Neoadjuvant-Intent Immunotherapy in Advanced, Resectable Cutaneous Squamous Cell Carcinoma.

Importance: In clinical trials, preoperative immune checkpoint inhibitors (ICIs) have shown clinical activity in advanced cutaneous squamous cell carcinoma (cSCC). However, these studies excluded patients with relevant comorbidities. Objective: To evaluate radiologic and pathologic response rates to neoadjuvant-intent programed cell death protein 1 (PD-1) ICIs in a clinical population. Design, Setting, and Participants: This cohort study of patients who were treated with neoadjuvant cemiplimab or pembrolizumab for advanced cSCC from January 2018 to January 2023 was conducted at 2 academic institutions in Boston, Massachusetts. Median follow-up was 9.5 months (range, 1.2-40.5). Exposures: Cemiplimab or pembrolizumab. Main Outcomes and Measures: Primary outcomes were radiologic and pathologic response rates. Secondary outcomes were 1-year recurrence-free survival, progression-free survival, disease-specific survival, and overall survival. Results: This cohort study included 27 patients (including 9 patients [33.3%] with a history of lymphoma). Most patients were male (18 of 27 [66.7%]), with a median age of 72 years (range, 53-87 years). Most primary tumors were located on the head/neck (21 of 27 [77.8%]). There were no unexpected delays in surgery. The median number of doses before surgery was 3.5 (range, 1.0-10.0). Five patients (18.5%) ultimately declined to undergo planned surgery due to clinical responses or stability, and 1 (3.7%) did not undergo surgery due to progressive disease. The overall pathologic response rate (pathological complete response [pCR] or major pathological response) was 47.4% (9 of 19), and the overall radiologic response rate (radiologic complete response or partial response) was 50.0% (8 of 16). The pCR rate (7 of 19 [36.8%]) was higher than the radiologic complete response rate (2 of 16 [12.5%]). The pCR rate among patients with cSCC and concomitant lymphoma was 25.0%. The 1-year recurrence-free survival rate was 90.9% (95% CI, 50.8%-98.7%), progression-free survival was 83.3% (95% CI, 27.3%-97.5%), disease-specific survival was 91.7% (95% CI, 53.9%-98.8%), and overall survival was 84.6% (95% CI, 51.2%-95.9%). Conclusions and Relevance: The results of this cohort study support the reproducibility of neoadjuvant-intent immunotherapy for cSCC in the clinical setting, including for patients with a history of lymphoma. Outside of clinical trials, it is not infrequent for patients to opt out of surgery for regressing tumors. The inclusion of higher-risk patients and preference for nonsurgical treatment are 2 factors that might explain the numerically lower pathologic response rate in this institutional experience.

Assessing Longitudinal Treatment Efficacies and Alterations in Molecular Markers Associated with Glutamatergic Signaling and Immune Checkpoint Inhibitors in a Spontaneous Melanoma Mouse Model.

Previous work done by our laboratory described the use of an immunocompetent spontaneous melanoma-prone mouse model, TGS (TG-3/SKH-1), to evaluate treatment outcomes using inhibitors of glutamatergic signaling and immune checkpoint for 18 weeks. We showed a significant therapeutic efficacy with a notable sex-biased response in male mice. In this follow-up 18-week study, the dose of the glutamatergic signaling inhibitor was increased (from 1.7 mg/kg to 25 mg/kg), which resulted in improved responses in female mice but not male mice. The greatest reduction in tumor progression was observed in male mice treated with single-agent troriluzole and anti-PD-1. Furthermore, a randomly selected group of mice was removed from treatment after 18 weeks and maintained for up to an additional 48 weeks demonstrating the utility of the TGS mouse model to perform a ≥1-year preclinical therapeutic study in a physiologically relevant tumor-host environment. Digital spatial imaging analyses were performed in tumors and tumor microenvironments across treatment modalities using antibody panels for immune cell types and immune cell activation. The results suggest that immune cell populations and cytotoxic activities of T cells play critical roles in treatment responses in these mice. Examination of a group of molecular protein markers based on the proposed mechanisms of action of inhibitors of glutamatergic signaling and immune checkpoint showed that alterations in expression levels of xCT, γ-H2AX, EAAT2, PD-L1, and PD-1 are likely associated with the loss of treatment responses. These results suggest the importance of tracking changes in molecular markers associated with the mechanism of action of therapeutics over the course of a longitudinal preclinical therapeutic study in spatial and temporal manners.

