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

Domestic Animal Models of Central Nervous System Tumors: Focus on Meningiomas

Intracranial primary tumors (IPTs) are aggressive forms of malignancies that cause high mortality in both humans and domestic animals. Meningiomas are frequent adult IPTs in humans, dogs, and cats, and both benign and malignant forms cause a decrease in life quality and survival. Surgery is the primary therapeutic approach to treat meningiomas, but, in many cases, it is not resolutive. The chemotherapy and targeted therapy used to treat meningiomas also display low efficacy and many side effects. Therefore, it is essential to find novel pharmacological approaches to increase the spectrum of therapeutic options for meningiomas. This review analyzes the similarities between human and domestic animal (dogs and cats) meningiomas by evaluating the molecular and histological characteristics, diagnosis criteria, and treatment options and highlighting possible research areas to identify novel targets and pharmacological approaches, which are useful for the diagnosis and therapy of this neoplasia to be used in human and veterinary medicine.

Oral Antineoplastics in Acute Myeloid Leukemia: A Comprehensive Review

AML is a biologically and clinically heterogeneous disease that is associated with poor overall long-term survival. The expanding knowledge of genomic landscape in AML as well as advancements in molecular and chemical biology over the pathway in AML. After 40 years of stagnancy, the recent approval of numerous novel oral anti-leukemic agents for the treatment of AML has changed both the armamentarium of medications and treatment paradigms. These agents have unique clinical considerations in terms of administration, adverse effects, and monitoring parameters which may differ from clinician's historical expectations. Understanding the data, indication and clinical considerations for such novel oral anti-leukemic agents is paramount for clinicians caring patients with AML.

Non-surgical Management of Locally Advanced Basal Cell Carcinoma of the Upper Extremity With Vismodegib

Basal cell carcinoma (BCC) is a common skin malignancy that can present reconstructive challenges in patients with locally advanced diseases of the extremities. This article highlights three cases of locally advanced BCC of the extremities managed with vismodegib (Erivedge, Genentech). Vismodegib is a sonic hedgehog pathway (Shh) inhibitor approved by the FDA for use in metastatic or recurrent BCC. All three patients in our case series demonstrated significant clinical responses with reductions in tumor size which obviated the need for complex reconstructive surgery or amputation.

Advances in the drug management of basal cell carcinoma

INTRODUCTION

Basal cell carcinoma (BCC) is the most common skin cancer in humans. Recently, BCCs were suggested to be classified into 'easy to treat' and 'difficult to treat,' and different therapeutic options are suggested for their management.

AREAS COVERED

In this review, the authors discuss treatment options that are approved, recommended for, or are still in development for treatment of BCC. The review covers approved local therapies, such as imiquimod and 5-fluorouracil, and systemic therapies, such as hedgehog inhibitors. New medical agents, investigated in clinical trials, are reviewed. These include: targeted therapies, such as GLI antagonists or anti-VEGFR agents, immunotherapies, such as checkpoint inhibitors, recombinant cytokines or silencing RNA, as well as intralesional virotherapies with modified adeno- or herpes viruses.

EXPERT OPINION

The progress made in recent years has improved the management of patients with advanced BCC; however, neither tumor targeting nor immune system engaging agents provide a cure. New treatment approaches directed not only to known targets but also the tumor microenvironment are in development and are anticipated to improve the management of difficult to treat BCC.

Combination of Pseudo-Natural Product Design and Formal Natural Product Ring Distortion Yields Stereochemically and Biologically Diverse Pseudo-Sesquiterpenoid Alkaloids

We describe the synthesis and biological evaluation of a new natural product-inspired compound class obtained by combining the conceptually complementary pseudo-natural product (pseudo-NP) design strategy and a formal adaptation of the complexity-to-diversity ring distortion approach. Fragment-sized α-methylene-sesquiterpene lactones, whose scaffolds can formally be viewed as related to each other or are obtained by ring distortion, were combined with alkaloid-derived pyrrolidine fragments by means of highly selective stereocomplementary 1,3-dipolar cycloaddition reactions. The resulting pseudo-sesquiterpenoid alkaloids were found to be both chemically and biologically diverse, and their biological performance distinctly depends on both the structure of the sesquiterpene lactone-derived scaffolds and the stereochemistry of the pyrrolidine fragment. Biological investigation of the compound collection led to the discovery of a novel chemotype inhibiting Hedgehog-dependent osteoblast differentiation.

