Pharmacokinetic dose-scheduling study of hedgehog pathway inhibitor vismodegib (GDC-0449) in patients with locally advanced or metastatic solid tumors

Efficacy and safety of sonidegib for the management of basal cell carcinoma: a drug safety evaluation

INTRODUCTION

Surgery is the standard management for most of basal cell carcinomas (BBCs). In some cases, also radiotherapy may be a valuable weapon as well as ablative and topical treatments. However, all these approaches may be limited by some tumor features. In this scenario, locally advanced BCCs (laBCC) and metastatic BCC, also defined as 'difficult-to-treat' BCC, remain the real treatment challenge. New knowledge on BCC pathogenesis, particularly the Hedgehog (HH) pathway, led to the development of new selective therapies such as vismodegib and sonidegib. In particular, sonidegib is an orally administered small molecules, which inhibits the HH signaling pathway through the binding to SMO receptor, recently approved for the management of adult patients with laBCC who are not amenable to curative surgery or radiation therapy.

AREAS COVERED

The purpose of this review is to analyze and discuss the efficacy and safety of sonidegib for the management of BCC, to provide a broad perspective on the currently available data.

EXPERT OPINION

Sonidegib is a valuable weapon for the management of difficult-to-treat BCC. Current data showed promising results in terms of effectiveness and safety. However, more studies are needed to underline its role in BCC management, also considering the presence of vismodegib, and to investigate its use in a long-term period.

Pharmacokinetics and pharmacodynamics of Hedgehog pathway inhibitors used in the treatment of advanced or treatment-refractory basal cell carcinoma

INTRODUCTION

Sonidegib and vismodegib are currently the only US Food and Drug Administration and European Medicines Agency-approved small-molecule Hedgehog pathway inhibitors (HHIs)for treating adults with advanced or refractory basal cell carcinoma (BCC) that is not amenable to conventional surgery or radiotherapy. At this time, there are no head-to-head clinical trials comparing these two HHIs for efficacy and safety to assist clinicians with determining which HHI may be best suited for their patients.

AREAS COVERED

This review briefly describes the pathogenesis of BCC, provides a detailed overview of the key pharmacokinetic profile differences between sonidegib and vismodegib, explains their pharmacodynamics, and highlights the therapeutic considerations when either HHI is used to treat special patient populations.

EXPERT OPINION

Although both HHIs act at the same molecular target in the Hedgehog pathway, there are significant differences in their pharmacokinetic profiles that may play a potential role in their efficacy and safety. Evidence-based recommendations serve to inform clinicians until direct comparative clinical trials of sonidegib versus vismodegib are conducted to determine the clinical relevance of the reported differences in their pharmacokinetic properties.

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.

Advances in Management and Therapeutics of Cutaneous Basal Cell Carcinoma

Simple Summary

Basal cell carcinoma (BCC) is the most common malignancy in humans with a range of treatment options available. Tumor and patient characteristics aid in risk-stratification, which influences treatment considerations. Here, we review the advancements in surgical, topical, field, immunotherapeutic, molecular-targeted, and experimental treatment modalities that can be employed in the correct clinical setting for the treatment of BCC.

Abstract

Basal cell carcinoma (BCC), the most common cancer in humans, is a malignant neoplasm of cells derived from the basal layer of the epidermis. Tumor characteristics such as histologic subtype, primary versus recurrent tumor, anatomic location, size, and patient attributes determine the risk level and acceptable treatment options. Surgical options offer histologic confirmation of tumor clearance. Standard excision provides post-treatment histologic assessment, while Mohs micrographic surgery (MMS) provides complete margin assessment intraoperatively. Additional treatment options may be employed in the correct clinical context. Small and low-risk BCCs, broad field cancerization, locally-advanced disease, metastatic disease, cosmetic concerns, or morbidity with surgical approaches raise consideration of other treatment modalities. We review herein a range of treatment approaches and advances in treatments for BCC, including standard excision, MMS, electrodesiccation and curettage, ablative laser treatment, radiation therapy, targeted molecular therapies, topical therapies, field therapies, immunotherapy, and experimental therapies.

Enhancing the Bioavailability and Efficacy of Vismodegib for the Control of Skin Cancer: In Vitro and In Vivo Studies

Skin cancer is the most frequent cancer throughout the world. Vismodegib (VSD) is a hedgehog blocker approved for the prevention and treatment of skin cancer. VSD, however, is poorly bioavailable and has been linked to side effects. This work focused on designing a nano-invasome gel as a vehicle for enhancing the permeation, bioavailability, and efficacy of VSD. Additionally, the combined effect of terpenes and ethanol was studied on the permeation of VSD compared with liposomes. The prepared VSD-loaded invasomes (VLI) formulation included cineole (1%v/v), cholesterol (0.15%w/w), phospholipid (2%w/w), and ethanol (3%v/v) and displayed an entrapment efficiency of 87.73 ± 3.82%, a vesicle size of 188.27 ± 3.25 nm, and a steady-state flux of 9.83 ± 0.11 µg/cm²/h. The VLI formulation was vigorously stirred into a carbopol base before being characterized in vivo to investigate the permeation, bioavailability, and efficacy of VSD. The VLI gel enhanced the dermal permeation of VSD and, as a result, had 3.59 times higher bioavailability with excellent antitumor action as compared to oral VSD. In summary, as an alternative to oral administration for skin cancer treatment, invasomes are efficient carriers for delivering VSD and enhancing its transdermal flux into deep skin layers.

Using drug scheduling to manage adverse events associated with hedgehog pathway inhibitors for basal cell carcinoma

Basal cell carcinoma (BCC) is the most common malignancy and form of skin cancer worldwide; advanced BCC, either as locally advanced BCC (laBCC) or metastatic BCC (mBCC), can cause substantial tissue invasion and morbidity. Until the recent availability of the hedgehog pathway inhibitors (HHIs) sonidegib and vismodegib, treatment options for advanced BCC were limited. These agents demonstrate efficacy in patients with laBCC and mBCC; however, the adverse events (AEs) associated with these agents can lead to treatment interruption or discontinuation and reduced quality of life, all of which significantly impact long-term adherence to therapy, which might affect clinical outcome. Given that most AEs are class-related effects, switching HHIs does not appear to lead to a significantly different AE profile, underscoring the importance of maintaining patients on their first HHI. Interrupting treatment of sonidegib and vismodegib does not appear to undermine the efficacy of these agents and is therefore a practical option to manage AEs in order to maintain continued treatment and disease control.

