Efficacy of Brigatinib in Patients With Advanced ALK-Positive NSCLC Who Progressed on Alectinib or Ceritinib: ALK in Lung Cancer Trial of brigAtinib-2 (ALTA-2)

Introduction: Brigatinib is a potent next-generation ALK tyrosine kinase inhibitor approved for treatment-naive and crizotinib-refractory advanced ALK-positive (ALK+) NSCLC. We evaluated brigatinib after other next-generation ALK tyrosine kinase inhibitors. Methods: In this single-arm, phase 2, ALK in Lung Cancer Trial of brigAtinib-2 (NCT03535740), patients with advanced ALK+ NSCLC whose disease progressed on alectinib or ceritinib received brigatinib 180 mg once daily (after 7-d 90-mg lead-in). Primary end point was independent review committee (IRC)-assessed overall response rate (ORR). Circulating tumor DNA (ctDNA) was analyzed. Results: Among 103 patients (data cutoff: September 30, 2020; median follow-up [range]: 10.8 [0.5–17.7] mo), confirmed IRC-ORR was 26.2% (95% confidence interval [CI]: 18.0–35.8), median duration of response, 6.3 months (95% CI: 5.6–not reached), and median progression-free survival (mPFS), 3.8 months (95% CI: 3.5–5.8). mPFS was 1.9 months (95% CI: 1.8–3.7) in patients with ctDNA-detectable baseline ALK fusion (n = 64). Among 86 patients who progressed on alectinib, IRC-ORR was 29.1% (95% CI: 19.8–39.9); mPFS was 3.8 months (95% CI: 1.9–5.4). Resistance mutations were present in 33.3% (26 of 78) of baseline ctDNA; 54% (14 of 26) of mutations were G1202R; 52% (33 of 64) of patients with detectable ALK fusion had EML4-ALK variant 3. Most common all-grade treatment-related adverse events were increased creatine phosphokinase (32%) and diarrhea (27%). The mean dose intensity of brigatinib (180 mg once daily) was 85.9%. Conclusions: In ALK in Lung Cancer Trial of brigAtinib-2, brigatinib was found to have a limited activity in patients with ALK+ NSCLC post-ceritinib or post-alectinib therapy. mPFS was longer with brigatinib in patients without baseline detectable plasma ALK fusion.