Neoadjuvant Cemiplimab for Stage II to IV Cutaneous Squamous-Cell Carcinoma.

BACKGROUND: In a pilot study involving patients with cutaneous squamous-cell carcinoma, a high percentage of patients had a pathological complete response with the use of two doses of neoadjuvant cemiplimab before surgery. Data from a phase 2 study are needed to confirm these findings. METHODS: We conducted a phase 2, confirmatory, multicenter, nonrandomized study to evaluate cemiplimab as neoadjuvant therapy in patients with resectable stage II, III, or IV (M0) cutaneous squamous-cell carcinoma. Patients received cemiplimab, administered at a dose of 350 mg every 3 weeks for up to four doses, before undergoing surgery with curative intent. The primary end point was a pathological complete response (the absence of viable tumor cells in the surgical specimen) on independent review at a central laboratory, with a null hypothesis that a pathological complete response would be observed in 25% of patients. Key secondary end points included a pathological major response (the presence of viable tumor cells that constitute ≤10% of the surgical specimen) on independent review, a pathological complete response and a pathological major response on investigator assessment at a local laboratory, an objective response on imaging, and adverse events. RESULTS: A total of 79 patients were enrolled and received neoadjuvant cemiplimab. On independent review, a pathological complete response was observed in 40 patients (51%; 95% confidence interval [CI], 39 to 62) and a pathological major response in 10 patients (13%; 95% CI, 6 to 22). These results were consistent with the pathological responses determined on investigator assessment. An objective response on imaging was observed in 54 patients (68%; 95% CI, 57 to 78). Adverse events of any grade that occurred during the study period, regardless of whether they were attributed to the study treatment, were observed in 69 patients (87%). Grade 3 or higher adverse events that occurred during the study period were observed in 14 patients (18%). CONCLUSIONS: Neoadjuvant therapy with cemiplimab was associated with a pathological complete response in a high percentage of patients with resectable cutaneous squamous-cell carcinoma. (Funded by Regeneron Pharmaceuticals and Sanofi; ClinicalTrials.gov number, NCT04154943.).

Assessment of endpoint definitions in recurrent and metastatic mucosal head and neck squamous cell carcinoma trials: Head and Neck Cancer International Group consensus recommendations.

Transparent and precise endpoint definitions are a crucial aspect of clinical trial conduct and reporting, and are used to communicate the benefit of an intervention. Previous studies have identified inconsistencies in endpoint definitions across oncological clinical trials. Here, the Head and Neck Cancer International Group assessed endpoint definitions from phase 3 trials or trials considered practice-changing for patients with recurrent or metastatic mucosal head and neck squamous cell carcinoma, published between 2008 and 2021. We identify considerable and global heterogeneity in endpoint definitions, which undermines the interpretation of results and development of future studies. We show how fundamental components of even incontrovertible endpoints such as overall survival vary widely, highlighting an urgent need for increased rigour in reporting and harmonisation of endpoints.

Assessment of endpoint definitions in curative-intent trials for mucosal head and neck squamous cell carcinomas: Head and Neck Cancer International Group consensus recommendations.

Robust time-to-event endpoint definitions are crucial for the assessment of treatment effect and the clinical value of trial interventions. Here, the Head and Neck Cancer International Group investigated endpoint use in phase 3 trials and trials considered potentially practice-changing published between 2008 and 2021 in the curative-intent setting for patients with mucosal head and neck squamous cell carcinoma. Of the 92 trials reviewed, we show that all core components of endpoint reporting were heterogeneous, including definitions of common terms, such as overall survival and progression-free survival. Our report highlights the urgent need for harmonisation of fundamental components of clinical trial endpoints and the engagement of all stakeholders to ensure the transparent reporting of endpoint details.

Immune checkpoint inhibitor therapy for advanced cutaneous squamous cell carcinoma in Australia: a retrospective real world cohort study.

