Complete response of a large basosquamous carcinoma following treatment with cemiplimab and vismodegib

The anti-PD-1 antibody cemiplimab has demonstrated effectiveness in the setting of locally advanced basal cell carcinoma (BCC) and squamous cell carcinoma. We describe a case of a large, locally invasive basosquamous carcinoma, an aggressive type of BCC, invading the left sternocleidomastoid muscle with near compression of the left internal jugular vein producing a severe anaemia secondary to ulceration and chronic blood loss. The patient was initially started on vismodegib monotherapy but failed to respond. He was then started on cemiplimab in addition to vismodegib. Improvement was noted after one cycle. After 21 cycles of cemiplimab, the left shoulder ulcerated lesion was completely re-epithelialised. He remains in complete remission after 31 cycles of cemiplimab in addition to vismodegib.

Treatment of basal cell carcinoma with intralesional interferon alfa-2b: an open-label clinical trial

INTRODUCTION

Basal cell carcinoma (BCC) is the most common cutaneous cancer. We report the efficacy and aesthetic outcome of intralesional IFN-α 2b injection for the treatment of BCC and compare with the surgical method.

MATERIALS AND METHODS

Intralesional IFN-α 2b was injected in 58 BCC lesions from 20 patients three times a week for three weeks. Control group was retrospectively selected among patients who underwent surgical method (standard surgical excision) for BCC including 58 lesions from 24 patients. All patients were followed up for one year in terms of recurrence and cosmetic outcome.

RESULTS

Two patients (four lesions) failed to complete the treatment period. After three weeks, 40 (68.96%) lesions were completely cured. Nine (15.51%) lesions achieved complete healing in less than 9 sessions. Five (8.62%) lesions were completely cured by an extra week of injection. In aggregate, complete healing was observed in 54 (93.10%) lesions. In the surgery group, complete lesion elimination was detected in 52 (89.65%) lesions (p = 0.40). After one year, cosmetic outcome was significantly more favorable in the study group compared to the surgery group (p = 0.003). Recurrence was not detected in any of the groups after one year follow-up.

CONCLUSION

Intralesional IFN-α 2b injection is an appropriate treatment choice for BCC.

CLINICAL TRIAL REGISTRY

We used Iranian registery of Clinical trials; The IRCT code is: 2017093017756N30.

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.

Clinical Characteristics of an Italian Patient Population with Advanced BCC and Real-Life Evaluation of Hedgehog Pathway Inhibitor Safety and Effectiveness

BACKGROUND

Advanced basal cell carcinoma (aBCC) represents a complex and clinically heterogeneous group of lesions for which curative surgery and/or radiotherapy is unlikely. Systemic therapy with hedgehog pathway inhibitors (HHIs) changed the treatment landscape for this complex patient population.

OBJECTIVES

The aims of the present study are to describe the clinical characteristics of a real-life Italian cohort diagnosed with aBCC and to investigate effectiveness and safety of HHI.

METHODS

A multicenter observational study was performed by twelve Italian centers in the period January 1, 2016 - October 15, 2022. Patients aged ≥18 years and diagnosed with aBCC (locally advanced [laBCC] and metastatic BCC [mBCC]) were eligible for the study. Methods for investigating tumor response to HHI included clinical and dermatoscopic evaluation, radiological imaging, and histopathology. For HHI safety assessment, therapy-related adverse events (AEs) were reported and graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

RESULTS

We enrolled 178 patients under treatment with HHI: 126 (70.8%) and 52 patients (29.2%) received sonidegib and vismodegib, respectively. Comprehensive data on HHI effectiveness and disease outcome were available for 132 (74.1%) of 178 patients: 129 patients had a diagnosis of laBCC (n = 84, sonidegib; n = 45, vismodegib) and 3 patients of mBCC (n = 2, vismodegib; n = 1, sonidegib, off-label). Objective response rate was 76.7% (95% confidence interval [CI]: 82.3-68.7) and 33.3% (95% CI: 88.2-1.7) for laBCC (complete response [CR]: 43/129; PR: 56/129) and mBCC (CR: 0/3; PR: 1/3), respectively. High-risk aBCC histopathological subtypes and occurrence of >2 therapy-related AEs were significantly associated with nonresponse to HHI therapy ([OR: 2.61; 95% CI: 1.09-6.05; p: 0.03] and [OR: 2.74; 95% CI: 1.03-7.9; p: 0.04]), respectively. Majority of our cohort (54.5%) developed at least 1 therapy-related AE, most of which were mild-moderate in severity.

