Hedgehog Inhibitors Beyond Clinical Complete Response in Basal Cell Carcinoma: Should I Stop or Should I Go?

INTRODUCTION

In advanced basal cell carcinoma (BCC), the issue of whether Hedgehog inhibitors (HHIs) should be stopped or not after clinical complete response (cCR) achievement remains an unmet clinical need.

MATERIALS AND METHODS

We conducted a retrospective, multicenter study across 7 Italian dermato-oncology units including patients with BCC who continued vismodegib after cCR between 2012 and 2019. We assessed the relationship between the duration of vismodegib intake (days to cCR [DTCR], days to stop after cCR [DTS], total treatment days [TTD]), and disease-free survival (DFS). Reasons to stop vismodegib were (R1) toxicity and (R2) disease recurrence. The relationship between DTCR, DTS, TTD, and DFS in the whole population and in R1 subgroup was assessed by Pearson's correlation coefficient (P < .05) and Bayesian statistics (BF10).

RESULTS

Sixty-eight BCC patients with a median (m) age of 75.5 years (39-100) were included. Most patients were male (N = 43, 63%), without Gorlin syndrome (N = 56, 82%) and with head and neck area as primary site (N = 51, 75%). After cCR, out of 68 patients, 90% (N = 61/68) discontinued vismodegib: 82% (N = 50/61) due to toxicity (R1), and 18% (N = 11/61) due to recurrence (R2). Conversely, 10% (N = 7/68) continued vismodegib until last follow-up. In the whole population (N = 68), cCR was achieved with a mDTCR of 180.50 days. DFS showed a significant correlation with DTS (P < .01, BF10 = 39.2) and TTD (P < .01, BF10 = 35566), while it was not correlated to DTCR (BF10 < 0.1). The analysis of R1 subgroup (N = 50) confirmed these results. DFS correlated with DTS in all recurrent patients (N = 38, r = 0.44, P < .01) and in the recurrent patients who stopped vismodegib for toxicity (N = 26, r = 0.665, P < .01). DFS was longer when vismodegib was maintained for >2 months after cCR (mDFS > 2 months, N = 54 vs. ≤ 2 months, N = 14: 470 vs. 175 d, P < .01).

CONCLUSIONS

Our retrospective results suggest that HHIs should be continued after cCR to improve DFS in BCC.

A multicenter real-world analysis of risk factors, therapeutics, and outcomes of patients with metastatic basal cell carcinoma

BACKGROUND

Metastatic basal cell carcinoma (mBCC) is rare and there are limited data regarding patient and tumor risk factors, optimal treatments, and disease prognosis.

OBJECTIVE

To assess patient and tumor characteristics, therapeutics, and outcomes of mBCC stratified by location of metastasis.

METHODS

Retrospective cohort study of 53 patients with mBCC treated at 4 large academic centers in Boston, Massachusetts; Philadelphia, Pennsylvania; and Cleveland, Ohio between January 1, 2005 and December 31, 2021.

RESULTS

A total of 53 patients with mBCC were identified across 4 centers, 22 (42%) of whom had mBCC with spread limited to lymph nodes and 31 (58%) patients with distant organ spread (with or without lymph node involvement). Overall, half (n = 11) of patients with nodal metastasis achieved complete remission of disease, compared with just 1 (3%) patient with distant metastasis. The 5-year survival for nodal and distant metastatic patients was 89.3% and 61.0%, respectively.

LIMITATIONS

Small sample size due to disease rarity.

CONCLUSIONS AND RELEVANCE

Patients with nodal disease are more likely to have disease remission whereas patients with distant metastasis are more likely to have persistent disease and die from their disease. However, 5-year survival rates exceed 50%, even for stage IV disease.

