Alectinib versus chemotherapy in crizotinib-pretreated anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer: results from the phase III ALUR study

Background

This is the first trial to directly compare efficacy and safety of alectinib versus standard chemotherapy in advanced/metastatic anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC) patients who have progressed on, or were intolerant to, crizotinib.

Patients and methods

ALUR (MO29750; NCT02604342) was a randomized, multicenter, open-label, phase III trial of alectinib versus chemotherapy in advanced/metastatic ALK-positive NSCLC patients previously treated with platinum-based doublet chemotherapy and crizotinib. Patients were randomized 2 : 1 to receive alectinib 600 mg twice daily or chemotherapy (pemetrexed 500 mg/m² or docetaxel 75 mg/m², both every 3 weeks) until disease progression, death, or withdrawal. Primary end point was investigator-assessed progression-free survival (PFS).

Results

Altogether, 107 patients were randomized (alectinib, n = 72; chemotherapy, n = 35) in 13 countries across Europe and Asia. Median investigator-assessed PFS was 9.6 months [95% confidence interval (CI): 6.9–12.2] with alectinib and 1.4 months (95% CI: 1.3–1.6) with chemotherapy [hazard ratio (HR) 0.15 (95% CI: 0.08–0.29); P < 0.001]. Independent Review Committee-assessed PFS was also significantly longer with alectinib [HR 0.32 (95% CI: 0.17–0.59); median PFS was 7.1 months (95% CI: 6.3–10.8) with alectinib and 1.6 months (95% CI: 1.3–4.1) with chemotherapy]. In patients with measurable baseline central nervous system (CNS) disease (alectinib, n = 24; chemotherapy, n = 16), CNS objective response rate was significantly higher with alectinib (54.2%) versus chemotherapy (0%; P < 0.001). Grade ≥3 adverse events were more common with chemotherapy (41.2%) than alectinib (27.1%). Incidence of AEs leading to study-drug discontinuation was lower with alectinib (5.7%) than chemotherapy (8.8%), despite alectinib treatment duration being longer (20.1 weeks versus 6.0 weeks).

Conclusion

Alectinib significantly improved systemic and CNS efficacy versus chemotherapy for crizotinib-pretreated ALK-positive NSCLC patients, with a favorable safety profile.

Trial registration

ClinicalTrials.gov NCT02604342; Roche study MO29750

Chromosome 5 imbalance mapping in breast tumors from BRCA1 and BRCA2 mutation carriers and sporadic breast tumors

Comparative genomic hybridization (CGH) analysis has shown that chromosome 5q deletions are the most frequent aberration in breast tumors from BRCA1 mutation carriers. To map the location of putative 5q tumor suppressor gene(s), 26 microsatellite markers covering chromosome 5 were used in loss of heterozygosity (LOH) analysis of breast tumors from BRCA1 (n = 42) and BRCA2 mutation carriers (n = 67), as well as in sporadic cases (n = 65). High-density array CGH was also used to map chromosome 5 imbalance in 10 BRCA1 tumors. A high LOH frequency was found in BRCA1 tumors (range 19-82%), as compared to BRCA2 and sporadic tumors (ranges 11-44% and 7-43%, respectively). In all, 11 distinct chromosome 5 regions with LOH were observed, the most frequent being 5q35.3 (82%), 5q14.2 (71%) and 5q33.1 (69%) in BRCA1 tumors; 5q35.3 (44%), 5q31.3 (43%) and 5q13.3 (43%) in BRCA2 tumors and 5q31.3 (43%) in sporadic tumors. Array CGH analysis confirmed the very high frequency of 5q deletions, including candidate tumor suppressor genes such as XRCC4, RAD50, RASA1, APC and PPP2R2B. In addition, 2 distinct homozygous deletions were identified, spanning regions of 0.7-1.5 Mbp on 5q12.1 and 5q12.3-q13.1, respectively. These regions include only a few genes, most notably BRCC3/DEPDC1B (pleckstrin/G protein interacting and RhoGAP domains) and PIK3R1 (PI3 kinase P85 regulatory subunit). Significant association (p < or = 0.05) was found between LOH at certain 5q regions and factors of poor prognosis, including negative estrogen and progesterone receptor status, high grade, large tumor size and high portion of cells in S-phase. In conclusion, our results confirm a very high prevalence of chromosome 5q alterations in BRCA1 tumors, pinpointing new regions and genes that should be further investigated.

Deletions on chromosome 4 in sporadic and BRCA mutated tumors and association with pathological variables

BACKGROUND

Chromosomal aberrations in breast tumors from BRCA1 and BRCA2 germ-line mutation carriers are considerably more frequent than what is seen in sporadic breast tumors. According to Comparative Genomic Hybridisation analysis (CGH), deletions on chromosome 4 are one of the most frequent events in BRCA1-associated tumors, suggesting inactivation of specific tumor suppressor genes.

MATERIALS AND METHODS

In the present study, 16 microsatellite markers covering chromosome 4 were used to map loss of heterozygosity (LOH) in tumors from BRCA1 (n=41) as well as in tumors from BRCA2 (n=66) mutation carriers and in tumors from unselected cases of breast cancer (n =68).

RESULTS

The frequency of LOH in these groups ranged from 16-73% in BRCA1-associated tumors, 13-42% in BRCA2-associated tumors and 8-33% in unselected tumors. LOH was significantly more frequent in BRCA1-associated tumors as compared to BRCA2-associated tumors and unselected tumors, and particularly high (over 70%) at 4q35.2. Pathological variables that were found significantly associated (p< or =0.05) with LOH at specific markers were: high percentage of cells in S-phase, negative estrogen receptor status, young age at diagnosis and large tumors. Deletion mapping indicates the existence of seven non-overlapping regions at chromosome 4, which were identified in all three groups of tumors. Three of these seven regions, 4p16.3-p16.1, 4q27-q32.1 and 4q35.1-4qter, have not been reported in breast cancer previously.

CONCLUSION

The results manifest the frequent alterations of chromosome 4 in BRCA1-associated breast tumors and indicate the location of several genes of potential importance in breast cancer development.