PD-1 inhibition therapy for advanced cutaneous squamous cell carcinoma: a retrospective analysis from the University of Southern California

Cutaneous Squamous Cell Carcinoma: An Updated Review

Representing the second most common skin cancer, the incidence and disease burden of cutaneous squamous cell carcinoma (cSCC) continues to increase. Surgical excision of the primary site effectively cures the majority of cSCC cases. However, an aggressive subset of cSCC persists with clinicopathological features that are indicative of higher recurrence, metastasis, and mortality risks. Acceleration of these features is driven by a combination of genetic and environmental factors. The past several years have seen remarkable progress in shaping the treatment landscape for advanced cSCC. Risk stratification and clinical management is a top priority. This review provides an overview of the current perspectives on cSCC with a focus on staging, treatment, and maintenance strategies, along with future research directions.

Personalized treatment concepts in extraocular cancer

Background

The periocular skin is neoplasms-prone to various benign and malignant. Periocular malignancies are more aggressive and challenging to cure and repair than those in other skin areas. In recent decades, immunotherapy has significantly advanced oncology, allowing the autoimmune system to target and destroy malignant cells. Skin malignancies, especially periocular tumors, are particularly sensitive to immunotherapy. This technique has dramatically impacted the successful treatment of challenging tumors.

Main text

Extraocular cancers, including eyelid (basal cell carcinoma, squamous cell carcinoma, melanoma, merkel cell carcinoma), conjunctival tumors (conjunctival melanoma, ocular surface squamous neoplasia) and other rare tumors, are unique and challenging clinical situations. Several genetic alterations associated with the pathogenesis of these diseases have been identified, and molecular mechanism are essential for the development of the immunotherapy agents, such as Hedgehog pathway inhibitors (vismodegib and sonidegib) for basal cell carcinoma, BRAF/MEK inhibitors (vemurafenib, dabrafenib, and encorafenib) for melanoma, and immune checkpoint inhibitors (Avelumab, pembrolizumab) for Merkel cell carcinoma.

Conclusions

The optimal treatment for periocular skin cancer depends on the type and size of the tumor and whether it involves orbital and adnexal structures. Adjuvant and neoadjuvant therapy with chemotherapy-targeted therapies and immune checkpoint inhibitors should be considered based on tumor type, tumor molecular profile, expected response rate, and candidacy for systemic treatment.

METTL3-mediated HPV vaccine enhances the effect of anti PD-1 immunotherapy to alleviate the development of cutaneous squamous cell carcinoma

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) develops from epithelial keratinocytes by dysregulation of self-renewal and differentiation. Recent studies have found that the size and number of cSCC tumors gradually decrease or even disappear after HPV vaccination. However, the role of the HPV vaccine in the cSCC mechanism is poorly understood.

OBJECTIVE

The aim of this study is to investigate the effect and mechanism of the HPV vaccine in cSCC.

METHODS

Immunofluorescence was used to study the immune infiltrating cells in the tumor tissues of patients with cSCC. The effects of the HPV vaccine on cSCC cells and tissues were studied by Cell Culture, Real-time PCR, Western Blot, Cytotoxicity Assay, Enzyme-linked Immunosorbent Assay, m6A Blotting, CCK-8 Assay, m6A Ribonucleic acid Methylation Quantification and tumor transplantation.

RESULTS

The HPV vaccine enhanced the toxic effect of CD8+T cells on cSCC cells and promoted the secretion of multiple cytokines by CD8+T cells. In addition, HPV vaccines can increase tumor sensitivity to anti-PD-1 therapy by downregulating METTL3 in tumor tissue, with the combination of HPV vaccine and PD-1 monoclonal antibodies producing enhanced immune cell infiltration compared to PD-1 blockade alone.

STUDY LIMITATIONS

It is important to note the limitations of this study, including the small sample size, the construction of the mouse model, and the choice of HPV vaccine and PD-1 monoclonal antibody, which may limit the generalization of our findings to a wider population.

