Citations

7510 Background: We previously demonstrated that PFS may be a candidate surrogate endpoint for OS in ES-SCLC using data from 3 randomized trials (Foster, Cancer 2011). Here, we sought to formally assess the patient- and trial-level surrogacy of PFS using data from 9 additional randomized phase II and III trials conducted by the NCI-funded cancer cooperative groups since 1986. Methods: Individual patient data from all 12 trials (3178 patients: 9 phase III and 3 phase II) were pooled. OS was the primary endpoint in all phase III trials; 3 phase III and 1 phase II trial were positive per protocol. Patient-level surrogacy (Kendall’s tau) was assessed using the Clayton copula bivariate survival model. Trial-level surrogacy was assessed via association of the log hazard ratios on OS and PFS across trials, including: weighted (by trial size) least squares regression of Cox model effects (R² WLS) and weighted (by trial size) correlation of the copula effects (R² Copula). One trial had 4 treatment arms thus 14 total two-arm comparisons were made. Results: With a median follow-up of 41.8 months in the 106 patients still alive, the median OS and PFS across trials were 9.7 months (95% CI: 9.5, 9.9) and 5.7 months (95% CI: 5.5, 5.8), respectively. There were 3120 PFS events in total (2564 disease progressions and 556 deaths without progression). The median time from progression to death was 4.1 months (95% CI: 3.9, 4.3). PFS showed modest association with OS at the patient-level (tau= 0.56) and at the trial-level (R² WLS = 0.58; R² Copula (standard error) = 0.55 (0.29)). The 95% CIs for the predicted HR for OS given observed HR on PFS under a weighted leave-one-out prediction always included the observed HR for OS; however such intervals were wide, suggesting uncertainty on the practical use of PFS as a surrogate for OS in this setting. Conclusions: PFS failed to demonstrate surrogacy for OS in ES-SCLC based on this large pooled analysis. Given that the difference in the median PFS and OS is less than 6 months, we recommend using OS as the primary endpoint in phase III trials of previously untreated ES-SCLC.

7007 Background: In 2004, preliminary results of CALGB 9633 demonstrated statistically significant evidence that adjuvant chemotherapy with paclitaxel and carboplatin (PC) improved disease-free (DFS) and overall survival (OS) in resected stage IB NSCLC. Indeed, the study was closed early by the DSMB after a planned interim analysis demonstrated a p value for OS less than a prespecified stopping boundary. However, two larger trials, NCIC-JBR10 and ANITA, have shown significant OS advantages with adjuvant chemo, but failed to demonstrate improved survival in the stage IB subset. This report provides more mature data from CALGB 9633. Methods: InCALGB 9633, stage IB patients (pts) were randomized following resection to paclitaxel 200 mg/m2 and carboplatin AUC 6 q3wks ×4 cycles or to observation. While initially planned to accrue 500 pts, the accrual rate was <50% of expected. Because slow accrual allowed longer observation times for each pt, the accrual target was reduced to 384 pts. OS is the primary endpoint. The redesigned study had 80% power to detect a hazard ratio (HR) of 0.67 after 150 observed deaths using a 1-tailed logrank test conducted at the 0.05 level of significance. Results: Between 9/15/96 and 11/26/03, 344 pts were randomized. Median follow-up is 54 mo. Demographics and toxicity has been previously reported (JCO Sup, 22:621a, 2004). The current intent-to-treat analysis shows a significant improvement in DFS favoring adjuvant chemo (HR=0.74; 90% 2-sided CI: 0.57–0.96; p=0.027). There is a trend toward improvement in OS that is not significant (HR=0.80; 90% CI: 0.60–1.07; p=0.10). There is, however, a significant advantage in 3-yr survival (79% vs. 70%; p=0.045). Five-yr survival is not different (60% vs. 57%; p=0.32), although median follow-up is <5 yrs and CIs are wide. Continued follow-up is planned since only 131 of 150 deaths required for final analysis have been observed. Conclusions: This updated but “preliminary” analysis no longer shows a significant OS advantage for adjuvant chemotherapy in stage IB NSCLC. However, the re-designed study does not have adequate power to detect small differences in OS that may be clinically significant. Advantages in DFS and 3-yr survival support continued consideration of adjuvant PC in stage IB NSCLC. [Table: see text]

