Good CNS Response to Alectinib Reported in Previously Treated ALK-Positive Non–Small Cell Lung Cancer
In a pooled analysis reported in the Journal of Clinical Oncology, Gadgeel et al found that alectinib (Alecensa) was associated with good central nervous system (CNS) response in patients with ALK-positive non–small cell lung cancer (NSCLC) previously treated with crizotinib (Xalkori).
Study Details
The analysis included 136 patients with baseline CNS metastases (60% of the overall population) from 2 single-arm phase II studies of alectinib (600 mg twice per day). Of them, 50 patients (37%) had measurable CNS disease.
Prior CNS radiotherapy had been received by 95 patients (70%), with 55 completing radiotherapy more than 6 months before starting alectinib. Median duration of prior crizotinib was 350 days, and median time from the last dose of crizotinib to the first dose of alectinib was 15 days (range = 7–676 days). The best response on crizotinib was a partial response in 49% of patients and stable disease in 27%.
The primary endpoint in both phase II studies was independent review committee–assessed objective response rate. The current analysis details the additional independent review committee endpoints of CNS objective response rate, CNS disease control rate, and CNS duration of response.
Outcomes
Median follow-up was 12.4 months (range = 0.9–19.7 months). Among patients with measurable CNS disease at baseline, CNS objective response rate was 64.0% (95% confidence interval [CI] = 49.2%–77.1%), CNS disease control rate was 90.0% (95% CI = 78.2%–96.7%), and median CNS duration of response was 10.8 months (95% CI = 7.6–14.1 months).
Among all patients with CNS disease, CNS objective response rate was 42.6% (95% CI = 34.2%–51.4%), CNS disease control rate was 85.3% (95% CI = 78.2%–90.8%), and median CNS duration of response was 11.1 months (95% CI = 10.3 months to not evaluable). The CNS objective response rate was 35.8% (95% CI = 26.2%–46.3%) among patients with prior radiotherapy and 58.5% (95% CI = 42.1%–73.7%) for patients without prior radiotherapy.
The investigators concluded: “Alectinib showed good efficacy against CNS metastases, in addition to systemic activity, in crizotinib-refractory ALK-positive NSCLC.”
Shirish M. Gadgeel, MD, of Karmanos Cancer Institute, Wayne State University, Detroit, is the corresponding author of the Journal of Clinical Oncology article.
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