1293PCetuximab in patients with unresectable cutaneous squamous cell carcinoma is safe and effective: A real-life analysis

Background: Approximately 20-30% of non-melanoma skin cancers are squamous cell carcinomas of the skin (SCCS). SCCS incidence is increasing and they often occur in elderly or immunosuppressed patients (pts). SCCS can progress to stages impossible to treat by surgical excision or radiotherapy. Cisplatin-based combinations show efficacy but are too toxic for elderly pts. Cetuximab (Ce) demonstrates 69% disease control rate (DCR) at 6 weeks but in few, highly selected pts. This study aims to evaluate the efficacy of Ce in non-selected pts with SCCS. Methods: This retrospective study included pts with relapsing unresectable or metastatic SCCS treated with Ce monotherapy (weekly loading dose 400 and 250 mg/m²). The primary objective was DCR at 6 weeks. 60 pts (38 male) with local relapses of metastatic CSCC (100%), were treated between 30/05/2007 and 07/04/2017 in 13 centers. Median age was 83.1 yrs (min 47.4, max 96.1 yrs). Two-thirds of pts had one or two comorbidities, including 13% (n = 8) with immune disorder. 54% had local relapse. Main metastatic locations were nodes (n = 15), lung (n = 8) and skin (n = 5). 90% were chemotherapy-naïve, 57% had previous radiotherapy, and all were primarily resected. Mean time between previous treatment and Ce was 20.1 months (min 0, max 300). Mean Ce injection number was 24.8 (min 4, max 60). Results: Complete response, partial response, stabilization (S) and progression were 7%, 48%, 32% and 13%, respectively, at 6 weeks and 2%, 42%, 29% and 27% at 3 months. 90% of pts experienced at least a disease S as best overall response. Ce was discontinued in 1 patient after first injection due to grade III infusion-related toxicity. All other grade III toxicities were cutaneous (n = 8) with 5 discontinuations. No toxic deaths were reported. Median follow-up, progression-free survival and overall survival were 11.7 months [95% CI: 9.6-30.1], 9.7 months [95% CI: 4.8-43.4] and 17.5 months [95% CI: 9.4-43.1] respectively. Conclusions: Cetuximab is a safe and efficient treatment for patients, even very old, with SCCS. The toxicity profile of Ce compares very favorably with cisplatine-based protocols. These results indicate that Ce is a promising platform to test new combinations. Legal entity responsible for the study: Centre Antoine Lacassagne. Funding: Merck KGaA. Disclosure: F. Peyrade: Board member: Merck KGaA. All other authors have declared no conflicts of interest.