Efficacy, rate of tumor response, and safety of a short course (12-24 weeks) of oral vismodegib in various histologic subtypes (infiltrative, nodular, and superficial) of high-risk or locally advanced basal cell carcinoma, in an open-label, prospective case series clinical trial

Hedgehog pathway inhibitors for locally advanced and metastatic basal cell carcinoma: A real-world single-center retrospective review

Basal cell carcinoma (BCC) is highly curable by surgical excision or radiation. In rare cases, BCC can be locally destructive or difficult to surgically remove. Hedgehog inhibition (HHI) with vismodegib or sonidegib induces a 50-60% response rate. Long-term toxicity includes muscle spasms and weight loss leading to dose decreases. This retrospective chart review also investigates the impact of CoQ10 and calcium supplementation in patients treated with HHI drugs at a single academic medical center from 2012 to 2022. We reviewed the charts of adult patients diagnosed with locally advanced or metastatic BCC treated with vismodegib or sonidegib primarily for progression-free survival (PFS). Secondary objectives included overall survival, BCC-specific survival, time to and reasons for discontinuation, overall response rate, safety and tolerability, use of CoQ10 and calcium supplements, and insurance coverage. Of 55 patients assessable for outcome, 34 (61.8%) had an overall clinical benefit, with 25 (45.4%) having a complete response and 9 (16.3%) a partial response. Stable disease was seen in 14 (25.4%) and 7 (12.7%) progressed. Of the 34 patients who responded to treatment, 9 recurred. Patients who were rechallenged with HHI could respond again. The median overall BCC-specific survival rate at 5 years is 89%. Dose reductions or discontinuations for vismodegib and sonidegib occurred in 59% versus 24% of cases, or 30% versus 9% of cases, respectively. With CoQ10 and calcium supplementation, only 17% required a dose reduction versus 42% without. HHI is highly effective for treating advanced BCC but may require dosing decreases. Sonidegib was better tolerated than vismodegib. CoQ10 and calcium supplementation can effectively prevent muscle spasms.

Signaling Pathways and Therapeutic Strategies in Advanced Basal Cell Carcinoma

Non-melanoma skin cancers (NMSCs) are the most common human neoplasms world-wide. In detail, basal cell carcinoma (BCC) is the most frequent malignancy in the fair-skinned population. The incidence of BCC remains difficult to assess due to the poor registration practice; however, it has been increasing in the last few years. Approximately, 85% of sporadic BCCs carry mutations in Hedgehog pathway genes, especially in PTCH, SUFU and SMO genes, which lead to the aberrant activation of GLI transcriptional factors, typically silent in cells of adult individuals. The management of advanced BCC (aBCC), both metastatic (mBCC) and locally advanced BCC (laBCC), not candidates for surgical excision or radiotherapy, remains challenging. The discovery of mutations in the Hh signaling pathway has paved the way for the development of Hh pathway inhibiting agents, such as vismodegib and sonidegib, which have represented a breakthrough in the aBCC management. However, the use of these agents is limited by the frequent occurrence of adverse events or the development of drug resistance. In this review, we thoroughly describe the current knowledge regarding the available options for the pharmacological management of aBCCs and provide a forward-looking update on novel therapeutic strategies that could enrich the therapeutic armamentarium of BCC in the near future.

Sonidegib in Locally Advanced Basal Cell Carcinoma: A Monocentric Retrospective Experience and a Review of Published Real-Life Data

Basal cell carcinoma (BCC) represents the most common skin cancer and locally advanced BCC (laBCC) refers to an aggressive, large, infiltrative BCC that cannot be treated by surgery or radiotherapy. Sonidegib is a Hedghehog inhibitor (HHi) indicated for laBCC. This is a monocentric retrospective real-life study of laBCCs receiving Sonidegib treatment. Although Sonidegib is widely used, since its approval by Food and Drug Administration in 2015, only a limited number of real-life experiences have been reported. Eleven patients, including four patients diagnosed with Basal Cell Naevus syndrome, received treatment with Sonidegib for laBCCs. Seven (63.6%) patients experienced adverse events (AEs) but only three had to discontinue treatment and were therefore excluded from the following results. Four patients (50%) achieved complete clinical remission (CR); in all cases the remission was confirmed by biopsy. Partial response (PR) was found in three patients out of eight (37.5%). One patient out of eight (12.5%) showed a steady disease (SD). None of the patients showed signs of progression during treatment with HHi. Sonidegib showed the same efficacy in treating laBCCs as already seen in trials. All four patients suffering from Basal Cell Naevus syndrome achieved disease control by being treated with Sonidegib. Consequently, we strongly advise the joint management of laBCCs through a multidisciplinary team whenever feasible.