OBJECTIVES: To review the outcomes of immune checkpoint inhibitor (ICI) treatment of advanced cutaneous squamous cell carcinoma (CSCC) outside clinical trials. STUDY DESIGN: Retrospective observational study; review of patient records in fifteen Australian institutions. SETTING, PARTICIPANTS: All Australian adults with locally advanced or metastatic CSCC not amenable to curative surgery or radiotherapy treated with ICIs, 5 May 2017 - 23 May 2022, through a cemiplimab compassionate access scheme (Therapeutic Goods Administration Special Access Scheme) or who personally covered the cost of pembrolizumab prior to the start of the access scheme. MAIN OUTCOME MEASURES: Best overall response rate (ORR) according to standardised assessment criteria using the hierarchy: Response Evaluation Criteria in Solid Tumors (RECIST 1.1), the modified World Health Organization clinical response criteria, and the Positron Emission Tomography Response Criteria (PERCIST 1.0); overall and progression-free survival. RESULTS: A total of 286 people with advanced CSCC received ICI therapy during May 2017 - May 2022 (cemiplimab, 270; pembrolizumab, 16). Their median age was 75.2 years (range, 39.3-97.5 years) and 232 were men (81%); median follow-up time was 12.2 months (interquartile range, 5.5-20.5 months). Eighty-eight people (31%) were immunocompromised, 27 had autoimmune disease, and 59 of 277 (21%) had ECOG performance scores of 2 or 3. The ORR was 60% (166 of 278 evaluable patients): complete responses were recorded for 74 (27%) and partial responses for 92 patients (33%). Twelve-month overall survival was 78% (95% confidence interval [CI], 72-83%); progression-free survival was 65% (95% CI, 58-70%). Poorer ECOG performance status was associated with poorer overall survival (per unit: adjusted hazard ratio [aHR], 3.0; 95% CI, 2.0-4.3) and progression-free survival (aHR, 2.4; 95% CI, 1.8-3.3), as was being immunocompromised (overall: aHR, 1.8; 95% CI, 1.1-3.0; progression-free: aHR, 1.8; 95% CI, 1.2-2.7). Fifty-five people (19%) reported immune-related adverse events of grade 2 or higher; there were no treatment-related deaths. CONCLUSION: In our retrospective study, the effectiveness and toxicity of ICI therapy were similar to those determined in clinical trials. Our findings suggest that ICIs could be effective and well tolerated by people with advanced CSCC who are ineligible for clinical trials.

Neoadjuvant cemiplimab and surgery for stage II-IV cutaneous squamous-cell carcinoma: follow-up and survival outcomes of a single-arm, multicentre, phase 2 study.

BACKGROUND: We previously reported rates of pathological complete responses (51% [95% CI 39-62] per independent central review, the primary endpoint) and major pathological responses (13% per independent central review, a secondary endpoint) to neoadjuvant cemiplimab (an anti-PD-1 inhibitor) among 79 patients with locoregionally advanced, resectable cutaneous squamous cell carcinoma. Here, we present follow-up data, including event-free, disease-free, and overall survival. METHODS: This single-arm, multicentre, phase 2 study included patients aged 18 years or older with resectable stage II-IV (M0) cutaneous squamous cell carcinoma and Eastern Cooperative Oncology Group performance status of 0 or 1. Patients received up to four planned doses of neoadjuvant cemiplimab 350 mg intravenously every 3 weeks followed by curative-intent surgery. After surgery, per investigator discretion, patients received either adjuvant cemiplimab for up to 48 weeks, radiotherapy, or observation alone. Secondary endpoints included in this follow-up analysis are event-free survival, disease-free survival, and overall survival, all summarised using the Kaplan-Meier method. Activity and safety endpoints were analysed for all enrolled patients who received at least one dose of neoadjuvant cemiplimab. In this report, safety data are reported for all patients who received at least one dose of adjuvant cemiplimab. This trial is registered with ClinicalTrials.gov, NCT04154943, has completed enrolment and follow-up is ongoing. FINDINGS: Between March 20, 2020, and July 8, 2021, 79 patients were enrolled. Median age was 73 years (IQR 66-81), 67 (85%) patients were male, 12 (15%) were female, 69 (87%) were White, one was Asian (1%), one was other race (1%), and race was not reported for eight (10%). As of data cutoff (Dec 1, 2022), median follow-up was 18·7 months (IQR 15·6-22·1) for all 79 patients. Among 70 patients who had surgery, 65 (93%) had post-surgical management data: 32 (49%) of 65 were observed postoperatively, 16 (25%) received adjuvant cemiplimab, and 17 (26%) received adjuvant radiotherapy. 11 (14%) of 79 patients had event-free survival events, with an estimated 12-month event-free survival of 89% (95% CI 79-94) for all patients. None of 40 patients who had a pathological complete response and one (10%) of ten patients with major pathological response had recurrence. Six (9%) of 70 patients who completed surgery had a disease-free survival event, with an estimated 12-month disease-free survival of 92% (95% CI 82-97). Nine (11%) of 79 patients died, with an estimated 12-month overall survival for all patients of 92% (95% CI 83-96). Four (25%) of 16 patients who received adjuvant cemiplimab treatment had grade 3 adverse events, including one (6%) who had increased blood potassium, one (6%) who had traumatic limb amputation, and two who had serious adverse events (one [6%] cardiomyopathy and one [6%] hypophysitis). There were no grade 4 adverse events or treatment-related deaths. INTERPRETATION: For patients with resectable stage II-IV cutaneous squamous cell carcinoma, neoadjuvant cemiplimab followed by surgery might be a potential treatment option, addressing a substantial unmet need. FUNDING: Regeneron Pharmaceuticals and Sanofi.

