Additive Intralesional Interleukin-2 Improves Progression-Free Survival in a Distinct Subgroup of Melanoma Patients with Prior Progression under Immunotherapy

Comparative real-world outcomes of stage III melanoma patients treated with talimogene laherparepvec or interleukin 2

Background

Talimogene laherparepvec (T-VEC) and interleukin-2 (IL-2) are both used in the intralesional treatment of melanoma skin metastases. T-VEC received regulatory approval from the European Medicines Agency and the U.S. Food and Drug Administration in 2015, while IL-2 has been used off-label for this purpose for many years. Despite their use in clinical practice, there is a lack of comparative data on the efficacy and safety of these treatments.

Objectives

This retrospective study aimed to compare the efficacy and safety of intralesional T-VEC and IL-2 in non-resectable stage III patients with melanoma treated at a single center between January 2016 and September 2024.

Methods

We identified eligible patients using the Central Malignant Melanoma Registry and the local University Hospital Pharmacy database. Overall survival (OS) and progression-free survival (PFS) were calculated. Furthermore, best response rates and occurrence of adverse events (AEs) were compared between the T-VEC and the IL-2 group. Concomitant systemic treatment was allowed.

Results

A total of 62 patients were included, with 37 receiving T-VEC and 25 receiving IL-2 as first-line therapy. Ten patients received both therapies subsequently. The median PFS for the cohort was 5.0 months, and the median OS was 34.0 months. No significant differences in PFS (p = 0.790), OS (p = 0.894), or best response rates (p = 0.468) were found between groups. Common AEs included local injection site reactions and fever, with no severe events leading to discontinuation by a physician.

Conclusion

No significant differences in PFS, OS, or best response rates were observed between IL-2 and T-VEC treatments. The choice of therapy may be influenced by factors such as availability, physician preference, and patient-specific considerations.

Efficacy of CTLA-4 checkpoint therapy is dependent on IL-21 signaling to mediate cytotoxic reprogramming of PD-1+CD8+ T cells

The mechanisms underlying the efficacy of anti-programmed cell death protein 1 (PD-1) and anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) therapy are incompletely understood. Here, by immune profiling responding PD-1+CD8+ T (TResp) cell populations from patients with advanced melanoma, we identified differential programming of TResp cells in response to combination therapy, from an exhausted toward a more cytotoxic effector program. This effect does not occur with anti-PD-1 monotherapy. Single-cell transcriptome and T cell receptor repertoire analysis was used to identify altered effector programming of expanding PD-1+CD8+ T cell clones with distinct regulon usage, STAT1 and STAT3 utilization and antitumor specificity connected to interleukin (IL)-21 signaling in combination and anti-CTLA-4 monotherapy. Therapeutic efficacy of CTLA-4 blockade was lost in B16F10 melanoma models with either Il21r- deficiency or anti-IL-21 receptor blockade. Together, these results show how IL-21 signaling to TResp is critical for anti-CTLA-4-based checkpoint therapies and highlight major signaling differences to anti-PD-1 monotherapy.

Current and emerging intralesional immunotherapies in cutaneous oncology

Immunotherapies have revolutionized the management of advanced cutaneous malignancies. However, some patients fail to respond to these therapies, others are ineligible because of comorbidities, and a minority of patients experience treatment-limiting systemic immune-related adverse events. To address these issues and expand treatment options for patients with early-stage disease, a variety of immunotherapies are being developed for direct intratumoral administration. Agents including oncolytic viruses, monoclonal antibodies, cytokines, peptides, and pattern-recognition receptor agonists have been engineered to evoke a local immune response while minimizing systemic toxicity and have shown favorable results in preclinical and early clinical testing. This review covers the current landscape of intratumoral immunotherapies for the treatment of cutaneous melanoma, squamous cell carcinoma, and basal cell carcinoma, highlighting the diverse array of agents being explored and their potential benefits and challenges.

Eosinophilic granulocytes as a potential prognostic marker for cancer progression and therapeutic response in malignant melanoma

The importance of eosinophilic granulocytes in cancer has been widely discussed in recent years. The current study reviews the evidence on the role of eosinophilic granulocytes in melanoma as a prognostic marker for cancer progression and the efficacy of treatment with modern immune checkpoint inhibitors. A total of 33 human clinical studies were included in the review, with heterogeneous data due to differences in patients populations, study design and inclusion of small study groups. However, 28 of the 33 studies suggested that eosinophilic granulocytes could be used as a prognostic biomarker for outcome and/or potential response to systemic treatment and/or occurrence of adverse events in melanoma patients. Nevertheless, the exact role of eosinophils remains to be elucidated. Further prospective, larger and better controlled studies are warranted to clarify the significance of eosinophilic granulocytes in patients with melanoma, in more details.

Intratumoral nanobody-IL-2 fusions that bind the tumor extracellular matrix suppress solid tumor growth in mice

Confining cytokine exposure to the tumors would greatly enhance cancer immunotherapy safety and efficacy. Immunocytokines, cytokines fused to tumor-targeting antibodies, have been developed with this intention, but without significant clinical success to date. A critical limitation is uptake by receptor-expressing cells in the blood, that decreases the dose at the tumor and engenders toxicity. Small-format immunocytokines, constructed with antibody fragments, are hypothesized to improve tumor specificity due to rapid systemic clearance. However, effective design criteria for small-format immunocytokines need further examination. Here, we engineer small interleukin-2 (IL-2) immunocytokines fused to nanobodies with nanomolar to picomolar affinities for the tumor-specific EIIIB domain of fibronectin (also known as EDB). Upon intravenous delivery into immunocompetent mice, such immunocytokines led to similar tumor growth delay as size-matched untargeted IL-2. Intratumoral (i.t.) delivery imparted improved survival dependent on affinity to EIIIB. I.t. administration offers a promising avenue to deliver small-format immunocytokines, given effective affinity for the tumor microenvironment.

Eosinophil-lymphocyte interactions in the tumor microenvironment and cancer immunotherapy

Eosinophils are important effector cells and therapeutic targets in allergic diseases. Emerging data indicate that eosinophils infiltrate a variety of solid tumor types and have pleiotropic activities by at least two non-mutually exclusive mechanisms: direct interactions with tumor cells, and intricate cross-talk with lymphocytes. In light of the immune checkpoint inhibition revolution in cancer therapy, we review eosinophil-lymphocyte interactions in the tumor microenvironment. We also analyze potential interactions between eosinophils and lymphocyte subsets, including T cells, natural killer cells and innate lymphoid cells. We provide perspectives on the consequences of these interactions and how eosinophils are accessory cells that can affect the response to various forms of T cell-mediated immunotherapies and might be therapeutically targeted to improve cancer immunotherapy.