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.

Clinical activity of PD-1 inhibition in the treatment of locally advanced or metastatic basal cell carcinoma

Background

Basal cell carcinoma (BCC) is the most common malignancy worldwide, yet the management of patients with advanced or metastatic disease is challenging, with limited treatment options. Recently, programmed death receptor 1 (PD-1) inhibition has demonstrated activity in BCC after prior Hedgehog inhibitor treatment.

Methods

We conducted a multicenter, retrospective analysis of BCC patients treated with PD-1 inhibitor therapy. We examined the efficacy and safety of PD-1 therapy, as well as clinical and pathological variables in association with outcomes. Progression-free survival (PFS), overall survival (OS) and duration of response (DOR) were calculated using Kaplan-Meier methodology. Toxicity was graded per Common Terminology Criteria for Adverse Events V.5.0.

Results

A total of 29 patients with BCC who were treated with PD-1 inhibition were included for analysis, including 20 (69.0%) with locally advanced and 9 (31.0%) with metastatic disease. The objective response rate was 31.0%, with five partial responses (17.2%), and four complete responses (13.8%). Nine patients had stable disease (31.0%), with a disease control rate of 62.1%. The median DOR was not reached. Median PFS was 12.2 months (95% CI 0.0 to 27.4). Median OS was 32.4 months (95% CI 18.1 to 46.7). Two patients (6.9%) developed grade 3 or higher toxicity, while four patients (13.8%) discontinued PD-1 inhibition because of toxicity. Higher platelets (p=0.022) and any grade toxicity (p=0.024) were significantly associated with disease control rate.

Conclusions

The clinical efficacy of PD-1 inhibition among patients with advanced or metastatic BCC in this real-world cohort were comparable to published trial data. Further investigation of PD-1 inhibition is needed to define its optimal role for patients with this disease.

Non-Surgical Treatments for Keratinocyte Carcinomas

Skin cancer is the most common malignancy worldwide, comprising approximately 30% of all human tumors. In recent decades, the incidence of keratinocyte carcinomas, which include basal cell carcinoma and cutaneous squamous cell carcinoma, has been steadily increasing globally (Rogers et al. in JAMA Dermatol 151(10):1081-1086. https://doi.org/10.1001/jamadermatol.2015.1187 , 2015; Nehal and Bichakjian in N Engl J Med 379(4):363-374. https://doi.org/10.1056/nejmra1708701 , 2018). Most tumors are cured with surgical excision; however, some tumors are best treated with non-surgical approaches. Superficial tumors can often be cured with non-surgical methods whereas more advanced stage tumors may not be amenable to surgery. Additionally, surgical treatment may not be available for all populations depending on geographic location and accessibility to care. This article reviews commonly utilized nonsurgical options such as cryotherapy, photodynamic therapy, topical treatments, and radiation as well as systemic treatments including immunotherapies and chemotherapies.

Pembrolizumab in Patients with Refractory Cutaneous Squamous Cell Carcinoma: A Phase II Trial

INTRODUCTION

Patients with advanced cutaneous squamous cell carcinoma (CSCC) have a poor prognosis. Blocking the PD-1-PD-L1 axis has shown promising activity in this patient population. We assessed the safety and antitumor activity of PD-1 inhibitor pembrolizumab in patients with refractory advanced CSCC.

METHODS

This was a prespecified subgroup analysis of patients with advanced CSCC who enrolled in an open-label, phase II clinical trial for pembrolizumab in patients with refractory rare cancers during 2016-2018. Patients received pembrolizumab 200 mg intravenously every 21 days until progressive disease, unacceptable adverse event, or completion of 24 months of treatment. The primary endpoint was nonprogression rate (NPR) at 27 weeks; secondary endpoints included safety, objective response rate (ORR) per irRECIST, clinical benefit rate (CBR), progression-free survival, and overall survival.

RESULTS

Twenty patients with refractory CSCC enrolled; 19 were evaluable for efficacy. Median follow-up time was 44.1 months. The NPR at 27 weeks was 37% (95% CI 0.16-0.62). Three patients had a complete response (CR), three had a partial response, and one had stable disease, for an ORR of 32% and a CBR of 37%; median duration of response was 27.3 months. All three patients with a CR remained free of recurrence at the time of writing. Severe treatment-related adverse events (grade ≥ 3) occurred in 10% of patients (2/20). PD-L1 expression was not correlated with response to pembrolizumab.

CONCLUSION

A long-term follow-up confirms pembrolizumab's antitumor activity and safety profile in patients with refractory CSCC. Patients with a CR may experience cure.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02721732, Registered March 29, 2016.

Phase 2 study of pembrolizumab in patients with advanced rare cancers

Background

Patients with advanced rare cancers have poor prognosis and few treatment options. As immunotherapy is effective across multiple cancer types, we aimed to assess pembrolizumab (programmed cell death 1 (PD-1) inhibitor) in patients with advanced rare cancers.