CONCLUSIONS

Our results demonstrate the effectiveness and safety profile of HHI and confirm the reproducibility of pivotal trial results in real-life clinical setting.

Concomitant medication use does not appear to alter long-term efficacy of sonidegib for advanced basal cell carcinoma: a post hoc analysis based on the 42-month BOLT study

BACKGROUND

Sonidegib is approved to treat locally advanced basal cell carcinoma (laBCC) in patients not amenable to surgery or radiation. The BOLT trial demonstrated durable efficacy of sonidegib in laBCC patients over 42 months. BCC is most common in the elderly, who often take chronic medications.

OBJECTIVES

We evaluated the efficacy of sonidegib (200 mg daily) in laBCC patients on select concomitant medications.

MATERIALS & METHODS

In the Phase II BOLT study, laBCC patients were randomized 1:2 to sonidegib 200 mg:800 mg daily. The primary endpoint was objective response rate (ORR) per central review. Post hoc assessments included ORR and duration of response (DOR) per investigator review for patients on concomitant medications.

RESULTS

At 42 months, ORR for laBCC patients taking sonidegib 200 mg daily (n=66) was 71.2% and DOR was 15.7 months according to investigator review. Patients on select concomitant medications (n=37) had an ORR of 73.0%; DOR was not estimable.

CONCLUSION

Administration of sonidegib with concomitant medications, excluding strong cytochrome P450 3A4/5 inhibitors/inducers, does not appear to alter its efficacy in laBCC patients.

Repurposing antifungal drugs for cancer therapy

BACKGROUND

Repurposing antifungal drugs in cancer therapy has attracted unprecedented attention in both preclinical and clinical research due to specific advantages, such as safety, high-cost effectiveness and time savings compared with cancer drug discovery. The surprising and encouraging efficacy of antifungal drugs in cancer therapy, mechanistically, is attributed to the overlapping targets or molecular pathways between fungal and cancer pathogenesis. Advancements in omics, informatics and analytical technology have led to the discovery of increasing "off-site" targets from antifungal drugs involved in cancerogenesis, such as smoothened (D477G) inhibition from itraconazole in basal cell carcinoma.

AIM OF REVIEW

This review illustrates several antifungal drugs repurposed for cancer therapy and reveals the underlying mechanism based on their original target and "off-site" target. Furthermore, the challenges and perspectives for the future development and clinical applications of antifungal drugs for cancer therapy are also discussed, providing a refresh understanding of drug repurposing.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review may provide a basic understanding of repurposed antifungal drugs for clinical cancer management, thereby helping antifungal drugs broaden new indications and promote clinical translation.

Non-Invasive Treatment of Basal Cell Carcinoma: Photodynamic Therapy Following Curettage

BACKGROUND

To investigate the effectiveness, safety, patient satisfaction, and cosmetic outcome of Methyl Aminolevulinate-Photodynamic Therapy (MAL-PDT) following curettage in order to make recommendations for its use in dermatology practices.

METHODS

A retrospective chart review of patients who received MAL-PDT following curettage for the indication of basal cell carcinoma (BCC) between 2009 and 2016 at a single private clinic in Ontario, Canada. Two hundred and seventy-eight patients with 352 BCC lesions were included, consisting of 44.2% males (n=123) and 55.8% females (n=155) with a mean age of 57.24 years. The primary outcome measurement consisted of the cure rate. Secondary outcome measurements included side effects, patient satisfaction, and cosmetic outcome, as reported in the medical charts.

RESULTS

The overall cure rate was 90.3% (n=318). After controlling for age, sex, and lesion type, nasal lesions were approximately 2.82 (95% CI: 1.24-6.40, P=0.01) times more likely to experience a recurrence. 18.3% of patients (n=51) reported side effects, the most common being burning (n=19). Of those who expressed satisfaction, 100% (n=25) reported being happy. Of lesions with cosmetic data, 90.3% displayed a good response (n=149).

CONCLUSION

MAL-PDT following curettage is an effective and safe treatment option for BCC lesions with a good cosmetic outcome and suggested high patient satisfaction. J Drugs Dermatol. 2023;22(5): doi:10.36849/JDD.7133.