Patterns of initial distant metastases in 151 patients undergoing surveillance for treated Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is associated with high rates of recurrence and distant metastatic progression. Current guidelines for surveillance imaging are not evidence based. Better characterization of the pattern of distant metastatic spread will better inform surveillance and facilitate earlier detection of metastases. OBJECTIVES: This retrospective study aimed to assess potential relationships between primary tumour site and site of initial distant metastasis, time to distant metastasis, overall survival (OS) and MCC-specific death (MSD). METHODS: Patients with local or regional (Stage I-III) disease who were treated with curative intent and progressed to Stage IV were included in this study (n = 151). Fisher's exact test was used to assess differences in patterns of initial distant metastases based on primary tumour site. Time to initial distant metastasis was calculated from date of MCC diagnosis. OS and MSD were calculated from date of initial distant metastasis to date of death from any or MCC-related causes, respectively. RESULTS: Of 151 patients included in analysis, 89 (58.9%) had a single initial distant metastatic site, and 62 (41.1%) had multiple sites. Patients with upper limb primary tumours were significantly less likely to develop distant lymph node or liver metastases (p = 0.02 and 0.04, respectively). Median time to distant metastasis was 11 months (IQR 6.7-17.9 months). Median OS was 15.3 months, and was shorter for patients with liver (7.0 months, p = 0.0004) or bone metastases (8.9 months, p < 0.0001). Using skin/soft tissue metastasis as a reference group, patients with multiple metastatic sites had significantly higher hazards of MSD (HR = 3.46 univariate, 3.77 multivariate analysis). Time to distant metastasis, OS and MSD did not differ by viral status. CONCLUSION: Sites of initial distant metastasis are related to primary tumour sites and survival outcomes. Because patients often have multiple initial metastases, full-body cross-sectional rather than region-specific imaging may facilitate earlier detection of metastatic disease.

Cemiplimab for Kidney Transplant Recipients With Advanced Cutaneous Squamous Cell Carcinoma.

PURPOSE: Cemiplimab is approved for treating locally advanced or metastatic cutaneous squamous cell carcinoma (CSCC). Solid organ transplant recipients have been excluded from immunotherapy trials, given concern for allograft rejection despite their increased risk of skin cancers. Chronic immunosuppression is necessary to prevent organ rejection but may attenuate antitumor response with PD-1 inhibitors. METHODS: We report a phase I study of cemiplimab for kidney transplant recipients (KTRs) with advanced CSCC. After cross-taper to a mammalian target of rapamycin (mTOR) inhibitor and pulsed dose corticosteroids (prednisone 40 mg once daily, the day before and on days 1-3 of each cycle, followed by 20 mg once daily on days 4-6, then 10 mg once daily until the day before each subsequent cycle), patients received cemiplimab 350 mg intravenously once every 3 weeks for up to 2 years and were assessed for response every 8 weeks. The primary end point was the rate of kidney rejection, with key secondary end points including rate and duration of response, and survival. RESULTS: Twelve patients were treated. No kidney rejection or loss was observed. A response to cemiplimab was observed in five of 11 evaluable patients (46%; 90% CI, 22 to 73), including two with durable responses beyond a year. Median follow-up was 6.8 months (range, 0.7-29.8). Treatment-related grade 3 or greater adverse events occurred in five patients (42%), including diarrhea, infection, and metabolic disturbances. One patient died of angioedema and anaphylaxis attributed to mTOR inhibitor cross-taper. CONCLUSION: mTOR inhibitor and corticosteroids represent a favorable immunosuppressive regimen for KTRs with advanced CSCC receiving immunotherapy. This combination resulted in durable antitumor responses with no kidney rejection events (funded by Regeneron Pharmaceuticals [ClinicalTrials.gov identifier: NCT04339062]).

Tumor-Associated Macrophages in Merkel Cell Carcinoma: Old Balances, New Checks.

A recent report sheds light on the tumor-associated macrophages (TAM) in Merkel cell carcinoma (MCC), and the association of S100A8-expressing TAMs with resistance to anti-PD-(L)1 inhibitors. These data improve our understanding about why some tumors with brisk tumor-infiltrating lymphocytes do not respond to immunotherapy and provide a compelling rationale to target myeloid checkpoints in MCC. See related article by Tabachnick-Cherny et al., p. xxxx.

Tumor-associated Macrophages in Merkel Cell Carcinoma: Old Balances, New Checks.

A recent report sheds light on the tumor-associated macrophages (TAMs) in MCC, and the association of S100A8-expressing TAMs with resistance to anti-PD-(L)1 inhibitors. These data improve our understanding about why some tumors with brisk TIL do not respond to immunotherapy and provide a compelling rationale to target myeloid checkpoints in MCC.

