Mobocertinib May Have Limited Intracranial Activity in EGFR Exon 20 Insertion+ NSCLC With Baseline Brain Mets

Mobocertinib (Exkivity) may have limited intracranial activity in patients with EGFR exon 20 insertion–positive, non–small cell lung cancer (NSCLC) with brain metastases at baseline, given the numerically lower response rate observed with the agent in this population, according to data from a study presented during the 2022 ASCO Annual Meeting.¹

However, patients who did not have brain metastases at enrollment, but whose disease progressed to the brain after initial mobocertinib treatment, were found to derive a benefit from remaining on study therapy.

“Patients with disease progression in the brain may derive overall benefit from ongoing mobocertinib treatment with combination [radiotherapy] to treat the brain lesions,” Pasi A. Jänne, MD, PhD, of Dana-Farber Cancer Institute, and colleagues, wrote in a poster featuring the data.

This 3-part, open label, multicenter study (NCT02716116) comprised 114 patients [median age, 60 years; 66% female; 60% Asian) with an ECOG status 0 to 1 who had at least 1 or more prior lines of therapy for locally advanced/metastatic EGFR exon 20 insertion-positive NSCLC. At baseline, 35% of patients had brain metastases.

Patients received mobocertinib at 160 mg once daily and were allowed to continue treatment beyond progressive disease at the discretion of the investigator if there was determined to be a clinical benefit. Additionally, patients with brain metastases were required to have the brain lesions treated and no symptoms of such prior to enrollment.

Confirmed objective response rate (cORR) was 28% (n = 32;) and median duration of response (DOR) was 17.5 months in the overall platinum-pretreated cohort (n = 64). Additionally, cORR was 34% (n = 25) among previously treated patients with no baseline brain metastases, compared with 18% (n = 7) among those with baseline metastases; and progression free survival was 9.2 and 3.7 months, respectively.

Among patients in the platinum-pretreated cohort, 21 (33%) had a first site of the disease involving the brain and 11 (17%) had first site of disease progression in the brain only. Of those 21 patients, 81% remained on mobocertinib beyond disease progression and 19% continued treatment for at least 6 months. And out of 43 patients who had first site of disease progression that did not involve the brain, 65% continued treatment with mobocertinib — 9% for at least 6 months.

“These results suggest that mobocertinib may have limited intercranial activity given the high frequency of first PD in brain (25%) and numerically IRC-assessed cORR in patients with baseline brain metastases,” the authors wrote in the abstract.

Of the 21 patients with first site of disease progression in the brain, 7 received brain radiotherapy and remained on mobocertinib (3 patients for 6 months or more and 1 patient for 12 months or more). Additionally, 12 patients remained on this treatment but did not receive radiotherapy.

“Optimal strategies for treating advanced EGFR exon-driven NSCLC with brain metastasis warrant continued investigation,” the authors concluded in their abstract.

Reference

1. Jaane P, Ramalingam S, Yang J, et al. Mobocertinib (TAK-788) in EGFR exon 20 insertion (ex20ins)+ metastatic non–small cell lung cancer (mNSCLC): treatment (tx) beyond progressive disease (PD) in platinum-pretreated patients (pts) with and without intracranial PD. J Clin Oncol. 2022; 40 (suppl 16):9099. doi:10.1200/JCO.2022.40.16_suppl.9099