CONCLUSIONS

It is hoped that this research will contribute to a deeper understanding of the role of the HPV vaccine in the treatment of cSCC. HPV vaccine is expected to become an important approach to alleviate the development of cSCC.

Risk factors and novel predictive model for metastatic cutaneous squamous cell carcinoma: a population-based analysis

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin malignancies. Patients with metastatic cSCC (mcSCC) tended to have unfavorable prognosis. However, there is no available models to evaluate the survival outcomes for these patients. This study retrospectively collected mcSCC cases identified from The Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2018. All patients were randomly divided into the training and validation cohorts. The independent factors which predicted the cancer-specific survival (CSS) were identified by Cox proportional hazard regression analysis, and were used to build nomogram. he discrimination ability of nomograms was evaluated using the concordance index (C-index). The receiver operating characteristic (ROC) curve and the corresponding area under the curve (AUC) at 1, 3, and 5 years were calculated to estimate the predictive accuracy. The performance of this nomogram was evaluated by the calibration curves. The decision curve analyses (DCAs) were conducted to assess the clinical usefulness of the models. Based on the novel nomograms, all patients were classified into low- and high-risk groups. Kaplan-Meier curves were plotted to compare the survival outcomes of two groups. All analyses were conducted by R software (Version 4.1.3). A total of 916 patients were included. Age, marital status, location of the primary sites, number of metastases, T stage, N stage, surgical resection of the primary sites, radiotherapy of the primary sites, and chemotherapy were significantly associated with CSS. A nomogram predicting CSS was built based on these parameters. C-index and ROC curves of nomogram showed promising discriminating and predicting ability for CSS. Survival analysis showed that patients in the low-risk group had significant superior CSS time than those in the high-risk group (median CSS time: 15.0 vs. 5.0 months, p < 0.001). In conclusion, we developed and validated a novel nomogram predicting the CSS in metastatic cSCC patients. This nomogram could be used to assess the prognosis of metastatic cSCC patients, and help clinicians evaluating optimal treatment options for individual patient.

Immune Checkpoint Inhibitors in Advanced Cutaneous Squamous Cell Carcinoma: Real-World Experience from a Canadian Comprehensive Cancer Centre

Immune checkpoint inhibitors (ICI) cemiplimab and pembrolizumab have revolutionized the treatment of advanced cutaneous squamous cell carcinoma (cSCC). We aimed to evaluate the effectiveness and safety of ICI in a real-world cSCC population, including patients with conditions that would exclude clinical trial participation. In this single-center, retrospective cohort study, we included all non-trial patients with advanced cSCC treated with ICI between 2017 and 2022. We evaluated investigator-assessed best overall response (BOR) and immune-related adverse events (irAEs). We correlated survival outcomes with age, performance status, immune status and irAEs. Of the 36 patients identified, the best overall response (BOR) to ICI was a partial response (PR) in 41.7%, a complete response (CR) in 27.8%, and stable disease in (SD) 13.9%. The progression-free survival (PFS) rate for 1 year was 58.1%; the median PFS was 21.3 months (95% CI 6.4-NE). The 1-year overall survival (OS) was 76.7%, and the median OS was 38.6 months (95% CI 25.4-NE). Immune-compromised patients, ECOG performance 2-3, and age ≥ 75 years were not significantly associated with PFS or OS. IrAE grades 3-4 were seen in 13.9% of patients. In our Canadian experience with real-world patients, ICI was an effective and safe treatment for advanced cSCC patients. Patients achieved great benefits with ICI regardless of age, immune status or ECOG performance status. We acknowledge the small sample size and retrospective methodology as the main limitations of our study.

Primary cemiplimab treatment for orbital squamous cell carcinoma is effective and may alleviate the need for orbital exenteration

PURPOSE

To evaluate the effectiveness of cemiplimab, a Programmed-cell-death-1(PD-1) protein inhibitor, for the treatment of cutaneous periocular-locally-advanced squamous-cell-carcinoma (POLA-SCC) with orbital-invasion.

