Multicenter randomized controlled phase III clinical trial using TNFerade (TNF) with chemoradiation (CRT) in patients with locally advanced pancreatic cancer (LAPC): Interim analysis (IA) of overall survival (OS)
4605 Intro: Local control of LAPC with CRT has historically demonstrated survival benefit vs. RT alone. TNF is a nonreplicating adenovirus vector delivering human tumor necrosis factor (TNF-α). Results from a phase II study with TNF in LAPC indicated a possible survival advantage. To confirm these findings, a randomized, open-label, controlled Pancreatic Cancer Trial with TNF (PACT) study was developed. Methods: The TNF arm received a 5 wk treatment of qw intratumoral inj of 4x1011 PU TNF, cont. iv 5-FU and 50.4Gy radiation. The standard of care (SOC) arm received CRT alone. Both groups received adjuvant gemcitabine(G) with the option of erlotinib(E). An IA of OS (primary efficacy endpoint) was planned after the first third (92) of the expected 276 total death events (from a total patient n=330). Nonparametric logrank of OS was planned; in addition, a lognormal model was used to account for an evident separation of the survival curves after the median. Results: 185 pts were available for OS analysis (117-TNF+SOC and 68-SOC). Survival in the TNF+SOC group demonstrated a HR of 0.753 (CI [0.494 - 1.15]) relative to SOC. Best fit parametric lognormal analysis indicated a median survival of 11.1 mo with TNF+SOC and 8.7 mo with SOC; nonparametric methods indicated a MS of 9.9 mo for both arms, with a pronounced “late effect” (75th percentile 19.4 mo with TNF+SOC and 11.8 mo with SOC). Prognostic information (G and E use, stage, etc) indicated equivalent distribution between groups. Conclusions: HR results of the OS IA indicate an encouraging trend in favor of the TNF treated group. Parametric medians may better reflect the true HR than nonparametric methods since the latter do not reflect the shape of the OS distribution. A second IA is planned after 2/3 total events. [Table: see text]