Search

e21116 Background: Osimertinib (OSI) is a potent irreversible EGFR TKI approved for 1st line therapy advanced EGFR+ NSCLC and for 2nd line T790M+ pts. The AURA trial showed promising results even in pts with T790M- NSCLC after no immediate prior OSI in locally advanced or metastatic EGFR+ NSCLC, T790M undetectable or unknown, after 1st line EGFR TKI and subsequent chemotherapy. Methods: This phase II trial was performed to investigate the role OSI in locally advanced or metastatic EGFR+ NSCLC, T790M undetectable or unknown, after 1st line EGFR TKI (1 or 2 generation) and subsequent chemotherapy. Eligible pts (M or F, > 18 years, ECOG 0-2) received OSI (80 mg/day) until disease progression or unacceptable toxicity. Objective response rate (ORR) was the primary endopoint. Assuming a 10% attrition rate, 90 pts were planned to be enrolled according to the Optimal Simon’s 2 stage design. In the first stage, 32 pts were planned to be accrued, and if ≤ 3 responses were observed the study would be stopped. Otherwise, 49 additional pts were planned to be accrued. The null hypothesis would have been rejected if ≥ 12 responses were observed. This design yields a type I error rate of 0.05 and 80% power. Results: From May 2017 to October 2020, a total of 54 pts were enrolled (17 M and 37 F, mean age 66 years). The study was stopped early due to an extremely slow enrolment rate. However, the ORR of 31.5% (95% CI 19.5% - 45.5%) was significantly higher than the null hypothesis of 9% (p