Supraorbital Basosquamous Carcinoma Treated with Cemiplimab Followed by Sonidegib: A Case Report and Review of the Literature

Basal cell carcinoma (BCC) is a skin cancer with low local aggressiveness and a low tendency to metastasize. Basosquamous Carcinoma (BSC) represents an aggressive histological subtype of BCC with intermediate features between Squamous Cell Carcinoma (SCC) and BCC. Cemiplimab is currently approved as first-line therapy in SCC and second-line therapy in BCC patients who have progressed on or are intolerant of a Hedgehog pathway Inhibitor (HHI). Our study describes the case of a 59-year-old man with BSC who was successfully treated with 5 cycles of Cemiplimab as first-line therapy and Sonidegib as second-line therapy. Currently, the efficacy of Cemiplimab against BSC and other histopathological subtypes of BCC has not been fully elucidated, as has the role of sequential or combination therapy with Cemiplimab and HHI in the management of BSC. The aim of this case report is to highlight the need to outline the use of checkpoint inhibitors in BCCs and focus attention on the synergistic role of Cemiplimab and HHIs in such a controversial entity as BSC.

Sustained Suppression of Gorlin Syndrome-Associated Basal Cell Carcinomas with Vismodegib or Sonidegib: A Case Series

Nevoid basal-cell carcinoma syndrome (Gorlin syndrome) is characterized by numerous cutaneous basal cell carcinomas mediated by mutations in the hedgehog pathway. Vismodegib or sonidegib represent promising treatment options. We identified 10 Gorlin patients who were treated with sonidegib (n = 6) or vismodegib (n = 4) between March 2012 and March 2022. We analyzed the activity, toxicity, and duration of the response to oral hedgehog inhibitors. The number of new tumors that developed prior to treatment or after treatment as well as the time of response and durability of responses were assessed. All patients achieved a complete remission. With a 30.7 ± 48.4-month median follow-up, the drug treatment significantly reduced the number of new basal cell cancers from a mean of 28.3 ± 24.6 prior to treatment to a mean of 1.4 ± 2.0 during treatment (p = 0.0048). The median time to develop a new basal cell cancer was 47.3 months. Three patients eventually developed localized recurrences. After resection, ongoing treatment suppressed the development of additional lesions. One patient developed numerous new drug-resistant basal cell cancers and died of acute leukemia. Six patients required treatment modifications for toxicity. Sustained hedgehog inhibitor treatment can suppress the progression of both new and existing basal cell carcinomas for an extended period. Drug administration schedule adjustments improved tolerance without altering efficacy, potentially contributing to a prolonged response duration.

Emerging therapeutic options for periorbital and orbital cutaneous basal and squamous cell carcinomas

PURPOSE

Recently, several new therapies have emerged to address locally advanced cutaneous basal cell and squamous cell carcinomas. Given the constraints of the ocular adnexa and orbit, this review was designed to discuss the role of these modalities in this region.

METHODS

A PubMed search was carried out to analyze the utility of United States Food and Drug Administration-approved therapies to address these malignancies. The data presented in the identified investigations were analyzed and abstracted.

RESULTS

Multiple novel interventions may be useful in the management of periocular cutaneous basal cell and squamous cell carcinomas, including imiquimod, hedgehog inhibitors, and immunotherapy. While many of these treatments have not been specifically explored in the orbit and ocular adnexa, the literature generally shows favorable response rates. However, adverse events were common in these studies.

CONCLUSIONS

Several novel treatments may address periorbital cutaneous malignancies, and these therapies may be particularly useful in patients with unresectable disease and those who are poor surgical candidates.

The current clinical approach to difficult-to-treat basal cell carcinomas

INTRODUCTION

Basal cell carcinoma (BCC) is the most common malignant tumor in adult white populations. If BCCs are not treated for years, if they cause massive destruction of the surrounding tissues, if they are considered unresectable or not eligible for radiotherapy they become progressively 'locally advanced' (laBCC) or metastatic (mBCC). These tumors are defined as 'difficult-to-treat BCC.'