Evaluation of Hedgehog Pathway Inhibition on Nevoid Basal Cell Carcinoma Syndrome Fibroblasts and Basal Cell Carcinoma-Associated Fibroblasts: Are Vismodegib and Sonidegib Useful to Target Cancer-Prone Fibroblasts?

Activating mutations in the Hh pathway underlies the development of sporadic and familial skin BCC. For these oncogenic proliferations displaying ligand-independent activation of the intracellular pathway, two molecules have been approved for therapeutic purposes: vismodegib and sonidegib. Improper Hh signalling occurs in many human tumours also via a paracrine mechanism (ligand-dependent) in which the secretion of Hh ligands by stromal cells support tumour growth. On the other hand, the mobilization of neoplastic stroma by cancer cells is sustained by the activation of Hh signalling in surrounding fibroblasts suggesting a central role of this bidirectional crosstalk in carcinogenesis. Additionally, loss-of-function mutations in the PTCH1 gene in the context of NBCCS, an autosomal dominant disorder predisposing to multiple BCCs, determine tumour permissive phenotypes in dermal fibroblasts. Here, profiling syndromic and BCC-associated fibroblasts unveiled an extraordinary similarity characterized by overexpression of several Hh target genes and a marked pro-inflammatory outline. Both cell types exposed to Hh inhibitors displayed reversion of the tumour-prone phenotype. Under vismodegib and sonidegib treatment, the Wnt/β-catenin pathway, frequently over-active in tumour stroma, resulted down-regulated by pAKT-GSK3β axis and consequent increase of β-catenin turnover. Overall, this study demonstrated that vismodegib and sonidegib impacting on fibroblast tumour supportive functions might be considered in therapy for BCC independently to the mutation status of Hh components in neoplastic cells.

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.

Expression of Glioma-associated oncogene homolog 1 as biomarker with sonidegib in advanced basal cell carcinoma

The pivotal BOLT (Basal cell carcinoma Outcomes with LDE225 [sonidegib] Treatment) study established the durable efficacy and manageable toxicity of sonidegib 200 mg once daily (QD) through 42 months in patients with advanced basal cell carcinoma (BCC). This secondary analysis used expression of Glioma-associated oncogene homolog 1 (GLI1) as a biomarker to assess the extent of Hedgehog pathway inhibition by sonidegib in patients with locally advanced BCC (laBCC) and metastatic BCC (mBCC). The study enrolled 230 patients, 79 and 151 receiving sonidegib 200 and 800 mg QD, respectively. At week 17, GLI1 expression was reduced from baseline by a median percentage (95% confidence interval) of 88.7% (54.6%-93.0%) and 97.0% (77.5%-98.9%) for aggressive laBCC, 97.5% (80.3%-98.8%) and 95.0% (80.7%-97.5%) for nonaggressive laBCC, and 99.1% (96.4%-99.6%) and 99.3% (95.9%-99.9%) for mBCC in the 200 and 800 mg groups, respectively. Substantial repression of GLI1 was observed in patient subgroups stratified by age, sex, BCC cytological subtype, Eastern Cooperative Oncology Group performance status, lesion site, baseline number of BCCs, and prior radiotherapy. Results support further studies on the inhibition of Hedgehog pathway genes by sonidegib in patients with laBCC and mBCC.

A Physiologically Based Pharmacokinetic Model of Vismodegib: Deconvoluting the Impact of Saturable Plasma Protein Binding, pH-Dependent Solubility and Nonsink Permeation

Vismodegib displays unique pharmacokinetic characteristics including saturable plasma protein binding to alpha-1 acid glycoprotein (AAG) and apparent time-dependent bioavailability leading to non-linear PK with dose and time, significantly faster time to steady-state and lower than predicted accumulation. Given these unique characteristics, a PBPK model was developed to explore mechanistic insights into saturable protein binding and complex oral absorption processes and de-convolute the impact of these independent non-linear processes on vismodegib exposure. Simcyp V18 was used for model development; oral absorption was characterized using the multi-layer gut wall (M-ADAM) model and mechanistic permeability model, incorporating transport across an unstirred boundary layer (UBL) between the luminal fluid and enterocyte in each segment of the gastrointestinal tract. PBPK simulations were compared with observed PK data from clinical trials in oncology patients and healthy subjects. Saturation of vismodegib protein binding to AAG led to substantially lower total drug accumulation, time to steady-state, and Css_total. For free exposure, Css_free and accumulation were unchanged, but time to steady-state was substantially reduced. Vismodegib oral absorption declined with both dose and dosing frequency; the concentration gradient driving vismodegib oral absorption declined with multiple doses, leading to a 32% decrease in vismodegib f_a from first dose to steady-state. Fed simulations suggested that increased solubility and dissolution are partially offset by reduced permeability across the UBL due to slower diffusion of micelle-bound drug. This work demonstrates the value of PBPK modeling to simultaneously capture and de-convolute multi-faceted absorption and disposition processes and provide mechanistic insights for compounds with complex pharmacokinetics.

Secondary Resistant Mutations to Small Molecule Inhibitors in Cancer Cells

Secondary resistant mutations in cancer cells arise in response to certain small molecule inhibitors. These mutations inevitably cause recurrence and often progression to a more aggressive form. Resistant mutations may manifest in various forms. For example, some mutations decrease or abrogate the affinity of the drug for the protein. Others restore the function of the enzyme even in the presence of the inhibitor. In some cases, resistance is acquired through activation of a parallel pathway which bypasses the function of the drug targeted pathway. The Catalogue of Somatic Mutations in Cancer (COSMIC) produced a compendium of resistant mutations to small molecule inhibitors reported in the literature. Here, we build on these data and provide a comprehensive review of resistant mutations in cancers. We also discuss mechanistic parallels of resistance.