Chronic Use of Hydrochlorothiazide and Risk of Skin Cancer in Caucasian Adults: A PharmLines Initiative Inception Cohort Study

Photosensitizing properties of hydrochlorothiazide may increase skin cancer risk. To date, study findings on the association between hydrochlorothiazide use and skin cancer risk are inconsistent, notably regarding confounding and dose-response. The aim of this study was to investigate the association between hydrochlorothiazide use and incidence of skin cancer in a cohort of unselected Caucasian adults, taking dosing into account. As part of the PharmLines Initiative, which links data from the Lifelines Cohort Study and prescription database IADB.nl, patients aged ≥ 40 years were included from Lifelines, a prospective population-based cohort study in the north of the Netherlands. Skin cancer incidence was compared between subjects starting hydrochlorothiazide treatment (n = 608), subjects starting treatment with other antihypertensives (n = 508), and non-antihypertensive long-term medication users (n = 1,710). Cox regression analyses were performed to obtain hazard ratios, adjusted for potential confounders. The risk of any skin cancer, keratinocyte carcinoma, basal cell carcinoma and squamous cell carcinoma was not significantly increased in general hydrochlorothiazide users. A clear association was observed between high cumulative hydrochlorothiazide use (≥ 5,000 defined daily dose; ≥ 125,000 mg) and the risk of any skin cancer (adjusted hazard ratio 5.32, 95% confidence interval (95% CI) 2.40-11.81), keratinocyte carcinoma (adjusted hazard ratio 7.31, 95% CI 3.12-17.13), basal cell carcinoma (adjusted hazard ratio 7.72, 95% CI 3.11-19.16) and squamous cell carcinoma (adjusted hazard ratio 19.63, 95% CI 3.12-123.56). These findings should lead to awareness with high use of hydrochlorothiazide in Caucasian adults.

Expression of β-Catenin, E-Cadherin, and α-Smooth Muscle Actin in Basal Cell Carcinoma Before Photodynamic Therapy in Non-recurrent and Recurrent Tumors: Exploring the Ability of Predicting Photodynamic Therapy Outcome

Photodynamic therapy (PDT) is an effective and cosmetically beneficial treatment of low-risk basal cell carcinomas (BCCs). To optimize PDT response, it is important to correctly select tumors. We sought to find markers that could identify such tumors beyond contributions from clinical and histological examination. Studies have shown that β-catenin, E-cadherin, and α-smooth muscle actin (SMA) expression can indicate BCC aggressiveness/BCC invasiveness. We wanted to use these markers in an explorative study to investigate whether they were differently expressed among non-recurring compared with recurring BCCs, to evaluate their ability of predicting PDT outcome. Fifty-two BCCs were stained with antibodies against β-catenin, E-cadherin, and α-SMA, and evaluated using immunoreactive score (IRS), subcellular localization, and stromal protein expression. Results showed that IRS of E-cadherin was significantly different among recurring compared with non-recurring BCCs and with area under a receiver operating characteristic curve of 0.71 (95% confidence interval: 0.56-0.86, p=0.025). Stromal β-catenin expression significantly increased among recurring BCCs. Some recurring BCCs had intense expression in the deep invading tumor edge. In conclusion, E-cadherin, and stromal and deep edge β-catenin expression were most prominent in BCCs that recurred post-PDT, suggesting they could potentially predict PDT outcome. Further studies are needed to investigate whether these results are of clinical value.

Octenidine Versus Dispase Gels for Wound Healing After Cryosurgery Treatment in Patients with Basal Cell Carcinoma

For a specific group of patients with basal cell carcinoma (small, low risk), cryosurgery could be the suggested treatment, which results in the formation of an ulcer in the lesion area. The proteolytic enzymes' contribution to the wound healing is an ongoing research goal. Preclinical animal experiments in the Laboratory of the Pharmaceutical Technology Department of the National and Kapodistrian University of Athens have showed that a dose of 5 U/mL of dispase gel after the formation of tissue rashes, significantly promoted wound healing. Herein, a feasibility study in 16 patients enrolled by the First Department of Dermatology of Andreas Syggros Hospital was designed: 5 U/mL of dispase gel (once every 3 days) versus a drug reference containing octenidine (daily administration). The evaluation of the healing effect, safety, and tolerance was done on days 1 (cryosurgery), 2, 7, 21, and 60. The study end point was considered either the ulcer complete healing or the eighth week since treatment initiation. Wound healing was faster with dispase gel and hemoglobin reduced rapidly after the seventh day. Yet, hydration was higher in the control group. Our non-parametric analysis provides evidence that the dispase gel shows faster healing compared to the reference drug, in humans, meriting further investigation in larger human sample sizes before massive production of the product.