AREAS COVERED

A comprehensive search on PubMed was conducted to identify relevant literature about the several approved and recommended treatment options for the management of difficult-to-treat BCC published from January 2012 to July 2022. Surgical options, radiotherapy, hedgehog inhibitors, immunotherapy, and combined treatments are discussed. The keywords used were basal cell carcinoma; difficult-to-treat BCC; management of difficult-to-treat BCC; surgical therapy; radiotherapy; hedgehog inhibitors; immunotherapy.

EXPERT OPINION

Identifying the best approach to DTT BCCs is one of the main challenges for the dermato-oncologist. The introduction of HHI for the treatment of advanced BCCs has revolutionized the clinical management of DTT BCCs. The immune checkpoint inhibitor cemiplimab has been approved for the treatment of locally advanced or metastatic BCC refractory to HHI therapy or in patients intolerant to HHI therapy. Multidisciplinary teams (MDTs) play a key role in managing these complex patients.

The association of cemiplimab plus sonidegib for synchronous cutaneous squamous cell carcinoma and basal cell carcinoma of the head and neck: Two case reports

Basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) are the most frequent cancers in humans, with cumulative ultraviolet radiation exposure, aging, and immunodepression as the main risk factors. In most cases, these malignancies arise in the head and neck area, and they can be treated with locoregional therapies. A minority of cases require systemic therapy. Currently, Sonic Hedgehog inhibitors (i.e., vismodegib and sonidegib) have been approved for advanced BCC, while the PD-1 checkpoint inhibitor cemiplimab has been approved as a first-line treatment for cSCC and as a second-line treatment for BCC. Nevertheless, there is a clinical need for an effective and safe systemic therapies for advanced synchronous (syn) BCC/cSCC not amenable to local treatments. International guidelines do not provide specific recommendations for patients affected by this condition, and no case reports on the full-dose association of these medications have been previously reported. Here, we present the cases of two elderly patients affected by synBCC/cSCC of the head and neck, who received combined therapy with cemiplimab and sonidegib at full dose and standard schedule, achieving remarkable clinical benefit and long-term responses, without major adverse events. The instance of a feasible treatment for patients with advanced synBCC/cSCC will become increasingly frequent with the advancement of life expectancy in the global population, and the synergistic activity of targeted therapies and immunotherapy-administered either in association or sequentially-deserves to be further explored.

Topical Delivery of Hedgehog Inhibitors: Current Status and Perspectives

Systemic treatment with hedgehog inhibitors (HHis) is available to treat basal cell carcinomas but their utility is limited by adverse effects. Topical delivery methods may reduce adverse effects, but successful topical treatment depends on sufficient skin uptake, biological response, and time in tumor tissue. The aim of this review was to evaluate the current status of topical HHi delivery for BCCs and discuss barriers for translating systemic HHis into topical treatments. A literature search identified 16 preclinical studies and 7 clinical trials on the topical delivery of 12 HHis that have been clinically tested on BCCs. Preclinical studies on drug uptake demonstrated that novel formulations, and delivery- and pre-treatment techniques enhanced topical HHi delivery. Murine studies showed that the topical delivery of sonidegib, itraconazole, vitamin D₃ and CUR-61414 led to biological responses and tumor remission. In clinical trials, only topical patidegib and sonidegib led to at least a partial response in 26/86 BCCs and 30/34 patients, respectively. However, histological clearance was not observed in the samples analyzed. In conclusion, the incomplete clinical response could be due to poor HHi uptake, biodistribution or biological response over time. Novel topical delivery techniques may improve HHi delivery, but additional research on cutaneous pharmacokinetics and biological response is needed.

