Neoadjuvant Atezolizumab in Patients With Surgically Resectable Advanced Cutaneous Squamous Cell Carcinoma

PURPOSE To evaluate the feasibility of administering three doses of neoadjuvant atezolizumab before curative surgical resection in patients with advanced cutaneous squamous cell carcinoma (cSCC). PATIENTS AND METHODS This single-arm phase II trial included patients with cSCC of the head and neck with stage III or IV disease, or stage II lesions for which standard therapy would incur an unacceptable morbidity. Patients received up to three doses of atezolizumab at a fixed dose of 1,200 mg every 21 days before undergoing surgical resection. The primary end point was the percentage of patients able to complete three doses of therapy and be eligible for surgical resection without discontinuation due to toxicity or progression. Secondary end points included unconfirmed RECIST 1.1 response rate, pathological response rate (major and complete pathological response), and safety and tolerability of atezolizumab. RESULTS Twenty patients were enrolled and treated. Sixteen (80%) of 20 patients completed three doses of atezolizumab, and all patients were eligible for surgical resection. A pathological complete response was seen in seven (35%; 95% CI, 15.4 to 59.2) patients, and a major pathological response (<10% viable tumor) was seen in four (20%; 95% CI, 5.7 to 43.7) patients. RECIST responses were seen in eight (40%; 95% CI, 19.1 to 64.0) patients, and one (5%) patient progressed. Grade 3 or higher adverse events were seen in one (5%) patient who developed pneumonitis after the first dose of atezolizumab. CONCLUSION Neoadjuvant atezolizumab is feasible and well tolerated in patients with advanced cSCC and results in a high rate of major and complete pathological responses.