Randomized phase II study evaluating veliparib (ABT-888) with temozolomide in patients with metastatic melanoma

BACKGROUND

Veliparib (ABT-888) is a potent, orally bioavailable, small-molecule inhibitor of the DNA repair enzymes poly ADP-ribose polymerase-1 and -2. Veliparib enhances the efficacy of temozolomide (TMZ) and other cytotoxic agents in preclinical tumor models.

PATIENTS AND METHODS

In this multicenter, double-blind trial, adults with unresectable stage III or IV metastatic melanoma were randomized 1:1:1 to TMZ plus veliparib 20 or 40 mg, or placebo twice daily. Efficacy end points included progression-free survival (PFS), overall survival (OS), and objective response rate (ORR).

RESULTS

Patients (N = 346) were randomized between February 2009 and January 2010. Median [95% confidence interval (CI)] PFS was 3.7 (3.0-5.5), 3.6 (1.9-4.1), and 2 (1.9-3.7) months in the 20-mg, 40-mg, and placebo arms, respectively. Median (95% CI) OS was 10.8 (9.0-13.1), 13.6 (11.4-15.9), and 12.9 (9.8-14.3) months, respectively; ORR was 10.3%, 8.7%, and 7.0%. Exploratory analyses showed patients with low ERCC1 expression had longer PFS when TMZ was combined with veliparib. Toxicities were as expected for TMZ. The frequencies of thrombocytopenia, neutropenia, and leukopenia were significantly increased in the veliparib groups. Grade 3 or 4 adverse events, mainly hematologic toxicities, were seen in 55%, 63%, and 41% of patients in the 20-mg, 40-mg, and placebo arms, respectively.

CONCLUSIONS

Median PFS with 20 and 40 mg veliparib almost doubled numerically compared with placebo, but the improvements did not reach statistical significance. OS was not increased with veliparib. Toxicities were similar to TMZ monotherapy, but with increased frequency.

Simultaneous suppression of the MAP kinase and NF-κB pathways provides a robust therapeutic potential for thyroid cancer

The MAP kinase and NF-κB signaling pathways play an important role in thyroid cancer tumorigenesis. We aimed to examine the therapeutic potential of dually targeting the two pathways using AZD6244 and Bortezomib in combination. We evaluated their effects on cell proliferation, cell-cycle progression, apoptosis, cell migration assay, and the activation of the MAPK pathway in vitro and the in vivo using tumor size and immunohistochemical changes of Ki67 and ppRB. We found inhibition of cell growth rate by 10%, 20%, and 56% (p <0.05), migration to 55%, 61%, and 29% (p <0.05), and induction of apoptosis to 10%, 15%, and 38% (p <0.05) with AZD6244, Bortezomib, or combination, respectively. Induction of cell cycle arrest occurred only with drug combination. Dual drug treatment in the xenograft model caused a 94% reduction in tumor size (p <0.05) versus 15% with AZD6244 and 34% with Bortezomib (p < 0.05) and also reduced proliferative marker Ki67, and increased pRb dephosphorylation. Our results demonstrate a robust therapeutic potential of combining AZD6244 and Bortezomib as an effective strategy to overcome drug resistance encountered in monotherapy in the treatment of thyroid cancer, strongly supporting clinical trials to further test this strategy.

The impact of thyroid nodule size on the risk of malignancy in follicular neoplasms

BACKGROUND/AIM

Studies have shown that the risk of malignancy in follicular neoplasms is as high as 30%. Often, surgery is recommended for such lesions, not for therapeutic purposes but as a diagnostic method, leading to increased hospital costs and related morbidities. Recent studies have suggested that tumor size predicts malignant potential of these follicular neoplasms. Our aim was to identify the impact of nodule size on the risk of malignancy for such lesions.

PATIENTS AND METHODS

A retrospective medical chart review was undertaken for patients who underwent thyroid surgery at a single academic North American Institution. A total of 120 follicular lesions, follicular neoplasms (Bethesda category IV) or follicular lesions of undetermined significance (Bethesda category III) in 110 patients undergoing thyroid surgery were evaluated. Nodule size as measured by ultrasound, fine-needle aspiration cytological results, and final histopathology reports were reviewed. Analysis was performed by classification according to nodule size: <3 cm, ≥3 cm, <4 cm and ≥4 cm.

RESULTS

Out of the 120 nodules, 48 (40%) were reported to be malignant on final pathological examination. The malignancy rate in nodules<3 cm and ≥ 3cm was 41% and 37.8%, respectively (p=0.84). When 4 cm was used as the cut-off, the rate in nodules<4 cm and ≥4 cm was 40.6% and 37.5%, respectively (p=0.82).

