remain encouraging and provide therapeutic options for selected patients while new drugs are in development.

Medical management of metastatic medullary thyroid cancer

Medullary thyroid cancer (MTC) is an aggressive form of thyroid cancer that occurs in both heritable and sporadic forms. Discovery that mutations in the rearranged during transfection (RET) proto-oncogene predispose to familial cases of this disease has allowed for presymptomatic identification of gene carriers and prophylactic surgery to improve the prognosis of these patients. A significant number of patients with the sporadic type of MTC and even those with familial disease still present with lymph node or distant metastases, making surgical cure difficult. Over the past several decades, many different types of therapy for metastatic disease have been attempted with limited success. Improved understanding of the molecular defects and pathways involved in both familial and sporadic MTC has resulted in new hope for these patients with the development of drugs targeting the specific alterations responsible. This new era of targeted therapy with kinase inhibitors represents a significant step forward from previous trials of chemotherapy, radiotherapy, and hormone therapy. Although much progress has been made, additional agents and strategies are needed to achieve durable, long-term responses in patients with metastatic MTC. This article reviews the history and results of medical management for metastatic MTC from the early 1970s up until the present day.

Sorafenib in the treatment of radioiodine-refractory differentiated thyroid cancer: a meta-analysis

The advent of biologically targeted agents and increased understanding of thyroid carcinogenesis have generated much interest in the development of biologically targeted therapeutic agents for thyroid cancer. Among them, sorafenib is the most commonly studied drug. The current meta-analysis was carried out to estimate the efficacy and safety of sorafenib administered in radioiodine-refractory differentiated thyroid cancer patients. An electronic search was conducted using PubMed/MEDLINE and EMBASE. Statistical analyses were carried out using either random-effects or fixed-effects models according to heterogeneity. All the statistical analyses were carried out using the Stata version 12.0 software. Seven eligible studies were identified. The final results indicated that 22% of the patients (95% CI: 15-28) achieved a partial response. Hand-foot syndrome, diarrhea, fatigue, rash, weight loss, and hypertension were the most frequently observed adverse effects (AEs) associated with sorafenib use and the incidence of these AEs (all grades) was 80% (95% CI: 68-91), 68% (95% CI: 59-77), 67% (95% CI: 57-78), 66% (95% CI: 50-82), 52%(95% CI: 33-72), and 31% (95% CI: 21-42) respectively. Sixty-two percent (95% CI: 36-89) patients required dose reductions due to toxicity of sorafenib. As far as PR and AEs are concerned, the results of this meta-analysis indicate that sorafenib has a modest effect in patients with radioiodine-refractory differentiated thyroid cancer and the high incidence of AEs associated with this agent may affect the quality of patients' lives. Though the use of sorafenib in the treatment of radioiodine-refractory differentiated thyroid cancer is considered promising by most physicians working in this field, more effective agents with less toxicity and cost are still needed.

New therapeutic options for advanced forms of thyroid cancer

INTRODUCTION

While the vast majority of patients with thyroid cancer have an excellent prognosis, those with more aggressive courses experience significant morbidity and mortality. Advanced forms of thyroid cancer are typically refractory to standard therapy. Numerous agents with potential usefulness in the treatment of advanced thyroid cancer have recently come under study.

AREAS COVERED

This article reviews agents identified through a systematic review of the scientific literature as being under investigation for treatment of advanced thyroid cancer. A search of both PubMed and the NCI Clinical Trials website was performed to identify such agents having reached Phase II or III testing. Improved understanding of cancer cell signaling pathways has led to the identification of > 500 kinases as potential therapeutic targets. Additional agents of interest include those that inhibit neoangiogenesis, alter epigenetic factors or stimulate antitumor immune reactions. While presently available agents have shown promise in improving progression-free survival (PFS), complete responses are not seen and significant adverse side effects are encountered.

EXPERT OPINION

The development of numerous new anticancer agents holds the promise of treatment regimens that will extend PFS and ultimately overall survival in patients with advanced thyroid cancer. Anticipated future developments include individualized, multimodal treatment regimens based on specific tumor cell biology and driver mutations.

Sunitinib therapy in metastatic papillary thyroid cancer

We present the case of a 51-year-old woman with a follicular variant of papillary thyroid carcinoma. After surgery she experienced a relapse. Chemotherapy treatment led only to disease stabilization. In August 2009, we decided to start therapy with sunitinib 50 mg daily in an intermittent schedule (4 weeks on/2 weeks off). A CT scan after 3 months of treatment showed partial remission of disease according to the RE-CIST criteria. The patient continued sunitinib until January 2011, when CT evidenced progression in the mediastinal lymph nodes and pleura. Genetic analyses were carried out to determine if the clinical response in our patient was correlated with the presence of RET or BRAF mutations. No RET/PTC rearrangements or BRAF-V600E mutation, which are the two most common genetic alterations detected in papillary thyroid carcinoma, were found. It can be hypothesized that the activity of sunitinib in this patient was due to its antiangiogenic properties.

Multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma: an update

CONTEXT

Over the last decade, our knowledge of the multiple endocrine neoplasia (MEN) type 2 syndromes MEN2A and MEN2B and familial medullary thyroid carcinoma (FMTC) has expanded greatly. In this manuscript, we summarize how recent discoveries have enhanced our understanding of the molecular basis of these diseases and led to improvements in the diagnosis and management of affected patients.

EVIDENCE ACQUISITION

We reviewed the English literature through PubMed from 2000 to the present, using the search terms medullary thyroid carcinoma, multiple endocrine neoplasia type 2, familial medullary thyroid carcinoma, RET proto-oncogene, and calcitonin.

EVIDENCE SYNTHESIS

Over 70 RET mutations are known to cause MEN2A, MEN2B, or FMTC, and recent findings from studies of large kindreds with these syndromes have clouded the relationship between genotype and phenotype, primarily because of the varied clinical presentation of different families with the same RET mutation. This clinical variability has also confounded decisions about the timing of prophylactic thyroidectomy for MTC, the dominant endocrinopathy associated with these syndromes. A distinct advance has been the demonstration through phase II and phase III clinical trials that molecular targeted therapeutics are effective in the treatment of patients with locally advanced or metastatic MTC.

CONCLUSIONS

The effective management of patients with MEN2A, MEN2A, and FMTC depends on an understanding of the variable behavior of disease expression in patients with a specific RET mutation. Information gained from molecular testing, biochemical analysis, and clinical evaluation is important in providing effective management of patients with either early or advanced-stage MTC.

Biomarkers for anti-angiogenic therapy in cancer

Angiogenesis, the development of new vessels from existing vasculature, plays a central role in tumor growth, survival, and progression. On the molecular level it is controlled by a number of pro- and anti-angiogenic cytokines, among which the vascular endothelial growth factors (VEGFs), together with their related VEGF-receptors, have an exceptional position. Therefore, the blockade of VEGF signaling in order to inhibit angiogenesis was deemed an attractive approach for cancer therapy and drugs interfering with the VEGF-ligands, the VEGF receptors, and the intracellular VEGF-mediated signal transduction were developed. Although promising in pre-clinical trials, VEGF-inhibition proved to be problematic in the clinical context. One major drawback was the generally high variability in patient response to anti-angiogenic drugs and the rapid development of therapy resistance, so that, in total, only moderate effects on progression-free and overall survival were observed. Biomarkers predicting the response to VEGF-inhibition might attenuate this problem and help to further individualize drug and dosage determination. Although up to now no definitive biomarker has been identified for this purpose, several candidates are currently under investigation. This review aims to give an overview of the recent developments in this field, focusing on the most prevalent tumor species.

Clinical, safety, and economic evidence in radioactive iodine-refractory differentiated thyroid cancer: a systematic literature review

BACKGROUND

Thyroid cancer is the most common endocrine malignancy, with differentiated thyroid cancer (DTC) comprising ~93% of all thyroid cancers. While most cases of DTC are curable with the use of surgery and radioactive iodine (RAI) ablation of the remaining thyroid remnant, prognosis is dire and treatment options limited when DTC becomes RAI-refractory (RAI-R). Standard cytotoxic chemotherapy has limited efficacy, making enrollment in clinical trials of novel targeted therapies the preferred treatment approach. Thus, we conducted a comprehensive systematic review of the clinical trial scientific literature with a focus on efficacy, safety, and economics to identify all potential treatment options that have been or are currently being evaluated for the treatment of RAI-R DTC.

METHODS

Embase.com (including Medline), Medline In-Process and other nonindexed citations, the Cochrane Libraries, ClinicalTrials.gov, and relevant recent conference proceedings were searched using predefined search criteria. Important inclusion criteria included English language, randomized controlled studies or interventional single-arm studies only, and studies of drug therapies only. Search results were screened utilizing the discretion of multiple researchers, and key data were abstracted.

RESULTS

Forty-five unique trials (16 full-text, 4 conference abstracts, and 25 ClinicalTrials.gov entries) were included in the clinical review. No studies that met criteria for inclusion in the economic review were identified. Among 20 trials with results available, all were Phase II and only one was randomized. The most commonly studied drugs were tyrosine kinase inhibitors (TKIs); other drugs included celecoxib, doxorubicin with interferon alpha-2b, rosiglitazone, selumetinib (AZD6244), thalidomide, VEGF trap, and vorinostat. Overall, efficacy and safety profiles were specific to treatment regimen, with objective response rates (ORR) ranging from 0% on gefitinib, rosiglitazone, VEGF trap, and vorinostat to 50% on lenvatinib, a TKI.

CONCLUSIONS

Limited clinical research and no economic research has been conducted in RAI-R DTC. Certain treatments, notably TKIs, have shown promise in Phase II trials, and two Phase III randomized placebo-controlled trials are ongoing. New research on the economic and humanistic burden of RAI-R DTC must be paired with the clinical evidence currently in development to examine the existing burden and future promise in treating patients with RAI-R DTC.