Vismodegib: A Review in Advanced Basal Cell Carcinoma

Vismodegib (Erivedge^®) is the first-in-class, oral small molecule inhibitor of the Hedgehog (Hh) pathway, abnormal activation of which is associated with basal cell carcinoma (BCC). In the USA, vismodegib is indicated for the treatment of adults with metastatic BCC (mBCC) or with locally-advanced BCC (LaBCC) that has recurred following surgery or who are not candidates for surgery, and who are not candidates for radiation. Similarly, in the EU, vismodegib is indicated for the treatment of adult patients with symptomatic mBCC, or with laBCC inappropriate for surgery or radiotherapy. The full European approval of vismodegib was based on the results of two phase II, open-label, noncomparative, international trials (ERIVANCE BCC and STEVIE), both of which showed high rates of tumour control in the indicated patient populations, including individuals with or without Gorlin syndrome. These studies also showed that vismodegib has an acceptable and manageable tolerability profile characterized by a number of class-related treatment-emergent adverse events, including muscle spasms, taste disturbances, alopecia, weight loss and asthenia (fatigue). Primary and secondary resistance to vismodegib has been documented, albeit at a low rate compared with some other targeted therapies. Vismodegib is therefore an effective and generally well tolerated systemic therapy for patients with mBCC and laBCC that can no longer be suitably controlled with surgery and/or radiotherapy. Historically, it is the first member of a class of drugs (Hh pathway inhibitors) that are now considered to be first-line treatment options for such individuals.

Pharmacokinetic and Pharmacodynamic Considerations for Drugs Binding to Alpha-1-Acid Glycoprotein

According to the free drug hypothesis only the unbound drug is available to act at physiological sites of action, and as such the importance of plasma protein binding primarily resides in its impact on pharmacokinetics and pharmacodynamics. Of the major plasma proteins, alpha-1-acid glycoprotein (AAG) represents an intriguing one primarily due to the high affinity, low capacity properties of this protein. In addition, there are marked species and age differences in protein expression, homology and drug binding affinity. As such, a thorough understanding of drug binding to AAG can help aid and improve the translation of pharmacokinetic/pharmacodynamic (PK/PD) relationships from preclinical species to human as well as adults to neonates. This review provides a comprehensive overview of our current understanding of the biochemistry of AAG; endogenous function, impact of disease, utility as a biomarker, and impact on PK/PD. Experimental considerations are discussed as well as recommendations for understanding the potential impact of AAG on PK through drug discovery and early development.

New developments in the treatment of basal cell carcinoma: update on current and emerging treatment options with a focus on vismodegib

Basal cell carcinoma (BCC) is the most common form of skin cancer worldwide. Although most BCCs can be treated by relatively simple surgical or nonsurgical methods, some patients with BCC may eventually develop advanced disease which can either be locally destructive or even include metastatic spread. The present review summarizes the current literature on the treatment of both early and advanced BCC with a focus on the hedgehog inhibitor vismodegib which has become an integral part of the management of patients with advanced BCC since its regulatory approval in 2012.

Small Molecule Inhibitors of the Hedgehog Pathway in the Treatment of Basal Cell Carcinoma of the Skin

Basal cell carcinoma (BCC) is the most common type of skin cancer, with rising incidence rates primarily attributed to an aging population and ultraviolet radiation exposure. While the majority of BCCs are localized and respond to standard therapies, a very small minority of these tumors become locally destructive or metastasize. These advanced BCCs may not be amenable to localized treatment with surgery and/or radiation therapy. Most BCCs result from mutations in key receptors in the Hedgehog (HH) signaling pathway. As a result, identification of drugs that inhibit the receptor Smoothened (SMO) in the HH pathway has resulted in novel therapeutic approaches to treating patients with advanced BCC. These HH-pathway inhibiting medications have shown efficacy in clinical trials, and two medications, vismodegib and sonidegib, have received FDA approval. However, several limitations of these drugs have been identified, including treatment-limiting adverse events, drug resistance, and the formation of additional malignancies. This paper aims to summarize the clinical trials leading to the approval of SMO inhibitors, as well as reviewing potential mechanisms driving tumor resistance and the formation of cutaneous squamous cell carcinomas. Strategies to overcome some of these challenges, including the development of drugs that inhibit other downstream targets in the HH pathway, are the subject of ongoing clinical trials.

Long-term efficacy and safety of sonidegib in patients with locally advanced and metastatic basal cell carcinoma: 30-month analysis of the randomized phase 2 BOLT study

BACKGROUND

Patients with locally advanced basal cell carcinoma (laBCC) or metastatic BCC (mBCC), two difficult-to-treat populations, have had limited treatment options. Sonidegib, a hedgehog pathway inhibitor (HPI), was approved in laBCC based on results from the BOLT trial.

OBJECTIVE

To evaluate long-term efficacy and safety of sonidegib in laBCC and mBCC in the BOLT 18- and 30-month analyses.

METHODS

BOLT (NCT01327053, ClinicalTrials.gov), a double-blind phase 2 study, enrolled patients from July 2011 until January 2013. Eligible HPI-treatment-naïve patients with laBCC not amenable to curative surgery/radiotherapy or mBCC were randomized 1 : 2 to sonidegib 200 mg (laBCC, n = 66; mBCC, n = 13) or 800 mg (laBCC, n = 128; mBCC, n = 23). Tumour response was assessed per central and investigator review.

RESULTS

With 30 months of follow-up, among patients treated with sonidegib 200 mg (approved dose), objective response rates were 56.1% (central) and 71.2% (investigator) in laBCC and 7.7% (central) and 23.1% (investigator) in mBCC. Tumour responses were durable as follows: median duration of response was 26.1 months (central) and 15.7 months (investigator) in laBCC and 24.0 months (central) and 18.1 months (investigator) in mBCC. Five patients with laBCC and three with mBCC in the 200-mg arm died. Median overall survival was not reached in either population; 2-year overall survival rates were 93.2% (laBCC) and 69.3% (mBCC). In laBCC, efficacy was similar regardless of aggressive or non-aggressive histology. Sonidegib 200 mg continued to have a better safety profile than 800 mg, with lower rates of grade 3/4 adverse events (43.0% vs. 64.0%) and adverse events leading to discontinuation (30.4% vs. 40.0%).

CONCLUSION

Sonidegib continued to demonstrate long-term efficacy and safety in these populations. These data support the use of sonidegib 200 mg per local treatment guidelines.