Clinicopathological characteristics and clinical morbidity in high-risk head and neck cutaneous squamous cell carcinoma patients in Western Australia.

BACKGROUND: There is no registry data on morbidity and mortality of high-risk cutaneous squamous cell carcinoma (cSCC) in Australia. AIM: To examine the clinicopathological features, mortality and morbidity in high-risk cSCC patients in Western Australia (WA). METHODS: A retrospective cohort study was conducted through hospital record review on cSCC patients discussed at multidisciplinary meetings at the two largest WA hospitals between March 2015 and December 2016. RESULTS: Of 141 patients, 129 were evaluable, with median follow up of 43.9 (range 3.0-53.2) months. Patients were predominantly older males (84%) with significant comorbidities (Charlson Comorbidity Index (CCI) ≥5; 76%) and history of previous nonmelanoma skin cancer (57%) with advanced disease (57% stage IV without distant metastasis; American Joint Committee on Cancer, 7th edition). Pathological high-risk features were common including nodal extracapsular extension (47%) and cranial nerve involvement (16%). Clinical morbidity was significant with a median of 2 (range 0-13) excisions and 2 (range 0-21) cSCC-related hospitalisations for any cSCC event following the index case discussion. Recurrences of the primary index lesion occurred in 60% of patients and 20% had ≥2 recurrences. Median overall survival for patients with nonmetastatic disease was 39.8 (range 25.9-53.7) months and 16.1 (range 0.2-32.0) months for metastatic disease. CCI ≥5, advanced nodal stage and ≥2 recurrences were significantly associated with mortality on multivariable analyses (P < 0.05). Nodal extracapsular extension and any recurrences were identified as significant risk factors for disease-specific mortality on multivariable analyses (P < 0.05). CONCLUSION: High-risk cSCC patients have significant health needs represented by high-baseline comorbidities, multiplicity of cSCC events and the number of healthcare-associated interventions. There is an unmet need for robust cancer data collection.

PD-1 Blockade with Cemiplimab in Advanced Cutaneous Squamous-Cell Carcinoma.

