In a Korean phase II study reported in the Journal of Clinical Oncology, Myung-Ju Ahn, MD, PhD, and colleagues found that osimertinib was active in patients with metastatic or recurrent non–small cell lung cancer (NSCLC) with uncommon EGFR mutations.
Myung-Ju Ahn, MD, PhD
In the multicenter study, 36 evaluable patients enrolled between March 2016 and October 2017 with EGFR mutations excluding the exon 19 deletion, L858R and T790M mutations, and exon 20 insertion received 80 mg of osimertinib once daily until disease progression or unacceptable toxicity. Osimertinib was first-line therapy for metastatic disease in 61% of patients. EGFR mutations included G719X (n = 19, 53%), followed by L861Q (n = 9, 25%), S768I (n = 8, 22%), and others (n = 4, 11%).
Median follow-up was 20.6 months. Objective response on RECIST version 1.1 was observed in 18 patients (50%; all partial responses); stable disease was observed in an additional 14 patients (39%). Median duration of response was 11.2 months. Median progression-free survival was 8.2 months, with 6- and 12-month rates of 64% and 39%. Median overall survival was not reached, with 12- and 18-month rates of 86% and 56%.
The most common adverse events of any grade were rash (31%), pruritus (25%), decreased appetite (25%), diarrhea (22%), and dyspnea (22%). Grade 3 or 4 adverse events were observed in two patients (grade 3 dyspnea and grade 3 headache, respectively). No cases of interstitial pneumonitis or QT prolongation were observed.
The investigators concluded, “Osimertinib demonstrated favorable activity with manageable toxicity in patients with NSCLC harboring uncommon EGFR mutations.”
Dr. Ahn, of Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was funded by AstraZeneca and the Bio & Medical Technology Development Program of the National Research Foundation funded by the Korean government. For full disclosures of the study authors, visit ascopubs.org.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.