Phase I Study of LY2940680, a Smo Antagonist, in Patients with Advanced Cancer Including Treatment-Naïve and Previously Treated Basal Cell Carcinoma

Purpose: The purpose of this study was to determine a recommended phase II dose and schedule of LY2940680 (taladegib) for safe administration to patients with locally advanced/metastatic cancer.Experimental Design: This was a phase I, multicenter, open-label study of oral LY2940680. The maximum tolerable dose (MTD) was determined using a 3+3 design, the dose was confirmed, and then treatment-naïve and previously hedgehog (Hh)-inhibitor-treated patients with basal cell carcinoma (BCC) were enrolled.Results: Eighty-four patients were treated (dose escalation, n = 25; dose confirmation, n = 19; and BCC dose expansion, n = 40). Common treatment-emergent adverse events were dysgeusia [41 (48.8%)], fatigue [40 (47.6%)], nausea [38 (45.2%)], and muscle spasms [34 (40.5%)]. Four patients experienced events (3 were grade 3; 1 was grade 2) that were considered dose-limiting toxicities (DLT). The MTD was determined to be 400 mg because of DLTs and dose reductions. Pharmacokinetic analyses showed no clear relationship between exposure and toxicity. Analysis of Gli1 mRNA from skin biopsies from unaffected areas suggested that all doses were biologically active [inhibition median of 92.3% (80.9% to 95.7%)]. All clinical responses (per RECIST 1.1) were in patients with BCC (n = 47); the overall and estimated response rate was 46.8% (95% confidence interval, 32.1%-61.9%). Responses were observed in patients previously treated with Hh therapy (11/31) and in Hh treatment-naïve (11/16) patients.Conclusions: LY2940680 treatment resulted in an acceptable safety profile in patients with advanced/metastatic cancer. Clinical responses were observed in patients with locally advanced/metastatic BCC who were previously treated with Hh therapy and in Hh treatment-naïve patients. Clin Cancer Res; 24(9); 2082-91. ©2018 AACR.

Vismodegib

Vismodegib (GDC-0449, Erivedge^®) is a small molecule antagonist of the hedgehog (Hh) pathway that binds to smoothened (SMO) and leads to inhibition of an aberrant activation of the Hh pathway. Dysregulated Hh signaling results in uncontrolled proliferation in basal cell carcinoma (BCC) and has also been found present in medulloblastoma, and many other cancers such as those of gastrointestinal tract, brain, lung, breast, and prostate. In January 2012, vismodegib became the first agent to target the Hh pathway to receive approval by the United States Food and Drug Administration (FDA) and in July 2013 approval by the European Medicines Agency (EMA) followed for the treatment of adult patients with symptomatic metastatic BCC, or locally advanced BCC inappropriate for surgery or radiotherapy. The role of vismodegib in other malignancies than BCC has still to be investigated.

Spotlight on vismodegib in the treatment of basal cell carcinoma: an evidence-based review of its place in therapy

Vismodegib is approved for the treatment of adult patients with metastatic (mBCC) or locally advanced basal cell carcinoma (laBCC) that have recurred following surgery or for those who are not good candidates for surgery (risk/benefit ratio is against patient's benefit, either because of the general condition or because of the expected morbidity from the surgery) or radiation therapy. This article provides an evidence-based review of its current place in therapy. Analytically, the clinical implications in the management of laBCCs and mBCCs and possible new indications, including the neoadjuvant use before surgical excision, are discussed, while in the end, the challenges regarding class-related adverse events and their optimal management are highlighted.

CXCL14 is a candidate biomarker for Hedgehog signalling in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is associated with aberrant expression of developmental pathways, including Hedgehog (Hh). As Hh signalling contributes to multiple pro-fibrotic processes, Hh inhibition may represent a therapeutic option for IPF. However, no non-invasive biomarkers are available to monitor lung Hh activity.

METHODS

We assessed gene and protein expression in IPF and control lung biopsies, mouse lung, fibroblasts stimulated in vitro with sonic hedgehog (SHh), and plasma in IPF patients versus controls, and cancer patients before and after treatment with vismodegib, a Hh inhibitor.

RESULTS

Lung tissue from IPF patients exhibited significantly greater expression of Hh-related genes versus controls. The gene most significantly upregulated in both IPF lung biopsies and fibroblasts stimulated in vitro with SHh was CXCL14, which encodes a soluble secreted chemokine whose expression is inhibited in vitro by the addition of vismodegib. CXCL14 expression was induced by SHh overexpression in mouse lung. Circulating CXCL14 protein levels were significantly higher in plasma from IPF patients than controls. In cancer patients, circulating CXCL14 levels were significantly reduced upon vismodegib treatment.

CONCLUSIONS

CXCL14 is a systemic biomarker that could be used to identify IPF patients with increased Hh pathway activity and monitor the pharmacodynamic effects of Hh antagonist therapy in IPF.

TRIAL REGISTRATION NUMBER

Post-results, NCT00968981.

Hedgehog pathway inhibition in advanced basal cell carcinoma: latest evidence and clinical usefulness

Treatment of locally advanced basal cell carcinomas (laBCCs) with large, aggressive, destructive, and disfiguring tumors, or metastatic disease is challenging. Dysregulation of the Hedgehog (Hh) signaling pathway has been identified in the vast majority of basal cell carcinomas (BCCs). There are two United States Food and Drug Administration (US FDA)-approved Hh pathway inhibitors (HPIs) that exhibit antitumor activity in advanced BCC with an acceptable safety profile. Common adverse effects include muscle spasms, dysgeusia, alopecia, fatigue, nausea and weight loss.

The Prognostic Significance of the Hedgehog Signaling Pathway in Colorectal Cancer

Despite significant advances in the management of colorectal cancer (CRC) the identification of new prognostic biomarkers continues to be a challenge. Since its initial discovery, the role of the Hedgehog (Hh) signaling pathway in carcinogenesis has been extensively studied. We herein review and comment on the prognostic significance of the Hh signaling pathway in CRC. The differential expression of Hh pathway components between malignant and nonmalignant conditions as well as correlation of Hh activation markers with various clinicopathological parameters and the effect on disease-free survival, overall survival, and disease recurrence in patients with CRC is summarized and discussed. According to the studies reviewed herein the activation of the Hh pathway seems to be correlated with adverse clinicopathological features and worse survival. However, to date study results show significant variability with regard to the effect on outcomes. Such results need to be interpreted carefully and emphasize the need for further well designed studies to characterize the actual influence of the Hh pathway in CRC prognosis.

