Intratumor therapy in rodents with aqueous clam extracts.

A therapeutic effect was observed when an aqueous extract of the common clam (Mercenaria mercenaria) was injected directly into and around small, superficial, and slowly growing solid s.c. adenovirus 12 and SV40 virus-induced tumors in hamsters. The treatment was given daily or at selected intervals. Half of 74 treated hamsters showed complete tumor regression within 4 weeks after the 1st injection. No systemic toxicity was evident. The hamsters were apparently normal during an observation period of 4 to 9 months following tumor regression. The remaining treated tumors grew after partial regression and killed the hosts. In parallel control studies, 75 tumor-bearing hamsters either were untreated or were treated with various placebos, including 8.5% NaCl solution and heated clam extract. All these control tumors grew to a large size and killed the hamsters. A limited number of melanomas in CDF1 mice were similarly treated with clam extract, and one-third showed complete regression.