Andrew G. Gianoukakis

Lenvatinib versus Placebo in Radioiodine-Refractory Thyroid Cancer

BACKGROUND Lenvatinib, an oral inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, fibroblast growth factor receptors 1 through 4, platelet-derived growth factor receptor α, RET, and KIT, showed clinical activity in a phase 2 study involving patients with differentiated thyroid cancer that was refractory to radioiodine (iodine-131). METHODS In our phase 3, randomized, double-blind, multicenter study involving patients with progressive thyroid cancer that was refractory to iodine-131, we randomly assigned 261 patients to receive lenvatinib (at a daily dose of 24 mg per day in 28-day cycles) and 131 patients to receive placebo. At the time of disease progression, patients in the placebo group could receive open-label lenvatinib. The primary end point was progression-free survival. Secondary end points included the response rate, overall survival, and safety. RESULTS The median progression-free survival was 18.3 months in the lenvatinib group and 3.6 months in the placebo group (hazard ratio for progression or death, 0.21; 99% confidence interval, 0.14 to 0.31; P<0.001). A progression-free survival benefit associated with lenvatinib was observed in all prespecified subgroups. The response rate was 64.8% in the lenvatinib group (4 complete responses and 165 partial responses) and 1.5% in the placebo group (P<0.001). The median overall survival was not reached in either group. Treatment-related adverse effects of any grade, which occurred in more than 40% of patients in the lenvatinib group, were hypertension (in 67.8% of the patients), diarrhea (in 59.4%), fatigue or asthenia (in 59.0%), decreased appetite (in 50.2%), decreased weight (in 46.4%), and nausea (in 41.0%). Discontinuations of the study drug because of adverse effects occurred in 37 patients who received lenvatinib (14.2%) and 3 patients who received placebo (2.3%). In the lenvatinib group, 6 of 20 deaths that occurred during the treatment period were considered to be drug-related. CONCLUSIONS Lenvatinib, as compared with placebo, was associated with significant improvements in progression-free survival and the response rate among patients with iodine-131-refractory thyroid cancer. Patients who received lenvatinib had more adverse effects. (Funded by Eisai; SELECT ClinicalTrials.gov number, NCT01321554.).

Evidence for an Association between Thyroid-Stimulating Hormone and Insulin-Like Growth Factor 1 Receptors: A Tale of Two Antigens Implicated in Graves’ Disease

Thyroid-stimulating hormone receptor (TSHR) plays a central role in regulating thyroid function and is targeted by IgGs in Graves’ disease (GD-IgG). Whether TSHR is involved in the pathogenesis of thyroid-associated ophthalmopathy (TAO), the orbital manifestation of GD, remains uncertain. TSHR signaling overlaps with that of insulin-like grow factor 1 receptor (IGF-1R). GD-IgG can activate fibroblasts derived from donors with GD to synthesize T cell chemoattractants and hyaluronan, actions mediated through IGF-1R. In this study, we compare levels of IGF-1R and TSHR on the surfaces of TAO and control orbital fibroblasts and thyrocytes and explore the physical and functional relationship between the two receptors. TSHR levels are 11-fold higher on thyrocytes than on TAO or control fibroblasts. In contrast, IGF-1R levels are 3-fold higher on TAO vs control fibroblasts. In pull-down studies using fibroblasts, thyrocytes, and thyroid tissue, Abs directed specifically against either IGF-1Rβ or TSHR bring both proteins out of solution. Moreover, IGF-1Rβ and TSHR colocalize to the perinuclear and cytoplasmic compartments in fibroblasts and thyrocytes by confocal microscopy. Examination of orbital tissue from patients with TAO reveals similar colocalization to cell membranes. Treatment of primary thyrocytes with recombinant human TSH results in rapid ERK phosphorylation which can be blocked by an IGF-1R-blocking mAb. Our findings suggest that IGF-1R might mediate some TSH-provoked signaling. Furthermore, they indicate that TSHR levels on orbital fibroblasts are considerably lower than those on thyrocytes and that this receptor associates with IGF-1R in situ and together may comprise a functional complex in thyroid and orbital tissue.

Aberrant Expression of the Insulin-Like Growth Factor-1 Receptor by T Cells from Patients with Graves’ Disease May Carry Functional Consequences for Disease Pathogenesis