METHODS

Multicentre real-world retrospective study. Demographic and clinical data were collected and analysed for patients with biopsy-proven POLA-SCC(AJCC-T4) with orbital-invasion who were treated with cemiplimab at one of four tertiary medical centres in 2019-2022.

RESULTS

The cohort included 13 patients, 8 males and 5 females, of median age 76 years (IQR65-86). The median duration of treatment was 5.0months (IQR3.5-10.5) and the median follow-up time, 15.0 months (IQR10.5-30). The overall response rate was 69.2%. Complete response was documented in seven patients (53.8%), partial response in two (15.4%), stable disease in one (7.7%), and progressive disease in two (15.4%); in one patient (7.7%), response was not evaluable. Six complete responders (46.1% of the cohort) received no further treatment and did not have a recurrence during an average follow-up of 6.14 (±6.9) months from treatment cessation. None of the patients underwent orbital-exenteration. The majority of adverse events were mild (grade-1), except for a moderate increase in creatinine level (grade-2), severe bullous dermatitis (grade-3), and myocarditis (grade-5) in one patient each. Four patients (30.7%) died during the follow-up period, all of whom had an Eastern-Cooperative-Oncology-Group score of 4 at presentation.

CONCLUSIONS

To our knowledge, this is the largest study to date on cemiplimab therapy for cutaneous POLA-SCC with orbital-invasion. Treatment was shown to be effective, with an overall response rate of 69.2%. Cemiplimab holds promise for the treatment of patients with tumours invading the orbit as it may alleviate the need for orbital exenteration.

Medical treatment for ocular surface squamous neoplasia

Ocular surface squamous neoplasia (OSSN) is the most common non-melanocytic tumour of the ocular surface. Surgical excision with wide margins using the "no-touch" method was originally the most popular treatment for OSSN. However, in the past two decades, the use of topical medications for OSSN treatment has gained a reputation amongst ophthalmologists for being an effective alternative to surgical excision. Furthermore, technological advancements, such as those seen in high-resolution optical coherence tomography (HR-OCT) for the anterior segment, have facilitated the diagnosis and monitoring of OSSN. When selecting a topical agent, interferon alpha-2b (IFNα-2b) and 5-fluorouracil (5-FU) are two of the gentlest medications used for OSSN and are often considered first line therapies due to their high-resolution rates and mild side effect profiles. Mitomycin C (MMC), on the other hand, has a highly toxic profile; therefore, while effective, in our hands it is considered as a second-line treatment for OSSN if the other modalities fail. In addition, newer and less studied agents, such as immune checkpoint inhibitors, retinoic acid, aloe vera, and anti-vascular endothelial growth factor have anti-neoplastic properties and have shown potential for the treatment of OSSN. We enclose an updated literature review of medical treatments for OSSN.

Immunotherapy in advanced cutaneous squamous cell carcinoma: Sydney west cancer network experience

BACKGROUND

Cutaneous squamous cell carcinoma (CSCC) is the second most common malignancy in the Caucasian population. A minority of cases are inoperable at presentation, recur or develop metastatic disease with a historical 5-year overall survival of ~10%. Treatment options in this setting are generally palliative. Immunotherapy has emerged as a new paradigm in managing these patients.

METHODS

Patients presenting to Sydney West Cancer Network with locally advanced or metastatic CSCC treated with the anti-PD1 agent cemiplimab were identified. Response to treatment was objectively assessed based on RECIST1.1 or PERCIST criteria. Primary end point was objective response rate (ORR). Secondary end points included progression-free survival (PFS), overall survival (OS), therapy toxicity, and predictors of treatment response.

RESULTS

A total of 19 patients were identified with a median age of 76 (range 56-94) and 4 immunosuppressed. The longest follow up duration was 28 months. ORR, complete response (CR), and partial response (PR) were 68% (13/19), 53% (10/19), and 16% (3/19), respectively. Median PFS was 12 months (95% CI 9-14) whilst median OS was not reached by end of study. Responders (CR or PR) had significantly superior OS compared to those with no response (P < 0.01). A primary site of head and neck cancer was significantly associated with ORR (P = 0.04). A single patient experienced Grade 3 toxicity with the rest being Grades 0-1.