Targeting the tumor stroma for cancer therapy

Tumors are comprised of both cancer cells and surrounding stromal components. As an essential part of the tumor microenvironment, the tumor stroma is highly dynamic, heterogeneous and commonly tumor-type specific, and it mainly includes noncellular compositions such as the extracellular matrix and the unique cancer-associated vascular system as well as a wide variety of cellular components including activated cancer-associated fibroblasts, mesenchymal stromal cells, pericytes. All these elements operate with each other in a coordinated fashion and collectively promote cancer initiation, progression, metastasis and therapeutic resistance. Over the past few decades, numerous studies have been conducted to study the interaction and crosstalk between stromal components and neoplastic cells. Meanwhile, we have also witnessed an exponential increase in the investigation and recognition of the critical roles of tumor stroma in solid tumors. A series of clinical trials targeting the tumor stroma have been launched continually. In this review, we introduce and discuss current advances in the understanding of various stromal elements and their roles in cancers. We also elaborate on potential novel approaches for tumor-stroma-based therapeutic targeting, with the aim to promote the leap from bench to bedside.

Signaling pathways in the regulation of cancer stem cells and associated targeted therapy

Cancer stem cells (CSCs) are defined as a subpopulation of malignant tumor cells with selective capacities for tumor initiation, self-renewal, metastasis, and unlimited growth into bulks, which are believed as a major cause of progressive tumor phenotypes, including recurrence, metastasis, and treatment failure. A number of signaling pathways are involved in the maintenance of stem cell properties and survival of CSCs, including well-established intrinsic pathways, such as the Notch, Wnt, and Hedgehog signaling, and extrinsic pathways, such as the vascular microenvironment and tumor-associated immune cells. There is also intricate crosstalk between these signal cascades and other oncogenic pathways. Thus, targeting pathway molecules that regulate CSCs provides a new option for the treatment of therapy-resistant or -refractory tumors. These treatments include small molecule inhibitors, monoclonal antibodies that target key signaling in CSCs, as well as CSC-directed immunotherapies that harness the immune systems to target CSCs. This review aims to provide an overview of the regulating networks and their immune interactions involved in CSC development. We also address the update on the development of CSC-directed therapeutics, with a special focus on those with application approval or under clinical evaluation.

The Role of Surgery After Remission of Nonsystemic Extensive Periorbital Basal Cell Carcinoma Treated by Vismodegib: A Systematic Review

BACKGROUND

Eyelid basal cell carcinoma (BCC) is usually cured by surgery. However, for a minority of patients, extensive disease progression and recurrence contraindicate surgery or radiotherapy because of severe ocular morbidity. The hedgehog signaling pathway inhibitor vismodegib is becoming the key treatment for this specific form.

OBJECTIVE

The aim of this review was to define the role of surgery after vismodegib treatment.

MATERIALS AND METHODS

A literature search of the PubMed, Cochrane Library, ScienceDirect, and Embase databases was conducted for all articles published up to March 2021 to identify studies that examined treatment of BCC of the eyelid by vismodegib.

RESULTS

Level 1 evidence was found for the use of vismodegib as neoadjuvant therapy in locally advanced eyelid BCC contraindicated to surgery and/or radiotherapy with a rather good tolerance of treatment. Level 3 evidence was found for the role of surgical excision of residual clinically suspicious lesions as for the indication of eyelid reconstruction after mapping or during residual tumoral resection if frozen sections or Mohs surgery were performed.

CONCLUSION

Vismodegib is a well-tolerated treatment for advanced periorbital BCC. The hedgehog signaling pathway inhibitor vismodegib is a potential treatment option in patients with these challenging tumors.

Cemiplimab for locally advanced and metastatic basal cell carcinoma

INTRODUCTION

Locally advanced basal cell carcinoma (laBCC) represents approximatively 1% of all BCCs. Metastatic BCC (mBCC) is even more rare. Most cases are observed in immunocompromised patients, particularly solid organ transplant recipients (OTRs). When surgery and/or radiation therapy for laBCC or mBCC is not reasonable, oral hedgehog inhibitor (HHI) therapy may be initiated. LaBCC or mBCC patients with primary or secondary resistance, progression or intolerance to HHIs could benefit from programmed cell death protein-1 (PD-1) inhibitors as this has recently been published for cemiplimab, a recombinant IgG4 human monoclonal antibody anti-PD-1 for the intravenous treatment of laBCC and mBCC.

AREAS COVERED

Principal studies evaluating the efficacy and safety of cemiplimab for laBCC and mBCC are presented and discussed.

EXPERT OPINION

Cemiplimab is the first FDA (2021) approved anti-PD-1 antagonist for the systemic treatment of laBCC and mBCC which had previously shown disease progression on or intolerance to HHIs. Experts currently recommend cemiplimab as a first-line systemic alternative. As cemiplimab therapy is associated with a risk of organ graft rejection, advantages and disadvantages should be evaluated for every individual OTR patient with laBCC or mBCC, eligible for cemiplimab 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.

