Phase I study of MVE-2 evaluating toxicity and biologic response modification capability

Biological Effects and Antitumor Activity Induced by Benzocaine Conjugated Anionic Polymers

Three maleic anhydride copolymers [poly(maleic anhydride-vinyl acetate), poly(maleic anhydride-styrene) and poly(maleic anhydride-methyl methacrylate)] were prepared as well as the corresponding benzocaine conjugates. The maleic anhydride moiety was hydrolyzed to the corresponding polycarboxylate anions and then biologically evaluated using pyran copolymer as the standard. All of the polymers showed internal organ toxicity of the liver, kidneys and spleen which increased with increasing molecular weight, however, the benzocaine derivatives decreased this effect in most cases. The biological evaluations included hemoglobin levels, hematocrit levels, red blood indices and mean cell volumes which were increased on an average of 50%. The blood protein profiles were not changes significantly; on average they were changed about ±50%. The unmodified copolymers decreased the major serum and cholesterol levels by ∼75%. The copolymers (with or without) benzocaine decreased both the blood sugar and enzyme profiles. The antitumour activity was evaluated against Walker carcinosarconoma; although the benzocaine enhanced these effects, only pyran and the 18,000 Mw benzocaine-modified poly(maleic anhydride-vinyl acetate) produced significant effects.

Application of chemical immunomodulators to the treatment of cancer and AIDS

A number of potential advantages, development of promising new agents, and the discovery of synergy with cytokines or cell products continue to spur research into the application of chemical immunomodulators for the treatment of cancer and AIDS. In preclinical in vitro and in vivo systems, chemical immunomodulators definitely modulate the immune system and have therapeutic efficacy. Although clinical trials have shown the ability of these agents to modulate the human immune system, thus far chemical immunomodulators have generally not fulfilled the therapeutic promise generated in animal models for the treatment of human diseases. While the discrepancy in results between animal models and human trials is obvious, the basis is not apparent. Species differences in elimination kinetics, presentation of active drug at the site of action, and the development of tachyphylaxis have been postulated as reasons for the minimal activity of these agents in humans. In addition, the use of investigational techniques established for cytotoxic agents may not be appropriate for immunomodulators. As with any immunomodulator, determining an optimal immunostimulatory dose and schedule and applying the therapy to patients with minimal tumor burden would perhaps be more appropriate than use of a maximally tolerated dose in patients with advanced disease. A dose-immunological effect relationship has recently been demonstrated for levamisole at doses higher than those used for many years in levamisole trials (99). While research and clinical investigation have identified several potentially useful chemical immunomodulators, the elementary understanding of the biochemical mechanisms involved in immunoregulation remains basic. Future research must elucidate these mechanisms, particularly in humans, to maximize the benefits of chemical immunomodulators as single agents or combined with cytotoxic chemotherapeutic agents, surgery, radiation therapy, other immunomodulators, and antiviral agents.