CONCLUSION

This study confirms the clinical efficacy of cemiplimab in patients with advanced CSCC with many experiencing a durable response and an acceptable adverse effect profile.

Immune checkpoint inhibitors in advanced cutaneous squamous cell carcinoma: A systemic review and meta-analysis

BACKGROUND

To evaluate the immune checkpoint inhibitors (CPI) for the treatment of patients with advanced cutaneous squamous cell carcinoma (CSCC).

MATERIALS AND METHODS

A meta-analysis was conducted, and the efficacy and safety of CPI were assessed.

RESULTS

A total of 13 studies with 980 patients were included. The pooled objective response rate (ORR) and disease control rate were 47.2% and 64.4%, separately. In addition, patients with primary tumor located in head and neck (odds ratio [OR]: 0.374, 95% confidence interval [CI]: 0.219-0.640, p < 0.001) and positive expression of programmed death ligand 1 (OR: 0.364, 95% CI: 0.158-0.842, P = 0.018) had superior ORR during CPI treatment. The incidence of progression free survival at 6 and 12 months was 59.3% and 52.8%, and 80.6% and 76.4% for overall survival. As for safety, the overall incidence of adverse events with all grades and 3-4 grade was 76.9% and 20.2%.

CONCLUSIONS

Our systematic review confirmed the satisfying efficacy and acceptable toxicity of CPI for advanced CSCC.

Response to First-Line Treatment with Immune-Checkpoint Inhibitors in Patients with Advanced Cutaneous Squamous Cell Carcinoma: A Multicenter, Retrospective Analysis from the German ADOReg Registry

Cutaneous squamous cell carcinoma (cSCC) is a common malignancy of the skin and has an overall favorable outcome, except for patients with an advanced stage of the disease. The efficacy of checkpoint inhibitors (CPI) for advanced cSCC has been demonstrated in recent clinical studies, but data from real-world cohorts and trial-ineligible cSCC patients are limited. We retrospectively investigated patients with advanced cSCC who have been treated with CPI in a first-line setting at eight German skin cancer centers registered within the multicenter registry ADOReg. Clinical outcome parameters including response, progression-free (PFS) and overall survival (OS), time-to-next-treatment (TTNT), and toxicity were analyzed and have been stratified by the individual immune status. Among 39 evaluable patients, the tumor response rate (rwTRR) was 48.6%, the median PFS was 29.0 months, and the median OS was not reached. In addition, 9 patients showed an impaired immune status due to immunosuppressive medication or hematological diseases. Our data demonstrated that CPI also evoked tumor responses among immunocompromised patients (rwTRR: 48.1 vs. 50.0%), although these responses less often resulted in durable remissions. In line with this, the median PFS (11 vs. 40 months, p = 0.059), TTNT (12 months vs. NR, p = 0.016), and OS (29 months vs. NR, p < 0.001) were significantly shorter for this patient cohort. CPI therapy was well tolerated in both subcohorts with 15% discontinuing therapy due to toxicity. Our real-world data show that first-line CPI therapy produced strong and durable responses among patients with advanced cSCC. Immunocompromised patients were less likely to achieve long-term benefit from anti-PD1 treatment, despite similar tumor response rates.

Anti-PD-1 for the treatment of advanced cutaneous squamous cell carcinoma in elderly patients: a French multicenter retrospective survey

Background

Anti-PD1 agents are currently recommended as first-line treatment in advanced cutaneous squamous cell carcinoma (acSCC) by updated European guidelines. Although acSCC frequently affects elderly patients with multiple comorbidities, this subset of patients is often excluded of registration clinical trials.

Purpose

To assess anti-PD-1 efficacy and safety in elderly acSCC patients in real-life conditions and describe this specific population with oncogeriatric evaluation tools.

