Acronyms in medicine are often a hoot. We have the four-drug combination called FOLFIRINOX. Recently, here at Pancreatica we reported on a study of a three-drug version of the above termed: OFF. Now comes a review of the regimen of S-1 plus oxaliplatin by Japanese researchers, which combination they term: SOX. In a sense SOX is very similar to OFF, as both regimens essentially involve the coupling of a thymidylate synthase inhibitor (TS-inhibitor) together with oxaliplatin (platinum drug). Also, they are both abbreviated forms of FOLFIRINOX.
S-1 is given orally, and is a formulation of the chemo drug tegafur with added modulators: gimeracil and oteracil. S-1 is a TS-inhibitor, and a pro-drug of fluorouracil which functionally becomes 5-FU when metabolized. It has been studied extensively in Japan, and there has been approved for use in treatment of stomach cancer, colo-rectal cancer, biliary cancer, head and neck cancer, non-small cell lung cancer, metastatic breast cancer, and pancreatic cancer. S-1 is also under study in the U.S.
Koike and colleagues from the University of Tokyo published the results of their research in the November issue of the journal Cancer Chemotherapy and Pharmacology which reviews the results of the SOX regimen given after patients with advanced pancreatic cancer were deemed refractory to initial treatment with gemcitabine. 30 patients with advanced pancreatic cancer were given the S-1 plus oxaliplatin regiment as second line over a two year period. The median progression-free survival duration was 5.6 months, and the median overall survival duration was found to be 9.1 months. The side-effects were adjudged to present a reasonable profile.
The authors conclude that the SOX regimen is a reasonably effective option as second-line treatment for pancreatic cancer.
Dale O’Brien, MD