New insight into the treatment of advanced differentiated thyroid cancer

The vast majority of patients with differentiated thyroid cancer (DTC) are treated successfully with surgery and radioactive iodine ablation, yet the treatment of advanced cases is frustrating and largely ineffective. Systemic treatment with conventional cytotoxic chemotherapy is basically ineffective in most patients with advanced DTC. However, a better understanding of the genetics and biologic basis of thyroid cancers has generated opportunities for innovative therapeutic modalities, resulting in several clinical trials. We aim to delineate the latest knowledge regarding the biologic characteristics of DTC and to describe the available data related to novel targeted therapies that have demonstrated clinical effectiveness.

Update on thyroid cancer treatment

Surgery and radioiodine therapy are usually effective for most patients with differentiated thyroid cancer. However, poorly differentiated and anaplastic thyroid carcinomas represent a challenge to physicians on the basis of the current cancer treatment modalities. These cancer subtypes are often lethal and refractory to radioiodine therapy as well as most of the common chemotherapy drugs. Several kinase inhibitors are promising targeted therapies for these malignancies; however, clinical trials involving these drugs have provided controversial results and their clinical use is still under debate. Advanced medullary thyroid carcinomas may also be refractory to conventional therapies and novel kinase inhibitors may also be useful to control tumor progression in certain patients. Novel evidence is emerging that thyroid cancer is a stem cell disease, thereby implying that the driving force of thyroid cancers is a subset of undifferentiated cells (thyroid cancer stem cells) with unlimited growth potential and resistance to conventional therapeutic regimens. Thyroid cancer stem cells have been proposed as responsible for tumor invasiveness, metastasis, relapse and differentiation. Therefore, drugs that selectively target these cells could serve as a cornerstone in the treatment of poorly differentiated thyroid cancer.

Differentiated thyroid cancers: a comprehensive review of novel targeted therapies

Differentiated thyroid carcinoma (DTC) accounts for more than 90% of new thyroid cancer diagnoses, and includes papillary, follicular and Hürthle cell carcinoma. The prognosis for the vast majority of individuals diagnosed with DTC is excellent, with current treatment that includes surgery, radioactive iodine ablation and postoperative thyroid-stimulating hormone suppression. Unfortunately, the small proportion of individuals who develop radioactive iodine-resistant recurrent disease have few treatment options, and the vast majority will eventually die from their disease. Recently, several novel targets for anticancer agents have been identified and offer new hope for thyroid cancer patients diagnosed with progressive disease. In addition to targeting genes commonly altered in thyroid cancer, which include mutations in BRAF, RAS and RET, proangiogenic growth factor receptors and the sodium-iodide symporter have also been targeted. Several clinical trials evaluating tyrosine kinase and angiogenesis inhibitors for treatment of individuals diagnosed with metastatic or treatment-refractory DTC are currently underway. The objective of this review is to evaluate recent clinical trials that have studied novel targeted drugs for treatment of DTC.

Differentiated thyroid cancer: management of patients with radioiodine nonresponsive disease

Differentiated thyroid carcinoma (papillary and follicular) has a favorable prognosis with an 85% 10-year survival. The patients that recur often require surgery and further radioactive iodine to render them disease-free. Five percent of thyroid cancer patients, however, will eventually succumb to their disease. Metastatic thyroid cancer is treated with radioactive iodine if the metastases are radioiodine avid. Cytotoxic chemotherapies for advanced or metastatic noniodine avid thyroid cancers show no prolonged responses and in general have fallen out of favor. Novel targeted therapies have recently been discovered that have given rise to clinical trials for thyroid cancer. Newer aberrations in molecular pathways and oncogenic mutations in thyroid cancer together with the role of angiogenesis in tumor growth have been central to these discoveries. This paper will focus on the management and treatment of metastatic differentiated thyroid cancers that do not take up radioactive iodine.

Update on immunomodulatory drugs (IMiDs) in hematologic and solid malignancies

INTRODUCTION

Thalidomide and its analogs [small molecule immunomodulatory drugs (IMiDs®)] are among the most successful new therapeutic agents of recent years. Thalidomide is now an integral part of multiple myeloma (MM) therapy. Lenalidomide has been approved for the treatment of patients with relapsed MM and 5q-myelodysplastic syndromes (MDS). Currently, more than 400 clinical trials are evaluating the activity of lenalidomide, alone or in combination with other conventional or novel therapies, in newly diagnosed MM and 5q-MDS. Based on their broad range of actions within the tumor microenvironment, IMiDs are currently also evaluated in a wide variety of additional hematologic and solid malignancies.

AREAS COVERED

This paper reviews the historic development of thalidomide and its derivatives and presents novel insights into their mode of action. Moreover, it discusses up-to-date clinical trials investigating IMiDs and potential future research and therapeutic perspectives in MM and other malignancies.