BACKGROUND: No systemic therapies have been approved for the treatment of advanced cutaneous squamous-cell carcinoma. This cancer may be responsive to immune therapy, because the mutation burden of the tumor is high and the disease risk is strongly associated with immunosuppression. In the dose-escalation portion of the phase 1 study of cemiplimab, a deep and durable response was observed in a patient with metastatic cutaneous squamous-cell carcinoma. METHODS: We report the results of the phase 1 study of cemiplimab for expansion cohorts of patients with locally advanced or metastatic cutaneous squamous-cell carcinoma, as well as the results of the pivotal phase 2 study for a cohort of patients with metastatic disease (metastatic-disease cohort). In both studies, the patients received an intravenous dose of cemiplimab (3 mg per kilogram of body weight) every 2 weeks and were assessed for a response every 8 weeks. In the phase 2 study, the primary end point was the response rate, as assessed by independent central review. RESULTS: In the expansion cohorts of the phase 1 study, a response to cemiplimab was observed in 13 of 26 patients (50%; 95% confidence interval [CI], 30 to 70). In the metastatic-disease cohort of the phase 2 study, a response was observed in 28 of 59 patients (47%; 95% CI, 34 to 61). The median follow-up was 7.9 months in the metastatic-disease cohort of the phase 2 study. Among the 28 patients who had a response, the duration of response exceeded 6 months in 57%, and 82% continued to have a response and to receive cemiplimab at the time of data cutoff. Adverse events that occurred in at least 15% of the patients in the metastatic-disease cohort of the phase 2 study were diarrhea, fatigue, nausea, constipation, and rash; 7% of the patients discontinued treatment because of an adverse event. CONCLUSIONS: Among patients with advanced cutaneous squamous-cell carcinoma, cemiplimab induced a response in approximately half the patients and was associated with adverse events that usually occur with immune checkpoint inhibitors. (Funded by Regeneron Pharmaceuticals and Sanofi; ClinicalTrials.gov numbers, NCT02383212 and NCT02760498 .).

BRAF Inhibition in BRAFV600E-Positive Anaplastic Thyroid Carcinoma.

The efficacy of targeted monotherapy for BRAF(V600E)-positive anaplastic thyroid carcinomas (ATC) is not established. We report 2 cases of BRAF(V600E)-positive ATC treated with a BRAF inhibitor. A 49-year-old woman with a T4bN1bM0 ATC manifested symptomatic metastatic disease 8 weeks after radical chemoradiotherapy. Within 1 month of BRAF inhibitor monotherapy, a complete symptomatic response was observed, with FDG-PET scan confirming metabolic and radiologic response. Treatment was terminated after 3 months because of disease progression. The patient died 11 months after primary diagnosis. A 67-year-old man received first-line BRAF inhibitor for a T4aN1bM0 ATC. Within 10 days of treatment his pain had stabilized and his tumor had clinically halved in size. Stable disease was achieved for 11 weeks but the patient died 11 months after diagnosis because of disease progression. BRAF inhibitor monotherapy in ATC may obtain clinical benefit of short duration. Upfront combination therapy should be investigated in this patient subgroup.

Differential mechanisms of CDKN2A (p16) alteration in oral tongue squamous cell carcinomas and correlation with patient outcome.

CDKN2A (p16) disruption is reported as a frequent event in head and neck squamous cell carcinomas that confers poor prognosis. We investigated the frequency of different potential mechanisms of CDKN2A inactivation in oral tongue squamous cell carcinomas (OTSCC) and their impact on patient outcome. From a cohort of 153 OTSCC patients, 131 formalin fixed paraffin embedded blocks of pre-treatment primary tumours were suitable for further molecular analysis. We assessed CDKN2A (p16) levels by immunohistochemistry (IHC), promoter methylation status by methylation-sensitive high resolution melting, mutation status by Sanger sequencing, gene copy number variation by fluorescence in situ hybridisation, and correlated these with patient outcome. We found that the majority of OTSCC did not overexpress p16 (110/116, 95%), assessed by IHC. The frequency of CDKN2A mutations was 20% (21/103), homozygous loss was 7% (7/97), hemizygous loss 31% (30/97), and promoter methylation was 18% (20/113). We found no evidence of these mechanisms in 24/106 (23%) p16 IHC negative tumours. No significant correlation was identified between any potential mechanism of CDKN2A inactivation and clinical features, including smoking status and age. There was a non-significant trend for worse overall survival for p16 IHC negative patients versus positive patients (HR = 1.81, 95% CI = 0.44-7.47, p = 0.40). No relationship was found between mechanisms of CDKN2A disruption and patient outcome. In conclusion, we demonstrate that CDKN2A alteration is a frequent event in OTSCC tumourigenesis. However, no correlation was identified between different potential mechanisms of CDKN2A disruption and clinical characteristics or patient outcome.

