1. Thymidylate Synthase Expression and Outcome of Patients Receiving Pemetrexed for Advanced Nonsquamous Non–Small-Cell Lung Cancer in a Prospective Blinded Assessment Phase II Clinical Trial
- Author
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Dean A. Fennell, Tuan S. Nguyen, Carla Visseren-Grul, Keith M. Kerr, R. Shah, Marianne Nicolson, Geraldine Skailes, David Ferry, Paul D. Taylor, Vanessa Potter, Scott P. Myrand, Kenneth J. O'Byrne, Sunil Upadhyay, Valerie Andre, and Mayukh Das
- Subjects
Oncology ,Adult ,Male ,Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Guanine ,Lung Neoplasms ,Phases of clinical research ,Pemetrexed ,Adenocarcinoma ,Real-Time Polymerase Chain Reaction ,Thymidylate synthase ,Immunoenzyme Techniques ,Glutamates ,Internal medicine ,Carcinoma, Non-Small-Cell Lung ,Antineoplastic Combined Chemotherapy Protocols ,medicine ,Clinical endpoint ,Humans ,Prospective Studies ,RNA, Messenger ,Prospective cohort study ,Lung cancer ,Survival rate ,Aged ,Neoplasm Staging ,biology ,business.industry ,Reverse Transcriptase Polymerase Chain Reaction ,Hazard ratio ,Thymidylate Synthase ,Middle Aged ,medicine.disease ,Prognosis ,Surgery ,Survival Rate ,biology.protein ,Female ,Cisplatin ,Neoplasm Recurrence, Local ,business ,medicine.drug ,Follow-Up Studies - Abstract
Full-text article is free to read on the publisher website. INTRODUCTION In retrospective analyses of patients with nonsquamous non-small-cell lung cancer treated with pemetrexed, low thymidylate synthase (TS) expression is associated with better clinical outcomes. This phase II study explored this association prospectively at the protein and mRNA-expression level. METHODS Treatment-naive patients with nonsquamous non-small-cell lung cancer (stage IIIB/IV) had four cycles of first-line chemotherapy with pemetrexed/cisplatin. Nonprogressing patients continued on pemetrexed maintenance until progression or maximum tolerability. TS expression (nucleus/cytoplasm/total) was assessed in diagnostic tissue samples by immunohistochemistry (IHC; H-scores), and quantitative reverse-transcriptase polymerase chain reaction. Cox regression was used to assess the association between H-scores and progression-free/overall survival (PFS/OS) distribution estimated by the Kaplan-Meier method. Maximal χ analysis identified optimal cutpoints between low TS- and high TS-expression groups, yielding maximal associations with PFS/OS. RESULTS The study enrolled 70 patients; of these 43 (61.4%) started maintenance treatment. In 60 patients with valid H-scores, median (m) PFS was 5.5 (95% confidence interval [CI], 3.9-6.9) months, mOS was 9.6 (95% CI, 7.3-15.7) months. Higher nuclear TS expression was significantly associated with shorter PFS and OS (primary analysis IHC, PFS: p < 0.0001; hazard ratio per 1-unit increase: 1.015; 95%CI, 1.008-1.021). At the optimal cutpoint of nuclear H-score (70), mPFS in the low TS- versus high TS-expression groups was 7.1 (5.7-8.3) versus 2.6 (1.3-4.1) months (p = 0.0015; hazard ratio = 0.28; 95%CI, 0.16-0.52; n = 40/20). Trends were similar for cytoplasm H-scores, quantitative reverse-transcriptase polymerase chain reaction and other clinical endpoints (OS, response, and disease control). CONCLUSIONS The primary endpoint was met; low TS expression was associated with longer PFS. Further randomized studies are needed to explore nuclear TS IHC expression as a potential biomarker of clinical outcomes for pemetrexed treatment in larger patient cohorts. © 2013 by the International Association for the Study of Lung Cancer.
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- 2013
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