Background Platinum and etoposide with thoracic radiation followed by prophylactic cranial irradiation constitute the standard treatment for limited‐stage small cell lung cancer (LS‐SCLC). Many patients with LS‐SCLC are elderly with comorbidities. Methods Individual patient data were collected from 11 phase 2 or 3 trials for LS‐SCLC conducted by the National Clinical Trials Network and activated from 1990 to 2010. The primary endpoint was overall survival (OS); the secondary endpoints were progression‐free survival (PFS), the rate of severe adverse events, and off‐treatment reasons. The outcomes were compared for patients 70 years old or older (elderly patients) and patients younger than 70 years (younger patients). Results Individual patient data from 1049 younger patients (81%) and 254 elderly patients (19%) were analyzed. In the multivariate model, elderly patients, in comparison with younger patients, had worse OS (hazard ratio [HR], 1.38; 95% confidence interval [CI], 1.18‐1.63; median OS for elderly patients, 17.8 months; OS for younger patients, 23.5 months) and worse PFS (HR, 1.19; 95% CI, 1.03‐1.39; median PFS for elderly patients, 10.6 months; median PFS for younger patients, 12.3 months). Elderly patients, in comparison with younger patients, experienced more grade 5 adverse events (8% vs 3%; P < .01) and more grade 3 or higher dyspnea (11% vs 7%; P = .03) but less grade 3 or higher esophagitis/dysphagia (14% vs 19%; P = .04) and less grade 3 or higher vomiting (11% vs 17%; P = .01). Elderly patients completed treatment less often, discontinued treatment because of adverse events and patient refusal more frequently, and died during treatment more frequently. Conclusions Elderly patients with LS‐SCLC have worse PFS and OS and more difficulty in tolerating therapy. Future trials should incorporate assessments of elderly patients, novel monitoring of adverse events, and more tolerable radiation and systemic therapies.

Abstract Purpose The aim of this study was to investigate whether progression-free survival (PFS) can be considered a surrogate endpoint for overall survival (OS) in malignant mesothelioma. Materials and Methods Individual data were collected from 15 Cancer and Leukemia Group B (615 patients) and 2 North Central Cancer Treatment Group (101 patients) phase II trials. The effects of 5 risk factors for OS and PFS, including age, histology, performance status (PS), white blood cell count, and European Organisation for Research and Treatment of Cancer (EORTC) risk score, were used in the analysis. Individual-level surrogacy was assessed by Kendall’s tau through a Clayton bivariate Copula survival (CBCS) model. Summary-level surrogacy was evaluated via the association between logarithms of the hazard ratio (log HR)—log HROS and log HRPFS—measured in R2 from a weighted least-square (WLS) regression model and the CBCS model. Results The median PFS for all patients was 3.0 months (95% confidence interval [CI], 2.8–3.5 months) and the median OS was 7.2 months (95% CI, 6.5–8.0 months). Moderate correlations between PFS and OS were observed across all risk factors at the individual level, with Kendall’s tau ranging from 0.46 to 0.47. The summary-level surrogacy varied among risk factors. The Copula R2 ranged from 0.51 for PS to 0.78 for histology. The WLS R2 ranged from 0.26 for EORTC and PS to 0.67 for age. Conclusions The analyses demonstrated low to moderate individual-level surrogacy between PFS and OS. At the summary level, the surrogacy between PFS and OS varied significantly across different risk factors. With a short postprogression survival and a moderate correlation between PFS and OS, there is no evidence that PFS is a valid surrogate endpoint for OS in malignant mesothelioma.