Expert opinion on sonidegib efficacy, safety and tolerability

Introduction: Hedgehog inhibitors are an alternative treatment option for patients with advanced BCCs not eligible for standard therapies due to lack of efficacy, high recurrence risk, and high-rate morbidity. Sonidegib, an oral smoothened antagonist, has been approved for the treatment of adult patients with locally advanced basal cell carcinoma. Several studies and randomized controlled trials have been conducted in order to evaluate the efficacy, safety, and tolerability of this new molecule.Areas covered: The aim of this article is to provide a complete overview on the use of sonidegib for the treatment of advanced BCCs describing the efficacy, safety, and drug tolerability of this drug.Expert opinion: Sonidegib, with a different pharmacokinetics profile from that of the other SMO-inhibitor vismodegib, demonstrated to be an efficacious and well-tolerated treatment in patients with locally advanced BCC. Although several drug-related adverse events have already been described, different strategies should be taken into account to better manage this small molecule while avoiding treatment discontinuation. The use of sonidegib as neoadjuvant therapy or combined with other hedgehog pathway inhibitors targeting different sites and to date, only available for pre-clinical studies, should also be considered.

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.

Metastatic Basal Cell Carcinoma of the Skin: A Comprehensive Literature Review, Including Advances in Molecular Therapeutics

Basal cell carcinoma (BCC) of the skin is the most common type of malignant human tumor. In Europe, the incidence of BCC ranges from 44.6 to 128 cases per 100,000 inhabitants annually, whereas in the United States, the yearly incidence rate ranges between 500 and 1500. The global incidence has been calculated to be as high as 10 million cases of BCC per year. There are 2 main clinical patterns of BCC-the familial BCC in basal cell nevus syndrome and sporadic BCC. The etiology of cutaneous BCC is usually the result of the interaction between solar ultraviolet radiation and genetic factors. Somatic or germline mutations in the effector components of the hedgehog signaling pathway (ie, PTCH1, PTCH2, SMO or SUFU genes) are responsible for ∼90% of the cases of both sporadic and familial BCC, all causing a constitutive activation of the hedgehog pathway. Cutaneous BCC very rarely metastasizes, and diagnosis in metastatic sites can be very difficult. Metastatic BCC has weakly effective therapeutic options with a poor prognosis until few years ago. In 2012, small-molecule therapies, involving inactivation of the hedgehog signaling pathway, and capable of reducing tumor growth and progression have been introduced into clinical practice for advanced (locally advanced or metastatic) BCC. We performed a comprehensive literature review on metastatic BCC and found at least 915 cases reported to date. In addition, we extensively discussed the differential diagnosis of metastatic BCC, and outlined the advances in clinical therapeutics involving these small molecules.

Advances in multidisciplinary therapy for meningiomas

Surgery has long been established as the first-line treatment for the majority of symptomatic and enlarging meningiomas, and evidence for its success is derived from retrospective case series. Despite surgical resection, a subset of meningiomas display aggressive behavior with early recurrences that are difficult to treat. The decision to radically resect meningiomas and involved structures is balanced against the risk for neurological injury in patients. Radiation therapy has largely been used as a complementary and safe therapeutic strategy in meningiomas with evidence primarily stemming from retrospective, single-institution reports. Two of the first cooperative group studies (RTOG 0539 and EORTC 22042) evaluating the outcomes of adjuvant radiation therapy in higher-risk meningiomas have shown promising preliminary results. Historically, systemic therapy has resulted in disappointing results in meningiomas. However, several clinical trials are under way evaluating the efficacy of chemotherapies, such as trabectedin, and novel molecular agents targeting Smoothened, AKT1, and focal adhesion kinase in patients with recurrent meningiomas.

Treatment of periocular basal cell carcinoma with neoadjuvant vismodegib

Purpose

To report a case of a locally advanced periocular basal cell carcinoma treated with neoadjuvant Vismodegib therapy prior to surgery.

