1159P - Characterization of melanoma of unknown primary in the era of immunotherapy and targeted therapy in Spain: Results from the prospective real-world study GEM 1801

Background

The clinical presentation of patients (pts) diagnosed with melanoma of unknown primary (MUP) is not clearly known, like their therapeutic assignment and their evolution in terms of responses obtained, toxicity, and relapse profile in the actuality.

Methods

GEM1801 is a prospective observational study including pts with melanoma that analyzes the clinical and pathological disease presentation patterns, the different lines of treatment choices and the health outcomes derived from treatments. Here we focus on the clinical and evolution characterization of pts diagnosed with MUP.

Results

From Aug 2018 to Dec 2022, 893 evaluable pts were enrolled, 133 (14.9%) being MUP. Median age was 63 years (range 24-93), 81 (60.9%) male. Distal metastases were present in 117 (88%) pts with most (50.4%) having ≥ 3 affected organs, including ganglia (53.4%), lung (41.4%) or brain (30.1%). LDH was elevated in 50 (37.6%) pts. BRAF was mutated in 79 (54.9%) pts. Adjuvant therapy was administered to 28 (21.1%) pts with MUP, being immunotherapy less frequently prescribed than in pts with known primary (17.3% vs 27.1%; p=0.017). Immunotherapy was also less frequent for the 1^st line in the metastatic/locally advanced setting (53.6% vs 64%; p=0.039). Conversely, more pts with MUP were enrolled in clinical trials exploring combo of immunotherapy and targeted therapy (9.1% vs 4.8%; p=0.074). Table: 1159P

IT = Immunotherapy; TT = Targeted therapy.

Conclusions

MUP in Spain comprises a population with a multiorgan presentation and frequent brain metastasis, which was followed by worse outcomes than the general melanoma population. Having MUP diagnosis seems to influence the therapeutic assignment, specially for immunotherapy schemes.

Clinical trial identification

NCT03605771.

Editorial acknowledgement

We acknowledge MFAR Clinical Research staff for their assistance in the development of this abstract.

Legal entity responsible for the study

Grupo Español Multidisciplinar de Melanoma (GEM).

Funding

GEM through industry partners Novartis, Pierre Fabre, Incyte, BMS, Roche y MSD.

Disclosure

E. Muñoz-Couselo: Financial Interests, Personal, Speaker, Consultant, Advisor: BMS, MSD, Novartis, Pierre Fabre, Sanofi, Roche; Other, Personal, Advisory Board: Amgen, BMS, MSD, Novartis, Pierre Fabre, Roche, Sanofi; Other, Personal, Other, Honoraria: Amgen, BMS, Novartis, Pierre Fabre, Roche; Other, Personal, Principal Investigator: Amgen, BMS, GSK, MSD, Novartis, Pierre Fabre, Roche, Sanofi. E. Espinosa: Financial Interests, Personal, Speaker, Consultant, Advisor: BMS, Novartis, Pierre Fabre; Financial Interests, Personal, Advisory Role: MSD. L.A. Fernández-Morales: Financial Interests, Personal, Speaker, Consultant, Advisor: BMS, MSD, Pierre Fabre, Roche, Novartis, Pfizer. T. Puértolas: Financial Interests, Personal, Advisory Role: Bristol Myers Squibb, Immunocore, Novartis, Seagen; Other, Personal, Other, Travel, Accommodation, Expenses: Novartis, MSD, Pierre Fabre. I. Márquez-Rodas: Financial Interests, Personal, Advisory Board: BMS, MSD, Novartis, Pierre Fabre, Roche, GSK, AstraZeneca, Celgene, Regeneron, Sanofi, Merck Serono, Highlight Therapeutics, Bioline Rx, Sun Pharma, Immunocore; Financial Interests, Personal and Institutional, Coordinating PI: Pierre Fabre; Financial Interests, Institutional, Coordinating PI, GEM1802 clinical trial: Novartis; Financial Interests, Institutional, Coordinating PI, GEM1801 clinical study: BMS, Roche, Pierre Fabre, Incyte, MSD; Financial Interests, Institutional, Coordinating PI, National coordinator of Spotlight 203 clinical trial: Highlight Therapeutics; Non-Financial Interests, Advisory Board: Spanish Melanoma group. All other authors have declared no conflicts of interest.