Analysis of residual disease in periocular basal cell carcinoma following hedgehog pathway inhibition: Follow up to the VISORB trial

Basal cell carcinoma (BCC) is a common skin cancer caused by deregulated hedgehog signaling. BCC is often curable surgically; however, for orbital and periocular BCCs (opBCC), surgical excision may put visual function at risk. Our recent clinical trial highlighted the utility of vismodegib for preserving visual organs in opBCC patients: 67% of patients displayed a complete response histologically. However, further analysis of excision samples uncovered keratin positive, hedgehog active (Gli1 positive), proliferative micro-tumors. Sequencing of pre-treatment tumors revealed resistance conferring mutations present at low frequency. In addition, one patient with a low-frequency SMO W535L mutation recurred two years post study despite no clinical evidence of residual disease. Sequencing of this recurrent tumor revealed an enrichment for the SMO W535L mutation, revealing that vismodegib treatment enriched for resistant cells undetectable by traditional histology. In the age of targeted therapies, linking molecular genetic analysis to prospective clinical trials may be necessary to provide mechanistic understanding of clinical outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT02436408.

Topical Delivery of Hedgehog Inhibitors: Current Status and Perspectives

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

The Use of Retinoids for the Prevention and Treatment of Skin Cancers: An Updated Review

Retinoids are natural and synthetic vitamin A derivatives that are effective for the prevention and the treatment of non-melanoma skin cancers (NMSC). NMSCs constitute a heterogenous group of non-melanocyte-derived skin cancers that impose substantial burdens on patients and healthcare systems. They include entities such as basal cell carcinoma and cutaneous squamous cell carcinoma (collectively called keratinocyte carcinomas), cutaneous lymphomas and Kaposi’s sarcoma among others. The retinoid signaling pathway plays influential roles in skin physiology and pathology. These compounds regulate diverse biological processes within the skin, including proliferation, differentiation, angiogenesis and immune regulation. Collectively, retinoids can suppress skin carcinogenesis. Both topical and systemic retinoids have been investigated in clinical trials as NMSC prophylactics and treatments. Desirable efficacy and tolerability in clinical trials have prompted health regulatory bodies to approve the use of retinoids for NMSC management. Acceptable off-label uses of these compounds as drugs for skin cancers are also described. This review is a comprehensive outline on the biochemistry of retinoids, their activities in the skin, their effects on cancer cells and their adoption in clinical practice.

Novel Approaches in Non-Melanoma Skin Cancers—A Focus on Hedgehog Pathway in Basal Cell Carcinoma (BCC)

Basal cell carcinoma (BCC) is one of the most common neoplasms in the population. A good prognosis and mainly non-aggressive development have made it underdiagnosed and excluded from the statistics. Due to the availability of efficient surgical therapy, BCC is sometimes overlooked in the search for novel therapies. Most clinicians are unaware of its complicated pathogenesis or the availability of effective targeted therapy based on Hedgehog inhibitors (HHI) used in advanced or metastatic cases. Nevertheless, the concomitance and esthetic burden of this neoplasm are severe. As with other cancers, its pathogenesis is multifactorial and complicated with a network of dependencies. Although the tumour microenvironment (TME), genetic aberrations, and risk factors seem crucial in all skin cancers, in BCC they all have become accessible as therapeutic or prevention targets. The results of this review indicate that a central role in the development of BCC is played by the Hedgehog (Hh) signalling pathway. Two signalling molecules have been identified as the main culprits, namely Patched homologue 1 (PTCH1) and, less often, Smoothened homologue (SMO). Considering effective immunotherapy for other neoplastic growths being introduced, implementing immunotherapy in advanced BCC is pivotal and beneficial. Up to now, the US Food and Drug Administration (FDA) has approved two inhibitors of SMO for the treatment of advanced BCC. Sonidegib and vismodegib are registered based on their efficacy in clinical trials. However, despite this success, limitations might occur during the therapy, as some patients show resistance to these molecules. This review aims to summarize novel options of targeted therapies in BCC and debate the mechanisms and clinical implications of tumor resistance.