Real-World Experience of Immune-Checkpoint Inhibitors in Older Patients with Advanced Cutaneous Squamous Cell Carcinoma.

BACKGROUND: Older patients are often underrepresented in clinical trials owing to exclusionary comorbidities, which are more common with age. Chemotherapy is poorly tolerated in older comorbid advanced cutaneous squamous cell carcinoma (CSCC) patients; however, little is known on the efficacy and tolerability of immune-checkpoint inhibitors (ICIs) in this population. To our knowledge, this is the largest dedicated report on a cohort of older patients with advanced CSCC treated with immunotherapy to date. OBJECTIVE: The aim was to report outcomes of ICI use in a real-world older cohort with advanced CSCC. PATIENTS AND METHODS: A single-centre retrospective audit of all patients treated via an access scheme providing ICIs to patients with advanced CSCC was conducted. Participants were ≥ 70 years of age and had advanced CSCC not amenable to curative surgery or radiotherapy. Best overall response rate (ORR), 12-month overall survival (OS) and progression-free survival (PFS), and toxicity rates were assessed. RESULTS: A total of 53 patients were analysed. The median age was 81.8 years (range 70.1-96.8); 81% were male; 34% were immunocompromised; and 34% had an Eastern Cooperative Oncology Group (ECOG) performance status score of ≥ 2. The ORR was 57%, and 12-month OS and PFS were 63% (95% confidence interval [CI] 44-78) and 41% (95% CI 25-57), respectively. Thirty-two per cent developed an immune-related adverse event (irAE), but only two patients experienced a grade 3 irAE, with no treatment-related deaths. Higher ECOG score was associated with worse OS and PFS. No significant association was identified for increasing age, sex, Charlson Comorbidity Index score, or immunocompromised status. CONCLUSIONS: ICIs have demonstrated efficacy and have an acceptable safety profile among older patients with advanced CSCC, with comparable efficacy to what has been demonstrated in current clinical trials.

Assessment of perineural spread in advanced cutaneous squamous cell carcinomas treated with immunotherapy.

BACKGROUND: Cutaneous squamous cell carcinoma (CSCC) has a propensity for perineural spread (PNS) which is associated with poorer treatment outcomes. Immunotherapy is the new standard of care treatment for advanced CSCC resulting in durable responses. PNS is not captured by traditional response assessment criteria used in clinical trials, e.g. RECIST 1.1, and there is limited literature documenting radiological PNS responses to immunotherapy. In this study we assess PNS responses to immunotherapy using a modified grading system. METHODS: This is an Australian single-center retrospective review of patients with advanced CSCC who were treated with immunotherapy between April 2018 and February 2022 who had evidence of PNS on pre-treatment magnetic-resonance imaging (MRI). The primary outcome was blinded overall radiological response in PNS using graded radiological criteria, post-commencement of immunotherapy. Three defined timepoints (< 5 months, 5-10 months, > 10 months) were reviewed. Secondary outcomes included a correlation between RECIST 1.1 and PNS assessments and the assessment of PNS on fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT). RESULTS: Twenty CSCC patients treated with immunotherapy were identified. Median age was 75.7 years and 75% (n = 15) were male. All patients had locoregionally advanced disease and no distant metastases. Median follow-up was 18.5 months (range: 2-59). 70% (n = 14) demonstrated a PNS response by 5 months. Three patients experienced pseudoprogression. One patient had PNS progression by the end of study follow up. RECIST 1.1 and PNS responses were largely concordant at > 10 months (Cohen's Kappa 0.62). 5/14 cases had features suspicious for PNS on FDG-PET/CT. CONCLUSIONS: PNS response to immunotherapy can be documented on MRI using graded radiological criteria. High response rates were seen in PNS with the use of immunotherapy in this cohort and these responses were largely concordant with RECIST 1.1 assessments. FDG-PET/CT demonstrated limited sensitivity in the detection of PNS.

