Hedgehog Pathway Inhibitors and Their Utility in Basal Cell Carcinoma: A Comprehensive Review of Current Evidence

Immune microenvironment of basal cell carcinoma and tumor regression following combined PD-1/LAG-3 blockade

Systemic treatment options for patients with locally advanced or metastatic basal cell carcinoma (BCC) are limited, particularly when tumors are refractory to anti-programmed cell death protein-1 (PD-1). A better understanding of immune checkpoint expression within the BCC tumor microenvironment may inform combinatorial treatment strategies to optimize response rates. CD3, PD-1, programmed death ligand-1 (PD-L1), lymphocyte activation gene 3 (LAG-3), and T-cell immunoglobulin domain and mucin domain 3 (TIM-3)+ cell densities within the tumor microenvironment of 34 archival, histologically aggressive BCCs were assessed. Tumor infiltrating lymphocyte (TIL) expression of PD-1, PD-L1, and LAG-3, and to a lesser degree TIM-3, correlated with increasing CD3+ T-cell densities (Pearson's r=0.89, 0.72, 0.87, and 0.63, respectively). 100% of BCCs (34/34) demonstrated LAG-3 and PD-1 expression in >1% TIL; and the correlation between PD-1 and LAG-3 densities was high (Pearson's r=0.89). LAG-3 was expressed at ~50% of the level of PD-1. Additionally, we present a patient with locally-advanced BCC who experienced stable disease during and after 45 weeks of first-line anti-PD-1 (nivolumab), followed by a partial response after the addition of anti-LAG-3 (relatlimab). Longitudinal biopsies throughout the treatment course showed a graduated increase in LAG-3 expression after anti-PD-1 therapy, lending support for coordinated immunosuppression and suggesting LAG-3 as a co-target for combination therapy to augment the clinical impact of anti-PD-(L)1.

The Role of Radiation Therapy in the Treatment of Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy in the United States. While surgery is considered as the main treatment modality for both cutaneous basal cell carcinoma (cBCC) and cutaneous squamous cell carcinoma (cSCC), radiotherapy plays an important role in the treatment of NMSC, both in the adjuvant setting for cases considered high-risk for recurrence, and in the definitive setting, when surgery is not feasible or desired by the patient. The last years have seen the emergence of immunotherapy treatment for cases of advanced cSCC in the palliative, and possibly neoadjuvant settings, making the treatment paradigm more complex. In this review, we attempt to describe the different radiation modalities available for the treatment of NMSC, the indications for adjuvant post-operative treatment with radiotherapy for cSCC, the role of radiotherapy in elective neck treatment, and the efficacy, safety, and toxicity profile of this treatment in these different settings. Furthermore, we aim to describe the efficacy of radiotherapy combined with immunotherapy as a promising horizon for treating advanced cSCC. We also aim to describe the ongoing clinical studies that attempt to examine future directions for the role of radiation treatment in NMSC.

Management of basal cell carcinoma with pulmonary metastasis

A man in his 50s presented with an ulcerative lesion within the left axillary fold that had progressively worsened over 18 months. Biopsy revealed an ulcerative basal cell carcinoma (BCC), which was surgically managed. CT chest scans done 7 months later assessed post-treatment of radiotherapy. This revealed pulmonary lesions, which were biopsy-proven metastatic BCC. Sonidegib, a hedgehog signalling inhibitor, was used for first-line treatment. Due to progressive disease, sonidegib was ceased. Cemiplimab, a checkpoint inhibitor, was used as second-line treatment based on a phase II trial demonstrating efficacy in the setting of metastatic BCC. CT reports were initially consistent with response but after 6 months of cemiplimab treatment, repeat CT chest scans revealed a decrease in size of the previously cited pulmonary lesions.This is a rare case of BCC metastases which has limited treatment options. This case provides insight of the patient experience on such treatment.

Nonsurgical treatment options for basal cell carcinoma

ABSTRACT

Basal cell carcinoma (BCC) is the most common form of nonmelanoma skin cancer. Surgery, including Mohs micrographic surgery, is considered the gold standard for the management of BCC, yet some patients may be unable to undergo surgery. This article describes effective nonsurgical options for treating superficial BCCs as well as some nodular and infiltrative BCCs.

