IFN-Gamma Expression as a Predictor of Response to Immune Checkpoint Inhibitors in First-Line Metastatic Melanoma (MAK)

IFN-Gamma Expression in Tumor Tissue and Blood as a Predictor of Response to Immune Checkpoint Inhibitors in the First-Line Treatment of Metastatic Melanoma

This study evaluates whether interferon-gamma (IFN-γ) expression in tumor tissue and peripheral blood can serve as a predictive biomarker of response to immune checkpoint inhibitors in the first-line treatment of metastatic melanoma.

Although immune checkpoint inhibitors have substantially improved outcomes in metastatic melanoma, not all patients respond to therapy. Reliable biomarkers that could help identify patients most likely to benefit from treatment are still lacking.

This study investigates the association between IFN-γ expression levels and objective treatment response. In addition, the study explores whether characteristics of the gut microbiome are associated with immunotherapy outcomes. The results may contribute to improved patient stratification and personalized treatment approaches in metastatic melanoma.

Study Overview

• Status: Completed
• Conditions: Skin Cancer; Metastatic Melanoma; Malignant Melanoma
• Intervention / Treatment: Drug: Pembrolizumab; Drug: Nivolumab; Drug: Ipilimumab/Nivolumab

Detailed Description

Immune checkpoint inhibitors have significantly improved survival in patients with metastatic melanoma. However, treatment response varies considerably, and a substantial proportion of patients do not achieve durable benefit. The identification of predictive biomarkers remains an important unmet clinical need.

This prospective, single-arm interventional study evaluates biological markers in patients receiving first-line immune checkpoint inhibitor therapy for metastatic melanoma. The primary objective is to assess whether interferon-gamma (IFN-γ) expression in tumor tissue and peripheral blood is associated with objective response to treatment.

Tumor IFN-γ expression is assessed using immunohistochemistry, and peripheral blood IFN-γ concentration is measured using enzyme-linked immunosorbent assay (ELISA). The study also evaluates additional biomarkers, including PD-L1 expression, to explore their potential predictive value.

Furthermore, the study investigates the relationship between gut microbiome composition and treatment outcomes. Microbiome diversity and bacterial taxonomic profiles are analyzed from stool samples to determine whether microbial characteristics are associated with response to immunotherapy.

The study is conducted at a single tertiary oncology center and includes adult patients with metastatic melanoma receiving standard-of-care first-line immune checkpoint inhibitor therapy. The findings aim to support improved risk stratification and biomarker-guided therapeutic decision-making.

• Study Type: Interventional
• Enrollment (Actual): 132
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Slovenia
  • Ljubljana, Slovenia, 1000
    • Institute of Oncology Ljubljana

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age over 18 years
• Cytologically or histologically verified malignant melanoma
• Stage IIID unresectable/IV according to AJCC classification (8th edition, 2018)
• Performance status WHO 0-2 (ECOG criteria)
• First-line systemic immunotherapy treatment (nivolumab, ipilimumab/nivolumab combination, pembrolizumab)
• CT triple scan/PET CT performed within 4 weeks prior to the first administration
• Signed informed consent for participation in the clinical study

Exclusion Criteria:

• Previous systemic therapy for melanoma
• Performance status WHO 3-4 (ECOG criteria)
• Contraindications for immunotherapy (known immune deficiency, active immunosuppressive treatment, or active autoimmune disease requiring treatment)
• Other malignant diseases (except cured basal cell carcinoma, squamous cell carcinoma, and other cured solid tumors without recurrence more than three years after treatment)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Other: Immune Checkpoint Inhibitor Therapy; Patients with metastatic malignant melanoma will be treated in the first line with immune checkpoint inhibitors: PD-1 inhibitors (pembrolizumab, nivolumab) or combination PD-1 and CTLA-4 inhibitors (ipilimumab/nivolumab).

Drug: Pembrolizumab; PD-1 inhibitor used as first-line immunotherapy in patients with metastatic malignant melanoma.; Drug: Nivolumab; PD-1 inhibitor used as first-line immunotherapy in patients with metastatic malignant melanoma.; Drug: Ipilimumab/Nivolumab; Combination immunotherapy with PD-1 inhibitor (nivolumab) and CTLA-4 inhibitor (ipilimumab) used as first-line treatment in metastatic malignant melanoma.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate (ORR) Assessed by Immune-Related RECIST (irRECIST)	Objective response rate defined as the proportion of participants achieving complete response (CR) or partial response (PR) according to immune-related Response Evaluation Criteria in Solid Tumors (irRECIST), based on CT or PET/CT imaging assessment.	Up to 28 weeks after treatment initiation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peripheral Blood IFN-Gamma Concentration Measured by ELISA	Interferon-gamma (IFN-γ) concentration in peripheral blood measured using enzyme-linked immunosorbent assay (ELISA) and reported in picograms per milliliter (pg/mL).	Baseline and up to 28 weeks after treatment initiation
Gut Microbiome Alpha Diversity Index Assessed by 16S rRNA Sequencing	Gut microbiome diversity assessed from stool samples using 16S rRNA sequencing. Alpha diversity will be quantified using the Shannon diversity index.	Baseline (up to 4 weeks before treatment initiation)
Relative Abundance of Bacterial Taxa in Stool Samples Assessed by 16S rRNA Sequencing	Relative abundance (%) of bacterial taxa assessed from stool samples using 16S rRNA sequencing.	Baseline (up to 4 weeks before treatment initiation)
Tumor Tissue IFN-Gamma Expression Assessed by Immunohistochemistry (IHC)	Interferon-gamma (IFN-γ) expression in tumor tissue measured using immunohistochemistry (IHC). Expression will be quantified using the Histochemical Score (H-score), a semi-quantitative scoring system ranging from 0 to 300. Higher H-scores indicate higher IFN-γ expression levels in tumor tissue.	Baseline (within 4 weeks before treatment initiation)

Collaborators and Investigators

• Sponsor: Institute of Oncology Ljubljana

Study record dates

Study Major Dates

• Study Start (Actual): March 31, 2024
• Primary Completion (Actual): March 31, 2024
• Study Completion (Actual): March 31, 2024

Study Registration Dates

• First Submitted: February 5, 2026
• First Submitted That Met QC Criteria: February 20, 2026
• First Posted (Actual): February 27, 2026

Study Record Updates

• Last Update Posted (Actual): March 2, 2026
• Last Update Submitted That Met QC Criteria: February 26, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Immunotherapy; Immune Checkpoint Inhibitors
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Neoplasms by Histologic Type; Skin Diseases; Neuroectodermal Tumors; Neoplasms, Germ Cell and Embryonal; Neoplasms, Nerve Tissue; Neuroendocrine Tumors; Nevi and Melanomas; Skin and Connective Tissue Diseases; Melanoma; Skin Neoplasms; Amino Acids, Peptides, and Proteins; Proteins; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal; Antibodies; Immunoglobulins; Immunoproteins; Blood Proteins; Serum Globulins; Globulins; Nivolumab; Ipilimumab; pembrolizumab
• Other Study ID Numbers: ERIDSPRA-0028/2022 (Other Identifier: Clinical Research Unit, Institute of Oncology Ljubljana)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No