Vismodegib for Basal Cell Carcinoma and Beyond: What Dermatologists Need to Know

Basal cell carcinoma (BCC) is the most common cutaneous malignancy. Although indolent, BCCs can be locally aggressive if untreated. Dysregulated hedgehog (Hh) signaling leads to uncontrolled proliferation in BCC. Vismodegib is a small-molecule antagonist of the Hh pathway that binds to smoothened (SMO), a transmembrane protein, and causes inhibition of an aberrant activation of the Hh pathway. Vismodegib is the first drug approved by the US Food and Drug Administration (FDA) for the management of locally advanced or metastatic BCC.

CYP11A1‑derived vitamin D hydroxyderivatives as candidates for therapy of basal and squamous cell carcinomas

Hydroxyderivatives of vitamin D3, including classical 1,25(OH)2D3 and novel CYP11A1‑derived hydroxyderivatives, exert their biological activity by acting as agonists on the vitamin D receptor (VDR) and inverse agonists on retinoid‑related orphan receptors (ROR)α and γ. The anticancer activities of CYP11A1‑derived hydroxyderivatives were tested using cell biology, tumor biology and molecular biology methods in human A431 and SCC13 squamous (SCC)‑ and murine ASZ001 basal (BCC)‑cell carcinomas, in comparison with classical 1,25(OH)2D3. Vitamin D3‑hydroxyderivatives with or without a C1α(OH) inhibited cell proliferation in a dose‑dependent manner. While all the compounds tested had similar effects on spheroid formation by A431 and SCC13 cells, those with a C1α(OH) group were more potent in inhibiting colony and spheroid formation in the BCC line. Potent anti‑tumorigenic activity against the BCC line was exerted by 1,25(OH)2D3, 1,20(OH)2D3, 1,20,23(OH)3D3, 1,20,24(OH)3D3, 1,20,25(OH)3D3 and 1,20,26(OH)3D3, with smaller effects seen for 25(OH)D3, 20(OH)D3 and 20,23(OH)2D3. 1,25(OH)2D3, 1,20(OH)2D3 and 20(OH)D3 inhibited the expression of GLI1 and β‑catenin in ASZ001 cells. In A431 cells, these compounds also decreased the expression of GLI1 and stimulated involucrin expression. VDR, RORγ, RORα and CYP27B1 were detected in A431, SCC13 and ASZ001 lines, however, with different expression patterns. Immunohistochemistry performed on human skin with SCC and BCC showed nuclear expression of all three of these receptors, as well as megalin (transmembrane receptor for vitamin D‑binding protein), the level of which was dependent on the type of cancer and antigen tested in comparison with normal epidermis. Classical and CYP11A1‑derived vitamin D3‑derivatives exhibited anticancer‑activities on skin cancer cell lines and inhibited GLI1 and β‑catenin signaling in a manner that was dependent on the position of hydroxyl groups. The observed expression of VDR, RORγ, RORα and megalin in human SCC and BCC suggested that they might provide targets for endogenously produced or exogenously applied vitamin D hydroxyderivatives and provide excellent candidates for anti‑cancer therapy.

In vitro 5-Fluorouracil resistance produces enhanced photodynamic therapy damage in SCC and tumor resistance in BCC

Non-melanoma skin cancer (NMSC) is the most common malignancy worldwide, with rising incidence in the recent years. It includes basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). Several non-invasive therapies have been developed for its treatment such as topical 5-Fluorouracil (5FU) and photodynamic therapy (PDT), among others. Despite both are appropriated for NMSC treatment, recurrence cases have been reported. To prevent this, in this work we explore the potential of the combination of PDT and 5FU to treat SCC and BCC. First we evaluate the efficacy of PDT in cells resistant to 5FU. For this purpose, we use SCC-13 and CSZ-1 cells, obtained from a human SCC and a murine BCC, respectively. We first induced 5FU resistance in these cell lines by repeated treatments with the drug and then, the efficacy to PDT was evaluated. The results obtained indicated that SCC-5FU resistant cells were sensible to PDT administration, whereas BCC-5FU resistant cells were also resistant to PDT. The observed responses in both cell lines are in concordance to Protoporphyrin IX (PpIX) and reactive oxygen species (ROS) levels produced after the incubation with MAL and subsequent light exposure. The obtained data support the fact that PDT seems to be an appropriate therapeutic option to be administered after 5FU resistance in SCC. However, PDT would not be a choice therapy for resistant BCC cells to 5FU.