A Retrospective Review and Comprehensive Tumour Profiling of Advanced Non-Melanomatous Cutaneous Spindle Cell Neoplasms Treated with Immune-Checkpoint Inhibitors.

Non-melanomatous cutaneous spindle cell neoplasms are a rare group of malignancies that present a diagnostic challenge, and for which there is a lack of consensus on how to best manage patients with advanced disease and only limited reports of immune-checkpoint inhibitor (ICI) responses. In this study, we performed a single-center retrospective review of treatment outcomes for all advanced non-melanomatous cutaneous spindle cell neoplasms treated with ICIs. Blinded histopathology reviews occurred to confirm each diagnosis. Comprehensive tumour profiling included whole exome sequencing for tumour mutational burden (TMB) and ultraviolet(UV) signatures, and immunohistochemistry for immune-cell infiltration (CD4/CD3/CD8/CD103/CD20) and immune-checkpoint expression (PD-L1/LAG3/TIGIT). Seven patients were identified. The objective response rate was 86% (6/7) with five complete responses (CR). Responses were durable with two patients in CR > 30 months after ICI commencement. All patients had high TMB and UV signatures. One patient had PD-L1 100% (combined positive score) with abundant immune-cell infiltration and LAG3 expression. In advanced non-melanomatous cutaneous spindle cell neoplasms, excellent responses to ICIs with durable disease control were observed. ICIs are worthy of further exploration in these patients. UV signatures and high TMB could be used to help select patients for treatment.

Trends in phase 1 oncology clinical trials across Australia; Analysis of ClinicalTrials.gov 2012-2022.

BACKGROUND: Phase 1 oncology trials provide access to new therapies and may improve cancer outcomes. Phase 1 trials conducted in the Asian-Pacific region are increasing at a faster rate than the global trend. This study aimed to describe the changing landscape of phase 1 oncology trials in Australia in the last decade. METHODS: This cross-sectional study reviewed phase 1 oncology trials registered on ClinicalTrials.gov conducted in Australia. Phase 1 trials were included for analysis if they enrolled adults with solid organ malignancies, used at least one systemic agent, and were first registered between January 1, 2012, and December 31, 2022. The number of trials, site locations, sponsor type, and drug class were analyzed using descriptive statistics. RESULTS: Over the 10-year period, ClinicalTrials.gov included 493 phase 1 clinical trials across 71 Australian sites. Most sites were in metropolitan locations; in Melbourne, trials were concentrated within selected sites, while in Sydney, trials were spread across a larger number of sites. The number of phase 1 trials per annum increased from 18 in 2012 to 75 in 2022. Since 2020, emerging biopharmaceutical companies have become the predominant sponsor type, a trend that is also seen globally. While most trial sponsors were North American (42%), there was increasing representation from Asian sponsors over the 10-year period (6% in 2012 to 39% in 2022). Immunomodulatory (45%) and targeted approaches (44%) accounted for most drug classes used alone or in combination. CONCLUSIONS: There are an increasing number of phase 1 trials conducted within Australia. Sponsors of phase 1 trials are increasingly from Asian countries and are more likely to be emerging biopharmaceutical companies.

Characterising B cell expression and prognostic significance in human papillomavirus positive oropharyngeal cancer.