Skin Cancer Research Goes Digital: Looking for Biomarkers within the Droplets

Skin cancer, which includes the most frequent malignant non-melanoma carcinomas (basal cell carcinoma, BCC, and squamous cell carcinoma, SCC), along with the difficult to treat cutaneous melanoma (CM), pose important worldwide issues for the health care system. Despite the improved anti-cancer armamentarium and the latest scientific achievements, many skin cancer patients fail to respond to therapies, due to the remarkable heterogeneity of cutaneous tumors, calling for even more sophisticated biomarker discovery and patient monitoring approaches. Droplet digital polymerase chain reaction (ddPCR), a robust method for detecting and quantifying low-abundance nucleic acids, has recently emerged as a powerful technology for skin cancer analysis in tissue and liquid biopsies (LBs). The ddPCR method, being capable of analyzing various biological samples, has proved to be efficient in studying variations in gene sequences, including copy number variations (CNVs) and point mutations, DNA methylation, circulatory miRNome, and transcriptome dynamics. Moreover, ddPCR can be designed as a dynamic platform for individualized cancer detection and monitoring therapy efficacy. Here, we present the latest scientific studies applying ddPCR in dermato-oncology, highlighting the potential of this technology for skin cancer biomarker discovery and validation in the context of personalized medicine. The benefits and challenges associated with ddPCR implementation in the clinical setting, mainly when analyzing LBs, are also discussed.

A Conservative Combined Laser Cryoimmunotherapy Treatment vs. Surgical Excision for Basal Cell Carcinoma

Surgical excision is the standard treatment for basal cell carcinoma (BCC), but it can be challenging in elderly patients and patients with comorbidities. The non-surgical guidelines procedures are usually regarded as monotherapy options. This quasi-experimental, non-randomized, comparative effectiveness study aims to evaluate the efficacy of a combined, conservative, non-surgical BCC treatment, and compare it to standard surgical excision. Patients with primary, non-ulcerated, histopathologically confirmed BCCs were divided into a conservative treatment (129 patients) and a standard surgery subgroup (50 patients). The conservative treatment consisted of ablative CO2 laser, cryosurgery, topical occlusive 5-fluorouracil, and imiquimod. The follow-up examinations were performed 3 months after remission, then every 3 to 6 months, and were extended with telephone follow-ups. Cosmetic-self assessment was recorded during a telephone follow-up. Subjects from the conservative subgroup presented a clearance rate of 99.11%, and a recurrence rate of 0.98%. No recurrences were recorded in the surgical group, nor during the telephone follow-up. There were no differences regarding adverse events (p > 0.05). A superior self-assessment cosmetic outcome was obtained using the conservative method (p < 0.001). This conservative treatment is suitable for elders and patients with comorbidities, is not inferior to surgery in terms of clearance, relapses, or local adverse events, and displays superior cosmetic outcomes.

Assessment of various efficacy outcomes using ERIVANCE-like criteria in patients with locally advanced basal cell carcinoma receiving sonidegib: results from a preplanned sensitivity analysis

Background

The BOLT study for sonidegib, a Hedgehog pathway inhibitor (HHI) approved for patients with locally advanced basal cell carcinoma (laBCC) not amenable to curative surgery or radiotherapy, used modified Response Evaluation Criteria in Solid Tumors (mRECIST) for laBCC tumor evaluation. The ERIVANCE study for vismodegib, another HHI, used a composite RECIST endpoint of ≥30% reduction in externally visible tumor or radiographic dimension, or complete ulceration resolution. This preplanned sensitivity BOLT analysis evaluated efficacy outcomes using ERIVANCE-like criteria in patients with laBCC who received sonidegib 200 mg once daily.

Methods

This phase 2, double-blind study randomized patients 1:2 to sonidegib 200:800 mg daily, respectively. Key endpoints included objective response rate (ORR), duration of response (DOR), complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD). laBCC tumors were assessed by both mRECIST and ERIVANCE-like criteria. Per mRECIST, an overall response of CR was based on negative histology; photographic assessment of CR, PR (scar/fibrosis only), SD (scar/fibrosis only), or not available (NA); and a magnetic resonance imaging response of CR or NA. An overall response of CR was primarily based on negative histology using ERIVANCE-like criteria.

Results

Per mRECIST criteria, ORR (95% confidence interval [CI]) by central and investigator review for patients with laBCC (n = 66) was 56.1% (43.3–68.3%) and 71.2% (58.7–81.7%), respectively. CR per central review was achieved in 3 (4.5%) patients and PR, SD, and PD occurred in 34 (51.5%), 23 (34.8%), and 1 (1.5%) patient, respectively. Median (95% CI) DOR was 26.1 months (not estimable [NE]).

Using ERIVANCE-like criteria, efficacy outcomes per central and investigator review were higher, with an ORR (95% CI) of 60.6% (47.8–72.4%) and 74.2% (62.0–84.2%), respectively. CR per central review was reached in 14 (21.2%) patients and PR, SD, and PD occurred in 26 (39.4%), 20 (30.3%), and 1 (1.5%) patient, respectively. DOR was unchanged with a median (95% CI) of 26.1 months (NE).