Treatment of Basal Cell Carcinoma with Electrochemotherapy: Insights from the InspECT Registry (2008–2019)

This prospective registry-based study aims to describe electrochemotherapy (ECT) modalities in basal cell carcinoma (BCC) patients and evaluate its efficacy, safety, and predictive factors. The International Network for Sharing Practices of Electrochemotherapy (InspECT) multicentre database was queried for BCC cases treated with bleomycin-ECT between 2008 and 2019 (n = 330 patients from seven countries, with 623 BCCs [median number: 1/patient; range: 1–7; size: 13 mm, range: 5–350; 85% were primary, and 80% located in the head and neck]). The procedure was carried out under local anaesthesia in 68% of cases, with the adjunct of mild sedation in the remaining 32%. Of 300 evaluable patients, 242 (81%) achieved a complete response (CR) after a single ECT course. Treatment naïvety (odds ratio [OR] 0.35, 95% confidence interval [C.I.] 0.19–0.67, p = 0.001) and coverage of deep tumour margin with electric pulses (O.R. 5.55, 95% C.I. 1.37–21.69, p = 0.016) predicted CR, whereas previous radiation was inversely correlated (O.R. 0.25, p = 0.0051). Toxicity included skin ulceration (overall, 16%; G3, 1%) and hyperpigmentation (overall, 8.1%; G3, 2.5%). At a 17-month follow-up, 28 (9.3%) patients experienced local recurrence/progression. Despite no convincing evidence that ECT confers improved outcomes compared with standard surgical excision, it can still be considered an opportunity to avoid major resection in patients unsuitable for more demanding treatment. Treatment naïvety and coverage of the deep margin predict tumour clearance and may inform current patient selection and management.

Sonidegib in the Treatment of Locally Advanced Basal Cell Carcinoma: a Retrospective Study

Sonidegib, a hedgehog pathway inhibitor, is indicated for treatment of locally advanced basal cell carcinoma, based on the results of the BOLT study. However, to date, no real-world study of sonidegib has been reported. An observational, retrospective, single-centre study (PaSoS study) was conducted. The primary objective was to evaluate the efficacy of sonidegib for treatment of locally advanced basal cell carcinoma in a real-world setting. Secondary objectives included modalities of use, tolerability, tumour evolution, and management after discontinuation. A total of 21 patients treated with sonidegib were included from March 2018 to January 2021. The median follow-up was 18.7 months and median exposure 7.0 months. Objective response (OR) rate was 81.0% (n = 17) including 6 (29%) patients with a complete response (CR). Disease control rate was 100%. First tumour response was rapid, with a median time of 2.3 months. Nine (43%) patients underwent surgery after sonidegib discontinuation, and no relapse was observed. All the patients experienced at least 1 adverse event (AE). Muscle spasms were the most frequent AE (n = 14; 67%), followed by dysgeusia (n = 8; 38%) and alopecia (n = 12; 57%). The efficacy and safety profile of sonidegib in this first-to-date real-life trial are consistent with prior results. Overall, real-world evidence corroborated sonidegib efficacy and tolerability as a first-line treatment for locally advanced basal cell carcinoma.

Single-cell analysis of human basal cell carcinoma reveals novel regulators of tumor growth and the tumor microenvironment

How basal cell carcinoma (BCC) interacts with its tumor microenvironment to promote growth is unclear. We use singe-cell RNA sequencing to define the human BCC ecosystem and discriminate between normal and malignant epithelial cells. We identify spatial biomarkers of tumors and their surrounding stroma that reinforce the heterogeneity of each tissue type. Combining pseudotime, RNA velocity-PAGA, cellular entropy, and regulon analysis in stromal cells reveals a cancer-specific rewiring of fibroblasts, where STAT1, TGF-β, and inflammatory signals induce a noncanonical WNT5A program that maintains the stromal inflammatory state. Cell-cell communication modeling suggests that tumors respond to the sudden burst of fibroblast-specific inflammatory signaling pathways by producing heat shock proteins, whose expression we validated in situ. Last, dose-dependent treatment with an HSP70 inhibitor suppresses in vitro vismodegib-resistant BCC cell growth, Hedgehog signaling, and in vivo tumor growth in a BCC mouse model, validating HSP70's essential role in tumor growth and reinforcing the critical nature of tumor microenvironment cross-talk in BCC progression.