Methods

In this open-label, phase 2 trial, patients with advanced rare cancers whose tumors had progressed on standard therapies, if available, within the previous 6 months were enrolled in nine tumor-specific cohorts and a 10th cohort for other rare histologies. Pembrolizumab 200 mg was administered intravenously every 21 days. The primary endpoint was non-progression rate (NPR) at 27 weeks; secondary endpoints were safety and tolerability, objective response rate (ORR), and clinical benefit rate (CBR).

Results

A total of 127 patients treated between August 15, 2016 and July 27, 2018 were included in this analysis. At the time of data cut-off, the NPR at 27 weeks was 28% (95% CI, 19% to 37%). A confirmed objective response (OR) was seen in 15 of 110 (14%) evaluable patients (complete response in one and partial response in 14). CBR, defined as the percentage of patients with an OR or stable disease ≥4 months, was 38% (n=42). Treatment was ongoing in 11 of 15 patients with OR at last follow-up. In the cohort with squamous cell carcinoma (SCC) of the skin, the NPR at 27 weeks was 36%, ORR 31%, and CBR 38%. In patients with adrenocortical carcinoma (ACC), NPR at 27 weeks was 31%, ORR 15%, and CBR 54%. In the patients with carcinoma of unknown primary (CUP), NPR at 27 weeks was 33%, ORR 23%, and CBR 54%. In the paraganglioma–pheochromocytoma cohort, NPR at 27 weeks was 43%, ORR 0%, and CBR 75%. Treatment-related adverse events (TRAEs) occurred in 66 of 127 (52%) patients, and 12 (9%) had grade ≥3 TRAEs. The most common TRAEs were fatigue (n=25) and rash (n=17). There were six deaths, all of which were unrelated to the study drug.

Conclusions

The favorable toxicity profile and antitumor activity seen in patients with SCC of skin, ACC, CUP, and paraganglioma–pheochromocytoma supports further evaluation of pembrolizumab in this patient population.

Trial registration number

NCT02721732

Neoadjuvant Therapy for Non-melanoma Skin Cancer: Updated Therapeutic Approaches for Basal, Squamous, and Merkel Cell Carcinoma

OPINION STATEMENT

Recently introduced systemic therapies for locally advanced and metastatic non-melanoma skin cancers (NMSCs) are paving the way for neoadjuvant approach. Although none of the therapeutic options has currently gained indication in this setting, neoadjuvant approach for NMSCs is an open field and we are likely to see huge developments in the near future. Targeted therapy with sonic hedgehog pathway inhibitors is very effective in locally advanced or multiple basal cell carcinomas while immunotherapy with immune checkpoint inhibitors appears to be promising for advanced cutaneous squamous cell carcinoma and Merkel cell carcinoma. To date, targeted therapy and immunotherapy represent the frontiers in NMSC therapeutic management and, according to recent studies, good results can be achieved.

Comparative efficacy of cemiplimab versus other systemic treatments for advanced cutaneous squamous cell carcinoma

Aim: To estimate the comparative efficacy of cemiplimab, a programmed cell death protein 1 inhibitor, versus EGFR inhibitors, pembrolizumab and platinum-based chemotherapy in terms of overall survival (OS) and progression-free survival. Patients & methods: We performed an indirect treatment comparison of cemiplimab and other available systemic therapies for patients with advanced cutaneous squamous cell carcinoma. Results: Cemiplimab was associated with benefits in OS (hazard ratios range: 0.07-0.52) and progression-free survival (hazard ratios range: 0.30-0.67) versus EGFR inhibitors and pembrolizumab (data from KEYNOTE-629). Cemiplimab was more efficacious versus platinum-based chemotherapy in terms of OS. Conclusion: Cemiplimab may offer improvements in survival for advanced cutaneous squamous cell carcinoma patients compared with existing systemic therapies.

Programmed cell death protein 1 inhibitors in advanced cutaneous squamous cell carcinoma: real-world data of a retrospective, multicenter study

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) is one of the most common malignancies of the skin. Even though most patients are sufficiently treated by surgical resection, some will eventually metastasize and need systemic therapy. Phase I and II studies have shown efficacy for programmed cell death protein 1 (PD-1) inhibitors, but cohort sizes are low and real-world data especially on long-term outcome are pending.

METHODS

Patients from six German skin cancer centers treated with PD-1 inhibitors (pembrolizumab, nivolumab or cemiplimab) for advanced cSCC were retrospectively studied. Internal patient records were analyzed for clinical outcome including response, progression-free survival (PFS), overall survival (OS) and toxicity.

