Summary Background Alectinib, a highly selective, central nervous system (CNS)-active anaplastic lymphoma kinase (ALK) inhibitor, demonstrated promising clinical activity in crizotinib-naïve and crizotinib-resistant ALK-positive non-small-cell lung cancer (NSCLC). This phase 2 study evaluated the safety and efficacy of alectinib in ALK-positive NSCLC patients who progressed on previous crizotinib. Methods This ongoing North American study (NCT01871805) enrolled patients with stage IIIB/IV ALK-positive NSCLC, who had progressed following crizotinib. Patients were treated with oral alectinib 600 mg twice daily until progression, death or withdrawal. Primary endpoint was overall response rate (ORR) by independent review committee (IRC) using RECIST v1.1. Secondary endpoints included progression-free survival (PFS), duration of response (DOR), intracranial ORR and DOR, safety, and patient-reported outcomes. The intent-to-treat population was used for efficacy and safety analyses, with the response evaluable population used for response endpoints. Findings A total of 87 patients were enrolled in the intent-to-treat population. All patients had received prior crizotinib therapy, and 64 patients (74%) had also received prior chemotherapy. Fifty-two patients (60%) had baseline CNS metastases, of whom 18 (35%) had received no prior brain radiation therapy. At the time of primary analysis (median follow-up 4.8 months), ORR by IRC was 48% (95% CI 36–60). Adverse events were predominantly grade 1 or 2, most commonly constipation, fatigue, myalgia and peripheral edema. The most common grade ≥3 AEs were changes in laboratory values, including increased blood creatine phosphokinase (in 8%, n=7), increased alanine aminotransferase (in 6% n=5), and increased aspartate aminotransferase (in 5% n=4). Interpretation Alectinib demonstrated clinical efficacy and was well tolerated in patients with ALK-positive NSCLC who had progressed on crizotinib. Alectinib was active in the CNS, as demonstrated by durable responses in the majority of crizotinib-resistant patients with CNS disease. Therefore, alectinib could be a suitable treatment for patients with ALK-positive disease who have progressed on crizotinib.

Purpose Crizotinib confers improved progression-free survival compared with chemotherapy in anaplastic lymphoma kinase (ALK)-rearranged non–small-cell lung cancer (NSCLC), but progression invariably occurs. We investigated the efficacy and safety of alectinib, a potent and selective ALK inhibitor with excellent CNS penetration, in patients with crizotinib-refractory ALK-positive NSCLC. Patients and Methods Alectinib 600 mg was administered orally twice daily. The primary end point was objective response rate (ORR) by central independent review committee (IRC). Results Of the 138 patients treated, 84 patients (61%) had CNS metastases at baseline, and 122 were response evaluable (RE) by IRC. ORR by IRC was 50% (95% CI, 41% to 59%), and the median duration of response (DOR) was 11.2 months (95% CI, 9.6 months to not reached). In 96 patients (79%) previously treated with chemotherapy, the ORR was 45% (95% CI, 35% to 55%). Median IRC-assessed progression-free survival for all 138 patients was 8.9 months (95% CI, 5.6 to 11.3 months). CNS disease control rate was 83% (95% CI, 74% to 91%), and the median CNS DOR was 10.3 months (95% CI, 7.6 to 11.2 months). CNS ORR in 35 patients with baseline measurable CNS lesions was 57% (95% CI, 39% to 74%). Of the 23 patients with baseline CNS metastases (measurable or nonmeasurable) and no prior radiation, 10 (43%) had a complete CNS response. At 12 months, the cumulative CNS progression rate (24.8%) was lower than the cumulative non-CNS progression rate (33.2%) for all patients. Common adverse events were constipation (33%), fatigue (26%), and peripheral edema (25%); most were grade 1 to 2. Conclusion Alectinib is highly active and well tolerated in patients with advanced, crizotinib-refractory ALK-positive NSCLC, including those with CNS metastases.