CONCLUSION

Increased thyroid nodule size does not increase the malignancy rate for follicular neoplasms. Hence, we recommend against routine total thyroidectomy for patients with follicular neoplasms based on the size criteria.

Diagnostic potential of ancillary molecular testing in differentiation of benign and malignant thyroid nodules

Fine needle aspiration (FNA) cytology, being the mainstay to diagnose thyroid nodules, does not provide definitive results in a subset of patients. The use of molecular markers testing has been described as a useful aid in differentiation of thyroid nodules that present with an indeterminate cytodiagnosis. Molecular tests, such as the Afirma gene classifier, mutational assay and immunohistochemical markers have been increasingly used to further increase the accuracy and defer unnecessary surgeries for benign thyroid nodules. However, in light of the current literature, their emerging roles in clinical practice are limited due to financial and technical limitations. Nevertheless, their synergistic implementation can predict the risk of malignancy and yield an accurate diagnosis. This review discusses the clinical utility of various molecular tests done on FNA indeterminate nodules to avoid diagnostic thyroidectomies and warrant the need of future multi-Institutional studies.

Impact of BRAF mutation status in the prognosis of cutaneous melanoma: an area of ongoing research

This review is intended to provide an updated role of molecular genetics and various targeted therapies that have been developed to treat advanced stages of melanoma. Because of the declining success in melanoma therapy, the curative treatment for advanced stage melanoma has been a challenge for clinicians. Several mutations such as N-RAS, p53, BRAF including mutant-BRAF that lead to activation of kinase pathway, are implicated in the development of malignant melanoma. However, the current literature depicts that the prognostic role of BRAF mutation in disease progression is still controversial. While its higher level in advanced stage disease is associated with decreased overall survival (OS), some studies show that it failed to confer as an independent prognostic predictor of the disease. This has also led researchers to accomplish newer therapeutic strategies that lead to improved disease-response and grant survival benefits. Vemurafenib, a BRAF inhibitor agent, is one of the few available targeted therapies that is FDA approved and provides promising results in metastatic disease. However, its resistance at an early stage is of great concern. Recent implementation of combinational therapies including "targeted therapy", immunotherapy, and biological agents has appealed many researchers to define the adjunctive role of available therapies and their limitations in advanced stage and metastatic melanoma. This commends the need for future multi-institutional studies to confirm the clinical validity of different therapeutic strategies on a large scale population.

Stem cell biology in thyroid cancer: Insights for novel therapies

Currently, thyroid cancer is one of the most common endocrine cancer in the United States. A recent involvement of sub-population of stem cells, cancer stem cells, has been proposed in different histological types of thyroid cancer. Because of their ability of self-renewal and differentiation into various specialized cells in the body, these putative cells drive tumor genesis, metastatic activity and are responsible to provide chemo- and radioresistant nature to the cancer cells in the thyroid gland. Our Review was conducted from previously published literature to provide latest apprises to investigate the role of embryonic, somatic and cancer stem cells, and discusses the hypothesis of epithelial-mesenchymal transition. Different methods for their identification and isolation through stemness markers using various in vivo and in vitro methods such as flow cytometry, thyrosphere formation assay, aldehyde dehydrogenase activity and ATP-binding cassette sub-family G member 2 efflux-pump mediated Hoechst 33342 dye exclusion have been discussed. The review also outlines various setbacks that still remain to target these tumor initiating cells. Future perspectives of therapeutic strategies and their potential to treat advanced stages of thyroid cancer are also disclosed in this review.

The impact of surgical volume on racial disparity in thyroid and parathyroid surgery

PURPOSE

The aim of this study was to evaluate the association between surgeon volume and patient outcomes among different race ethnicities undergoing thyroid or parathyroid surgery.

METHODS

The nationwide inpatient sample was used to identify all thyroidectomy and parathyroidectomy admissions from 2003 to 2009, using International Classification of Diseases, 9th Clinical Modification (ICD-9-CM) procedure codes. Race, demographic, and clinical characteristics of patients were collected, along with surgeon volume, to predict the length of stay (LOS), complication rates, mortality, and total charges by racial group, using univariate and multivariate analyses.

