Real-World Effectiveness, Safety, and Health-Related Quality of Life in Patients Receiving Adjuvant Nivolumab for Melanoma in Belgium and Luxembourg: Results of PRESERV MEL

Immune Checkpoint Inhibition-related Neuroinflammation Disrupts Cognitive Function

Combinatorial blockade of Cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and Programmed Cell Death Protein 1 (PD-1) significantly improve the progression-free survival of individuals with metastatic cancers, including melanoma. In addition to unleashing anti-tumor immunity, combination immune checkpoint inhibition (ICI) disrupts immune-regulatory networks critical for maintaining homeostasis in various tissues, including the central nervous system (CNS). Although ICI- and cancer-related cognitive impairments (CRCI) in survivors are increasingly becoming evident, our understanding of ICI-induced immune-related adverse effects (IREA) in the CNS remains incomplete. Here, our murine melanoma model reveals that combination ICI impairs hippocampal-dependent learning and memory, as well as memory consolidation processes. Mechanistically, combination ICI disrupted synaptic integrity, and neuronal plasticity, reduced myelin, and further predisposed CNS for exaggerated experimental autoimmune encephalomyelitis. Combination ICI substantially altered both lymphoid and myeloid cells in the CNS. Neurogenesis was unaffected, however, microglial activation persisted for two-months post- ICI, concurrently with cognitive deficits, which parallels clinical observations in survivors. Overall, our results demonstrate that blockade of CTLA-4 and PD-1 alters neuro-immune homeostasis and activates microglia, promoting long-term neurodegeneration and driving cognitive impairments. Therefore, limiting microglial activation is a potential avenue to mitigate CNS IRAE while maintaining the therapeutic benefits of rapidly evolving ICIs and their combinations.

SIGNIFICANCE

Despite the superior therapeutic efficacy of immune checkpoint inhibition (ICI) for cancers, its undesired effects on brain function are not fully understood. Here, we demonstrate that combination ICI elevates neuroinflammation, activates microglia, leading to detrimental neurodegenerative and neurocognitive sequelae.

Outcome of adjuvant immunotherapy in a real-world nation-wide cohort of patients with melanoma

BACKGROUND

Clinical trials have demonstrated promising outcomes for adjuvant immunotherapy in patients with resected melanoma. Real-life data provide valuable insights to support patient guidance and treatment decisions.

METHODS

Observational population-based study examining a national cohort of patients with resected stage III-IV melanoma referred for adjuvant therapy. Data were extracted from the Danish Metastatic Melanoma Database (DAMMED).

RESULTS

Between November 2018 and January 2022, 785 patients received adjuvant anti-PD-1. The majority had stage III resected melanoma (87%), normal LDH levels (80%), and performance score 0 (87%). Patients were followed for a median of 25.6 months (95%CI 24-28). The median recurrence-free survival (RFS) and melanoma-specific survival (MSS) were not reached. The RFS was 78% (95%CI 75-81), 66% (63-70), and 59% (55-63); MSS was 97% (95-98), 93% (91-95), and 87% (84-90) at 1-, 2-, and 3-year; respectively. Less than half (42%) of the patients finalized planned therapy, 32% discontinued due to toxicity, and 19% due to melanoma recurrence. Patients discontinuing adjuvant treatment prematurely, without recurrence, had similar outcomes as patients finalizing therapy. In a multivariable analysis, ipilimumab plus nivolumab did not improve outcomes compared to ipilimumab monotherapy as a first-line metastatic treatment after adjuvant anti-PD-1.

CONCLUSION

Survival outcomes in real-world patients with melanoma treated with adjuvant anti-PD-1 align with results from the randomized controlled trials. Patients discontinuing therapy prematurely, for other reasons than recurrence, had similar outcomes as patients finalizing planned treatment. First-line metastatic treatment with ipilimumab and nivolumab post-adjuvant anti-PD-1 did not show improved outcomes compared to ipilimumab/anti-PD-1 monotherapy.

Deciphering the role of adjuvant therapy in melanoma and its actual benefits

Numerous clinical trials have demonstrated a significant improvement in recurrence-free survival among melanoma patients receiving high-dose interferon-α, immune checkpoint inhibitors (pembrolizumab, nivolumab), and BRAF/MEK inhibitors (dabrafenib-trametinib). This study aimed to investigate whether these findings hold true in real-world conditions for patients with stage III and IV melanoma. In particular, the study explores the efficacy and side effects of adjuvant therapies, focusing on anti-PD-1 antibodies and BRAF/MEK inhibitors. While clinical trials have shown comparable efficacy, differences in side-effect profiles, especially the persistence of immune-related adverse events with anti-PD-1 antibodies, highlight the need for careful consideration in adjuvant settings. In the absence of established biomarkers for guiding adjuvant therapy decisions, it becomes imperative to transparently communicate the advantages and disadvantages of drug administration to patients. The study also delved into the impact of melanoma subtype and BRAF mutation status on the effectiveness of adjuvant therapy, emphasizing the need for further investigation.