Observations

A 63-year-old female presented to the oculoplastics clinic with biopsy-proven basal cell carcinoma of the right periorbital region causing significant cicatricial ectropion of the right lower eyelid. The medial canthal lesion involved nearly the entire right lower eyelid with extension onto the cheek, the medial half of the right upper eyelid, the palpebral and bulbar conjunctiva, as well as the right lacrimal system. CT imaging was suggestive of involvement of the extraocular muscles and other post-septal tissues. Fortunately, the patient had no metastatic disease. The extent of the tumor would have necessitated aggressive resection to achieve surgical cure. However, the patient preferred to attempt globe-sparing therapy with a goal of preserving cosmesis as much as possible. Various treatment options were discussed with the patient, including the use of Vismodegib, and the patient elected to pursue this treatment strategy. The goal of Vismodegib treatment was to reduce the tumor size enough to permit surgical resection of all tumor without significantly affecting cosmesis. After 11 months of treatment with Vismodegib, the tumor size had reduced significantly to the point where surgical intervention with minimal disfigurement could be offered. The patient underwent multidisciplinary approach with Mohs micrographic excision of the tumor paired with oculoplastic reconstructive surgery resulting in negative margins and satisfactory cosmetic results.

Conclusions and importance

Although addition study is required regarding Vismodegib as a primary or adjuvant therapeutic approach to periorbital basal cell carcinoma, this case illustrates the potential usefulness of this drug as an option in this context. This case provides information that may help the comprehensive ophthalmologist or oculoplastic specialist in counseling patients with locally advanced periorbital basal cell carcinoma.

Progress in triple negative breast carcinoma pathophysiology: Potential therapeutic targets

Triple-negative breast carcinoma (TNBC) is a subtype of breast carcinoma defined by negativity for estrogen receptor (ER) or progesterone receptor (PR) by immunohistochemical analysis and negativity for human epidermal growth factor receptor (Her2) by immunohistochemistry or in situ hybridization. TNBC is clinically marked by its high aggressiveness, particularly poor outcomes including a low survival rate, and the lack of specific and effective treatments. Therefore, new potential targets for the treatment of TNBC must be identified. This review summarizes recent evidence supporting novel targets and possible therapeutic regimens in the treatment of TNBC.

Gene-Related Response of Basal Cell Carcinoma to Biologic Treatment with Vismodegib

We aimed to characterise the response of locally advanced basal cell carcinoma (BCC) to systemic treatment with Vismodegib, a Hedgehog pathway inhibitor, by changes in the expression levels of Hedgehog pathway genes. Data were collected prospectively on 12 patients treated systemically for locally advanced BCC. Biopsy samples taken on admission and after treatment cessation were analysed pathologically and with the NanoString nCounter system to quantify the expression of 40 Hedgehog signaling pathway genes. Findings were compared before and after treatment, between complete and partial responders, and with localised BCC samples from 22 patients. Sixteen Hedgehog pathway genes changed significantly from before to after treatment. GAS1 was the only gene with a significantly different expression at baseline between complete responders (6 patients) and partial responders (4 patients) to Vismodegib (P = 0.014). GAS, GLIS2 and PRKACG1 showed different expression before treatment between the locally advanced and localised BCCs. The baseline expression level of GAS1 appears to be predictive of the response of locally advanced BCC to systemic Vismodegib treatment. A change in expression of many Hedgehog pathway genes, albeit expected by the known activity of Vismodegib, may nevertheless serve as an indicator of the response potential of the tumour.

A phase Ib study of sonidegib (LDE225), an oral small molecule inhibitor of smoothened or Hedgehog pathway, in combination with docetaxel in triple negative advanced breast cancer patients: GEICAM/2012-12 (EDALINE) study