Vismodegib in the treatment of basal cell carcinoma: indications for clinical practice

Basal cell carcinoma (BCC) is a frequent skin cancer which can cause substantial morbidity due to its location on the face, its frequency of relapse and its capacity to invade local tissues. The primary treatment of BCC usually involves surgery or radiotherapy. In patients who have exhausted surgical and radiotherapy options or with metastatic BCC, guidelines recommend the use of the Hedgehog pathway inhibitor vismodegib. This molecule is indicated for the treatment of adults with metastatic BCC, or with locally advanced BCC which has recurred following surgery or who are not eligible to surgery or radiation. This paper aims to provide suggestions on the optimal management of BCC patients treated with vismodegib in clinical practice, according to the large experience gained by a group of Italian dermatologists and oncologists. In particular, the focus of this paper will be on the monitoring of patients and the management of adverse events.

Reduced proliferation and increased apoptosis of the SGC‑7901 gastric cancer cell line on exposure to GDC‑0449

The sonic hedgehog (Shh) pathway is known to be vital in embryonic development and cancer propagation due to its irreplaceable role in cell proliferation and differentiation. GDC‑0449, a basal cell skin cancer target drug approved by the Food and Drugs Administration, is a smoothened (Smo)-specific antagonist. Although it has been clinically verified as a valid drug for the treatment of skin and pancreatic cancer, the application of GDC‑0449 in gastric cancer requires further investigation. In the present study, high-glucose Dulbecco's modified Eagle's medium with 10% fetal bovine serum was used for routine SGC‑7901 cell line culture. A Cell Counting Kit‑8 assay was employed for determination of the reproductive rate of the cells. Flow cytometry was performed to determine the apoptosis status of the SGC‑7901 cell line through Q4 analysis. Reverse transcription-quantitative polymerase chain reaction and Western blot analyses were used as target molecule detection vehicles. As expected, GDC‑0449 reduced the expression levels of Shh‑associated molecules, including Smo and gli1, compared with the blank group. The rate of cell proliferation was markedly limited and was accompanied by an increase in the apoptotic rate following GDC‑0449 exposure. In addition, further investigations confirmed B cell lymphoma‑2 (Bcl‑2) as the downstream molecular mechanism of GDC‑0449 efficacy. Of note, representatives of the cancer stem cell (CSC) surface marker, CD44 and CD133, demonstrated a similar trend to the Smo restriction observed. By repressing the expression of Bcl‑2, GDC‑0449 inhibited the normal proliferation of SGC‑7901 cells, and accelerated the apoptotic rate of the cells. It may also alter CSC properties due to the reduction in the expression of surface markers.

Semi-Mechanism-Based Population Pharmacokinetic Modeling of the Hedgehog Pathway Inhibitor Vismodegib

Vismodegib, approved for the treatment of advanced basal cell carcinoma, has shown unique pharmacokinetic (PK) nonlinearity and binding to α1-acid glycoprotein (AAG) in humans. A semi-mechanism-based population pharmacokinetic (PopPK) model was developed from a meta-dataset of 225 subjects enrolled in five clinical studies to quantitatively describe the clinical PK of vismodegib and identify sources of interindividual variability. Total and unbound vismodegib were analyzed simultaneously, together with time-varying AAG data. The PK of vismodegib was adequately described by a one-compartment model with first-order absorption, first-order elimination of unbound drug, and saturable binding to AAG with fast-equilibrium. The variability of total vismodegib concentration at steady-state was predominantly explained by the range of AAG level. The impact of AAG on unbound concentration was clinically insignificant. Various approaches were evaluated for model validation. The semi-mechanism-based PopPK model described herein provided insightful information on the nonlinear PK and has been utilized for various clinical applications.

Advanced basal cell carcinoma, the hedgehog pathway, and treatment options - role of smoothened inhibitors

Cutaneous basal cell carcinoma (BCC) is the most common human cancer and its incidence is rising worldwide. Ultraviolet radiation exposure, including tanning bed use, as well as host factors play a role in its development. The majority of cases are treated and cured with local therapies including surgery. Yet, the health care costs of diagnosis and treatment of BCCs in the US is substantial. In the United States, the cost of nonmelanoma skin cancer care in the Medicare population is estimated to be US$426 million per year. While rare, locally advanced BCCs that can no longer be controlled with surgery and/or radiation, and metastatic BCCs do occur and can be associated with significant morbidity and mortality. Vismodegib (GDC-0449), a smoothened inhibitor targeted at the hedgehog pathway, is the first US Food and Drug Association (FDA)-approved agent in the treatment of locally advanced, unresectable, and metastatic BCCs. This class of agents appears to be changing the survival rates in advanced BCC patients, but appropriate patient selection and monitoring are important. Multidisciplinary assessments are essential for the optimal care and management of these patients. For some patients with locally advanced BCC, treatment with a hedgehog inhibitor may eliminate the need for an excessively disfiguring or morbid surgery.

Inhibition of Gli/hedgehog signaling in prostate cancer cells by "cancer bush" Sutherlandia frutescens extract

Sutherlandia frutescens is a medicinal plant, traditionally used to treat various types of human diseases, including cancer. Previous studies of several botanicals link suppression of prostate cancer growth with inhibition of the Gli/hedgehog (Gli/Hh) signaling pathway. Here we hypothesized the anti-cancer effect of S. frutescens was linked to its inhibition of the Gli/Hh signaling in prostate cancer. We found a dose- and time-dependent growth inhibition in human prostate cancer cells, PC3 and LNCaP, and mouse prostate cancer cell, TRAMP-C2, treated with S. frutescens methanol extract (SLE). We also observed a dose-dependent inhibition of the Gli-reporter activity in Shh Light II and TRAMP-C2QGli cells treated with SLE. In addition, SLE can inhibit Gli/Hh signaling by blocking Gli1 and Ptched1 gene expression in the presence of a Gli/Hh signaling agonist (SAG). A diet supplemented with S. frutescens suppressed the formation of poorly differentiated carcinoma in prostates of TRAMP mice. Finally, we found Sutherlandioside D was the most potent compound in the crude extract that could suppress Gli-reporter in Shh Light II cells. Together, this suggests that the S. frutescens extract may exert anti-cancer effect by targeting Gli/Hh signaling, and Sutherlandioside D is one of the active compounds.