Eight Years of Real-Life Experience with Smoothened Inhibitors in a Swiss Tertiary Skin Referral Center

Simple Summary

Vismodegib and sonidegib are targeted therapies inhibiting the hedgehog pathway, a key driver in the pathogenesis of basal cell carcinoma (BCC). Hedgehog inhibitors (HhIs) are first-line therapy for locally advanced basal cell carcinoma (laBCC), metastatic basal cell carcinoma (mBCC) and multiple BCCs, when surgery and radiotherapy are no longer feasible. Safety and efficacy of the HhIs vismodegib and sonidegib have been shown in large prospective clinical trials. However, treatment of advanced basal cell carcinoma (aBCC) in daily practice includes patients who do not meet strict inclusion criteria and poses an additional challenge for treating physicians. This study aims to give an insight into a real-world experience in our tertiary skin referral center.

Abstract

Background: The hedgehog inhibitors vismodegib and sonidegib are approved for the treatment of advanced basal cell carcinoma. This study reports the experiences with these therapies in a tertiary skin referral center in daily practice. Methods: A retrospective, observational, single-center study analyzing medical records of patients with aBCC treated with a smoothened (SMO) inhibitor outside a clinical trial for at least one month between 2013 and 2021. Results: In total, 33 patients were included: 21 (64%) patients were treated with vismodegib, 3 (9%) patients with sonidegib and 9 (27%) patients with both treatments subsequently. With vismodegib, the best overall response was complete response (CR) in 33% cases, and partial response (PR) in 33% cases. Under sonidegib, 42% patients achieved CR and 17% PR. Mean duration to next treatment was 33 and 14 months for vismodegib and sonidegib, respectively. Adverse events varied in frequency between continuous and intermittent dosing and they were the most common reason for therapy discontinuation. Conclusions: Our real-world data illustrate the pitfalls and benefits of HhIs as well as the impact of different dosing regimens on adverse events, patient adherence and response. Treatment duration remains limited by adverse events and resistance. Additional treatment options, including immunotherapy and drug combinations, are needed.

Outcomes of adjunctive therapies post hedgehog inhibitors in the management of locally advanced basal cell carcinoma: A systematic review and pooled analysis

Management of patients with locally advanced basal cell carcinoma (laBCC) with traditional strategies has yielded suboptimal outcomes. Targeted treatments including hedgehog inhibitor therapy (HHIT) present limitations when utilized as monotherapy. Herein, we report evidence-based outcomes from available literature on multimodality treatments adjuvant to HHIT in laBCC management. Utilizing a systematic search strategy in PubMed, we identified studies published from inception to April 15, 2020, screened for definitive inclusion/exclusion criteria, and performed individual study quality assessment and pooled analysis to assess impact of adjunctive treatment-based responses post-HHIT on clinical response and recurrence outcomes. Twenty-nine studies (n = 103) were included. Primary findings include a complete response (CR) rate of 90.5%, the median follow-up of 12 months post-HHIT completion. The recurrence rate was 10.8% with 12-month median time to recurrence. Mohs micrographic surgery (MMS) had 100% CR post-HHIT, while no difference was observed between surgery and radiation therapy (RT). MMS and surgery had comparable 2-year recurrence free rates (RFR) at 87% and 86% respectively, while RT had the lower 2-year RFR at 67%. Male gender portended a more advanced stage at diagnosis and worse outcomes. In a subset analysis, periorbital laBCCs with orbital involvement had a CR rate of 81.8% versus 100% in those without orbital involvement, with similar rates of recurrence. Limited available quantitative data and possible publication bias were limitations. Pooled analysis of observational data supports use of adjunctive therapies post-HHIT to improve treatment response in patients with laBCC. Longer-term follow-up is needed to study recurrence rates after combination therapy.