Up-regulation of the Hedgehog (Hh) pathway is implicated in the genesis of a wide range of tumors including triple negative breast cancer (TNBC). Sonidegib is a potent and selective oral inhibitor of Smo, a key component of the Hh signaling pathway. We designed a phase I clinical study to explore the combination of sonidegib plus docetaxel (fixed dose at 75 mg/m²) in advanced TNBC patients. The primary objective was to ascertain the combination's maximum tolerated dose and the recommended phase II dose (RP2D), based on dose limiting toxicities (DLTs) in the first 2 cycles. A standard "3 + 3" design was followed including three dose levels (DL) of sonidegib: 400 mg (DL1), 600 mg (DL2), and 800 mg (DL3). Twelve patients were included. Sonidegib 800 mg orally q.d. plus docetaxel 75 mg/m² given intravenously on day 1 of 21-day cycles was established as the RP2D. No DLTs were observed at any DL. The median number of administered cycles at DL3 was 8 (range: 6 to 9). Grade 3 adverse events (AEs) at DL3 were neutropenia (66.7%), CPK increase (33.3%), leukopenia (33.3%), and paresthesia (33.3%), grade 4 AEs were not reported at this DL. At the RP2D, the combination showed antitumor activity in three out of 10 patients with measurable disease. Median time to progression for the overall study was 42.5 days (95% Confidence Interval: 29-155), and 188 days at DL3. No drug-to-drug interactions between sonidegib and docetaxel were found in the PK assessment. Trial Registration: EudraCT study number: 2013-001750-96. Study GEICAM/2012-12. TRIAL REGISTRATION: EudraCT study number: 2013-001750-96. Study GEICAM/2012-12. ClinicalTrials.gov: NCT02027376.

Hereditary multiple exostoses: are there new plausible treatment strategies?

Introduction

Hereditary multiple exostoses (HME) is a rare congenital pediatric disorder characterized by osteochondromas forming next to the growth plates in young patients. The osteochondromas cause multiple health problems that include skeletal deformities and chronic pain. Surgery is used to remove the most symptomatic osteochondromas but because of their large number, many are left in place, causing life-long problems and increasing the probability of malignant transformation. There is no other treatment to prevent or reduce osteochondromas formation at present.

Areas covered

Recent studies reviewable through PubMed are providing new insights into cellular and molecular mechanisms of osteochondroma development. The resulting data are suggesting rational and plausible new therapeutic strategies for osteochondroma prevention some of which are being tested in HME animal models and one of which is part of a just announced clinical trial.

Expert Commentary

This section summarizes and evaluates such strategies and points also to possible future alternatives.

Successful Craniotomy for Advanced Basal Cell Carcinomas with Cranial Bone Invasion and Dura Mater Infiltration - Unique Presentation in a Bulgarian Patient

BACKGROUND:

Basal cell carcinomas (BCC) located in the sun-exposed regions are a serious therapeutic challenge. Therefore early diagnosis and adequate therapy should be of a high priority for every dermatologic surgeon.

CASE PRESENTATION:

We are presenting a patient with multiple BCCs, located on the area of the scalp, who had been treated several years ago with electrocautery and curettage after histopathological verification. However, the last few years the tumours have advanced, infiltrating firstly the tabula external and a year later the tabula interna of the cranium. A computed -tomography (CT) imaging and radiography of the skull were performed to reveal the definite tumour localisation, needed for planning an one - step surgical intervention. Both of the instrumental examinations confirmed the existence of osteolytic tumour lesions. Craniotomy with precise removal of the BCCs infiltrating the cranial bone in all of its thickness was performed. Partial resection of dura mater was also performed also because intraoperative findings established the involvement of the dura. Histopathological verification revealed bone and dural invasion with clean resection margins. The bone defect was recovered with hydroxyapatite cement. Reconstruction as the shape of the skull was carefully modified and adapted to its initial size and form. Layered closure of the skin and soft tissues were performed after the complete removal of the BCCs. The postoperative period had no serious complications.

CONCLUSION:

Precisely managed therapy of BCC is curative in most of the cases as it ensures good prognosis for the patient.

