109P - Prognosis of patients with metastatic melanoma with initial stable disease during treatment with anti-PD-1 monotherapy

Background

Stable disease (SD) upon treatment with immune checkpoint inhibitors is generally associated with poorer survival outcomes than partial (PR) or complete response (CR). Yet, in the KEYNOTE-001 and -006 cohort, approximately half of patients with initial SD subsequently developed an objective response (OR) with improved survival outcomes. We present a real-world analysis of the prognosis of unresectable melanoma patients with SD at first evaluation after initiation of anti-PD-1 monotherapy.

Methods

The Danish Metastatic Melanoma Database (DAMMED) is a nation-wide registry on all Danish patients with unresectable melanoma eligible for systemic therapy. All patients diagnosed with unresectable cutaneous or unknown primary melanoma treated with single agent anti-PD-1 therapy, regardless of treatment line, were selected for analysis.

Results

1052 patients, treated between July 2014 and April 2022, were found eligible for analysis. At the initial evaluation, approximately 12 weeks after first anti-PD-1 administration, 232 patients (22.1%) had SD. Of these, 66 (28.4%) patients were alive and progression-free after a median follow up of 38.0 months while 87 (37.5%) later achieved PR (45) or CR (42). Overall, patients with initial SD had a median progression free survival (PFS) of 13.7 months and a median overall survival (OS) of 43.0 months. Grouping patients with initial SD by best overall response (BOR) revealed significantly different survival curves (p<0.001 for SD vs PR vs CR for both PFS and OS). In contrast, no significant differences were found when comparing the survival curves of patients with initial SD and subsequent OR to those of patients with initial OR (PFS: p=0.46 and p=0.83 for PR and CR, respectively; OS: p=0.69 and p=0.81, respectively). OS of patients with BOR SD was significantly better than the OS of patients with immediate PD (p<0.001).

Conclusions

More than one-third of patients with initial SD later obtain an OR with a prognosis similar to patients having the corresponding OR on first evaluation. Durable disease control is a common outcome following initial SD to anti-PD-1 monotherapy in melanoma.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

I.M. Noringriis: Financial Interests, Institutional, Research Grant, Research granted to our institution in order to initiate a biobank containing blood samples from patients with immune related adverse events. I am the principle investigator of the protocol: Sygeforsikringen, Novo Nordisk Fonden. M. Donia: Financial Interests, Personal, Other, Advisor: Achilles Therapeutics; Non-Financial Interests, Personal, Other, Sub-investigator of clinical trial with connected translational research: Bristol Myers Squibb; Non-Financial Interests, Personal, Proprietary Information, Proprietary data access: Bristol Myers Squibb; Non-Financial Interests, Personal, Proprietary Information, Proprietary data access: Genentech; Other, Personal, Other, Chairman of the Melanoma and Non-melanoma Skin Cancer Scientific Committee: Danish Medicines Council (Medicinrådet). L. Bastholt: Non-Financial Interests, Personal, Advisory Role, Scientific committee under Danish Medicines Agency regarding new treatments of melanoma, skin cancer and thyroid cancer: Danish Medicines Agency. C.A. Haslund: Financial Interests, Personal, Invited Speaker: MSD, GSK, BMS; Financial Interests, Institutional, Local PI: BMS, Tesaro, MSD, IO Biotech, Chimerix, Incyte; Financial Interests, Institutional, Coordinating PI: GSK, Celgene Aps. E. Ellebæk: Financial Interests, Personal, Invited Speaker: Pierre Fabre, BMS, Novartis, MSD, Pfizer; Other, Personal, Other, Travel and conference expenses: MSD, Pierre Fabre. I. Svane: Financial Interests, Personal, Advisory Board: BMS, Pierre Fabre, Novartis; Financial Interests, Personal, Invited Speaker: MSD, Pierre Fabre, Novartis, Roche, BMS; Financial Interests, Personal, Writing Engagement: MSD; Financial Interests, Personal, Stocks/Shares, Cofounder and Founder warrents: IO Biotech; Financial Interests, Institutional, Research Grant: Adaptimmune, Enara Bio, Lytix Biopharma, TILT Biotherapeutics; Financial Interests, Institutional, Funding: Evaxion; Non-Financial Interests, Personal, Principal Investigator: BMS, Novartis, Roche, TILT Biotherapeutics, Lytix Biopharma. All other authors have declared no conflicts of interest.