EXPERT OPINION

Although IMiDs have emerged as powerful agents for the treatment of hematologic and solid tumors, more preclinical and clinical studies are urgently needed both to increase our knowledge of their mechanisms of action, and to optimize their clinical use, in order to further improve the patient's quality of life and survival.

Anti-tumor activity of motesanib in a medullary thyroid cancer model

BACKGROUND

Medullary thyroid cancer (MTC) is frequently associated with mutations in the tyrosine kinase Ret and with increased expression of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2). Motesanib is an investigational, orally administered small molecule antagonist of VEGFR1, 2, and 3; platelet-derived growth factor receptor (PDGFR); Kit; and possibly Ret.

AIM

The aim of this study was to investigate the effects of motesanib on wildtype and mutant Ret activity in vitro and on tumor xenograft growth in a mouse model of MTC.

METHODS/RESULTS

In cellular phosphorylation assays, motesanib inhibited the activity of wild-type Ret (IC(50)=66 nM), while it had limited activity against mutant Ret C634W (IC(50)=1100 nM) or Ret M918T (IC(50)>2500 nM). In vivo, motesanib significantly inhibited the growth of TT tumor cell xenografts (expressing Ret C634W) and significantly reduced tumor blood vessel area and tumor cell proliferation, compared with control. Treatment with motesanib resulted in substantial inhibition of Ret tyrosine phosphorylation in TT xenografts and, at comparable doses, in equivalent inhibition of VEGFR2 phosphorylation in both TT xenografts and in mouse lung tissue.

CONCLUSIONS

The results of this study demonstrate that motesanib inhibited thyroid tumor xenograft growth predominantly through inhibition of angiogenesis and possibly via a direct inhibition of VEGFR2 and Ret expressed on tumor cells. These data suggest that targeting angiogenesis pathways and specifically the VEGF pathway may represent a novel therapeutic approach in the treatment of MTC.

New treatment modalities in advanced thyroid cancer

BACKGROUND

Thyroid cancer is a heterogeneous disease that is classified into differentiated thyroid carcinoma (DTC), undifferentiated/anaplastic thyroid carcinoma (ATC) and medullary thyroid carcinoma. Results of conventional treatment modalities in advanced thyroid cancer have been disappointing and therefore, new therapies are needed.

METHODS

We searched PubMed, The Cochrane Library, Medline and EMBASE databases and abstracts published in annual proceedings for new treatment modalities in advanced thyroid cancer. We also searched for ongoing trials in www.clinicaltrials.gov.

RESULTS

Six phase I, 17 phase II and 1 phase III trials with tyrosine kinase inhibitors were carried out. We found 2 pilot studies and 11 phase II trials with redifferentiation therapies, mainly in DTC. For antiproliferative approaches, three phase I and four phase II trials were found. Immunomodulatory gene therapy was tested in a pilot study in ATC patients. Two phase II trials were carried out with immunotherapy. One phase I and nine phase II trials were found with radionucleotide therapy in patients with DTC.

CONCLUSION

The developments in the treatment of advanced thyroid cancer are intriguing. Future trials should aim at combinations of targeted agents with or without other treatment modalities, and will hopefully contribute to further improvement of outcomes.

Thyroid dysfunction from antineoplastic agents

Unlike cytotoxic agents that indiscriminately affect rapidly dividing cells, newer antineoplastic agents such as targeted therapies and immunotherapies are associated with thyroid dysfunction. These include tyrosine kinase inhibitors, bexarotene, radioiodine-based cancer therapies, denileukin diftitox, alemtuzumab, interferon-α, interleukin-2, ipilimumab, tremelimumab, thalidomide, and lenalidomide. Primary hypothyroidism is the most common side effect, although thyrotoxicosis and effects on thyroid-stimulating hormone secretion and thyroid hormone metabolism have also been described. Most agents cause thyroid dysfunction in 20%-50% of patients, although some have even higher rates. Despite this, physicians may overlook drug-induced thyroid dysfunction because of the complexity of the clinical picture in the cancer patient. Symptoms of hypothyroidism, such as fatigue, weakness, depression, memory loss, cold intolerance, and cardiovascular effects, may be incorrectly attributed to the primary disease or to the antineoplastic agent. Underdiagnosis of thyroid dysfunction can have important consequences for cancer patient management. At a minimum, the symptoms will adversely affect the patient's quality of life. Alternatively, such symptoms can lead to dose reductions of potentially life-saving therapies. Hypothyroidism can also alter the kinetics and clearance of medications, which may lead to undesirable side effects. Thyrotoxicosis can be mistaken for sepsis or a nonendocrinologic drug side effect. In some patients, thyroid disease may indicate a higher likelihood of tumor response to the agent. Both hypothyroidism and thyrotoxicosis are easily diagnosed with inexpensive and specific tests. In many patients, particularly those with hypothyroidism, the treatment is straightforward. We therefore recommend routine testing for thyroid abnormalities in patients receiving these antineoplastic agents.