Methods

A multicenter retrospective study including acSCC patients at least 70 years old treated with PD-1 inhibitors was conducted in French referral centers. The primary endpoint was the overall response rate (ORR). Secondary endpoints included safety data, time to response (TTR), duration of response (DOR), overall survival (OS), and progression-free survival (PFS).

Results

63 patients were included. ORR was 57.1% (95% CI 44.0–69.5), median TTR and DOR were 3 and 5.5 months respectively. Median OS was not reached (95% CI 12.5 months-not reached) at data cut-off after a median follow-up of 8 months while median PFS was 8 months. (95% CI 5 months-not reached). Grade 3–5 adverse effects occurred in 47.6% of patients. 41.3% of patients experienced degradation of ECOG performance status during anti-PD-1 treatment. Nutritional state worsened in 27% of patients and 57.1% lost weight during treatment.

Conclusion

In this particular subset of acSCC patients PD-1 inhibitors obtain results similar to those obtained in younger populations included in pivotal clinical trials, with acceptable safety. A specific oncogeriatric evaluation at treatment initiation and during follow-up appears important in this setting most notably to help manage toxicity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-022-04246-0.

Novel MSH6 mutation predicted metastasis in eyelid and periocular squamous cell carcinoma

BACKGROUND

Our previous research revealed the relative local aggressiveness of eyelid and periocular squamous cell carcinoma (EPSCC), but its distinct genetic characteristics involved remain unknown.

OBJECTIVES

We conducted this study based on next-generation sequencing to identify the genetic distinctiveness of EPSCC and damaging mutations for possible etiology and poor prognosis.

METHODS

We performed sequencing using a 556-gene panel (smartonco) in 48 EPSCCs. Cox hazards model was applied to explore mutated genes that increase risk of metastasis and death. Pathogenesis of the mutations was predicted by sequence alignment algorithms.

RESULTS

The most commonly mutated genes were KMT2C (N=17, 35%), LRP1B (N=14, 29%), KMT2D (N=12, 25%), PTCH1(N=10, 21%) and TP53(N=10, 21%). DNA mismatch repair (MMR) genes (42%) like MSH6(19%) and MLH3(12%) were among the most frequently mutated genes. Cell cycle regulators including TP53(21%) and CDKN2A (10%) were less frequently mutated than in other squamous cell carcinomas (SCCs). Ultra violet exposure, MMR deficiency and aging were the main etiology. Of note, KMT2C has a deleterious mutation hotspot. Patients burdened with MSH6 mutation has a higher risk of overall metastasis (P=0.045, HR=5.165) and nodal metastasis (P=0.022, HR=14.038). Moreover, a hotspot mutation MSH6^E52A brought an even higher risk of nodal metastasis (P=0.011, HR=18.745).

CONCLUSIONS

EPSCCs displayed a unique mutation profile from cutaneous SCCs and mucosal SCCs. We have identified novel damaging mutations in epigenetic regulators like KMT2C boosted early onset of EPSCCs in addition to UVR, aging or MMR deficiency. And malfunction of MMR genes worsened prognosis.

Identifying Candidates for Immunotherapy among Patients with Non-Melanoma Skin Cancer: A Review of the Potential Predictors of Response

BACKGROUND

Non-melanoma skin cancer (NMSC) stands as an umbrella term for common cutaneous malignancies, including basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC), together with rarer cutaneous cancers, such as Merkel cell carcinoma (MCC) and other forms of adnexal cancers. The majority of NMSCs can be successfully treated with surgery or radiotherapy, but advanced and metastatic stages may require systemic approaches such as immunotherapy with immune checkpoint inhibitors (ICIs).

SUMMARY

Since immunotherapy is not effective in all patients and can potentially lead to severe adverse effects, an important clinical question is how to properly identify those who could be suitable candidates for this therapeutic choice. In this paper, we review the potential features and biomarkers used to predict the outcome of ICIs therapy for NMSCs. Moreover, we analyze the role of immunotherapy in special populations, such as the elderly, immunocompromised patients, organ transplant recipients, and subjects suffering from autoimmune conditions.

