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Osimertinib Overcomes Asymptomatic Brain Metastases in Lung Adenocarcinoma
A phase 2 investigation on the intracranial activity of osimertinib for asymptomatic brain metastases confirmed high efficacy for patients with Thr790Met-positive and epidermal growth factor (EGFR)-tyrosine kinase inhibitor (TKI) sensitizing mutant lung adenocarcinoma.
“While intracranial activity of osimertinib is documented in larger trials, a prospective study focusing exclusively on patients with asymptomatic brain metastases has not been reported,” explained Nir Peled, MD, PhD, FCCP, Shaare Zedek Medical Center, Israel, and co-authors.
A total of 48 patients were enrolled to the non-randomized, 3-arm prospective study.
The regimen to treat metastatic EGFR-mutant lung adenocarcinoma was osimertinib 80 mg daily. The 3 arms consisted of a treatment naïve (TN) arm with 20 patients, previously treated with an EGFR-TKI and Thr790Met positive with 18 patients, or negative for mutations with 10 patients. For those with isolated intracranial progression, osimertinib dosing was escalated to 160 mg.
The primary endpoints were intracranial objective response rate (iORR) and intracranial disease control rate (iDCR). The secondary endpoint was intracranial progression-free survival (iPFS).
Results confirmed the iORRs for each arm were 84.2%, 66.7%, and 50%, respectively. Further, the iDCRs were 94.7%, 94.4%, and 80%. The median iPFS was 11.8 months (95% CI, 7.7 to NA), 7.6 months (95% CI, 5.3-NA), and 6.3 moths (95% CI, 3.9 to NA).
The researchers noted that pooled iORR was 54% from all treatment arms.
“Osimertinib demonstrated high efficacy on brain metastases. All trial arms displayed a significant decrease in the number and diameter of target lesions. Osimertinib should be considered a viable option for EGFR-mutant patients with brain involvement regardless of their Thr790Met mutation status,” concluded Dr Peled, et al.—Alexa Stoia
