[The Case of a Patient with Gastric Cancer Who Showed No Neutropenia Only When Using the Generic S-1 Adjuvant Chemotherapy Formulation].

ABSTRACT

We report the case of a 72-year-old female who underwent laparoscopic total gastrectomy for gastric cancer. The pathological diagnosis was pT3, N1, M0, pStage II B. She received adjuvant chemotherapy with the TS-1®combination OD tablet, beginning 48 days after gastrectomy. The first course was stopped at day 7 because of neutropenia. The dose was decreased, a second course was started, and the patient completed her second course without neutropenia. After completion of the second course, we discovered that she had taken generic drugs(NKS-1®combination OD tablet)during the second course. She was enrolled in a clinical trial in which the administration of generic drugs was not permitted, as per the protocol. Beginning with the third course, we once again treated her with TS-1, and we observed a return of neutropenia in every subsequent course. We decreased the dose of TS-1 and changed the administration schedule each time. She exhibited no neutropenia only when using the generic S-1 formulation. It is possible that the anti-tumor effect of the generic S-1 formulation, and its associated adverse events, are not identical to the innovator formulation.