KEY MESSAGES

Many clinical, serum, histopathological, and genetic features have been investigated as potential predictors of response in NMSCs treated with ICIs. Although this field of research is very promising, definitive, cost-effective, and reproducible biomarkers are still lacking and further efforts are needed to validate the suggested predictors in larger cohorts.

Advanced or Metastatic Cutaneous Squamous Cell Carcinoma: The Current and Future Role of Radiation Therapy in the Era of Immunotherapy

Simple Summary

Nodal and distant metastases of cutaneous squamous cell carcinomas are very rare and lead to dismal prognoses. Immunotherapy is approved only for cutaneous squamous cell carcinoma patients not amenable to surgery or curative radiation therapy. Radiation therapy has a clear role as an adjuvant treatment for locally advanced disease. Radiation therapy may also have an important role in inoperable and metastatic disease. Oligometastatic disease is a condition that needs to be defined for this carcinoma. This review aims to offer to the readers a comprehensive overview of studies about the role of radiotherapy in the management of advanced or metastatic cutaneous squamous cell carcinomas, also assuming possible further developments in the light of the recent discoveries about tumor biology. The present paper has the merit of re-focusing great attention on the efficacy and cost-effectiveness of radiotherapy in these not yet properly explored scenarios.

Abstract

Radiation therapy (RT) is an effective therapeutic option for small localized cutaneous squamous cell carcinoma (cSCC) among patients who are not eligible for or refuse surgery. RT also has a defined role as an adjuvant treatment in cases of adverse features that predispose to tumor recurrence after local excision. Since the development of cSCC is often a late consequence of chronic sun exposure, its occurrence is more common among elderly patients whose comorbidities may contraindicate surgical procedures. These could be impeded not only by frail medical conditions but also by technical issues. Indeed, an aggressive locoregional behavior of cSCC may culminate in unresectability due to widespread invasion of neighboring tissues. Moreover, cSCC could develop distant metastases. Both locally advanced and metastatic cSCCs carry a poor prognosis. In these scenarios, recent discoveries of tumor molecular targets are promoting the use of promising systemic therapies, especially immunotherapy, over RT. However, the results from using immunotherapy and, even more so, of chemotherapy are still not optimal. By contrast, advances in radiation delivery equipment can safely treat even large and complex-shaped cSCC targets in challenging body sites. In addition, RT could also have a role in metastatic cSCC settings by enhancing the effectiveness of concomitant immunotherapy. The aim of this review is to summarize and comment on the body of literature about the use of radiotherapy for operable and inoperable locally advanced cSCCs and for metastatic ones in an attempt to define its current and future role.

Management of elderly patients with advanced cutaneous squamous cell carcinoma

The incidence of cutaneous squamous cell carcinoma has been increasing rapidly in recent years, especially among the elderly. The purpose of this review article is to summarize the findings of studies on systemic therapy for advanced cutaneous squamous cell carcinoma, to review geriatric screening tools, which can assess frailty and predict treatment outcomes, and discuss the indications of their use in advanced cases. A literature review revealed that studies on systemic therapy for advanced cutaneous squamous cell carcinoma often included relatively older patients. However, there has been little research on the safety and efficacy of systemic therapy for advanced disease that takes older age and frailty into account. Notably, studies on geriatric screening for skin cancer have been conducted in recent years, mainly to detect early-stage resectable cases. The Geriatric 8 screening tool is considered the most useful for predicting post-operative complications in patients with early-stage cancer, as it can evaluate comorbidities, polypharmacy and cognition, has appropriate measurement properties, can be quickly executed and is clinically relevant, easily understandable and interpretable. This geriatric screening tool may also be applicable in advanced-stage cancer. In conclusion, despite the fact that advanced cutaneous squamous cell carcinoma occurs mainly in the elderly, the importance of geriatric screening has not yet been fully appreciated by dermato-oncologists. In the future, geriatric screening tools should be actively used in clinical trials for the appropriate assessment of drug efficacy and toxicity in elderly patients with advanced cutaneous squamous cell carcinoma.

