title: Does gastric acid suppression affect sunitinib efficacy in patients with advanced or metastatic renal cell cancer?
abstract: BACKGROUND
  Renal cell cancer is a chemotherapy-insensitive cancer treated by vascular endothelial growth factor receptor antagonists. Recently, a question has arisen on whether there is an interaction between tyrosine kinase inhibitors, such as sunitinib, and acid suppressing agents.
  
  
  METHODS
  A retrospective chart review was conducted for patients at two tertiary care centers who received sunitinib between 1 January 2006 and 31 March 2013. Using electronic systems and a province-wide electronic health records database, medication dispensing records were obtained. A univariate Cox's proportional hazard model determined if acid suppression had effects on progression-free survival and overall survival.
  
  
  RESULTS
  Of 383 patient charts reviewed, 231 were included in the study. Patients on intermittent acid suppression, lost to follow-up or received sunitinib for less than one week were excluded from the study. The median age of the study population was 65. Patients who received no acid suppression (n = 186) had a median progression-free survival of 23.6 weeks (95% CI, 19.0-31.9 weeks) and patients who received continuous acid suppression (n = 45) had a median progression-free survival of 18.9 weeks (95% CI, 11.0-23.7 p = 0.04). A median overall survival of 62.4 weeks (95% CI, 42.0-82.7 weeks) was observed in the group with no acid suppression, while a median overall survival of 40.9 weeks (95% CI, 26.1-74.4 weeks) was observed in the continuous acid suppression group (p = 0.02).
  
  
  CONCLUSIONS
  There was a significant difference in progression-free survival and overall survival between the acid suppressed and no acid suppression groups. Further research is required to confirm this potential interaction.
authors.affiliation: Pharmacy Department, Cross Cancer Institute, Canada Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Canada.
authors.forename: Vincent H
authors.initials: VH
authors.lastname: Ha
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Canada Pharmacy Department, Tom Baker Cancer Centre, Canada.
authors.forename: Margaret
authors.initials: M
authors.lastname: Ngo
authors.affiliation: Department of Medical Oncology, Cross Cancer Institute, Canada.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Chu
authors.affiliation: Experimental Oncology Department, Cross Cancer Institute, Canada.
authors.forename: Sunita
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Department of Medical Oncology, Cross Cancer Institute, Canada Michael.Sawyer@albertahealthservices.ca.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Sawyer
authors.affiliation: Pharmacy Department, Cross Cancer Institute, Canada.
authors.forename: Carole R
authors.initials: CR
authors.lastname: Chambers
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000863:Antacids / Q000009:adverse effects*; D002292:Carcinoma, Renal Cell / Q000188:drug therapy*; D018572:Disease-Free Survival; D004347:Drug Interactions / Q000502:physiology; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D007680:Kidney Neoplasms / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D011758:Pyrroles / Q000627:therapeutic use*; D012189:Retrospective Studies; D000077210:Sunitinib
chemical_list: D000863:Antacids; D007211:Indoles; D011758:Pyrroles; D000077210:Sunitinib
keywords: Sunitinib; overall survival; progression-free survival; proton pump inhibitors; renal cell cancer