Breakthrough in Melanoma Treatment: Researchers Identify Predictive Biomarkers

Strategic Insights -

Researchers at Alfred Health in Melbourne, Victoria, Australia, have made a significant discovery in the field of melanoma treatment. A study published in the Journal for ImmunoTherapy of Cancer reveals that the expansion of a specific type of immune cell, known as Ki67-positive effector T-cells, after just one cycle of combined PD-1 and CTLA-4 blockade, can predict treatment response. Additionally, the study found that a higher frequency of a molecule called TIM-3 on CD8+ T-cells is associated with severe toxicity.

Key Takeaways:

  • The study analyzed blood samples from 51 patients with advanced melanoma before and after one cycle of combined PD-1 and CTLA-4 blockade.
  • The researchers found that patients who failed to respond to treatment had fewer T cells before treatment compared to age-matched healthy controls.
  • One cycle of treatment restored patient T cells to levels equivalent to healthy controls through the expansion and activation of memory and regulatory T cells.
  • The study identified a correlation between pre-treatment PD-1 expression levels and T-cell expansion, as well as upregulation of molecules such as Ki67, ICOS, TIM-3, and TIGIT on effector CD4+ and CD8+ T cells.
  • Greater upregulation of Ki67 in CD4+ central memory cells significantly differentiated responders and non-responders after one cycle of treatment.
  • Higher on-treatment TIM-3 frequency within CD8+ T cells differentiated patients who experienced severe toxicity.

Statistics:

  • 20 patients (39%) failed to respond to treatment.
  • 29 patients (57%) experienced severe toxicity.
  • Pre-treatment, patients had fewer T cells than age-matched healthy controls (median 892 vs 1297 cells/L, p=0.0004).
  • Patients who demonstrated a significant expansion of Ki67-positive effector T-cells had an area under the curve (AUC) of 0.74 (95% CI 0.59 to 0.88) to differentiate responders and non-responders.
  • Patients who had higher on-treatment TIM-3 frequency within CD8+ T cells had an AUC of 0.74 (95% CI 0.59 to 0.88) to differentiate those who experienced severe toxicity.

Sources:

  • "Expansion of a circulating Ki67-positive effector T-cell population following combined PD-1 and CTLA-4 blockade for melanoma is predictive of treatment response." Journal for ImmunoTherapy of Cancer, 2025,13(10).
  • https://doi-org.sdpl.idm.oclc.org/10.1136/jitc-2025-012317.