Conclusions

Overall, applying ERIVANCE-like criteria to patients with laBCC receiving sonidegib 200 mg daily yielded higher response rates vs mRECIST criteria.

Trial registration

BOLT registration: ClinicalTrials.gov (NCT01327053) on March 30, 2011.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08968-1.

Hedgehog Pathway Inhibitors against Tumor Microenvironment

Targeting the hedgehog (HH) pathway to treat aggressive cancers of the brain, breast, pancreas, and prostate has been ongoing for decades. Gli gene amplifications have been long discovered within malignant glioma patients, and since then, inhibitors against HH pathway-associated molecules have successfully reached the clinical stage where several of them have been approved by the FDA. Albeit this success rate implies suitable progress, clinically used HH pathway inhibitors fail to treat patients with metastatic or recurrent disease. This is mainly due to heterogeneous tumor cells that have acquired resistance to the inhibitors along with the obstacle of effectively targeting the tumor microenvironment (TME). Severe side effects such as hyponatremia, diarrhea, fatigue, amenorrhea, nausea, hair loss, abnormal taste, and weight loss have also been reported. Furthermore, HH signaling is known to be involved in the regulation of immune cell maturation, angiogenesis, inflammation, and polarization of macrophages and myeloid-derived suppressor cells. It is critical to determine key mechanisms that can be targeted at different levels of tumor development and progression to address various clinical issues. Hence current research focus encompasses understanding how HH controls TME to develop TME altering and combinatorial targeting strategies. In this review, we aim to discuss the pros and cons of targeting HH signaling molecules, understand the mechanism involved in treatment resistance, reveal the role of the HH pathway in anti-tumor immune response, and explore the development of potential combination treatment of immune checkpoint inhibitors with HH pathway inhibitors to target HH-driven cancers.

Glasdegib plus low-dose cytarabine for acute myeloid leukemia: Practical considerations from advanced practitioners and pharmacists

Objective

Acute myeloid leukemia (AML) is primarily a disease of older adults. These patients may not be candidates for intensive treatment, and there has been an ongoing need for treatment options for this group. We review the use of glasdegib, a hedgehog-pathway inhibitor available for use in combination with low-dose cytarabine (LDAC).

Data Sources: PubMed and relevant congress abstracts were searched using the term “glasdegib”. In addition, based on our experience with glasdegib, we considered treatment aspects of particular relevance to pharmacists and advanced practitioners.

Data Summary: In a randomized phase II study, the combination of glasdegib plus LDAC demonstrated superior overall survival versus LDAC alone (hazard ratio 0.51, 80% confidence interval 0.39–0.67, p = 0.0004). The trial reported adverse events (AEs) of special relevance for older patients, such as hematologic events, gastrointestinal toxicity, and fatigue, as well as AEs associated with Hh-pathway inhibitors (alopecia, muscle spasms, dysgeusia). Educating patients about typical AEs can facilitate adherence as well as early AE identification and proactive management. For LDAC, which is a long-established therapy in AML, various stages of delivery need consideration, with attention to individual circumstances. Practical measures such as dispensing a longer supply can reduce the number of return clinic visits, providing a meaningful difference for many patients.

Conclusions

Pharmacists and advanced practitioners play important roles in treatment with glasdegib plus LDAC. Ultimately, framing plans for treatment delivery within the individual circumstances of each patient may enable them to stay on therapy longer, giving them the greatest potential to achieve benefit.

Recent Advances in Signaling Pathways Comprehension as Carcinogenesis Triggers in Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most common malignant skin tumor. BCC displays a different behavior compared with other neoplasms, has a slow evolution, and metastasizes very rarely, but sometimes it causes an important local destruction. Chronic ultraviolet exposure along with genetic factors are the most important risk factors involved in BCC development. Mutations in the PTCH1 gene are associated with Gorlin syndrome, an autosomal dominant disorder characterized by the occurrence of multiple BCCs, but are also the most frequent mutations observed in sporadic BCCs. PTCH1 encodes for PTCH1 protein, the most important negative regulator of the Hedgehog (Hh) pathway. There are numerous studies confirming Hh pathway involvement in BCC pathogenesis. Although Hh pathway has been intensively investigated, it remains incompletely elucidated. Recent studies on BCC tumorigenesis have shown that in addition to Hh pathway, there are other signaling pathways involved in BCC development. In this review, we present recent advances in BCC carcinogenesis.