A comprehensive review of the role of the hedgehog pathway and vismodegib in the management of basal cell carcinoma

BACKGROUND

Basal cell carcinoma (BCC) is the most common cancer. Most cases of BCCs are treated with only optimal surgical resection. However, unresectable, locally advanced or metastatic tumors might have potential to progress. In this patient group, there is no standardized treatment approach. Vismodegib is a new selective inhibitor of the hedgehog (Hh) pathway. This manuscript is aimed to review the efficacy of the Hh pathway inhibitor vismodegib in BCC patients with locally advanced or metastatic disease.

SCOPE

Vismodegib showed positive results in clinical studies. A computerized search of the PubMed and American Society of Clinical Oncology Meeting abstracts was performed, by searching for the following keywords: 'vismodegib', 'pathway', 'inhibitor', and 'targeted therapies for BCC'. The last search was done on 1 September 2014. Most of the vismodegib data depend on phase I and II trials.

FINDINGS

Preclinical and clinical studies have shown that Hh pathway activation occurs in BCC. In BCC patients the role of chemotherapy is not completely known. Although conventional chemotherapies like cisplatins increase the response rate in BCC, improvement in overall survival and progression free survival were not demonstrated. Results of both phase I and phase II studies have shown that vismodegib is a potential new treatment strategy for patients with locally advanced and metastatic BCC. As in previously published phase I trials, in the ERIVANCE BCC study the primary endpoint, objective response rate, significantly increased by 43% and 30% in patients with locally advanced and metastatic BCC, respectively. Because of the promising results in phase I and II trials, vismodegib was approved by the Food and Drug Administration (FDA) in the treatment of patients with BCC who are not suitable for surgery or radiotherapy or with relapsed locally advanced disease following surgery or metastatic disease.

CONCLUSION

Recent trials have shown that vismodegib has produced promising activity in patients with locally advanced and metastatic BCC. The ongoing studies with vismodegib in other solid tumors and BCC will shed light on more certain treatment pathways.

Efficacy and safety of vismodegib : a new therapeutic agent in the treatment of basal cell carcinoma

INTRODUCTION

Basal cell carcinoma (BCC) is the most common human malignancy. Treatment options for the minority of patients presenting with locally advanced inoperable or metastatic BCC are very limited. The hedgehog (Hh) pathway plays a crucial role in the pathogenesis of BCC. Recent advances in targeting this pathway have led to the development of a first-in-class, small-molecule oral Hh inhibitor, vismodegib (Erivedge®, Genentech).

AREAS COVERED

In this article, we review vismodegib with regard to its mechanism of action, clinical efficacy, safety and tolerability, and we consider the causes of emerging resistance to the drug.

EXPERT OPINION

Vismodegib is a welcome addition to the treatment paradigm for BCC. Approval was based on Phase II evidence, the patient number was relatively small, there was no control group or a comparator group and survival data have not been presented so longer term follow-up and larger exposure to the drug is required to fully appreciate its clinical utility into the future. With ongoing use of the drug in the nontrial population and further studies investigating its use in both early- and later-stage disease, we will get a better understanding of the drug and determine its place in the armamentarium against BCC.

Hedgehog signaling pathway: a novel target for cancer therapy: vismodegib, a promising therapeutic option in treatment of basal cell carcinomas

The Hedgehog signaling pathway is one of the major regulators of cell growth and differentiation during embryogenesis and early development. It is mostly quiescent in adults but inappropriate mutation or deregulation of the pathway is involved in the development of cancers. Therefore; recently it has been recognized as a novel therapeutic target in cancers. Basal cell carcinomas (BCC) and medulloblastomas are the two most common cancers identified with mutations in components of the hedgehog pathway. The discovery of targeted Hedgehog pathway inhibitors has shown promising results in clinical trials, several of which are still undergoing clinical evaluation. Vismodegib (GDC-0449), an oral hedgehog signaling pathway inhibitor has reached the farthest in clinical development. Initial clinical trials in basal cell carcinoma and medulloblastoma have shown good efficacy and safety and hence were approved by U.S. FDA for use in advanced basal cell carcinomas. This review highlights the molecular basis and the current knowledge of hedgehog pathway activation in different types of human cancers as well as the present and future prospects of the novel drug vismodegib.

Targeting EGFR and sonic hedgehog pathways for locally advanced eyelid and periocular carcinomas

For patients with metastatic or locally advanced eyelid and periocular carcinoma not amenable to surgical excision, targeted therapies have shown efficacy with better tolerability compared to cytotoxic chemotherapy. Overexpression of epithelial growth factor receptor was found in squamous cell carcinomas. Vismodegib targets the mutation in the hedgehog pathway identified in basal cell carcinoma and basal cell nevus syndrome. Targeted therapies provide a novel and potentially effective treatment alternative for patients with eyelid carcinoma not amendable for surgery, including those with metastatic, locally advanced disease, advanced age, and significant comorbidities. High cost, need for long-term treatment, and toxicity are relative limitations.

Cholestatic hepatic injury associated with vismodegib, aspirin, and naproxen use: a case study and review of vismodegib safety

BACKGROUND

Vismodegib is a novel hedgehog pathway inhibitor approved to treat advanced and metastatic basal cell carcinoma (BCC) in the United States. Several studies have demonstrated efficacy for treatment of new and existing BCC in both basal cell nevus syndrome (BCNS) and non-BCNS patients. However, severe and numerous adverse events are associated with vismodegib use. Therefore, we have also examined all of the currently published clinical trials and tabulated the available adverse events for review. The most frequently reported adverse events include muscle spasms (53.4%), dysgeusia/ageusia (49.3%), alopecia (38.8%), fatigue (32.0%), nausea (28.4%), weight loss (24.2%), and decreased appetite (16.5%).

CASE STUDY

We report a case of a previously healthy 72-year-old male with a history of innumerable BCCs who developed severe nausea, jaundice, and cholestasis with significantly elevated BUN, creatinine, and liver enzymes one month after starting vismodegib. The patient began using over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) to treat severe, vismodegib-induced myalgia. No other new medications were started. Our patient had no history of liver disease.

