Comparison of the antitumor effects of a synthetic biopolymer and standard adjuvants.

The synthetic biopolymer NED 137 is capable of stimulating an immune response to tumor antigen. This article compares the efficacy of NED 137 to bacille Calmette-Guerin, Corynebacterium parvum, pyran, levamisole, and Freund's complete adjuvant in a rat tumor model where adjuvant treatment is administered after excision of subcutaneous tumor implants. A single intraperitoneal injection of NED 137 at 30 mg/kg body weight prolonged survival beyond 60 days with no evidence of recurrent or metastatic disease, whereas with the other adjuvants, animals survived a mean of 30 to 40 days with 100% local recurrence and a 60% to 90% incidence of pulmonary metastases. Use of NED 137 resulted in a greater lysis of tumor cells compared to other adjuvants when assessed in an in vivo 51Cr release assay. A phase I clinical study of high-risk gastrointestinal cancer patients treated with NED 137 is reported at a median survival time of 23 weeks (103 patients). This group is compared to a historical control group from the same institution. No NED 137-related toxicity has been noted to date.