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.

Introduction:The FIR phase II study (NCT01846416) evaluated the efficacy and safety of anti-programmed death-ligand 1 (PD-L1) atezolizumab in advanced NSCLC selected by tumor cell (TC) or tumor-infiltrating immune cell (IC) PD-L1 expression.Methods: Patients with PD-L1 TC2/3 (PD-L1 staining on 5% of TC) or IC2/3 tumors (PD-L1 staining on 5% of IC; determined by SP142 PD-L1 immunohistochemistry assay) with paired fresh and archival histology samples were recruited into cohort 1 (chemotherapy-naive/>6 months between adjuvant chemotherapy and recurrence), cohort 2 ( second-line without brain metastases), or cohort 3 ( second-line with treated brain metastases). Patients received 1200 mg atezolizumab on day 1 (21-day cycles). Primary endpoint was investigator-assessed modified Response Evaluation Criteria in Solid Tumors, objective response rate (Response Evaluation Criteria in Solid Tumors v1.1). Secondary endpoints were overall survival, progression-free survival, duration of response, and safety. Results: Patients (N ¼ 138) were enrolled (137 evaluable for response: cohort 1, n ¼ 31; cohort 2, n ¼ 93; and cohort 3, n ¼ 13). Investigator-assessed objective response rate was 32%, 21%, and 23% for cohorts 1, 2, and 3, respectively. Treatment-related adverse events were reported in 81%, 67%, and 69% of patients, respectively, including grade 3-4 treatment-related adverse events in 16%, 19%, and 15%, respectively. Moreover, 88.6% (86 of 97) paired baseline tumor samples had <5% change in TC/IC PD-L1 expression over time.Conclusions: Atezolizumab monotherapy showed clinical activity in patients with NSCLC, including those with brain metastases; safety was consistent with previous trials. Atezolizumab has completed phase III monotherapy studies in second-line. Front-line trials are ongoing, confirming these favorable results.

To understand the molecular basis for variable sensitivity to the BH3 mimetic drug ABT-737, the abundance of Bcl-2 family members was assayed in a panel of small cell lung cancer cell lines whose sensitivity varied over a 2-log range. Elevated Noxa and Bcl-2 levels directly correlated with sensitivity to ABT-737, whereas Mcl-1 levels were similar in all cell lines tested regardless of sensitivity. Transgenically enforced expression of Noxa but not Bcl-2 resulted in increased sensitivity to ABT-737 in multiple cell lines. This increase was especially pronounced in the H209 cell line in which expression of Noxa resulted in a proportionate decline in Mcl-1 expression. Although overexpression of Noxa enhanced sensitivity of the H526 and H82 cell lines to ABT-737, it did not result in altered Mcl-1 levels. Similarly, small interfering RNA-mediated knockdown of Noxa expression in the H146 cell line, which increased resistance to ABT-737, did not result in altered Mcl-1 levels. Therefore, three of four cell lines studied failed to show Noxa-mediated regulation of Mcl-1 expression. However, despite failure to regulate Mcl-1 levels, Noxa blocked binding of Bim to Mcl-1 following its release from Bcl-2 by ABT-737. Finally, we observed that a 24-hour incubation of the H526 and WBA cell lines with ABT-737 resulted in increased Noxa expression, suggesting that Noxa may play a direct role in ABT-737-mediated apoptosis. These results indicate that Noxa expression is the critical determinant of ABT-737 sensitivity and loss of Noxa-mediated regulation of Mcl-1 expression may be an important feature of small cell lung cancer biology. [Mol Cancer Ther 2009;8(4):883-92]

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