Graves’ disease (GD), an autoimmune process involving thyroid and orbital tissue, is associated with lymphocyte abnormalities including expansion of memory T cells. Insulin-like growth factor receptor-1 (IGF-1R)-bearing fibroblasts overpopulate connective tissues in GD. IGF-1R on fibroblasts, when ligated with IgGs from these patients, results in the expression of the T cell chemoattractants, IL-16 and RANTES. We now report that a disproportionately large fraction of peripheral blood T cells express IGF-1R (CD3+IGF-R+). CD3+IGF-1R+ T cells comprise 48 ± 4% (mean ± SE; n = 33) in patients with GD compared with 15 ± 3% (n = 21; p < 10−8) in controls. This increased population of IGF-1R+ T cells results, at least in part, from an expansion of CD45RO+ T cells expressing the receptor. In contrast, the fraction of CD45RA+IGF-1R+ T cells is similar in GD and controls. T cells harvested from affected orbital tissues in GD reflect similar differences in the proportion of IGF-1R+CD3+ and IGF-1R+CD4+CD3+ cells as those found in the peripheral circulation. GD-derived peripheral T cells express durable, constitutive IGF-1R expression in culture and receptor levels are further up-regulated following CD3 complex activation. IGF-1 enhanced GD-derived T cell incorporation of BrdU (p < 0.02) and inhibited Fas-mediated apoptosis (p < 0.02). These findings suggest a potential role for IGF-1R displayed by lymphocytes in supporting the expansion of memory T cells in GD.

B Cells from Patients with Graves’ Disease Aberrantly Express the IGF-1 Receptor: Implications for Disease Pathogenesis

Graves’ disease (GD) is an autoimmune process involving the thyroid and connective tissues in the orbit and pretibial skin. Activating anti-thyrotropin receptor Abs are responsible for hyperthyroidism in GD. However, neither these autoAbs nor the receptor they are directed against have been convincingly implicated in the connective tissue manifestations. Insulin-like growth factor-1 receptor (IGF-1R)-bearing fibroblasts overpopulate connective tissues in GD and when ligated with IgGs from these patients, express the T cell chemoattractants, IL-16, and RANTES. Disproportionately large fractions of peripheral blood T cells also express IGF-1R in patients with GD and may account, at least in part, for expansion of IGF-1R+ memory T cells. We now report a similarly skewed B cell population exhibiting the IGF-1R+ phenotype from the blood, orbit, and bone marrow of patients with GD. This expression profile exhibits durability in culture and is maintained or increased with CpG activation. Moreover, IGF-1R+ B cells produce pathogenic Abs against the thyrotropin receptor. In lymphocytes from patients with GD, IGF-1 enhanced IgG production (p < 0.05) and increased B cell expansion (p < 0.02) in vitro while those from control donors failed to respond. These findings suggest a potentially important role for IGF-1R display by B lymphocytes in patients with GD in supporting their expansion and abnormal Ig production.

Monoclonal Pathogenic Antibodies to the Thyroid-Stimulating Hormone Receptor in Graves’ Disease with Potent Thyroid-Stimulating Activity but Differential Blocking Activity Activate Multiple Signaling Pathways

The thyroid target Ag for disease-inducing autoantibodies in Graves’ disease is the receptor for thyroid-stimulating hormone (TSH), but little is known about the molecular basis of this pathogenic Ab response. We describe the characteristics of two high- affinity mAbs developed from an experimental murine model of hyperthyroid Graves’ disease that exhibit potent thyroid-stimulating activity. Nanogram concentrations of the IgG mAbs KSAb1 and KSAb2 and their Fab induce full stimulation of the TSH receptor that is matched by the ligand TSH and, thus, act as full agonists for the receptor. However, KSAb1 and KSAb2 display differential activities in their ability to block TSH-mediated stimulation of the receptor, indicating subtle differences in their biological properties. In displacement studies, IgG and Fabs of KSAb1 and KSAb2 compete with Graves’ disease autoantibodies as well as thyroid-blocking Abs present in some hypothyroid patients, indicating a close relationship between these autoimmune determinants on the receptor. In passive transfer studies, single injections of microgram quantities of KSAb1 or KSAb2 IgG led to rapid elevation of serum thyroxine and a hyperthyroid state that was maintained for a number of days. The thyroid glands showed evidence of cell necrosis, but there was no accompanying mononuclear cell infiltrate. In studying their receptor activation pathways, both KSAb1 and KSAb2 provoked phosphorylation of the intracellular ERK1/2 pathway in primary thyrocytes, indicating that multiple signaling pathways may participate in the pathogenesis of Graves’ disease. In summary, our findings emphasize the similarities of the experimental mouse model in reproducing the human disorder and provide improved means for characterizing the molecular basis of this pathogenic response.

Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are rare neoplasms representing <5% of all pancreatic malignancies with an estimated incidence of 1–1.5 cases/100,000. PNETs are broadly classified as either functional or nonfunctional. Functional PNETs include insulinomas, gastrinomas, vasoactive intestinal peptideomas, glucagonomas, and somatostatinomas. The clinical manifestations associated with these tumors are the result of excessive hormonal secretion and action. The functional nature of these tumors makes pancreatic hormone testing critical not only for initial diagnosis but also for follow-up, because they are important tumor markers. Nonfunctional PNETs typically remain clinically silent until a substantial mass effect occurs. Although the majority of PNETs occur sporadically, it is important to recognize that these tumors may be associated with a variety of familial syndromes and in many cases genetic testing of PNET patients is warranted. This article familiarizes the reader with the clinical presentation and the biochemical, radiologic, and genetic testing indicated for diagnosis and follow-up of patients with PNET.

