Neoadjuvant pembrolizumab with chemotherapy for the treatment of stage IIB-IIIB resectable lung squamous cell carcinoma.

BACKGROUND: Researches on programmed cell death (PD-1) as neoadjuvant immunotherapy for resectable non-small cell lung cancer is underway, which brings hope for individuals with the disease. However, a study dedicated to lung squamous cell carcinoma (LUSC) specifically has yet to be conducted. Now, data from our pilot prospective research neoadjuvant study provide new insights in the field of neoadjuvant regimen for LUSC. METHODS: Between June 2019 and July 2020, 37 adults with untreated, surgically resectable stage IIB-IIIB LUSC were enrolled into this prospective study. Patients received 2 cycles of pembrolizumab (2 mg/kg) with chemotherapy (albumin-bound paclitaxel 100 mg/m2 on days 1 and 8 + carboplatin AUC 5) via intravenous administration every 3 weeks, and underwent surgical treatment 3-4 weeks after the second cycle. The primary endpoint of the study was the tumor pathologic complete response (pCR) rate. The toxicity profile, tumor major pathological remission, complete resection rate, response rate, and operative and postoperative complications were also evaluated. RESULTS: The postoperative pathological specimens of 17 (45.9%) patients suggested pCR. Neoadjuvant pembrolizumab with chemotherapy had an acceptable side-effect profile, and no patients withdrew from the study preoperatively due to disease progression or toxicity. A major pathological response occurred in 24 (64.9%) resected tumors. All tumors were completely resected (R0, 100%). According to the Response Evaluation Criteria in Solid Tumors (RESIST), a response was evaluated before surgery in 32 (86.5%) patients by computed tomography. Twenty-five (67.6%) patients underwent thoracoscopic surgery. No deaths or postoperative major complications requiring reoperation occurred. Recurrence or metastasis was found in 2 patients during follow-up of 2-14 months. CONCLUSIONS: The early outcomes of pembrolizumab with chemotherapy in the neoadjuvant setting as a novel treatment for resectable stage IIB-IIIB LUSC showed a high pCR rate that has not been seen previously, as well as a high R0 resection rate and a low toxicity profile. The long-term efficacy of this novel treatment and the validity of the present findings should be confirmed with longer follow-up and prospective comparative trials.