Erlotinib in the Treatment of Recurrent or Metastatic Cutaneous Squamous Cell Carcinoma: A Single-Arm Phase 2 Clinical Trial

BACKGROUND: Cutaneous squamous cell carcinoma (CSCC) is a very common malignancy in which most patients present with localized disease. Recurrent and metastatic disease is rare, and there is no standard therapy. These tumors frequently overexpress the epidermal growth factor receptor (EGFR). We conducted a phase 2 trial to determine the response rate to therapy with erlotinib, an EGFR tyrosine kinase inhibitor, in patients with locoregionally recurrent or metastatic CSCC that was not amenable to curative treatment (NCT01198028). METHODS: Eligible patients had CSCC not amenable to curative intent therapy. Patients who had previously received anti-EGFR targeted therapy were excluded. All patients received oral therapy with erlotinib 150mg daily. Response was assessed every 8 weeks, and treatment continued until progression, unacceptable toxicity, or withdrawal of consent. The primary end-point was overall response rate according to RECIST 1.1 criteria. RESULTS: A total of 39 patients received treatment during the trial; 29 of these patients were evaluable for response. The overall response rate was 10% (3/29); all responses were partial responses. The disease control rate (partial response + stable disease) was 72% (21/29). The median progression-free survival was 4.7 months (95% confidence interval, 3.5-6.2 months); the median overall survival was 13 months (95% confidence interval, 8.4-20.5 months). No unexpected toxicities were seen. CONCLUSION: Erlotinib therapy was feasible for most patients with incurable CSCC and was associated with expected toxicities. However, only a modest response rate of 10% was observed. Further study of EGFR tyrosine kinase inhibitors in this patient population is not warranted. (C) 2018 American Cancer Society.