Thyroid cancer: pathogenesis and targeted therapy

Therapeutic options for advanced, unresectable radioiodine-resistant thyroid cancers have historically been limited. Recent progress in understanding the pathogenesis of the various subtypes of thyroid cancer has led to increased interest in the development of targeted therapies, with potential strategies including angiogenesis inhibition, inhibition of aberrant intracellular signaling in the MAPK and PI3K/AKT/mTOR pathways, radioimmunotherapy, and redifferentiation agents. On the basis of a recent positive phase III clinical trial, the RET, vascular endothelial growth factor receptor (VEGFR), and epidermal growth factor receptor (EGFR) inhibitor vandetanib has received FDA approval as of April 2011 for use in the treatment of advanced medullary thyroid cancer. Several other recent phase II clinical trials in advanced thyroid cancer have demonstrated significant activity, and multiple other promising therapeutic strategies are in earlier phases of clinical development. The recent progress in targeted therapy is already revolutionizing management paradigms for advanced thyroid cancer, and will likely continue to dramatically expand treatment options in the coming years.

Emerging therapeutics for advanced thyroid malignancies: rationale and targeted approaches

INTRODUCTION

Thyroid cancer is an emerging public health concern. In the USA, its incidence has doubled in the past decade, making it the eighth most commonly diagnosed neoplasm in 2010. Despite this alarming increase, most thyroid cancer patients benefit from conventional approaches (surgery, radioiodine, radiotherapy, TSH suppression with levothyroxine) and are often cured. Nevertheless, a minority have aggressive tumors resistant to cytotoxic and other historical therapies; these patients sorely need new treatment options.

AREAS COVERED

Herein the biology and molecular characteristics of the common histological types of thyroid cancer are reviewed to provide context for subsequent discussion of recent developments and emerging therapeutics for advanced thyroid cancers.

EXPERT OPINION

Several kinase inhibitors, especially those targeting VEGFR and/or RET, have already demonstrated promising activity in differentiated and medullary thyroid cancers (DTC, MTC). Although of minimal benefit in DTC and MTC, cytotoxic chemotherapy with anti-microtubule agents and/or anthracyclines in combination with intensity-modulated radiation therapy appears to extend survival for patients with locoregionally confined anaplastic thyroid cancer (ATC), but to have only modest benefit in metastatic ATC. Further discovery and development of novel agents and combinations of agents will be critical to further progress in treating advanced thyroid cancers of all histotypes.

SEOM clinical guidelines for the treatment of thyroid cancer

Although thyroid cancer represents less than 1% of malignant tumours, its increased incidence detected in recent years and the appearance and development of new drugs targeting specific molecular targets has attracted the attention of the doctors involved in this pathology, especially medical oncologists. For this reason it is important at this critical point, when treatment may be substantially changed, to establish and agree updated guidelines. These guidelines should incorporate the newly developed strategies that, although still preliminary in evidence level, will surely have an important role, especially in relapsed and refractory tumours, which are unsuitable for surgical or radio-iodine treatment. Particular histological and molecular features of these tumours must be taken into account in order to optimise therapeutic approaches.

Novel molecular targeted therapies for refractory thyroid cancer

The incidence of thyroid cancer continues to increase and this neoplasia remains the most common endocrine malignancy. No effective systemic treatment currently exists for iodine-refractory differentiated or medullary thyroid carcinoma, but recent advances in the pathogenesis of these diseases have revealed key targets that are now being evaluated in the clinical setting. RET (rearranged during transfection)/PTC (papillary thyroid carcinoma) gene rearrangements, B-Raf gene mutations, and vascular endothelial growth factor receptor 2 (VEGFR-2) angiogenesis pathways are some of the known genetic alterations playing a crucial role in the development of thyroid cancer. Several novel agents have demonstrated promising responses. Of the treatments studied, multi-kinase inhibitors such as axitinib, sorafenib, motesanib, and XL-184 have shown to be the most effective by inducing clinical responses and stabilizing the disease process. Randomized clinical trials are currently evaluating these agents, results that may soon change the management of thyroid cancer.

Targeted therapy in refractory thyroid cancer: current achievements and limitations

Thyroid cancer refractory to conventional treatments lacks effective treatment. Targeted therapy is an emerging therapeutic strategy for these cancers, based on preliminary promising results. Tyrosine kinase inhibitors target both specific oncogenic pathways involved in thyroid cancer progression and aspecific mechanisms such as neoangiogenesis. They are generally well tolerated and most adverse events have low-to-moderate severity. Other classes of drugs have been tested, alone or in combination with tyrosine kinase inhibitors, but so far the results have been limited. The aim of this article is to describe the benefits and limitations of innovative drugs that are currently under investigation in patients with refractory thyroid cancer.