OBJECTIVES: The incidence of human papillomavirus positive oropharyngeal cancer (HPV+OPC) is increasing, and new biomarkers are required to better define prognostic groups and guide treatment. Infiltrating T cells have been well studied in head and neck cancer, however the presence and role of B cells and tertiary lymphoid structures (TLS) in the tumor microenvironment has not, even though the interplay between T and B cells is increasingly being recognised. MATERIALS AND METHODS: Using CD20 immunohistochemistry (IHC) to identify B cells and TLS in a cohort of 159 HPV + OPC patients, we semi-quantitatively scored abundance and location (intra-tumoral or stromal) and correlated findings with patient survival. RESULTS: 32% (51/157) of patients had high intra-tumoral (IT) abundance of CD20+ B cells (≥5%) and this was prognostic for improved overall survival (OS) with an adjusted hazard ratio (HR) of 0.2 (95 % CI 0.0-0.7, p = 0.014). We validated our results in an independent cohort comprising 171 HPV + OPC where 14% (23/171) were IT CD20+ high, again showing improved survival with an adjusted HR for OS of 0.2 (95 % CI 0.0-1.4, p = 0.003). Neither stromal abundance nor the presence of TLS were prognostic in either cohort. B cells were subtyped by multispectral IHC, identifying CD20+CD27+ cells, consistent with memory B cells, as the predominant subtype. Combined with validated biomarker CD103, a marker of tissue-resident memory T cells, IT CD20+ B cells abundance was able to prognostically stratify patients further. CONCLUSIONS: CD20+ B cell abundance has the potential to be used as a biomarker to identify good and poor prognosis HPV + OPC patients.

High response rate with extended dosing of cemiplimab in advanced cutaneous squamous cell carcinoma.

BACKGROUND: Cemiplimab (Libtayo®), a human monoclonal immunoglobulin G4 antibody to the programmed cell death-1 receptor, is approved for the treatment of patients with advanced cutaneous squamous cell carcinoma (CSCC), who are not candidates for curative surgery or curative radiation, using an every-3-weeks (Q3W) dosing interval. Pharmacokinetic modeling indicated that Ctrough of extended intravenous dosing of 600 mg every 4 weeks (Q4W) would be comparable to the approved intravenous dosage of 350 mg Q3W. We examined the efficacy, pharmacokinetics, and safety of cemiplimab dosed Q4W. METHODS: In this open-label, phase II trial (ClinicalTrials.gov identifier NCT02760498), the cohort of patients ≥18 years old with advanced CSCC received cemiplimab 600 mg intravenously Q4W for up to 48 weeks. Tumor measurements were recorded every 8 weeks. The primary endpoint was objective response rate by independent central review. RESULTS: Sixty-three patients with advanced CSCC were treated with cemiplimab. The median duration of follow-up was 22.4 months (range: 1.0-39.8). An objective response was observed in 39 patients (62%; 95% CI: 48.8% to 73.9%), with 22% of patients (n=14) achieving complete response and 40% (n=25) achieving partial response. The most common treatment-emergent adverse events were diarrhea, pruritus, and fatigue. CONCLUSIONS: Extended dosing of cemiplimab 600 mg intravenously Q4W exhibited substantial antitumor activity, rapid and durable responses, and an acceptable safety profile in patients with advanced CSCC. These results confirm that cemiplimab is a highly active therapy for advanced CSCC. Additional data would help ascertain the benefit-risk profile for the 600 mg intravenous dosing regimen compared with the approved regimen.

The Current Treatment Landscape of Cutaneous Squamous Cell Carcinoma.

Non-melanoma skin cancers (NMSCs) are the most common form of skin cancer worldwide. The global incidence of cutaneous squamous cell carcinoma (CSCC) is rising, with an estimated 2.4 million cases diagnosed in 2019. Chronic exposure to ultraviolet (UV) radiation is a major risk factor for developing CSCC. Most early-stage CSCCs are treated successfully with surgery or radiotherapy; however, locally advanced or metastatic disease can be associated with significant morbidity or mortality. Recently, the treatment paradigm for advanced CSCC has been revolutionised by the introduction of immunotherapy, which can achieve a response rate of approximately 50% with durable cancer control, and significant improvement in quality of life. With the regulatory approval of programmed death-1 (PD-1)-targeting drugs since 2018, immunotherapy is now recognised as the standard of care for first-line systemic therapy in advanced or metastatic CSCC.

Biology and Treatment Advances in Cutaneous Squamous Cell Carcinoma.

