LAUSR

e21201 Background: Osimertinib is one of the favoured treatment options in EGFR mutated NSCLC and was established as a treatment option in last 2-3 years. However the treatment pattern post-osimertinib failure is not established. Hence we conducted this audit to study the pattern of treatment post-osimertinib failure in India. Methods: This was a retrospective multi-centric audit of adult (age ≥18 years) EGFR mutated NSCLC patients who were treated with osimertinib and had failed. The treatment pattern of these patients was noted. Descriptive statistics were performed. Median with range was estimated for continuous variables while the percentage with 95% CI were estimated for ordinal and nominal variables. Results: We had 25 patients who had failed on osimertinib. Oligo-progression versus widespread progression was seen in 5 (20%) and 20 (80%) patients respectively. The median age was years 56.5 year (Range-26-71) with 4/25 (16%) of patients were elderly (≥65 years). Male-to-female ratio was 18:7 (72% males, 28% females).The ECOG PS at failure were 0-1 in 12 patients (48%), 2 in 11 patients(44%) and 3-4 in 2 patients (8%) patients. The treatment offered were platinum doublet in 14 patients (56%) with variable combinations with TKIs in 5 patients (20%) and bevacizumab in 4 patients(16%). A repeat NGS for assessing the mechanism of resistance was done in patients revealed new mutations in 6 patients (24%) with EGFR Exon 20 T790M being most common in 3 patients (12%). Conclusions: We conclude that, in real-world practice, platinum-doublet formed the backbone of treatment post-osimertinib progression, with variable combinations, most commonly, along with TKIs or bevacizumab. No standard guidelines for the treatment of patients post-osimertinib progression are available with variable responses and tolerability. Larger and prospective studies are needed to identify the best options of therapies in such patients.