Patient reported abdominal pain as a surrogate of the clinical benefit of tipifarnib in pancreatic cancer patients.
275 Background: Tumor CXCL12 expression identifies patients who may benefit from tipifarnib therapy. In pancreatic cancer, CXCL12 is known to decrease abdominal pain by inducing the migration of pain suppressing Schwann cells to tumor lesions. Given the association between CXCL12 and pain suppression, we investigated whether the absence of patient reported abdominal pain could be a surrogate of clinical benefit from tipifarnib in pancreatic cancer patients. Methods: We conducted a retrospective analysis of a randomized placebo-controlled trial comparing gemcitabine plus tipifarnib (GT) versus gemcitabine plus placebo (GP) in pancreatic adenocarcinoma patients. Tipifarnib was given at 200 mg bid orally continuously; gemcitabine at standard dosing. Primary study end point was overall survival. Results: 688 patients were enrolled of whom 155 (22.5%) reported no abdominal pain at study entry, 81 received GT and 74 GP. Baseline characteristics were balanced in the subset of patients with no reported abdominal pain (GT,GP): median age (63,59), female gender (35%,43%), ECOG 0-1 (89%,90%), metastatic disease (64%,70%), 6-month weight loss >10% (48%,39%), 6-month jaundice history (51%,45%), and prior Whipple surgery (16%,13%). Subjects receiving GT who did not report abdominal pain at study entry had higher frequency of locally advanced disease (36% vs 24%) and 6-month jaundice (51% vs 38%), and lower frequency of lung (6% vs 14%) and peritoneum (4% vs 13%) metastases than those reporting pain. No differences in survival were observed in the overall study. Median overall survival for GT was 193 vs 182 days for GP. Notably, absence of abdominal pain at study entry was associated with higher median survival in the GT arm (no pain, pain): 305 vs 176 days, HR=0.52, p<0.0001, whereas no significant effect was observed in the control arm: 184 vs 182 days. A trend for better survival with GT was observed in subset of patients with no abdominal pain at study entry (GT,GP): 305 vs 184 days, p=0.058. Conclusions: Absence of abdominal pain may serve as a surrogate of clinical benefit from tipifarnib in pancreatic cancer. (Van Cutsem et al. JCO 2004;22:1430-8; NCT00005648; Trial Sponsor: J&J PRD). Clinical trial information: NCT00005648.