Recovery of taste organs and sensory function after severe loss from Hedgehog/Smoothened inhibition with cancer drug sonidegib

Striking taste disturbances are reported in cancer patients treated with Hedgehog (HH)-pathway inhibitor drugs, including sonidegib (LDE225), which block the HH pathway effector Smoothened (SMO). We tested the potential for molecular, cellular, and functional recovery in mice from the severe disruption of taste-organ biology and taste sensation that follows HH/SMO signaling inhibition. Sonidegib treatment led to rapid loss of taste buds (TB) in both fungiform and circumvallate papillae, including disruption of TB progenitor-cell proliferation and differentiation. Effects were selective, sparing nontaste papillae. To confirm that taste-organ effects of sonidegib treatment result from HH/SMO signaling inhibition, we studied mice with conditional global or epithelium-specific Smo deletions and observed similar effects. During sonidegib treatment, chorda tympani nerve responses to lingual chemical stimulation were maintained at 10 d but were eliminated after 16 d, associated with nearly complete TB loss. Notably, responses to tactile or cold stimulus modalities were retained. Further, innervation, which was maintained in the papilla core throughout treatment, was not sufficient to sustain TB during HH/SMO inhibition. Importantly, treatment cessation led to rapid and complete restoration of taste responses within 14 d associated with morphologic recovery in about 55% of TB. However, although taste nerve responses were sustained, TB were not restored in all fungiform papillae even with prolonged recovery for several months. This study establishes a physiologic, selective requirement for HH/SMO signaling in taste homeostasis that includes potential for sensory restoration and can explain the temporal recovery after taste dysgeusia in patients treated with HH/SMO inhibitors.

Discovery of a Novel Inhibitor of the Hedgehog Signaling Pathway through Cell-based Compound Discovery and Target Prediction

Cell-based assays enable monitoring of small-molecule bioactivity in a target-agnostic manner and help uncover new biological mechanisms. Subsequent identification and validation of the small-molecule targets, typically employing proteomics techniques, is very challenging and limited, in particular if the targets are membrane proteins. Herein, we demonstrate that the combination of cell-based bioactive-compound discovery with cheminformatic target prediction may provide an efficient approach to accelerate the process and render target identification and validation more efficient. Using a cell-based assay, we identified the pyrazolo-imidazole smoothib as a new inhibitor of hedgehog (Hh) signaling and an antagonist of the protein smoothened (SMO) with a novel chemotype. Smoothib targets the heptahelical bundle of SMO, prevents its ciliary localization, reduces the expression of Hh target genes, and suppresses the growth of Ptch^+/- medulloblastoma cells.

DERMATOSCOPY AS A METHOD OF EVALUATING THE EFFICIENCY OF 5% CREAM IMYKVIMOD IN PATIENTS WITH BASAL CELL CARCINOMA OF SKIN

The aim. investigation of the possibilities of dermatoscopy as a method for evaluating the effectiveness of therapy with topical imiquimod in patients with superficial basal cell carcinoma (CCB). Materials and methods. the study included 24 patients with a superficial form of CCB, who for various reasons did not undergo excisional surgical intervention and who agreed to alternative drug therapy (officinal original topical imiquimod). Patients were divided into two groups, in which the efficacy of therapy was assessed either by clinical or by dermatoscopic signs. General results. the study demonstrated the importance of dermatoscopy as a method for assessing the effectiveness of therapy with topical imiquimod; Greater prognostic significance of dermatoscopy in comparison with a simple clinical examination of mass when assessing the moment of interruption of drug therapy with imiquimod.

Design, Synthesis, and Pharmacological Evaluation of 2-(2,5-Dimethyl-5,6,7,8-tetrahydroquinolin-8-yl)-N-aryl Propanamides as Novel Smoothened (Smo) Antagonists

A series of novel Smo antagonists were developed either by directly incorporating the basic skeleton of the natural product artemisinin or by first breaking artemisinin into structurally simpler and stable intermediates and then reconstructing into diversified heterocyclic derivatives, equipped with a Smo-targeting bullet. 2-(2,5-Dimethyl-5,6,7,8-tetrahydroquinolin-8-yl)-N-arylpropanamide 65 was identified as the most potent, with an IC₅₀ value of 9.53 nM against the Hh signaling pathway. Complementary mechanism studies confirmed that 65 inhibits Hh signaling pathway by targeting Smo and shares the same binding site as that of the tool drug cyclopamine. Meanwhile, 65 has a good plasma exposure and an acceptable oral bioavailability. Dose-dependent antiproliferative effects were observed in ptch+/-;p53-/- medulloblastoma cells, and significant tumor growth inhibitions were achieved for 65 in the ptch+/-;p53-/- medulloblastoma allograft model.