RESULTS

A total of 106,314 thyroid and parathyroid surgeries were included in the current analysis. Of these patients, 54 % were Caucasian, 11 % African American, 7 % Hispanic, and 3 % Asian. Mean LOS was longer for African American patients (4 ± 8.7 days) than for Caucasians (2.3 ± 5.5 days) [p < 0.001]. African Americans had higher overall complications (16.8 %) compared with Caucasians (11 %), Hispanics (13.5 %), and Asians (12 %) [p < 0.001]. In-hospital mortality was higher for African Americans (0.8 %) compared with that from other race groups (0.3 %) [p < 0.001]. Mean total charges were significantly higher for African Americans ($33,292 ± $67,387) compared with those for Caucasians ($22,855 ± $40,167) (p < 0.001). African Americans had less access to intermediate- (10-99 cases) and high- (>100 cases) volume surgeons compared with Caucasians-45 versus 49 %, and 16 versus 19 %, respectively (p < 0.001). Higher surgeon volume was associated with improved outcomes (p < 0.001). Racial disparity in all investigated outcomes was still significantly evident even after stratification by surgeon volume.

CONCLUSION

Higher surgeon volume is associated with improved patient outcomes. However, our data suggests that the observed racial disparities in thyroid and parathyroid surgery go beyond access to quality healthcare providers.

A novel mouse model of metastatic thyroid carcinoma using human adipose tissue-derived stromal/stem cells

BACKGROUND/AIM

Scientists have been in quest for the best in vivo model to evaluate chemotherapies for radioiodine-resistant metastatic thyroid carcinomas. Human adipose tissue-derived stromal/stem cells (ASCs) have been found to promote in vitro growth and in vivo tumorigenesis. In the present study, we describe a novel model of metastatic human thyroid carcinoma by combining ASCs with the papillary thyroid cancer, K1 cell line.

MATERIALS AND METHODS

Three groups of severe combined immunodefecient mice were investigated. The first group was injected subcutaneously with K1 cells plus ASCs, the second group with K1 cell only, and the last group with ASCs only. Mean tumor volumes and standard deviations were calculated and compared.

RESULTS

Concomitant injection of ASCs with the K1 cell line led to the development of significantly larger tumors compared to the other groups (p<0.05). In addition, the lungs of this group demonstrated gross tumor metastasis and pathological features of high-grade neoplasms.

CONCLUSION

In the present study we describe a novel mouse model using ASCs with the potential to be used for assessment of new treatments for the management of metastatic thyroid carcinomas.

Ectopic secretion of parathyroid hormone in a neuroendocrine tumor: a case report and review of the literature

Very few cases have been reported in which the production and secretion of intact PTH by a non-parathyroid tumor has been authenticated. This paper describes the case of a 73 year old white female with a clinical and biochemical profile characteristic of primary hyperparathyroidism. Sestamibi scan and comprehensive neck ultrasono-graphy failed to localize a cervical lesion. Because the clinical manifestations were striking, neck exploration was performed. Dissection of the central compartment identified a lesion. PTH levels dropped to normal within ten minutes after its removal. Intraoperative parathyroid hormone assays facilitated the successful surgical removal of the lesion. Pathological examination yielded a diagnosis of a neuroendocrine tumor. These results document the ectopic production of intact PTH by a neuroendocrine tumor and present a novel neoplastic cause of primary hyperparathyroidism. This is the second report of an ectopic neuroendocrine tumor in the head and neck which secreted intact PTH.

Comparison of ultrasound-guided biopsy technique for thyroid nodules with respect to adequacy of cytological material

BACKGROUND

Ultrasound-guided fine-needle aspiration cytology (FNAC) sampling of the thyroid represents a standard diagnostic procedure in the evaluation of thyroid nodules. The specimen can be acquired using either of two different techniques. In the first, the short axis is used with observation only of the tip of the needle whilst in the nodule. In the second technique, the long axis is used with the observation of the entire length of the needle. The decision to sample utilizing either technique was done randomly. This study is a retrospective review performed to compare these two techniques with regard to specimen adequacy.

METHODS

Ultrasound-guided FNACs were performed in 80 thyroid nodules between May 2008 and February 2009. One physician acquired the cytology specimens using one of these two methods after localization. Data on the type of technique and its diagnostic accuracy were collected.

RESULTS

Forty-nine of 80 thyroid nodules were sampled using the long-axis technique. The overall and deep-lesion diagnostic adequacies of specimens were significantly higher using this technique (93.9 and 95.1%, respectively, p < 0.01) than the short-axis technique. When comparing the long and short axes for superficial lesions, there was no significant difference in adequacy of the samples (p = 0.92).

CONCLUSIONS

This is the first study to compare long- and short-axis techniques with regard to specimen adequacy for thyroid nodules. The long-axis technique decreased the rate of inadequate material and provided more accurate cytological evaluation for deeper lesions.