CONCLUSIONS

Herein, we describe a potential serious adverse effect associated with vismodegib use. Whether the illness is directly attributable to the medication or the result of drug-drug interactions between vismodegib and NSAIDs, practitioners should be aware of the possibility of hepatic injury in patients on vismodegib. Furthermore, patients need to be informed of the potential risks of vismodegib and should be monitored closely to ensure that life-threatening complications of treatment are avoided.

Hedgehog signaling pathway and cancer therapeutics: progress to date

The Hedgehog (Hh) pathway is a developmental signaling pathway involved in numerous developmental processes, including determination of cell fate, patterning, proliferation, survival, and differentiation. While this pathway is silenced in most adult tissues, aberrant activation of it has been documented in a variety of malignancies. In cancers such as basal cell carcinoma (BCC), ligand-independent mechanisms lead to constitutive Hh pathway activation through mutations in components of the pathway, including patched-1 (PTCH1) or smoothened (SMO). On the contrary, numerous other solid and hematologic tumors have been shown to harbor ligand-dependent activation of the Hh pathway by autocrine or paracrine mechanisms. Given that aberrant Hh pathway signaling has been seen in a number of malignancies, this pathway has been an attractive target for drug development. While the best-characterized approach is to target the SMO receptor, other rational approaches for inhibiting the Hh pathway include inhibiting downstream components or directly binding Hh ligands. In January of 2012, vismodegib, a SMO antagonist, became the first agent to target the Hh pathway to receive approval by the United States Food and Drug Administration (FDA) after this agent showed remarkable activity in phase I and II trials for the treatment of BCC. Despite promising preclinical studies with Hh pathway inhibitors in other malignancies that have suggested a potential role for these agents, attempts to translate this potential to clinical benefit has been disappointing. Future efforts will require further careful interpretation and analysis to determine the potential determinants and predictors of efficacy. Currently, several phase I and II trials evaluating Hh inhibitors in a variety of tumor settings are underway.

Vismodegib: the proof of concept in Basal cell carcinoma

Although basal cell carcinoma (BCC) is the most common cancer worldwide, its metastatic dissemination is exceptional. Before 2012, we had a few treatment options available for metastatic or locally advanced cases. Management of these patients was complicated due to the lack of scientific data, the deterioration of a patient’s general status, the patient’s advanced age, and the presence of multiple comorbidities. The hedgehog signaling pathway is dysregulated in BCC. The exploration of this signaling pathway yielded to a major milestone in the treatment of advanced BCC. Vismodegib (GDC-0449), an oral small-molecule agent that targets the Hedgehog signaling pathway, demonstrates high levels of activity in clinical trials. It was approved in January 2012 for the treatment of locally advanced or metastatic BCC. Vismodegib confirms, once again, the interest in exploring the signal transduction pathways in cancers.

The sonic hedgehog factor GLI1 imparts drug resistance through inducible glucuronidation

Drug resistance is a major hurdle in oncology. Responses of acute myeloid leukaemia (AML) patients to cytarabine (Ara-C)-based therapies are often short lived with a median overall survival of months. Therapies are under development to improve outcomes and include targeting the eukaryotic translation initiation factor (eIF4E) with its inhibitor ribavirin. In a Phase II clinical trial in poor prognosis AML, ribavirin monotherapy yielded promising responses including remissions; however, all patients relapsed. Here we identify a novel form of drug resistance to ribavirin and Ara-C. We observe that the sonic hedgehog transcription factor glioma-associated protein 1 (GLI1) and the UDP glucuronosyltransferase (UGT1A) family of enzymes are elevated in resistant cells. UGT1As add glucuronic acid to many drugs, modifying their activity in diverse tissues. GLI1 alone is sufficient to drive UGT1A-dependent glucuronidation of ribavirin and Ara-C, and thus drug resistance. Resistance is overcome by genetic or pharmacological inhibition of GLI1, revealing a potential strategy to overcome drug resistance in some patients.

Vismodegib for the treatment of basal cell carcinoma: results and implications of the ERIVANCE BCC trial

ABSTRACT: 

The need for effective treatment of patients with locally advanced or metastatic basal cell carcinoma (BCC), in conjunction with major advances in the elucidation of the molecular basis of this tumor has led to the advent of new targeted therapies – namely, hedgehog inhibitors. The rationale for their use in patients with advanced BCC is based on their inhibitory effect on the hedgehog pathway, which is aberrantly activated in BCCs due to mutations of its primary components, PTCH1 and SMO genes. Vismodegib (GDC-0449) is an orally bioavailable hedgehog pathway inhibitor that selectively inhibits SMO. The ERIVANCE BCC study is a Phase II, international, multicenter clinical trial evaluating the efficacy and safety of vismodegib 150 mg once daily in patients with locally advanced or metastatic BCC. Vismodegib has been approved for the treatment of adult patients with metastatic BCC, or with locally advanced BCC that has recurred following surgery or who are not candidates for surgery or radiation therapy. This article will outline the rationale, design and available results from the ERIVANCE BCC study and discuss the clinical implications of vismodegib in the management of patients with BCC. Challenges regarding vismodegib use include the recurrence of BCC after drug discontinuation, the development of acquired resistance, the dramatic efficacy in patients with Gorlin syndrome, and class-related drug toxicity. Ongoing clinical trials aim to explore the role of vismodegib in the neoadjuvant setting prior to surgery, the potential use of alternate dosing regimens in order to limit chronic adverse events, as well as the identification of patients with BCC that are more likely to respond to this targeted therapy based on genotypic and/or phenotypic characteristics.

Vismodegib

Vismodegib (GDC-0449, Erivedge®) is a novel small molecule antagonist of the hedgehog (Hh) pathway that binds to smoothened (SMO) and leads to inhibition of an aberrant activation of the Hh pathway. Dysregulated Hh signaling results in uncontrolled proliferation in basal cell carcinoma (BCC) and has also been found present in medulloblastoma, and many other cancers such as those of gastrointestinal tract, brain, lung, breast, and prostate. In January 2012, vismodegib became the first agent to target the Hh pathway to receive approval by the United States Food and Drug Administration (FDA) and in July 2013 approval by the European Medicines Agency (EMA) followed for the treatment of adult patients with symptomatic metastatic BCC, or locally advanced BCC inappropriate for surgery or radiotherapy. At the moment, many trials are ongoing to further investigate the role of vismodegib in other malignancies than BCC.

