Sawsan Rashdan, MD, University of Texas (UT) Southwestern Medical Center, shares the main findings from her study titled “Safety and efficacy of osimertinib plus consolidative stereotactic ablative radiation (SABR) in advanced EGFR mutant non-small cell lung cancer (NSCLC): Results from a multi-center phase II trial.” The results were presented at the 2024 American Society of Clinical Oncology Annual Meeting.

Please introduce yourself by stating your name, title, organization, and relevant professional experience.

My name is Sawsan Rashdan. I'm an associate professor in the Division of Hematology and Oncology at UT Southwestern Medical Center. Since joining UT Southwestern in 2016, I have focused on lung cancer management.

Can you give some background about your study and what prompted you to undertake it?

First-line osimertinib is currently the standard of care for the treatment of metastatic EGFR-positive NSCLC. However, for the majority of patients, even though they achieve a good response to the treatment, this response is incomplete and residual disease remains. This residual disease will ultimately result in acquired resistance, which eventually leads to progression and death. So, the question that we're trying to answer in this study is whether eliminating or minimizing residual disease using consolidated radiation will improve the outcome and delay the emergence of resistance.

Can you briefly describe how the study was conducted?

Our study is a multicenter, single-arm phase 2 investigator-initiated trial, which included patients who are tyrosine kinase inhibitor (TKI) naïve, harbor the EGFR mutation, and have advanced NSCLC. These patients were not restricted by the number site or size of their metastases. They also should not have had any history of interstitial lung disease, and they should have had a good Eastern Cooperative Oncology Group (ECOG) performance status of less than 2.

In this study, we gave patients induction treatment with osimertinib in it for 8 weeks. If they had a good response to the treatment, we gave them stereotactic ablative radiation therapy (SBRT). Then, the patients went back on osimertinib until systemic disease progression or toxicity. We allowed subsequent stereotactic ablative radiation for oligoprogressive disease.

There was a total of 43 patients enrolled in the study. The primary objective was progression-free survival (PFS) and the secondary objectives were overall survival and duration of osimertinib and safety.

What were the main findings of your study?

Our results were positive. We found that the median PFS was 32.3 months, which exceeded the published historical standard from the FLAURA study of 18.9 months for first-line treatment with osminternib. We also found that the median overall survival was 45 months, which exceeded the published historical standard from the FLAURA study of 38.6 months for first-line treatment.

In terms of safety, we found that the combination of osminternib plus SBRT is safe, and overall, we did not see clear evidence of increased risk of pneumonitis in the context of osminternib plus radiation.

Looking ahead, what potential impact do you hope your findings will have on treatment strategies for advanced EGFR mutant NSCLC?

The results of our study are positive, but they are still not practice changing due to the small number of patients and the non-randomized nature of this study. More prospective randomized data are needed to validate the use of SBRT in the consolidative setting in metastatic EGFR-positive NSCLC and to better define the best timing for using radiation in this setting.