RESULTS

Of 46 evaluable patients (median age: 76 years), the overall response rate (RR) was 58.7%, including 15.2% with complete response. The disease control rate was 80.4%. Both median PFS and OS were not reached, Kaplan-Meier estimated 1-year PFS was 58.8%. Patients responding to therapy showed durable remission. Response was independent of the PD-1 inhibitor used and also independent of the presence of distant metastases vs. locally advanced disease. Two predictive factors were found: Patients with primaries located on the leg had a poorer therapy outcome and patients with high lactate dehydrogenase serum levels at baseline. Treatment was overall tolerated well, with less than 10% of patients discontinuing therapy due to toxicity.

CONCLUSIONS

PD-1 inhibitors fulfill the need for an efficient systemic therapy for advanced cSCC and should be the new standard of care. With high RRs and durable disease control, neoadjuvant and adjuvant regimens should be evaluated.

The Role of Anti-PD-1/PD-L1 in the Treatment of Skin Cancer

Skin cancers remain the most common group of cancers globally, and the incidence continues to rise. Although localized skin cancers tend to have excellent outcomes following surgical excisions, the less common cases that become surgically unresectable or metastatic have been associated with poor prognosis and suboptimal treatment responses to cytotoxic chemotherapy. Development of monoclonal antibodies to programmed cell death-1 receptor and its ligand (PD-1/PD-L1) have transformed the management of metastatic melanoma, squamous cell carcinoma, and Merkel cell carcinoma. These agents, as monotherapies, are associated with response rates of approximately 40-60%, many of which persist durably. Further efficacy is observed with combination immunotherapy in advanced melanoma. Early reports suggest similar activity in locally advanced or metastatic basal cell carcinoma. In this review, we describe common molecular features of skin cancers that may render them particularly susceptible to anti-PD-1/PD-L1 and detail results from key clinical trials of these agents across skin cancers. Overall, the superior response rates of skin cancer to anti-PD-1/PD-L1 compared with other solid tumor types are likely due, at least in part, to a high mutational burden and, in Merkel cell carcinoma, viral etiology. Although melanoma has been rigorously studied in the setting of anti-PD-1/PD-L1 treatment, more research is needed for the other skin cancer types to establish toxicity profiles, responses, and quality-of-life outcomes.

Medical treatment of advanced cutaneous squamous-cell carcinoma

Considering the rising incidence, cutaneous squamous-cell carcinoma (cSCC) has a high clinical relevance. In patients with localized cSCC, complete surgical resection is indicated. Radiotherapy should be performed in patients with non-resectable tumours or in patients who are not suitable for surgery. Systemic therapy is reserved for cSCC that are neither surgically nor radiotherapeutically curable due to their extensive local spread and/or local or distant metastasis. In the absence of prospective randomized phase 3 trials to evaluate and compare the efficacy and safety of chemotherapeutics, epidermal growth factor receptor (EGFR) inhibitors and anti-PD-1 antibodies, no final recommendation for systemic therapy can be given for patients with locally advanced or metastatic cSCC. Anti-PD-1 antibodies currently show promising results with response rates of up to 50% in both locally advanced and metastatic cSCC. Anti-PD-1 antibodies appear to achieve higher response rates compared with EGFR inhibitors, and the duration of response appears to be superior to both chemotherapy and EGFR inhibitors. Compared with chemotherapy, the side effect profile of anti-PD-1 antibodies appears to be favourable. Altogether, PD-1 inhibitors are expected to become the new standard of care for patients with locally advanced and metastatic cSCC. Currently, placebo-controlled clinical trials are investigating the adjuvant use of cemiplimab and pembrolizumab in patients undergoing resection and radiotherapy of high-risk cSCC. Patients not eligible for anti-PD-1 treatment, e.g. in organ transplant recipients, or in patients refractory to anti-PD-1 may be offered EGFR inhibitors and/or chemotherapies. Chemotherapies appear to be superior to EGFR inhibitors in terms of response rates, whereas EGFR inhibitors have a more favourable toxicity profile. EGFR inhibitors are therefore more suitable for multimorbid and/or frail elderly patients. By combining EGFR inhibitors with local therapy such as surgery or radiotherapy, response rates and duration of response may be improved.

Cutaneous Squamous Cell Carcinoma: From Biology to Therapy

Cutaneous squamous cell carcinoma (CSCC) is the second most frequent cancer in humans and its incidence continues to rise. Although CSCC usually display a benign clinical behavior, it can be both locally invasive and metastatic. The signaling pathways involved in CSCC development have given rise to targetable molecules in recent decades. In addition, the high mutational burden and increased risk of CSCC in patients under immunosuppression were part of the rationale for developing the immunotherapy for CSCC that has changed the therapeutic landscape. This review focuses on the molecular basis of CSCC and the current biology-based approaches of targeted therapies and immune checkpoint inhibitors. Another purpose of this review is to explore the landscape of drugs that may induce or contribute to the development of CSCC. Beginning with the pathogenetic basis of these drug-induced CSCCs, we move on to consider potential therapeutic opportunities for overcoming this adverse effect.

Cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) accounts for approximately 20% of all skin cancers. Its rising incidence represents a major public health concern. The majority of cSCC are curable by surgical resection. Although less than 5% of cSCC patients develop metastases or local recurrence after complete excision, advanced cSCC is difficult to treat. Until recently, no standard therapeutic regimen for advanced cSCC exists. Traditional therapies include chemotherapy and EGFR-targeted therapy, but their clinical benefit remains modest and has been demonstrated mostly in retrospective studies. On the contrary, PD-1 inhibitors dramatically improve outcomes in many immunocompetent cSCC patients, resulting in the approval of cemiplimab as the first FDA-approved systemic drug for patients with locally advanced or metastatic cSCC who are not candidates for curative surgery or radiation. In the coming years combination therapies are an emerging treatment strategy that could improve efficacy of PD-1 inhibitors in advanced cSCC. Moreover, several prospective controlled trials have been designed to explore the potential role of PD-1 inhibitors in the adjuvant and neodjuvant setting. Given the paucity of data, the management of immunocompromised cSCC patients requires a heightened awareness in this new era of cancer therapeutics.

Advanced cutaneous squamous cell carcinoma: real world data of patient profiles and treatment patterns

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) is one of the most common types of cancer in the Caucasian population, with an increasing incidence. cSCC is mostly a local invasive disease that can be treated surgically in the majority of the cases. However, in the case of advanced cSCC (acSCC), a multimodality approach also involving systemic therapies needs to be considered.

METHODS

One hundred and ninety-five patients diagnosed with acSCC (stages III and IV) treated in our centre between 2011 and 2018 were included. Patient and tumour characteristics along with treatment patterns were documented and analyzed. Descriptive analysis was performed and survival rates were estimated according to Kaplan-Meier and compared with the Log-rank test. Follow-up was defined as the time between diagnosis of advanced disease and last contact or death. All causes of death were considered as events.

RESULTS

The median follow-up was 21 months [IQR = (10.0; 21.0)]. The median age at time of advanced disease diagnosis was 78 years [IQR = (72; 84)], with 40.5% of the patients in stage III and 59.5% in stage IV. One hundred and forty-five patients had resectable tumours. In this group the median overall survival (mOS) was 59 months (95% CI: 28.2-89.8), significantly higher than the mOS in patients with inoperable tumour [n = 50; mOS: 19 months (96% CI: 7-31, P <0.0001)]. Patients receiving immunotherapy (n = 20) showed a statistically significant better survival compared to those treated with other systemic therapies (n = 37; mOS not reached vs. mOS: 22 months (95% CI: 6.5-43.5), P = 0.034). For patients without systemic therapy, a combination of surgery and radiotherapy provided better outcomes compared to radiotherapy alone or best supportive care (P <0.001).

CONCLUSION

Surgical complete resection should be the first therapeutic option for patients with acSCC. For patients with inoperable tumour, first-line immunotherapy should be preferably considered.

Programmed cell death 1 protein and programmed death-ligand 1 inhibitors in the treatment of nonmelanoma skin cancer: A systematic review

BACKGROUND

Immunotherapy using programmed cell death 1 protein (PD-1) or programmed death-ligand 1 (PD-L1) inhibitors has been increasingly reported in a variety of nonmelanoma skin cancers (NMSCs).

OBJECTIVE

To analyze the evidence of PD-1 and PD-L1 inhibitors in the treatment of NMSC.

METHODS

A primary literature search was conducted with the PubMed, Cochrane Library, EMBASE, Web of Science, and CINAHL databases through October 28, 2018, to include studies on the use of PD-1 or PD-L1 inhibitors in patients for NMSC. Two reviewers independently performed study selection, data extraction, and critical appraisal.

RESULTS

This systematic review included 51 articles. The most robust evidence was in the treatment of Merkel cell carcinoma and cutaneous squamous cell carcinomas, as supported by phase 1 and 2 clinical trials. Treatment of basal cell carcinoma, cutaneous sarcoma, sebaceous carcinoma, and malignant peripheral nerve sheath tumor also showed benefit with PD-1/PD-L1 inhibitors, but data are limited. There does not appear to be efficacy for PD-1/PD-L1 inhibitors in cutaneous lymphomas.

LIMITATIONS

More investigation is needed to determine the efficacy, tumor responsiveness, and the safety profile of PD-1 and PD-L1 inhibitors in NMSC.

CONCLUSION

PD-1 and PD-L1 inhibitors exhibit treatment efficacy in a variety of NMSCs.