Previously, the interim analysis of the multicenter, single-arm, phase 2 NEOS study (ChiCTR1800016948) demonstrated the promising efficacy and tolerable safety profile of neoadjuvant osimertinib in patients with resectable EGFR mutated NSCLC. Here we present the final efficacy and safety results of neoadjuvant osimertinib.
Eligible patients aged 18-75 with resectable, stage II-IIIB (T3-4N2), EGFR-mutant lung adenocarcinoma were enrolled and treated with osimertinib 80 mg once daily for six weeks followed by surgical resection. The primary endpoint was objective response rate assessed by investigator per RECIST v1.1. The secondary endpoints include safety, R0 resection rate, quality of life, major pathologic response (MPR) rate, pathological complete response (pCR) rate, and N2 downstaging rate.
Between October 17, 2018 and June 08, 2021, 88 patients were screened and 40 patients were finally enrolled. Of the 38 patients who completed 6-week osimertinib neoadjuvant treatment, the objective response rate was 71.1% (27/38). 32 patients underwent surgery (50% video-/robot-assisted thoracoscopic surgery; 50% open thoracotomy) and R0 resection was achieved in 30 (93.8%) of the resected patients. 10.7% of the 28 pathological evaluable patients achieved major pathological response, including one (3.6%) patient achieved pathological complete response. 13 (46.4%) patients had a ≥50% pathological response. Treatment-related adverse events (TRAEs) were observed in 24 (60%) patients during neoadjuvant treatment, including 3 (7.5%) had events of grade 3. No adverse event led to neoadjuvant treatment discontinuation occurred.
This study reported the data of neoadjuvant osimertinib in the largest prospective population to date. Osimertinib demonstrated satisfying efficacy and acceptable safety profile in the neoadjuvant setting and could be a promising therapy in patients with resectable EGFR mutated NSCLC.
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All authors have declared no conflicts of interest.