Defining the Role of GLI/Hedgehog Signaling in Chemoresistance: Implications in Therapeutic Approaches

Insight into cancer signaling pathways is vital in the development of new cancer treatments to improve treatment efficacy. A relatively new but essential developmental signaling pathway, namely Hedgehog (Hh), has recently emerged as a major mediator of cancer progression and chemoresistance. The evolutionary conserved Hh signaling pathway requires an in-depth understanding of the paradigm of Hh signaling transduction, which is fundamental to provide the necessary means for the design of novel tools for treating cancer related to aberrant Hh signaling. This review will focus substantially on the canonical Hh signaling and the treatment strategies employed in different studies, with special emphasis on the molecular mechanisms and combination treatment in regard to Hh inhibitors and chemotherapeutics. We discuss our views based on Hh signaling's role in regulating DNA repair machinery, autophagy, tumor microenvironment, drug inactivation, transporters, epithelial-to-mesenchymal transition, and cancer stem cells to promote chemoresistance. The understanding of this Achilles' Heel in cancer may improve the therapeutic outcome for cancer therapy.

The Role of Smoothened-Dependent and -Independent Hedgehog Signaling Pathway in Tumorigenesis

The Hedgehog (Hh)-glioma-associated oncogene homolog (GLI) signaling pathway is highly conserved among mammals, with crucial roles in regulating embryonic development as well as in cancer initiation and progression. The GLI transcription factors (GLI1, GLI2, and GLI3) are effectors of the Hh pathway and are regulated via Smoothened (SMO)-dependent and SMO-independent mechanisms. The SMO-dependent route involves the common Hh-PTCH-SMO axis, and mutations or transcriptional and epigenetic dysregulation at these levels lead to the constitutive activation of GLI transcription factors. Conversely, the SMO-independent route involves the SMO bypass regulation of GLI transcription factors by external signaling pathways and their interacting proteins or by epigenetic and transcriptional regulation of GLI transcription factors expression. Both routes of GLI activation, when dysregulated, have been heavily implicated in tumorigenesis of many known cancers, making them important targets for cancer treatment. Hence, this review describes the various SMO-dependent and SMO-independent routes of GLI regulation in the tumorigenesis of multiple cancers in order to provide a holistic view of the paradigms of hedgehog signaling networks involving GLI regulation. An in-depth understanding of the complex interplay between GLI and various signaling elements could help inspire new therapeutic breakthroughs for the treatment of Hh-GLI-dependent cancers in the future. Lastly, we have presented an up-to-date summary of the latest findings concerning the use of Hh inhibitors in clinical developmental studies and discussed the challenges, perspectives, and possible directions regarding the use of SMO/GLI inhibitors in clinical settings.

A lobulated mass on the upper back with prominent vasculature: A giant basal cell carcinoma

Basal cell carcinoma (BCC) is characterized by slow but locally invasive growth. Although there is low metastatic potential, if not treated early, these skin cancers can lead to significant morbidity and mortality. In this case report, we present a man with a neglected BCC that developed into what is termed a giant BCC or one that is greater than 5 cm. This tumor was discovered only upon workup of orthostatic lightheadedness and iron deficiency anemia. Although rare, basal cell carcinoma must be included on the differential of a large cutaneous lesion and may be a source of significant blood loss.

Sonidegib for the Treatment of Advanced Basal Cell Carcinoma

Basal cell carcinoma (BCC) accounts for almost 80% of skin cancers, and its healthcare workload burden is substantial within dermatology departments. Although most BCCs are small, well-defined tumors amenable of surgery or conservative procedures, in a small proportion of patients, BCCs can progress to an advanced stage including locally advanced BCC. The goal of the clinician in the treatment of BCC should be the right therapeutic approach at diagnosis, and different guidelines propose treatment strategies in order to prevent relapses or disease progression. In case of unresectable and untreatable BCC with radiotherapy, the first-choice medical therapy is Hedgehog-GLI (HH) pathway inhibitors. Sonidegib was approved by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) as a first-line treatment for adult patients with locally advanced BCC, becoming the second HH pathway inhibitor receiving approval after vismodegib. In this review, data on pharmacology, safety, tolerability, and efficacy of sonidegib are summarized and compared to those of vismodegib. Lastly, indications on the management of advanced basal cell carcinoma based on author’s clinical experience are provided.

