Osimertinib as first-line treatment for recurrent lung cancer patients with EGFR mutation

Background: Although osimertinib was approved as adjuvant therapy for lung cancer patients with EGFR mutation in various countries, there is still some ongoing debate as osimertinib has been approved based on disease-free survival (DFS) rather than overall survival (OS). We curated a case series in which we documented patterns of recurrence and efficacy and safety of osimertinib after recurrence.

Methods: Patients who received osimertinib as first-line treatment for postoperative recurrence between September 2018 and January 2023 were included. Clinicopathological factors, duration of osimertinib treatment (DoT), and adverse events were collected and analyzed.

Results: Twenty patients received osimertinib [male, n=6; median age, 75 years (range, 55-85 years)]. The EGFR mutation type was L858R in 11 patients and exon 19 deletion in eight patients. The performance status (PS) was 0 or 1 in all but two patients, who had symptomatic brain metastasis and were therefore PS 3. The first site of postoperative recurrence was locoregional in five patients and distant in 15 patients, including seven with brain metastasis. As of February 2023, 10 patients were still on osimertinib, including three with brain metastasis. Patients with brain metastasis or poor PS had a considerably shorter DoT than their counterparts. Three patients with symptomatic brain metastasis or leptomeningeal metastasis initially responded to osimertinib, but all died of disease progression. Five patients discontinued osimertinib due to serious adverse effects (pneumonitis, drug eruption, and heart failure).

Conclusions: Although osimertinib exerts great disease control, even in patients with brain metastasis or poor PS, their presence was associated with a poor prognosis, even with osimertinib treatment. Therefore, adjuvant osimertinib is recommended unless contraindicated.