Thyroid cancer: burden of illness and management of disease

OBJECTIVE

The incidence of thyroid cancer, the most common endocrine malignancy, has increased dramatically in the last fifty years. This article will review the standard approach to thyroid cancer treatment as well as novel therapies under investigation. We will also address potential cost considerations in the management of thyroid cancer.

STUDY DESIGN

A comprehensive literature search was performed.

METHODS

Review article.

RESULTS

The high prevalence of thyroid cancer and the availability of novel therapies for patients with metastatic disease have potential economic implications that have not been well-studied. Because many patients likely have very low morbidity from their cancers, better tools to identify the lowest risk patients are needed in order to prevent overtreatment. Improved risk stratification should include recognizing patients who are unlikely to benefit from radioactive iodine therapy after initial surgery and identifying those with indolent and asymptomatic metastatic disease that are unlikely to benefit from novel therapies. In patients with advanced incurable disease, randomized-controlled studies to assess the efficacy of novel agents are needed to determine if the costs associated with new agents are warranted.

CONCLUSIONS

Health care costs associated with the increased diagnosis of thyroid cancer remain unknown but are worthy of further research.

Efficacy of pazopanib in progressive, radioiodine-refractory, metastatic differentiated thyroid cancers: results of a phase 2 consortium study

BACKGROUND

Chemotherapy has historically proven ineffective in advanced differentiated thyroid cancers, but the realisation that various tyrosine kinases are activated in the disease suggested a potential therapeutic role for tyrosine-kinase inhibitors. We investigated the safety and efficacy of pazopanib.

METHODS

This phase 2 trial was done from Feb 22, 2008, to Jan 31, 2009, in patients with metastatic, rapidly progressive, radioiodine-refractory differentiated thyroid cancers. Each patient received 800 mg continuous pazopanib daily in 4-week cycles until disease progression, drug intolerance, or both occurred. Up to two previous therapies were allowed, and measurable disease with radiographic progression in the 6-month period before enrolment was a requirement for inclusion. The primary endpoint was any tumour response, according to the Response Evaluation Criteria in Solid Tumors 1.0. This study is registered with ClinicalTrials.gov, number NCT00625846.

FINDINGS

39 patients were enrolled. One patient had received no previous radioiodine therapy and another withdrew consent before treatment. Clinical outcomes could, therefore, be assessed in 37 patients (19 [51%] men, median age 63 years). The study is closed to accrual of new patients, but several enrolled patients are still being treated. Patients received a median of 12 cycles (range 1 to >23, total >383). Confirmed partial responses were recorded in 18 patients (response rate 49%, 95% CI 35-68), with likelihood of response lasting longer than 1 year calculated to be 66%. Maximum concentration of pazopanib in plasma during cycle one was significantly correlated with radiographic response (r=-0·40, p=0·021). 16 (43%) patients required dose reductions owing to adverse events, the most frequent of which (any grade) were fatigue (29 patients), skin and hair hypopigmentation (28), diarrhoea (27), and nausea (27). Two patients who died during treatment had pre-existing contributory disorders.

INTERPRETATION

Pazopanib seems to represent a promising therapeutic option for patients with advanced differentiated thyroid cancers. The correlation of the patient's response and pazopanib concentration during the first cycle might indicate that treatment can be individualised to achieve optimum outcomes. Assessment of pazopanib in an expanded cohort of patients with differentiated thyroid cancer, as well as in cohorts of patients with medullary and anaplastic thyroid cancers, is presently being done.

FUNDING

National Cancer Institute, supported in part by NCI CA15083 and CM62205.

Molecular and other novel advances in treatment of metastatic epithelial and medullary thyroid cancers

An understanding of the mutations of the proto-oncogenes and tumor suppressor genes that occur in thyroid cancers should eventually explain the diverse clinical characteristics of these tumors and also direct therapy. Some insights have already emerged in the last decade; some abnormalities in tumor genes are consistently associated with specific clinical and pathologic findings. These genetic abnormalities usually represent somatic mutations in tumors of follicular epithelial origin, as opposed to inherited mutations in medullary thyroid cancers of parafollicular C cells origin because most thyroid tumors are sporadic and not familial. This is different from the multiple endocrine neoplasia syndromes in which the primary tumorigenic gene mutations are inherited. This improved understanding of the molecular basis of these diseases has led to the development of novel targeted therapeutic approaches which will be discussed in this paper.

Targeted therapy of thyroid cancer

Systemic chemotherapies for advanced or metastatic thyroid carcinomas have been of only limited effectiveness. For patients with differentiated or medullary carcinomas unresponsive to conventional treatments, novel therapies are needed to improve disease outcomes. Multiple novel therapies primarily targeting angiogenesis have entered clinical trials for metastatic thyroid carcinoma. Partial response rates up to 30% have been reported in single agent studies, but prolonged disease stabilization is more commonly seen. The most successful agents target the vascular endothelial growth factor receptors, with potential targets including the mutant kinases associated with papillary and medullary oncogenesis. Two drugs approved for other malignancies, sorafenib and sunitinib, have had promising preliminary results reported, and are being used selectively for patients who do not qualify for clinical trials. Additional agents targeting tumor vasculature, nuclear receptors, epigenetic abnormalities, and the immune response to neoplasia have also been investigated. Randomized trials for several agents are underway that may lead to eventual drug approval for thyroid cancer. Treatment for patients with metastatic or advanced thyroid carcinoma now emphasizes clinical trial opportunities for novel agents with considerable promise. Alternative options now exist for use of tyrosine kinase inhibitors that are well tolerated and may prove worthy of regulatory approval for this disease.

