| Study | Agent | Subject and level of evidence | Patients n | RR % | PFS months | HR (95% CI) | OS months | HR (95%CI) | Interaction p-value |
| Douillard [16] (INTEREST Study) | Gefitinib | RCT and PRES second-line: gefitinib versus docetaxel | High 158 | 13 gefitinib versus 7.4 docetaxel; p = 0.04 | 2.5 versus 2.8 | 0.84 (0.59–1.19); p = 0.33 | 8.4 versus 7.5 | 1.09 (0.78–1.51); p = 0.62 | OS: p = 0.52 |
| Low 179 | NA | 2.1 versus 2.8 | 1.30 (0.93–1.83); p = 0.12 | 6.4 versus 7.7 | 0.93 (0.68–1.26); p = 0.64 | ||||
| Hirsch [17] (ISEL Study) | Gefitinib | RCT and URES second- or third-line: gefitinib versus placebo | High 114 | 16.4 gefitinib versus 3.0 placebo; p = NA | 4.5 versus 1.9 | 0.55# (0.34–0.89); p = NA | 8.3¶ versus 4.5 | 0.61 (0.36–1.04); p = 0.067 | NA |
| Low 256 | 3.2 versus 0; p = NA | 2.4 versus 3.9 | 1.25# (0.92–1.72); p = ns | 4.3¶ versus 6.2 | 1.16 (0.81–1.64); p = 0.417 | NA | |||
| Tsao [18] (BR21 Study) | Erlotinib | RCT and PRES second- or third-line: erlotinib versus placebo | High 25 | 5 versus 1; p = 0.03 | NA | NA | NA | 0.44 (0.23–0.82); p = 0.008 | OS: p = 0.10 |
| Low 41 | 0.59 (0.48–1.51); p = 0.85 |
RR: response rate; PFS: progression-free survival; HR: hazard ratio; OS: median overall survival; INTEREST: Iressa NSCLC Trial Evaluating Response and Survival Versus Taxotere; RCT: randomised clinical phase III trial; PRES: pre-planned retrospective exploratory study; NA: not available; ISEL: Iressa Survival Evaluation in Lung Cancer; URES: unplanned retrospective exploratory study; ns: nonsignificant difference. NA: not available; #: time to treatment failure; ¶: gefitinib group: high versus low: HR 0.78 (95% CI 0.54–1.13); p = ns.