1215P - United Kingdom (UK) real world study of adjuvant osimertinib in resected EGFR mutated lung cancer

Background

Osimertinib is licensed as adjuvant treatment for resected EGFR mutated stage IB-IIIA non-small cell lung cancer. In the ADAURA trial, it improved disease-free and overall survival (Tsuboi et al, 2023). Real-world dose compliance with oral anti-cancer agents is less than that in clinical trials (Greer et al, 2016). Establishing real-world adjuvant Osimertinib compliance is therefore important.

Methods

A multi-centre retrospective study, from 32 UK hospitals, of patients who received adjuvant Osimertinib since November 2021. Primary outcome: dose acceptability rates, defined as remaining on 80mg at point of data collection (irrespective of interruptions). Secondary outcomes assessed dose tolerability, including reductions, interruptions and cessations. SPSS was used for univariate and multivariate analysis and Kaplan-Meier discontinuation curves.

Results

Of 206 patients offered adjuvant osimertinib, 182 (88.3%) started treatment. Median duration of follow-up was 17.1 months. The dose acceptability rate was 54.4% (99/182), compared to 74.8% (252/337) in ADAURA. At univariate and multivariate analysis neither demographic variables, mutation type, nor surgical resection type affected dose acceptability. Osimertinib dose reduction, interruption and cessation rates were 33.5%, 39.0% and 18.7% respectively. The commonest reason for these were treatment adverse events (AE). All-grade AE were similar to those in ADAURA, the commonest were diarrhoea (42.9%), fatigue (40.1%) and rash (38.5%). The median time to dose reduction or cessations was 69 days, and was affected by type of AE (Table). 60.0% reduced or stopped Osimertinib by 100 days, and 89.2% by 1 year. Table: 1215P

Treatment related adverse events and dose acceptability, in patients who dose-reduced or stopped osimertinib

Conclusions

Dose reduction and cessation rates of adjuvant osimertinib are higher in the real-world than were found in ADAURA, primarily due to treatment AEs. These results should be considered when discussing adjuvant Osimertinib with patients in routine clinical practice.

Clinical trial identification

Not Applicable

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.