A phase 3, multicenter, double-blind, placebo-controlled trial of lenvatinib (E7080) in patients with 131I-refractory differentiated thyroid cancer (SELECT).

LBA6008 Background: Lenvatinib (LEN) is an oral tyrosine kinase inhibitor of the VEGFR1-3, FGFR1-4, PDGFRβ, RET, and KIT signaling networks. Based on efficacy results of the phase 2 study of patients (pts) with 131I-refractory differentiated thyroid cancer (RR-DTC), this phase 3 Study of (E7080) Lenvatinib in Differentiated Cancer of the Thyroid (SELECT) was developed. METHODS This randomized, double-blind, placebo (PBO)-controlled study enrolled pts with RR-DTC with documented disease progression within 13 months (mo). Pts were stratified by age (≤65, >65 years), region and ≤1 prior VEGFR-targeted therapies and randomized 2:1 to LEN or PBO (24mg/d, 28-d cycle). Upon progression, pts receiving PBO could crossover to open-label LEN. The primary endpoint was PFS assessed by Independent Radiologic Review; secondary endpoints included overall response rate (ORR; complete response [CR] + PR), overall survival (OS) and safety. RESULTS 392 pts (63.0 years median age; 51.0% male) were randomized. Pts on LEN had a significantly prolonged PFS vs PBO (hazard ratio 0.21, 95% confidence interval [CI] 0.14-0.31; P <.0001); median PFS was LEN: 18.3 mo (95% CI 15.1-not evaluable), PBO: 3.6 mo (95% CI 2.2-3.7). A LEN PFS benefit was observed in all predefined subgroups; median LEN PFS for pts with prior vs no prior VEGF-therapy was 15.1 mo (n=66) and 18.7 mo (n=195), respectively. Rates (n) of CRs were LEN: 1.5% (4), PBO: 0; PRs were LEN: 63.2% (165), PBO: 1.5% (2).Median exposure duration was LEN: 13.8 mo, PBO: 3.9 mo; median time to LEN response was 2.0 mo. Median OS has not been reached; deaths per arm were LEN: 71 (27.2%), PBO: 47 (35.9%). The 5 most common LEN treatment-related adverse events (TRAEs; any grade) were hypertension (68%), diarrhea (59%), appetite decreased (50%), weight loss (46%), nausea (41%). LEN grade ≥3 TRAEs (≥5%) were hypertension (42%), proteinuria (10%), weight loss (10%), diarrhea (8%), appetite decreased (5%). The dose was reduced in 78.5% of pts and discontinued due to adverse events (AEs) in 14.2% of pts. CONCLUSIONS LEN significantly improved PFS compared with PBO in pts with progressive RR-DTC. There were no unexpected toxicities and AEs were manageable. CLINICAL TRIAL INFORMATION NCT01321554.

Characterization of the anaemia associated with Graves' disease.

Background  Graves’ disease (GD) is associated with hyperthyroidism. Thyrotoxicosis adversely affects multiple organ systems including haematopoiesis. Anaemia occurring specifically in GD has not been systematically studied previously.

Management of Severe Thyrotoxicosis When the Gastrointestinal Tract Is Compromised

BACKGROUND The management of patients with severe thyrotoxicosis in the absence of a functional gastrointestinal tract represents an uncommon but significant clinical challenge associated with a high mortality rate. This article offers a literature review and discussion of the available management options in this setting. SUMMARY Treatment of severe thyrotoxicosis in patients unable to ingest medications by the oral route should focus on normalization of thyroid hormone levels utilizing conventional medical therapy for thyrotoxicosis, administered via non-oral routes. This includes thionamides, beta-blockers, iodine containing solutions, and glucocorticoids. When conventional medical therapy fails, plasmapheresis should be considered as a temporary therapeutic bridge until conventional therapies can be instituted effectively or emergent surgery performed. CONCLUSION Although a rare scenario, the management of patients with severe thyrotoxicosis in the absence of a functional gastrointestinal tract represents a challenging clinical situation. Endocrinologists and critical care physicians should be apprised of the available treatment modalities which must be instituted swiftly in order to avoid a catastrophic outcome.

Well differentiated follicular thyroid neoplasia: impact of molecular and technological advances on detection, monitoring and treatment.

Our understanding of the molecular mechanisms responsible for follicular thyroid cell oncogenesis has been advanced significantly in recent years. Specific genetic alterations and the molecular pathways they affect have been associated with particular histologic subtypes of well-differentiated thyroid cancer and are now being evaluated for their utility as clinical tools with diagnostic, prognostic and even therapeutic relevance. This paper focuses on the most common and clinically relevant genetic alterations shown to be consistently associated with well-differentiated thyroid carcinoma. We review the impact of recent molecular and technological advances on thyroid cancer standard of care and the practice of clinical medicine.