Hedgehog inhibitors in the treatment of advanced basal cell carcinoma: risks and benefits

INTRODUCTION

Basal cell carcinoma (BCC) is the most common non-melanoma skin cancer (NMSC). Although surgery is the first-line therapy for BCC, some cases can progress to an advanced or, rarely, a metastatic state and targeted therapy are required. The main pathway involved in BCC tumorigenesis is the Hedgehog (Hh) signaling pathway and its inhibition is among the few treatment options available for patients with advanced BCCs. Recent advances in targeting this pathway have led to the development of two small-molecule oral Hh inhibitors, vismodegib and sonidegib.

AREAS COVERED

The aim of this article is to provide a complete overview on the use of HPI for the treatment of advanced BCCs describing the efficacy, the benefits, and risks related to these small molecules.

EXPERT OPINION

To date, the class of Hh inhibitors has revolutionized the management of patients with advanced BCCs, even though they are usually related to a toxicity profile that may represent the major cause of treatment discontinuation; an accurate study of the Hh signaling pathway and the development of other small molecules could be useful to enlarge the armamentarium of treatment in order to assure patients a personalized approach to the choice of treatment.

Nonsurgical Options for the Treatment of Basal Cell Carcinoma

Objectives

The aim of this review article is to summarize the effectiveness, potential adverse events, and indications of the main nonsurgical treatment alternatives for basal cell carcinoma.

Methods

An extensive literature review was carried out. The most relevant articles were discussed and selected by the authors in order to provide a brief but evidence-based overview of the most common nonsurgical methods used for treating basal cell carcinoma.

Results

Although surgery and Mohs micrographic surgery are often considered the optimal treatment options for basal cell carcinoma, these tumors can also be treated successfully with destructive techniques (eg, curettage alone, cryosurgery, or electrodesiccation), photodynamic therapy, topical drugs (eg, 5-fluorouracil, imiquimod, or ingenol mebutate), radiotherapy, or hedgehog pathway inhibitors. When choosing between these alternatives, physicians must take into consideration the tumor's size, location, and histopathological subtype. Special care should be taken when treating recurrent tumors. Furthermore, physician experience is of great importance when using destructive techniques. Finally, patient preference, potential adverse events, and cosmetic outcome should also be considered.

Conclusions

Dermatologists and physicians treating basal cell carcinoma should have knowledge of and experience with the large arsenal of therapeutic alternatives available for the successful, safe, and individualized management of patients with basal cell carcinoma.

Basal cell carcinoma: Contemporary approaches to diagnosis, treatment, and prevention

As the most common human cancer worldwide and continuing to increase in incidence, basal cell carcinoma is associated with significant morbidity and cost. Continued advances in research have refined both our insight and approach to this seemingly ubiquitous disease. This 2-part continuing medical education series provides a comprehensive and contemporary review of basal cell carcinoma. The second article in this series will present both the current standard of care and newly developed approaches to diagnosis, treatment, and prevention of this disease.

Targeting the Hedgehog Pathway for Locally Advanced and Metastatic Basal Cell Carcinoma

Basal cell caricnoma (BCC), the most common periocular magliancy, is treated with complete surgical excision. However, in patients not amenable to surgery or when surgical resection means loss of vital organs or disfiguring procedures due to locally advanced or metastatic disease, targeting the hedgehog pathway offers a novel treatment approach for such patients. Mutation in PTCH1 and SMO has been identified in patients with basal cell nevoid syndrome as well as in patients with sporadic BCC. Inhibition of SMO by vismodegib or sonidegib, the two sonic hedgehog inhibitor drugs approved by the Food and Drug Administration in the United States, has shown overall response rate for locally advanced and metastatic BCC around 50%. The most common side effects were muscle cramps, weight loss, fatigue, and lost appetite. Resistance to vismodegib has been attributed to mutation in SMO or activation of RAS/MAPK pathway. New research into dual inhibition aims to overcome this resistance and provide more lasting response.

