Pembrolizumab and other immune checkpoint inhibitors in locally advanced or metastatic Merkel Cell Carcinoma: safety and efficacy

Local administration of immunotherapy for patients with skin cancer: A systematic review

Since the introduction of immune checkpoint inhibitors (ICIs) targeting PD-1 and CTLA-4 receptors, survival has improved significantly for patients with irresectable and metastatic skin cancer, including cutaneous squamous cell cancer and melanoma. However, systemic administration of these drugs is associated with immune related adverse events (irAEs), which can be severe, irreversible and even fatal. To reduce the risk of irAEs associated with systemic exposure to immunotherapeutic drugs, local administration of low doses could be considered. This systematic review provides an overview of early phase clinical trials with drugs that are currently under investigation for intratumoral administration in patients with melanoma and non-melanoma skin cancer.

The Evolving Treatment Landscape of Merkel Cell Carcinoma

OPINION STATEMENT

Merkel cell carcinoma (MCC) has a high risk of recurrence and requires unique treatment relative to other skin cancers. The patient population is generally older, with comorbidities. Multidisciplinary and personalized care is therefore paramount, based on patient preferences regarding risks and benefits. Positron emission tomography and computed tomography (PET-CT) is the most sensitive staging modality and reveals clinically occult disease in ~ 16% of patients. Discovery of occult disease spread markedly alters management. Newly diagnosed, localized disease is often managed with sentinel lymph node biopsy (SLNB), local excision, primary wound closure, and post-operative radiation therapy (PORT). In contrast, metastatic disease is usually treated systemically with an immune checkpoint inhibitor (ICI). However, one or more of these approaches may not be indicated. Criteria for such exceptions and alternative approaches will be discussed. Because MCC recurs in 40% of patients and early detection/treatment of advanced disease is advantageous, close surveillance is recommended. Given that over 90% of initial recurrences arise within 3 years, surveillance frequency can be rapidly decreased after this high-risk period. Patient-specific assessment of risk is important because recurrence risk varies widely (15 to > 80%: Merkelcell.org/recur) depending on baseline patient characteristics and time since treatment. Blood-based surveillance tests are now available (Merkel cell polyomavirus (MCPyV) antibodies and circulating tumor DNA (ctDNA)) with excellent sensitivity that can spare patients from contrast dye, radioactivity, and travel to a cancer imaging facility. If recurrent disease is locoregional, management with surgery and/or RT is typically indicated. ICIs are now the first line for systemic/advanced MCC, with objective response rates (ORRs) exceeding 50%. Cytotoxic chemotherapy is sometimes used for debulking disease or in patients who cannot tolerate ICI. ICI-refractory disease is the major problem faced by this field. Fortunately, numerous promising therapies are on the horizon to address this clinical need.

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.

Immune System Disorders, Cancer and Viral Infections: A New Treatment Opportunity for the Immune Checkpoint Inhibitors

The relationship between viral infections and cancer is well known and has been established for decades. Multiple tumours are generated from alterations secondary to viral infections 2 resulting from a dysregulation of the immune system in many cases. Certain causal relationships, such as that between the Epstein–Barr virus (EBV) in nasopharyngeal cancer or hepatitis C and B viruses in hepatocarcinoma, have been clearly established, and their implications for the prognosis and treatment of solid tumours are currently unknown. Multiple studies have evaluated the role that these infections may have in the treatment of solid tumours using immunotherapy. A possible relationship between viral infections and an increased response to immune checkpoint inhibitors (ICIs) has been established at a theoretical level in solid neoplasms, such as EBV-positive cavum cancer and human papillomavirus (HPV)-positive and oropharyngeal cancer. These could yield a greater response associated with the activation of the immune system secondary to viral infection, the consequence of which is an increase in survival in these patients. That is why the objective of this review is to assess the different studies or clinical trials carried out in patients with solid tumours secondary to viral infections and their relationship to the response to ICIs.

Clinical impact of immunotherapy in Merkel cell carcinoma patients: A systematic review and meta-analysis

BACKGROUND

Immunotherapy is emerging as an alternative treatment for Merkel cell carcinoma, but its long-term effects on response, survival, and safety are not well established. High-quality evidence is needed to estimate the efficacy of this treatment and to review the characteristics of patients and tumors that might improve outcomes.

OBJECTIVE

To summarize efficacy and safety of immunotherapy in patients with Merkel cell carcinoma.

METHODS

A systematic review was performed for studies published in MEDLINE, Web of Science, Scopus, and EMBASE. Two reviewers examined the literature and data extraction in duplicate. We estimated the proportions for objective responses, progression-free survival, overall survival, and treatment-related adverse events. Associations between objective response rate and immunobiologic markers were analyzed.

RESULTS

Six clinical trials of 201 patients treated with immunotherapy were included. The objective response rate was 51% (95% confidence interval, 0.40-0.62; I² = 37.1%) and grade ≥3 treatment-related adverse events were observed in 18% (95% confidence interval, 0.11-0.29; I² = 49.5%) of patients. No significant difference was observed between response rates and immunobiologic characteristics.

CONCLUSIONS

A significantly reduced tumor diameter with durable response rates and a safe profile are obtained with immunotherapy. Similar response rates achieved on either subgroup of viral status or programmed death ligand 1 expression suggests that it might act on multiple, unexplored pathways.