While compounds were discovered and synthesized that were somewhat radioprotective, no compound was found that was effective enough or non-toxic enough to suit their military purposes. When the results of their studies became public, medical researchers combed through their documents in search of compounds that might have a medically-related application. Medical researchers focussed on those compounds that offered the most significant radioprotective effects with the least physiologic toxicity. The effective agents were found to be among a class of anti-oxidant compounds known as aminothiols. Radiation therapy is one of the important and effective modalities of cancer treatment.
Radiation is utilized to eradicate malignant cells.
The interesting dilemma is that, in order for any compound to be useful it must affect the tumor and its surrounding normal tissues differentially, i.e., a radioprotectant must spare the normal tissue without increasing the radioresistance of the malignant tissue. If these opposite effects do not occur the compound would be of no value. Researchers determined that, in fact, such is the effect of WR-2721. WR-2721 protects normal tissue without significantly altering the radiosensitivity of the tumor. The mechanism of this effect is still unclear but it may be that the free radical scavenging WR-2721 reaches the normal tissue sooner after injection than it does the tumor, which usually has a deficient blood supply.