Angiogenesis-inhibitors for metastatic thyroid cancer

BACKGROUND

Systemic cytostatic therapies for advanced, metastatic thyroid carcinomas have been poorly effective. Tumor growth and metastasis depend on blood supply and blood vessel formation (angiogenesis). Therefore, inhibition of angiogenesis may represent a promising target for cancer therapy.

OBJECTIVES

To evaluate the benefits and risks of angiogenesis-inhibitors for metastatic thyroid cancer when given alone, or in combination with chemotherapy or radiotherapy.

SEARCH STRATEGY

We searched The Cochrane Library (2009, Issue 2), MEDLINE (January 2000 to May 2009) and EMBASE (January 2000 to May 2009) databases and abstracts published in annual proceedings for evidence. Attempts were made to identify studies from references in potentially relevant trials. We also searched for ongoing trials.

SELECTION CRITERIA

We planned to include randomized controlled trials that compared angiogenesis-inhibitors with other treatments, no treatment, or placebo in participants who had pathologically confirmed advanced thyroid cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently evaluated the search results against the selection criteria. Data extraction and risk of bias assessment were not performed because there were no studies that could be included.

MAIN RESULTS

We did not identify any studies which met our full inclusion criteria.

AUTHORS' CONCLUSIONS

There is currently no reliable evidence available from randomized controlled trials regarding the bene fi ts and harms of the use of angiogenesis-inhibitors for treating advanced thyroid cancer. Several trials are ongoing.

Standard and emerging therapies for metastatic differentiated thyroid cancer

Differentiated thyroid cancer accounts for >90% of cases of thyroid cancer, with most patients having an excellent prognosis. Distant metastases occur in 10%-15% of patients, decreasing the overall 10-year survival rate in this group to 40%. Radioactive iodine has been the mainstay of treatment for distant metastases, with good results when lesions retain the ability to take up iodine. For patients with metastatic disease resistant to radioactive iodine, treatment options are few and survival is poor. Chemotherapy and external beam radiotherapy have been used in these patients, but with disappointing results. In recent years, our understanding of the molecular pathways involved in thyroid cancer has increased and a number of molecular targets have been identified. These targets include the proto-oncogenes BRAF and RET, known to be common mutations in thyroid cancer; vascular endothelial growth factor receptor and platelet-derived growth factor receptor, associated with angiogenesis; and the sodium-iodide symporter, with the aim of restoring its expression and hence radioactive iodine uptake. There are now multiple trials of tyrosine kinase inhibitors, angiogenesis inhibitors, and other novel agents available to patients with metastatic thyroid cancer. This review discusses both traditional and novel treatments for metastatic differentiated thyroid cancer with a particular focus on emerging treatments for patients with radioactive iodine-refractory disease.

Targeted therapies in thyroid cancer

Differentiated thyroid carcinoma is the most frequent neoplasm of the endocrine system. Although thyroid cancer usually has an excellent prognosis, no therapeutic options are available for patients that develop metastases and are or became resistant to radioiodine therapy. The deeper knowledge of molecular aberrations that characterize tumor growth has provided novel targets in cancer therapy. Several proteins have been implicated as having a crucial role in the carcinogenesis of differentiated thyroid cancer, such as those involved in RET/PTC-RAS-RAF-MAPK pathway. Moreover, vascular aberrations and angiogenesis equilibrium have also been related to tumor growth. The development of new, targeted therapies and their encouraging initial results have opened a hopeful opportunity of treatment for these orphan therapy tumor patients.

Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the publication of the American Thyroid Association's guidelines for the management of these disorders was published in 2006, a large amount of new information has become available, prompting a revision of the guidelines.

METHODS

Relevant articles through December 2008 were reviewed by the task force and categorized by topic and level of evidence according to a modified schema used by the United States Preventative Services Task Force.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to optimal surgical management, radioiodine remnant ablation, and suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using ultrasound and serum thyroglobulin as well as those related to management of recurrent and metastatic disease.

CONCLUSIONS

We created evidence-based recommendations in response to our appointment as an independent task force by the American Thyroid Association to assist in the clinical management of patients with thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Phase I clinical trials in 56 patients with thyroid cancer: the M. D. Anderson Cancer Center experience

INTRODUCTION

Thyroid cancer is the most common endocrine malignancy. The outcomes of patients with relapsed thyroid cancer treated on early-phase clinical trials have not been systematically analyzed.