A multicenter real-world analysis of risk factors, therapeutics, and outcomes of patients with metastatic basal cell carcinoma.

BACKGROUND: Metastatic basal cell carcinoma (mBCC) is rare and there are limited data regarding patient and tumor risk factors, optimal treatments, and disease prognosis. OBJECTIVE: To assess patient and tumor characteristics, therapeutics, and outcomes of mBCC stratified by location of metastasis. METHODS: Retrospective cohort study of 53 patients with mBCC treated at 4 large academic centers in Boston, Massachusetts; Philadelphia, Pennsylvania; and Cleveland, Ohio between January 1, 2005 and December 31, 2021. RESULTS: A total of 53 patients with mBCC were identified across 4 centers, 22 (42%) of whom had mBCC with spread limited to lymph nodes and 31 (58%) patients with distant organ spread (with or without lymph node involvement). Overall, half (n = 11) of patients with nodal metastasis achieved complete remission of disease, compared with just 1 (3%) patient with distant metastasis. The 5-year survival for nodal and distant metastatic patients was 89.3% and 61.0%, respectively. LIMITATIONS: Small sample size due to disease rarity. CONCLUSIONS AND RELEVANCE: Patients with nodal disease are more likely to have disease remission whereas patients with distant metastasis are more likely to have persistent disease and die from their disease. However, 5-year survival rates exceed 50%, even for stage IV disease.

Combination oncolytic virus, radiation therapy, and immune checkpoint inhibitor treatment in anti-PD-1-refractory cancer.

BACKGROUND: Immunotherapies are becoming front-line treatments for many advanced cancers, and combinations of two or more therapies are beginning to be investigated. Based on their individual antitumor capabilities, we sought to determine whether combination oncolytic virus (OV) and radiation therapy (RT) may improve cancer outcomes. METHODS: To investigate the activity of this combination therapy, we used in vitro mouse and human cancer cell lines as well as a mouse model of skin cancer. After initial results, we further included immune checkpoint blockade, whose addition constituted a triple combination immunotherapy. RESULTS: Our findings demonstrate that OV and RT reduce tumor growth via conversion of immunologically 'cold' tumors to 'hot', via a CD8+ T cell-dependent and IL-1α-dependent mechanism that is associated with increased PD-1/PD-L1 expression, and the triple combination of OV, RT, and PD-1 checkpoint inhibition impedes tumor growth and prolongs survival. Further, we describe the response of a PD-1-refractory patient with cutaneous squamous cell carcinoma who received the triple combination of OV, RT, and immune checkpoint inhibitor (ICI), and went on to experience unexpected, prolonged control and survival. He remains off-treatment and is without evidence of progression for >44 months since study entry. CONCLUSIONS: Effective systemic antitumor immune response is rarely elicited by a single therapy. In a skin cancer mouse model, we demonstrate improved outcomes with combination OV, RT, and ICI treatment, which is associated with mechanisms involving augmented CD8+ T cell infiltration and IL-1α expression. We report tumor reduction and prolonged survival of a patient with skin cancer treated with combination OV, RT, and ICI. Overall, our data provide strong rationale for combining OV, RT, and ICI for treatment of patients with ICI-refractory skin and potentially other cancers.

A phase I trial of riluzole and sorafenib in patients with advanced solid tumors: CTEP #8850.

BACKGROUND: Overexpression of metabotropic glutamate receptor 1 (GRM1) has been implicated in the pathogenesis of multiple cancers. Riluzole, an inhibitor of glutamate release, showed synergistic antitumor activity in combination with the multi-kinase inhibitor sorafenib in preclinical models. This phase I trial identified the toxicity profile, dose-limiting toxicities, maximum tolerated dose (MTD), and pharmacokinetic and pharmacodynamic properties of riluzole combined with sorafenib in patients with advanced cancers. PATIENTS AND METHODS: Patients with refractory solid tumors were enrolled utilizing a 3+3 dose-escalation design. Riluzole was given at 100 mg PO BID in combination with sorafenib, beginning at 200 mg PO daily and escalating in 200 mg increments per level in 28-day cycles. Restaging evaluations were performed every 2 cycles. RESULTS: 35 patients were enrolled over 4 dose levels. The MTD was declared at dose level 3 (riluzole: 100 mg PO BID; sorafenib: 400 mg AM/200 mg PM). Pharmacokinetic analyses did not reveal definitive evidence of drug-drug interactions. Consistent decreases in phospho-forms of ERK and AKT in tumor tissue analyses with accompanying decrease in GRM1 expression and increase in pro-apoptotic BIM suggest target engagement by the combination. Best responses included a partial response in 1 (2.9%) patient with pancreatic acinar cell carcinoma with a KANK4-RAF1 fusion, and stable disease in 11 (36%) patients. CONCLUSION: Combination therapy with riluzole and sorafenib was safe and tolerable in patients with advanced solid tumors. The partial response in a patient with a RAF1 fusion suggests that further exploration in a genomically selected cohort may be warranted.