The pancreatic cancer microenvironment: A true double agent

The tumor microenvironment in pancreatic cancer is a complex balance of pro- and anti-tumor components. The dense desmoplasia consists of immune cells, extracellular matrix, growth factors, cytokines, and cancer associated fibroblasts (CAF) or pancreatic stellate cells (PSC). There are a multitude of targets including hyaluronan, angiogenesis, focal adhesion kinase (FAK), connective tissue growth factor (CTGF), CD40, chemokine (C-X-C motif) receptor 4 (CXCR-4), immunotherapy, and Vitamin D. The developing clinical therapeutics will be reviewed.

Emerging drugs for the treatment of myelofibrosis

INTRODUCTION

Myelofibrosis (MF) is a myeloproliferative neoplasm associated with significant disease burden composed of splenomegaly, constitutional symptoms and a reduced life expectancy. The advent of targeted treatments has provided new means by which to improve MF associated splenomegaly, symptoms, health-related quality of life and even mortality.

AREAS COVERED

We discuss the spectrum of targeted treatments currently under investigation for MF. We furthermore compare their effects on improving anemia, reducing fibrosis and splenomegaly and enhancing symptom control.

EXPERT OPINION

MF is a complex disorder, partly attributable to its heterogeneity. Although the severity of patient symptoms correlates with risk category, high symptom burden may also be observed in low-risk patients. Serial use of PRO tools allows clinicians to objectively evaluate the MF symptom burden, compare efficacy of therapies and adjust medications to improve symptom control. Novel targeted agents have proven superior to historic treatment regimens for symptom management. Promising treatment categories include JAK2 inhibitors, histone deacetylase inhibitors, hypomethylating agents, heat shock protein-90 inhibitors, hedgehog inhibitors, PI3-AKT-mTOR inhibitors, antifibrosing agents and telomerase inhibitors. The majority of therapies remain under investigation, either alone or in combination with other treatments. It is anticipated that these agents will be increasingly integrated into standard treatment algorithms for MF symptom management.

Hedgehog signaling inhibitors as anti-cancer agents in osteosarcoma

Osteosarcoma is a rare type of cancer associated with a poor clinical outcome. Even though the pathologic characteristics of OS are well established, much remains to be understood, particularly at the molecular signaling level. The molecular mechanisms of osteosarcoma progression and metastases have not yet been fully elucidated and several evolutionary signaling pathways have been found to be linked with osteosarcoma pathogenesis, especially the hedgehog signaling (Hh) pathway. The present review will outline the importance and targeting the hedgehog signaling (Hh) pathway in osteosarcoma tumor biology. Available data also suggest that aberrant Hh signaling has pro-migratory effects and leads to the development of osteoblastic osteosarcoma. Activation of Hh signaling has been observed in osteosarcoma cell lines and also in primary human osteosarcoma specimens. Emerging data suggests that interference with Hh signal transduction by inhibitors may reduce osteosarcoma cell proliferation and tumor growth thereby preventing osteosarcomagenesis. From this perspective, we outline the current state of Hh pathway inhibitors in osteosarcoma. In summary, targeting Hh signaling by inhibitors promise to increase the efficacy of osteosarcoma treatment and improve patient outcome.

Investigational agents in metastatic basal cell carcinoma: focus on vismodegib

Vismodegib (GDC-0449, 2-chloro-N-(4-chloro-3-(pyridin-2-yl)phenyl)-4-(methylsulfonyl)benzamide, Erivedge™) is a novel first-in-human, first-in class, orally bio-available Hedgehog pathway signaling inhibitor of the G-protein coupled receptor-like protein smoothened (SMO) which was approved in the United States on January 2012. This signaling pathway is involved in the carcinogenesis of several types of tumor, as exemplified by basal cell carcinoma. This review focuses on the role of the Hedgehog pathway in the pathogenesis of basal cell carcinoma, the pharmacology and the clinical activity of vismodegib, as well as a brief summary of investigational agents in development targeting this pathway.