Intratumoral injection of a streptococcal preparation, OK-432, before surgery for gastric cancer : a randomized trial

Background. The preoperative intratumoral injection with OK-432 (Picibanil, Chugai Pharmaceutical Co., Tokyo, Japan), an immunomodulatory agent prepared from an attenuated strain of streptococcus pyogenes, activates the regional immune system and causes degeneration of cancer tissue in carcinoma of the stomach. Methods. A multi-institutional randomized trial of OK-432 to determine its clinical usefulness was conducted. Three hundred and ninety-five patients with gastric cancer were assigned randomly either to receive or not to receive a preoperative intratumoral injection of OK-432. Among them, 277 patients with advanced cancer were treated by common postoperative chemoimmunotherapy consisting of mitomycin C, tegafur, and OK-432. All patients were followed for at least 5 years. Results. The adverse effects of OK-432 injected intratumorally predominantly were mild fever, anorexia, and abdominal pain, however, no treatment was required for these symptoms. Overall, there were no differences in outcome between the OK-432 and control groups. However, analysis based on stage showed that a preoperative intratumoral injection of OK-432 significantly improved the 5-year survival rate of patients with Stage III cancer (P = 0.0229), at 47.7% for the OK-432 group and 27.5% for the control group. In subset analysis, when the 5-year survival of patients with and without tumor infiltrating lymphocytes (TIL) was compared, OK-432 injected intratumorally had a significant positive effect on the group showing a moderate to marked number of TIL (P = 0.0438). Conclusion. These results showed that the intratumoral injection of OK-432 may improve survival of patients with Stage III gastric cancer.