Squamous cell carcinoma: 2021 updated review of treatment

Squamous cell carcinoma is the second most common cutaneous malignancy, requiring early diagnosis to prevent metastasis. Updated guidelines in the definition of clinical features, diagnostic modalities, grading, staging, surgical, and nonsurgical treatment methods are necessary. Diagnostic methods from biopsy, dermoscopy, and reflectance confocal microscopy have improved to include high-frequency ultrasonography, optical coherence tomography, and computed tomography. Non-surgical treatment methods include topical therapy, cryosurgery, photodynamic therapy, and radiation. Surgical treatment methods include surgical excision with margins and Mohs surgery. Clinical trials encourage further research to address the knowledge base of genetic variations and lymph node metastasis.

Immunotherapy and Systemic Treatment of Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinomas (cSCC) represent one of the most diagnosed non-melanoma skin cancers and its incidence is increasing globally. Whereas early stage and low risk cSCC is typically treated with surgery, and in some cases other localized therapeutic modalities, locally advanced or metastatic cSCC is a cause of significant morbidity and mortality that requires a different approach to therapy. Therapeutic attempts at treating advanced cSCC include a multi-disciplinary approach with considerations for surgery, radiation, and systemic therapies. In this review, we will discuss the various systemic therapies that have been trialed for advanced cSCC, beginning with the early cytotoxic and platinum-based agents as well as their corresponding limitations. We will then review the targeted approaches using EGFR inhibitors prior to discussing the more recent immunotherapeutics that have shown good tumor responses in this often-lethal disease.

Management of immune-related adverse events in anti-PD-1-treated patients with advanced cutaneous squamous cell carcinoma

Immune checkpoint inhibitors (ICI) have shown very promising results in the management of patients with inoperable or metastatic cutaneous squamous cell carcinoma (cSCC). However, ICI can cause a range of immune-related adverse events (irAEs) affecting a multitude of organs including skin, gastrointestinal tract, endocrine system, heart, lung, kidneys and the nervous system. In principle, clinical management irAEs does not change significantly with respect to the kind of cancer treated with ICI. However, advanced cSCC typically occurs in a clinically challenging patient population typically presenting with advanced age and/or significant comorbidities such as immunosuppression due to haematological malignancies and their respective treatment. Moreover, many patients with advanced cSCC are organ transplant patients taking immunosuppressants. As a consequence use of ICI per se and management of ICI-induced irAEs generates more complexity and difficulties in patients with cSCC compared to other entities. Here, we provide a brief review on the management of anti-programmed cell death protein 1-induced irAEs in patients with cSCC focusing on the characteristic clinical challenges present in this population.

Cemiplimab in an Elderly Frail Population of Patients With Locally Advanced or Metastatic Cutaneous Squamous Cell Carcinoma: A Single-Center Real-Life Experience From Italy

Background

Cutaneous squamous cell carcinoma (CSCC) is the second most common skin cancer whose incidence is growing parallel to the lengthening of the average lifespan. Cemiplimab, an antiPD-1 monoclonal antibody, is the first approved immunotherapy for patients with locally advanced CSCC (laCSCC) or metastatic CSCC (mCSCC) thanks to phase I and II studies showing high antitumor activity and good tolerability. Nevertheless, at present, very few data are available regarding cemiplimab in real-life experience and in frail, elderly, and immunosuppressed patients as well as regarding biomarkers able to predict response so as to guide therapeutic choices.

Patients and Methods

We built a retroprospective cohort study including 30 non-selected patients with laCSCC (25) and mCSCC (five) treated with cemiplimab from August 2019 to November 2020. Clinical outcomes, toxicity profile, and correlations with disease, patients, and peripheral blood parameters are explored.