The use of hedgehog antagonists in cancer therapy: a comparison of clinical outcomes and gene expression analyses

Hedgehog (HH) signaling, a critical developmental pathway, has been implicated in cancer initiation and progression. With vismodegib and sonidegib having been approved for clinical use, increasing numbers of HH inhibitors alone and in combination with chemotherapies are in clinical trials. Here we highlight the clinical research on HH antagonists and the genetics of response to these compounds in human cancers. Selectivity of HH inhibitors, determined by decreased pathway transcriptional activity, has been demonstrated in many clinical trials. Patients with advanced/metastatic basal cell carcinoma have benefited the most, whereas HH antagonists did little to improve survival rates in other cancers. Correlation between clinical response and HH gene expression vary among different cancer types. Predicting response and resistance to HH inhibitors presents a challenge and continues to remain an important area of research. New approaches combine standard of care chemotherapies and molecularly targeted therapies to increase the clinical utility of HH inhibitors.

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.

Article Commentary: Cancer Immunotherapy for the General Surgeon

Progress in the arena of cancer immunotherapy has been immense in recent years. The fact remains that most of the cancer resections in the United States are performed by general surgeons and not oncologic specialists. A busy practice in general surgery will invariably make it difficult to keep pace with such rapid advancement. This review offers a concise summary of the major concepts and trials that have driven the immunotherapy revolution and their implications for surgeons who deliver cancer care.

The molecular basis for current targets of NASH therapies

Introduction: Nonalcoholic steatohepatitis (NASH) is a leading cause of liver disease in children and adults, a major contributor to health-care expenditures, and now a leading reason for liver transplantation. Adopting lifestyle modifications with regular exercise and a focus on healthy eating habits is the primary recommendation. However, patients are often unable to achieve and sustain such changes for a variety of social, physical, psychological and genetic reasons. Thus, treatments that can prevent and reverse NASH and its associated fibrosis are a major focus of current drug development.Areas covered: This review covers the current understanding of lipotoxic liver injury in the pathogenesis of NASH and how lifestyle modification and the spectrum of drugs currently in clinical trials address the many pathways leading to the phenotype of NASH.Expert opinion: Contrary to the frequently expressed nihilistic view of our understanding of NASH and disappointment with clinical trial results, much is known about the pathogenesis of NASH and there is much reason to be optimistic that effective therapies will be identified in the next 5-10 years. Achieving this will require continued refinement of clinical trial endpoints, continued engagement of trial sponsors and regulatory authorities, and continued participation of dedicated patients in clinical trials.

[Synergistic effect of anti-PD1 immunotherapy then radiotherapy in advanced basal cell carcinoma]

INTRODUCTION

Vismodégib is the first-line treatment for non-operable or metastatic locally advanced basal cell carcinomas (LABCC), although complete response is rare and adverse effects are common. Immune checkpoint inhibitors are currently being evaluated in this indication. Herein we report a case of LABCC that responded dramatically to sequenced "immunotherapy then radiotherapy".

OBSERVATION

A 47-year-old male presented peri- and intra-orbital infiltrative LABCC that had been present for more than 10 years. After an initial response to vismodégib, further disease progression resulted in the introduction of successive lines of treatment (radiotherapy, platinum salts and itraconazole) without any significant response. Compassionate treatment with pembrolizumab was initiated. After eight courses, major clinical progression occurred with intraoral extension responsible for respiratory discomfort. Following withdrawal of pembrolizumab, high-energy radiotherapy was started with a spectacular response, both clinically and in terms of imaging.

DISCUSSION

The efficacy of "radiotherapy-immunotherapy" sequencing in melanoma has been reported, due in particular to the abscopal effect and radiosensitisation. In our case, where the sequence was inverted, immunotherapy may have enhanced the effects of radiotherapy through "immunosensitisation", whereas radiotherapy alone had previously been ineffective. This observation underlines the potential value of these treatments, either combined or in sequence, and their synergistic effects and optimal association require further evaluation.

[Primary basal cell carcinoma of the caruncle]

BACKGROUND

Primary basal cell carcinoma (BCC) of the caruncle is an extremely rare entity. Overall, only a few cases are described in the literature. With respect to the S2k guidelines on basal cell carcinoma of the skin, the eyelids, eyebrows and periorbital regions are regarded as zones with a high risk of recurrence. Due to its rarity hardly any data are available for primary BCC of the caruncle.

METHODS

This article is based on a comprehensive literature review and a case presentation.

RESULTS

In addition to a literature review this article reports the case of a 58-year-old male who presented at this department with a tumor of the caruncle. The histopathological examination revealed a BCC of the caruncle, which could be completely excised and showed no indications of recurrence in a follow-up period of 6 months.

CONCLUSION

Primary BCC of the caruncle must be considered as a differential diagnosis in the case of unclear caruncular tumors. Moreover, the current data indicate an increased risk of recurrence.