Cutaneous squamous cell carcinoma (CSCC) is the second most common skin cancer diagnosed worldwide. CSCC is generally localized and managed with local therapies such as excision and/or radiotherapy. For patients with unresectable or metastatic disease, recent improvements in our understanding of the underlying biology have led to significant advancements in treatment approaches-including the use of immune checkpoint inhibition (ICI)-which have resulted in substantial gains in response and survival compared to traditional cytotoxic approaches. However, there is a lack of understanding of the biology underpinning CSCC in immunocompromised patients, in whom the risk of developing CSCC is hundreds of times higher compared to immunocompetent patients. Furthermore, current ICI approaches are associated with significant risk of graft rejection in organ transplant recipients who make up a significant proportion of immunocompromised patients. Ongoing scientific and clinical research efforts are needed in order to maintain momentum to increase our understanding and refine our therapeutic approaches for patients with CSCC.

FDG-PET/CT imaging for evaluating durable responses to immune check point inhibitors in patients with advanced cutaneous squamous cell carcinoma.

BACKGROUND: The role of FDG-PET/CT imaging in assessing response to immunotherapy in advanced cutaneous squamous cell carcinoma (CSCC) is unknown. This study compared complete metabolic response (CMR) rates by FDG-PET and RECIST1.1 via CT or MRI in patients on cemiplimab for > 10 months. METHODS: This was a single-centre retrospective study of 15 patients treated with cemiplimab for advanced CSCC who had CT/MRI and FDG-PET/CT at > 10 months to assess metabolic treatment response. The median age was 73 years (range 55-84) and 93% were male. RECIST1.1 and PERCIST1.0 tumor responses were evaluated by blinded readers. RESULTS: Seventy-three percent (11/15) (95%CI 44.9, 92.2%) achieved a CMR on PET. Of these 11, on RECIST1.1 there was one complete response, 9 partial responses and one stable disease. CONCLUSIONS: In patients on cemiplimab for > 10 months, there was discordance between CR rates on FDG-PET versus RECIST1.1. FDG-PET/CT may have utility for clarifying depth of response in patients treated with immunotherapy for CSCC.

Immunotherapy to Avoid Orbital Exenteration in Patients With Cutaneous Squamous Cell Carcinoma.

BACKGROUND: Cutaneous squamous cell carcinoma (CSCC) of the head and neck can require complex and disfiguring surgery in order to achieve cure, which can be morbid and negatively impact patient quality of life. The management of advanced CSCC has been revolutionized by immunotherapy with current clinical trials also exploring its role in the neoadjuvant and adjuvant settings. Patients may decline morbid curative surgery, such as orbital exenteration, and the outcomes of immunotherapy use in this unique group of patients require further investigation. METHODS: We reviewed the records of 119 patients treated at a major Australian quaternary oncology centre with immunotherapy (either cemiplimab or pembrolizumab) for advanced CSCC. RESULTS: We identified 7 patients recommended curative surgery involving orbital exenteration after multidisciplinary discussion, who declined surgery due to concerns about morbidity and/or disfigurement. All 7 patients demonstrated a response to treatment, and six avoided orbital exenteration. Two patients experienced pseudoprogression. CONCLUSIONS: The management of CSCC can be complex and requires the input of a multidisciplinary team. Immunotherapy to avoid or reduce the extent of morbid definitive surgery is an emerging treatment option.

Delayed Response After Confirmed Progression (DR) and Other Unique Immunotherapy-Related Treatment Concepts in Cutaneous Squamous Cell Carcinoma.

Non-melanoma skin cancers are one of the most common cancers diagnosed worldwide, with the highest incidence in Australia and New Zealand. Systemic treatment of locally advanced and metastatic cutaneous squamous cell carcinomas has been revolutionized by immune checkpoint inhibition with PD-1 blockade. We highlight treatment issues distinct to the management of the disease including expansion of the traditional concept of pseudoprogression and describe delayed responses after immune-specific response criteria confirmed progressive disease with and without clinical deterioration. We term this phenomenon "delayed response after confirmed progression (DR)". We also discuss the common development of second primary tumors, heterogeneous disease responses, and expanding clinical boundaries for immunotherapy use.