Hedgehog Inhibitor Induction with Addition of Concurrent Superficial Radiotherapy in Patients with Locally Advanced Basal Cell Carcinoma: A Case Series

BACKGROUND

Locally advanced basal cell cancer is a rare and challenging clinical problem. Historically, these patients were treated with aggressive surgery or radiotherapy. Most sporadic basal cell carcinomas have somatic mutations in the hedgehog pathway. Oral hedgehog inhibitors induce rapid and often complete clinical responses in locally advanced basal cell tumors. Unfortunately, these responses are usually transient. We hypothesized that treatment failure represents persistence of drug resistant cells that could be eradicated by addition of localized radiotherapy.

MATERIALS AND METHODS

We performed a retrospective review of our patients with locally advanced basal cell cancer treated with sonidegib or vismodegib induction therapy who were treated with added superficial radiotherapy at the time of maximal response.

RESULTS

Twelve patients met inclusion criteria. All patients achieved a complete response following hedgehog inhibitor therapy with addition of radiotherapy. Progression-free survival at 40 months was 89%, with a median follow-up of 40 months. Relapses occurred in only 2 of 12 patients (16.6%). Nine patients experienced grade I-II toxicity from hedgehog inhibitor induction therapy (taste changes [3], weight loss [3], muscle cramps [3]). Eight patients experienced mild radiotherapy-induced skin toxicity during concurrent therapy. No patients had to discontinue treatment.

CONCLUSION

Induction therapy with hedgehog inhibitors followed by addition of concurrent radiation therapy resulted in an extremely high clinical response rate with relatively minor and reversible toxicity. This gave a high rate of progression-free survival and a low disease-specific progression rate. Further prospective evaluation of this treatment approach is needed to confirm the apparent clinical activity.

IMPLICATIONS FOR PRACTICE

Locally advanced basal cell cancers are challenging to treat. Previously, aggressive surgical resection or radiotherapy represented the best treatment options. Most basal cell cancers have somatic mutations in the hedgehog pathway. Oral inhibitors of this pathway produce rapid but transient clinical responses. This study reports 12 patients treated with hedgehog inhibitor induction therapy to near-maximal response. Addition of concurrent involved field radiotherapy resulted in a very high complete response rate with minimal toxicity. There was prolonged progression-free survival in 90% of patients. This study identified a novel treatment approach for patients with advanced basal cell carcinoma.

Predictive Factors of Non-Response to Vismodegib in Locally Advanced Basal-Cell Carcinoma

BACKGROUND

Vismodegib has shown clinical efficacy in the management of locally advanced basal cell carcinomas (laBCC). However, non-response to vismodegib is observed in 2-13.5% of patients in clinical studies. The purpose of this study was to identify factors associated with non-response to vismodegib in patients with laBCC.

METHODS

We carried out a retrospective multicenter study, including patients with laBCC treated with vismodegib, from July 2011 to May 2019. Response to treatment was assessed according to the RECIST 1.1 criteria. Patients were categorized as responders with a complete response or a partial response or non-responders with a stable disease or a progressive disease according to what has been observed during follow-up. Patient demographics, tumor profile, and treatment modalities were compared in responders and non-responders.

RESULTS

Eighty-three patients with laBCC were included in the study. Twenty-five (30.1%) were non-responders to vismodegib. History of treatment with radiotherapy, presence of muscle involvement and intermittent treatment with vismodegib were significantly associated with a non-response (p < 0.001, p = 0.025, p < 0.001). Bone involvement (p = 0.2) and morpheaform IaBCC subtype (p = 0.056) were more frequent in non-responders without reaching statistical significance.

CONCLUSION

In this study, non-response of laBCC to vismodegib therapy was associated with muscle involvement. Previous radiotherapy and intermittent use of vismodegib have been identified as causes favoring non-response to vismodegib. Due to the low numbers of patients included in the study, it is difficult to draw firm conclusions. Further studies are needed to confirm these data.

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.

Efficacy of Vismodegib in pigmented basal cell carcinoma: Appearances are deceiving

Basal cell carcinoma (BCC) is the most common skin cancer in humans. Pigmented basal cell carcinoma (pBCC) is a rare variant of BCC. Vismodegib, was the first drug to be approved for the treatment of locally advanced (laBCCs) or metastatic basal cell carcinoma. The aim of this study was to evaluate the efficacy of Vismodegib in patients with pBCCs. We retrospectively analyzed patients receiving Vismodegib as treatment for laBCCs presenting also various pBCCs. After 6 months of treatment, we performed excisional biopsies of pBCCs, that apparently at clinical and dermoscopic assessment did not respond to therapy. A total of nine patients were assessed. After 6 months of treatment, locally advanced target BCCs showed complete remission in four out of nine patients (44.4%), four patients (44.4%) were considered in partial remission and one patient (11%) showed no response to treatment. On the contrary, all the pBCCs showed both clinically and dermoscopically resistance to treatment. Therefore, clinically persistent pBCCs were surgically removed in three patients. Histology showed a complete elimination of the neoplastic cells together with features of previous regression. Our findings indicate that the efficacy of Vismodegib is higher than that documented by clinical or even dermatoscopic observation alone.