1064P Final results of CA209-9JC: A phase II study of first-line nivolumab in patients with advanced cutaneous squamous cell carcinoma

Background: Immune checkpoint blockade has emerged as a novel treatment option for patients (pts) with advanced cutaneous squamous cell carcinoma (AcSCC). Here, we present the final results of a single-arm, phase II study of the anti-PD-1 agent nivolumab (NIVO) in pts with advanced AcSCC. Methods: Systemic therapy-naïve pts with AcSCC not amenable to complete resection or radiation were treated with NIVO 3mg/kg every 2 weeks until disease progression, unacceptable toxicity or 12 months (mo) of treatment. The primary endpoint was the best objective response rate (bORR) as per RECIST 1.1 criteria. Secondary endpoints included safety, progression-free survival (PFS) and overall survival (OS). Results: Between October/2018 and October/2019, 24 pts with AcSCC were included, with a median age of 74 years (range 48-93). Most frequent primary sites were head/neck (41.7%) and trunk (29.2%), and 41.7% of the pts had received prior radiation-therapy. Locoregional disease (n=16; 66.6%) was the most common presentation, followed by locally advanced and metastatic disease (n=4; 16.6% each). The majority of pts (54.2%) completed 12 months of treatment with NIVO and entered active surveillance, and 37.4% developed disease progression while on treatment. All 24 pts were evaluable for response at this final analysis, and the bORR was 58.3% (14/24); 20.8% of the pts had progressive disease as the best response. Median duration of response has not been reached; median PFS was 12.7mo and estimated median OS was 20.7 mo. In univariate analyses, prior exposure to radiation therapy was associated with worse outcomes (p=0.035). Treatment-related AEs of any grade occurred in 21 pts (87.5%), and the most frequent were hypothyroidism, pruritus, lymphopenia, fatigue and arthralgias. Grade ≥3 treatment-related adverse events occurred in 6 pts (25%), and 1 patient discontinued NIVO due to toxicities. Conclusions: NIVO demonstrated pronounced antitumor activity and durable responses in systemic-treatment-naïve pts with AcSCC, with a favorable tolerability even in pts at advanced ages. These results reinforce the role of anti-PD-1 agents as standard treatment options for this disease. Clinical trial identification: NCT03834233. Legal entity responsible for the study: Instituto do Cancer do Estado de São Paulo, Universidade de São Paulo. Funding: BMS. Disclosure: R. Ramella Munhoz: Financial Interests, Personal, Invited Speaker: BMS; Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Invited Speaker: Sanofi; Financial Interests, Personal, Advisory Board: Sanofi; Financial Interests, Personal, Invited Speaker: Novartis; Financial Interests, Personal, Advisory Board: Daiichi Sankyo; Financial Interests, Personal, Expert Testimony: Daiichi Sankyo; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Invited Speaker: Merck Serono; Financial Interests, Personal, Advisory Board: Bayer; Financial Interests, Institutional, Invited Speaker: BMS; Financial Interests, Institutional, Invited Speaker: BMS; Financial Interests, Institutional, Invited Speaker: MSD; Financial Interests, Institutional, Invited Speaker: Roche; Financial Interests, Institutional, Invited Speaker: Novartis; Financial Interests, Institutional, Invited Speaker: Bayer. G. de Castro Jr.: Financial Interests, Personal, Invited Speaker: AstraZeneca; Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Advisory Board: BMS; Financial Interests, Personal, Invited Speaker: BMS; Financial Interests, Personal, Invited Speaker: Merck Serono; Financial Interests, Personal, Advisory Board: Merck Serono; Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Advisory Board: MSD; Financial Interests, Personal, Invited Speaker: Pfizer; Financial Interests, Personal, Invited Speaker: Pfizer; Financial Interests, Personal, Invited Speaker: Roche; Financial Interests, Personal, Advisory Board: Roche; Non-Financial Interests, Institutional, Principal Investigator: AstraZeneca; Non-Financial Interests, Institutional, Principal Investigator: BMS; Non-Financial Interests, Institutional, Principal Investigator: MSD; Non-Financial Interests, Institutional, Principal Investigator: Merck Serono; Non-Financial Interests, Institutional, Principal Investigator: Roche. All other authors have declared no conflicts of interest.