A Spontaneous Melanoma Mouse Model Applicable for a Longitudinal Chemotherapy and Immunotherapy Study.

Mouse models that reflect human disorders provide invaluable tools for the translation of basic science discoveries to clinical therapies. However, many of these in vivo therapeutic studies are short term and do not accurately mimic patient conditions. In this study, we used a fully immunocompetent, transgenic mouse model, TGS, in which the spontaneous development of metastatic melanoma is driven by the ectopic expression of a normal neuronal receptor, mGluR1, as a model to assess longitudinal treatment response (up to 8 months) with an inhibitor of glutamatergic signaling, troriluzole, which is a prodrug of riluzole, plus an antibody against PD-1, an immune checkpoint inhibitor. Our results reveal a sex-biased treatment response that led to improved survival in troriluzole and/or anti-PD-1-treated male mice that correlated with differential CD8+ T cells and CD11b+ myeloid cell populations in the tumor-stromal interface, supporting the notion that this model is a responsive and tractable system for evaluating therapeutic regimens for melanoma in an immunocompetent setting.

A phase Ib study of interleukin-2 plus pembrolizumab for patients with advanced melanoma.

Introduction: High-dose interleukin-2 (HD IL-2) and pembrolizumab are each approved as single agents by the U.S. F.D.A. for the treatment of metastatic melanoma. There is limited data using the agents concurrently. The objectives of this study were to characterize the safety profile of IL-2 in combination with pembrolizumab in patients with unresectable or metastatic melanoma. Methods: In this Phase Ib study, patients received pembrolizumab (200 mg IV every 3 weeks) and escalating doses of IL-2 (6,000 or 60,000 or 600,000 IU/kg IV bolus every 8 hours up to 14 doses per cycle) in cohorts of 3 patients. Prior treatment with a PD-1 blocking antibody was allowed. The primary endpoint was the maximum tolerated dose (MTD) of IL-2 when co-administered with pembrolizumab. Results: Ten participants were enrolled, and 9 participants were evaluable for safety and efficacy. The majority of the evaluable participants (8/9) had been treated with PD-1 blocking antibody prior to enrollment. Patients received a median of 42, 22, and 9 doses of IL-2 in the low, intermediate, and high dose cohorts, respectively. Adverse events were more frequent with increasing doses of IL-2. No dose limiting toxicities were observed. The MTD of IL-2 was not reached. One partial response occurred in 9 patients (11%). The responding patient, who had received treatment with an anti-PD-1 prior to study entry, was treated in the HD IL-2 cohort. Discussion: Although the sample size was small, HD IL-2 therapy in combination with pembrolizumab appears feasible and tolerable. Clinical trial registration: ClinicalTrials.gov, identifier NCT02748564.

A phase 1b single-arm trial of intratumoral oncolytic virus V937 in combination with pembrolizumab in patients with advanced melanoma: results from the CAPRA study.

BACKGROUND: CAPRA (NCT02565992) evaluated Coxsackievirus A21 (V937) + pembrolizumab for metastatic/unresectable stage IIIB-IV melanoma. METHODS: Patients received intratumoral V937 on days 1, 3, 5, and 8 (then every 3 weeks [Q3W]) and intravenous pembrolizumab 2 mg/kg Q3W from day 8. Primary endpoint was safety. RESULTS: Median time from first dose to data cutoff was 32.0 months. No dose-limiting toxicities occurred; 14% (5/36) of patients experienced grade 3‒5 treatment-related adverse events. Objective response rate was 47% (complete response, 22%). Among 17 responders, 14 (82%) had responses ≥ 6 months. Among 8 patients previously treated with immunotherapy, 3 responded (1 complete, 2 partial). Responses were associated with increased serum CXCL10 and CCL22, suggesting viral replication contributes to antitumor immunity. For responders versus nonresponders, there was no difference in baseline tumor PD-L1 expression, ICAM1 expression, or CD3+ infiltrates. Surprisingly, the baseline cell density of CD3+CD8- T cells in the tumor microenvironment was significantly lower in responders compared with nonresponders (P = 0.0179). CONCLUSIONS: These findings suggest responses to this combination may be seen even in patients without a typical "immune-active" microenvironment. TRIAL REGISTRATION NUMBER: NCT02565992.