PATIENTS AND METHODS

We reviewed the records of consecutive patients with metastatic thyroid cancer referred to the Phase I Clinical Trials Program from March 2006 to April 2008. Best response was assessed by Response Evaluation Criteria in Solid Tumors.

RESULTS

Fifty-six patients were identified. The median age was 55 yr (range 35-79 yr). Of 49 patients evaluable for response, nine (18.4%) had a partial response, and 16 (32.7%) had stable disease for 6 months or longer. The median progression-free survival was 1.12 yr. With a median follow-up of 15.6 months, the 1-yr survival rate was 81%. In univariate analysis, factors predicting shorter survival were anaplastic histology (P = 0.0002) and albumin levels less than 3.5 g/dl (P = 0.05). Among 26 patients with tumor decreases, none died (median follow-up 1.3 yr), whereas 52% of patients with any tumor increase died by 1 yr (P = 0.0001). The median time to failure in our phase I clinical trials was 11.5 months vs. 4.1 months for the previous treatment (P = 0.04).

CONCLUSION

Patients with advanced thyroid cancer treated on phase I clinical trials had high rates of partial response and prolonged stable disease. Time to failure was significantly longer on the first phase I trial compared with the prior conventional treatment. Patients with any tumor decrease had significantly longer survival than those with any tumor increase.

Recommendations of the Latin American Thyroid Society on diagnosis and management of differentiated thyroid cancer

The aims of these recommendations were to develop clinical guidelines for evaluation and management of patients with differentiated thyroid cancer applicable to Latin American countries. The panel was composed by 13 members of the Latin American Thyroid Society (LATS) involved with research and management of thyroid cancer from different medical centers in Latin America. The recommendations were produced on the basis of the expert opinion of the panel with use of principles of Evidence-Based Medicine. Following a group meeting, a first draft based on evidences and the expert opinions of the panel was elaborated and, later, circulated among panel members, for further revision. After, this document was submitted to the LATS members, for commentaries and considerations, and, finally, revised and refined by the authors. The final recommendations presented in this paper represent the state of the art on management of differentiated thyroid cancer applied to all Latin American countries.

Advances in chemotherapy of differentiated epithelial and medullary thyroid cancers

CONTEXT

Systemic chemotherapies for advanced or metastatic thyroid carcinomas have been of only limited effectiveness. For patients with differentiated or medullary carcinomas unresponsive to conventional treatments, novel therapies are needed to improve disease outcomes.

EVIDENCE ACQUISITION

The PubMed and Google Scholar search engines were used to identify publications and peer-reviewed meeting presentations addressing chemotherapy and targeted therapy for differentiated or medullary carcinoma.

EVIDENCE SYNTHESIS

Multiple novel therapies primarily targeting angiogenesis have entered clinical trials for metastatic thyroid carcinoma. Partial response rates up to 30% have been reported in single agent studies, but prolonged disease stabilization is more commonly seen. The most successful agents target the vascular endothelial growth factor receptors, with potential targets including the mutant kinases associated with papillary and medullary oncogenesis. Two drugs approved for other malignancies, sorafenib and sunitinib, have had promising preliminary results reported, and are being used selectively for patients who do not qualify for clinical trials. Randomized trials for several agents are underway that may lead to eventual drug approval for thyroid cancer.

CONCLUSION

Treatment for patients with metastatic or advanced thyroid carcinoma now emphasizes clinical trial opportunities for novel agents with considerable promise. Alternative options now exist for use of tyrosine kinase inhibitors that are well tolerated and may prove worthy of regulatory approval for this disease.

Intra-abdominal insular thyroid carcinoma metastasis

BACKGROUND

In thyroid cancer, metastases to intra-abdominal solid organs are uncommon and intra-peritoneal metastases are extremely rare. Here we present the management and outcome of a young patient with a large radioiodine resistant intra-peritoneal metastasis of insular thyroid cancer.

SUMMARY

A 28-year-old woman with known radioiodine resistant metastatic insular (poorly differentiated) thyroid carcinoma and multiple previous resected metastases presented with acute onset of bowel obstruction due to a large pelvic mass. The pelvic mass was resected and histologically confirmed to be an insular thyroid carcinoma metastasis. She made an uneventful recovery from her surgery and continues to have a good quality of life despite low volume metastatic disease.

CONCLUSION

As this patient demonstrates, a rational but aggressive surgical approach is warranted for patients with radioiodine-resistant metastatic thyroid disease.

[Angiogenesis and thyroid cancer]

During the last two decades, the understanding of molecular biology of thyroid cancers has greatly improved, and this has permitted the development of novel therapeutic tools in patients with refractory disease. Kinase inhibitors inhibit kinases of the vascular endothelial growth factor (VEGF) receptors, and by doing this inhibit angiogenesis, and some of these agents also inhibit other kinases of the MAPkinase pathway. These inhibitors are effective in differentiated and medullary thyroid cancers, and induce a partial response or a long term stabilisation in more than half of patients.