Vismodegib: an inhibitor of the Hedgehog signaling pathway in the treatment of basal cell carcinoma

OBJECTIVE

To review vismodegib, the first Food and Drug Administration (FDA)-approved Hedgehog (Hh) signaling pathway inhibitor, in the treatment of advanced basal cell carcinoma (BCC).

DATA SOURCES

MEDLINE and PubMed were searched using the terms vismodegib, GDC-0449, RG3616, and basal cell carcinoma for relevant clinical trials through September 2013. The FDA Web site, the National Clinical Trials registry, and abstracts from the American Society of Clinical Oncology (ASCO) were also evaluated to identify unpublished data and future clinical trials.

STUDY SELECTION/DATA EXTRACTION

All identified clinical and preclinical studies published in the English language were assessed, including selected references from the bibliographies of articles.

DATA SYNTHESIS

Activation of the Hh signaling pathway is well documented in BCC. Vismodegib is a small-molecule inhibitor of Hh signaling that acts by antagonizing the protein Smoothened (SMO), thereby preventing downstream transcriptional activation of genes involved in cell proliferation and survival. Vismodegib was approved by the FDA in January 2012 for the treatment of recurrent, locally advanced BCC (laBCC), or metastatic BCC (mBCC) for which surgery or radiation cannot be utilized. A pivotal phase 2 trial evaluating 104 patients demonstrated that treatment with vismodegib, 150 mg orally once daily, resulted in a 30% and 43% objective response rate in patients with mBCC and laBCC, respectively. The most common adverse effects from vismodegib were mild to moderate and included muscle spasms, dysgeusia, decreased weight, fatigue, alopecia, and diarrhea. However, clinical studies noted a high incidence of discontinuation of therapy by patients for reasons other than disease progression.

CONCLUSIONS

The approval of vismodegib represents the only targeted, prospectively studied treatment option for patients with advanced BCC. Further research assessing the utility of vismodegib in the treatment of other malignancies and the development of resistance patterns will more clearly define the role of Hedgehog inhibition in the broader scheme of oncological disorders.

Targeting hedgehog signaling in cancer: research and clinical developments

Since its first description in Drosophila by Drs Nusslein-Volhard and Wieschaus in 1980, hedgehog (Hh) signaling has been implicated in regulation of cell differentiation, proliferation, tissue polarity, stem cell maintenance, and carcinogenesis. The first link of Hh signaling to cancer was established through studies of Gorlin syndrome in 1996 by two independent teams. Later, it was shown that Hh signaling may be involved in many types of cancer, including skin, leukemia, lung, brain, and gastrointestinal cancers. In early 2012, the US Food and Drug Administration approved the clinical use of Hh inhibitor Erivedge/vismodegib for treatment of locally advanced and metastatic basal cell carcinomas. With further investigation, it is possible to see more clinical applications of Hh signaling inhibitors. In this review, we will summarize major advances in the last 3 years in our understanding of Hh signaling activation in human cancer, and recent developments in preclinical and clinical studies using Hh signaling inhibitors.

Phase I study of vismodegib in children with recurrent or refractory medulloblastoma: a pediatric brain tumor consortium study

PURPOSE

To investigate the safety, dose-limiting toxicities, and pharmacokinetics of the smoothened inhibitor vismodegib in children with refractory or relapsed medulloblastoma.

EXPERIMENTAL DESIGN

Initially, vismodegib was administered daily at 85 mg/m(2) and escalated to 170 mg/m(2). The study was then revised to investigate a flat-dosing schedule of 150 mg for patients with small body surface area (BSA, 0.67-1.32 m(2)) or 300 mg for those who were larger (BSA, 1.33-2.20 m(2)). Pharmacokinetics were performed during the first course of therapy, and the right knees of all patients were imaged to monitor bone toxicity. Immunohistochemical analysis was done to identify patients with Sonic Hedgehog (SHH)-subtype medulloblastoma.

RESULTS

Thirteen eligible patients were enrolled in the initial study: 6 received 85 mg/m(2) vismodegib, and 7 received 170 mg/m(2). Twenty eligible patients were enrolled in the flat-dosing part of the study: 10 at each dosage level. Three dose-limiting toxicities were observed, but no drug-related bone toxicity was documented. The median (range) vismodegib penetration in the cerebrospinal fluid (CSF) was 0.53 (0.26-0.78), when expressed as a ratio of the concentration of vismodegib in the CSF to that of the unbound drug in plasma. Antitumor activity was seen in 1 of 3 patients with SHH-subtype disease whose tumors were evaluable, and in none of the patients in the other subgroups.

CONCLUSIONS

Vismodegib was well tolerated in children with recurrent or refractory medulloblastoma; only two dose-limiting toxicities were observed with flat dosing. The recommended phase II study dose is 150 or 300 mg, depending on the patient's BSA. Clin Cancer Res; 19(22); 6305-12. ©2013 AACR.

Targeted therapy for orbital and periocular basal cell carcinoma and squamous cell carcinoma

PURPOSE

To review the literature on targeted therapy for orbital and periocular basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC) and provide examples of patients recently treated with such therapy.

METHODS

The authors reviewed the literature on clinical results of targeted therapy and the molecular basis for targeted therapy in orbital and periocular BCC and cutaneous SCC. The authors also present representative cases from their practice.

RESULTS

Mutation in the patched 1 gene (PTCH1) has been implicated in BCC, and overexpression of epidermal growth factor receptor (EGFR) has been shown in SCC. Vismodegib, an inhibitor of smoothened, which is activated upon binding of hedgehog to Ptc, has been shown to significantly decrease BCC tumor size or even produce complete resolution, especially in cases of basal cell nevus syndrome. Similarly, EGFR inhibitors have been shown to significantly decrease SCC tumor size in cases of locally advanced and metastatic disease. The authors describe successful outcomes after vismodegib treatment in a patient with basal cell nevus syndrome with numerous bulky lesions of the eyelid and periocular region and erlotinib (EGFR inhibitor) treatment in a patient with SCC who was deemed not to be a good surgical candidate because of advanced SCC of the orbit with metastasis to the regional lymph nodes, advanced age, and multiple medical comorbidities.

CONCLUSIONS

Targeted therapy using hedgehog pathway and EGFR inhibitors shows significant promise in treatment of orbital and periocular BCC and cutaneous SCC, respectively. Such targeted therapy may be appropriate for patients who are not good candidates for surgery.