Results

The median age was 81 years (range, 36-95), with 24 males and five patients having an immunosuppressive condition, while the frailty prevalence was 83% based on index derived from age, Eastern Cooperative Oncology Group performance status, and Charlson Comorbidity Index. We reported 23 responses (76.7%) with nine complete responses (30%). A statistically significant higher response rate was observed in head and neck primary tumors and in patients with hemoglobin level >12 g/dl. No difference was observed with respect to frailty, median age, sex, and body mass index. The baseline low neuthophil/lymphocyte ratio and low platelet/lymphocyte ratio resulted to be also correlated with a better response. Moreover, lymphocyte, neutrophil, and monocyte behaviors had an opposite trend in responders and non-responders. An overall response was reported in four of five immunosuppressed patients. Seventeen patients (57.6%) have an ongoing response and are still alive. Six responders had interrupted treatment (two for toxicity and four for personal choice) but maintained their response. The treatment was well tolerated by the majority of patients. The most common adverse events were fatigue in seven patients (23.3%) and skin toxicity in 10 patients (33.3%), including pruritus in six patients, rash in three patients, and bullous erythema in one patient.

Conclusions

In our real-life experience, cemiplimab showed a high antitumor activity with acceptable safety profile similar to those in trials with selected patients. Moreover, its antitumor activity resulted to be not impaired in very elderly patients and in those with immunocompromised status.

PD-1 inhibitors for cutaneous squamous cell carcinoma: A meta-analysis

PD-1 inhibitors are immunotherapeutic agents used in the treatment of advanced cutaneous squamous cell carcinoma (cSCC). This study aimed to determine the pooled objective response and disease control rates of patients with advanced cSCC treated with PD-1 inhibitors. Pubmed, Cochrane Library and EMBASE databases were searched up to 1 January 2021 to include eligible articles. Objective response rate (ORR) and disease control rate (DCR) were pooled and analysed. Subgroup analysis of the odds ratio (OR) for ORR for patients by PD-L1 tumour proportion score (TPS) was performed. Seven articles including a total of 453 patients were identified and included. Pooled estimate of ORR was 44% (95% CI: 39-49%, I²  = 23.7%) and of DCR was 66% (95% CI: 57-74%, I²  = 68.2%). Pooled odds ratio of ORR for patients by PD-L1 TPS was 2.81 (95% CI: 1.22-6.51, I²  = 0.0%). These results were derived from single-arm studies, some of which were retrospective. No head-to-head trials comparing PD-1 inhibitors have been reported. We present aggregate estimates of ORR and DCR for patients with advanced cSCC treated with PD-1 inhibitors, as well as subgroup analysis for ORR for patients by PD-L1 TPS.

The Tumor Microenvironment in SCC: Mechanisms and Therapeutic Opportunities

Squamous cell carcinoma (SCC) is the second most common skin cancer worldwide and, despite the relatively easy visualization of the tumor in the clinic, a sizeable number of SCC patients are diagnosed at advanced stages with local invasion and distant metastatic lesions. In the last decade, immunotherapy has emerged as the fourth pillar in cancer therapy via the targeting of immune checkpoint molecules such as programmed cell-death protein-1 (PD-1), programmed cell death ligand-1 (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). FDA-approved monoclonal antibodies directed against these immune targets have provide survival benefit in a growing list of cancer types. Currently, there are two immunotherapy drugs available for cutaneous SCC: cemiplimab and pembrolizumab; both monoclonal antibodies (mAb) that block PD-1 thereby promoting T-cell activation and/or function. However, the success rate of these checkpoint inhibitors currently remains around 50%, which means that half of the patients with advanced SCC experience no benefit from this treatment. This review will highlight the mechanisms by which the immune checkpoint molecules regulate the tumor microenvironment (TME), as well as the ongoing clinical trials that are employing single or combinatory therapeutic approaches for SCC immunotherapy. We also discuss the regulation of additional pathways that might promote superior therapeutic efficacy, and consequently provide increased survival for those patients that do not benefit from the current checkpoint inhibitor therapies.