• Clinical experience with gefitinib in Indian patients.

      Parikh, Purvish; Chang, Alex; Nag, Shona; Digumarti, Raghunadharao; Bhattacharyya, Gouri Shankar; Doval, Dinesh Chandra; Babu, Govind; Chacko, Raju Titus; Advani, Suresh; Ranade, Anantbhushan; et al. (2008-04)
      INTRODUCTION: Treatment options are limited in patients with advanced or refractory non-small cell lung cancer and lead to suboptimal outcome and/or benefit. The epidermal growth factor tyrosine kinase inhibitor gefitinib (IRESSA) has been approved in many countries. Increased responsiveness to gefitinib has been demonstrated in particular subsets of patients, for example never smokers and patients of Asian origin. However, to date, little is known of its use specifically in patients from India. METHODS: Retrospective ad hoc analysis of clinical data from experience with gefitinib in patients with advanced NSCLC from India enrolled in the IRESSA Survival Evaluation in Lung (ISEL) study (n = 77) or included in the gefitinib expanded-access program in India (n = 133). RESULTS: Among Indian patients enrolled in the ISEL study, median survival was 6.4 months with gefitinib and 5.1 month with placebo. The objective response rate in Indian patients was 14% with gefitinib versus 0% with placebo. In ISEL, tolerability data from Indian patients were consistent with the overall study population. In the Indian gefitinib expanded-access program, median survival was 6 months and gefitinib was well tolerated. CONCLUSIONS: Gefitinib seems well tolerated in Indian patients with advanced NSCLC, with some clinical benefit observed.
    • Epidermal growth factor receptor immunohistochemistry: comparison of antibodies and cutoff points to predict benefit from gefitinib in a phase 3 placebo-controlled study in advanced nonsmall-cell lung cancer.

      Hirsch, Fred R; Dziadziuszko, Rafal; Thatcher, Nick; Mann, Helen; Watkins, Claire; Parums, Dinah V; Speake, Georgina; Holloway, Brian; Bunn, Paul A; Franklin, Wilbur A; et al. (2008-03-01)
      BACKGROUND: The ISEL (Iressa Survival Evaluation in Lung Cancer) clinical trial evaluated the efficacy of gefitinib versus placebo in pretreated nonsmall-cell lung cancer patients. Two different antibodies, scoring systems, and cutoff points of epidermal growth factor receptor (EGFR) protein expression were compared to predict response and survival of enrolled patients. METHODS: EGFR expression was assessed in tumor samples by immunohistochemistry using the Dako EGFR pharmDx kit (scoring percent of tumor cells with positive staining) and Zymed monoclonal antibody clone 31G7 (scoring staining index derived from proportion of positive cells times staining intensity). RESULTS: Data for EGFR expression were available for 379 patients for Dako and 357 patients for Zymed antibody (22% and 21%, respectively, of trial population). Objective response rates in gefitinib-treated EGFR-positive patients defined with various cutpoints with Dako antibody varied between 8% and 12%, and with Zymed antibody between 10% and 13%. Lower cutoff points with Dako antibody provided the best discrimination between EGFR-positive and EGFR-negative patients for survival hazard ratios comparing gefitinib to placebo, with a significant treatment/cutoff point interaction for 10% cutoff point (P = .049). A similar but less apparent trend was noted for Zymed antibody, although the discrimination between hazard ratios was not significant for any cutoff point analyzed. CONCLUSIONS: Assessment with the Dako PharmDx kit and percentage of cells with positive staining may provide more accurate prediction of differential effect on survival with gefitinib than assessment with Zymed antibody and staining index. Using higher cutpoints to define positivity does not improve test discrimination.