But some impatient cancer researchers outside the trials took the seeming lack of toxicity as a bad sign, an indication that the drug wasn't working. That's the way our drugs work. But this drug was different. It wasn't chemotherapy. It wasn't poison.
Drugs used in chemotherapy are toxic, but antiangiogenic drugs work in a completely different way.
Signs of improvement Little by little, as the doses of endostatin were increased during the winter, a few reports began to leak out of the three medical centers that a few patients were doing better. In addition to the complete lack of toxicity, the doctors were saying quietly to each other that in some patients the tumors seemed to have stopped growing. Word from the clinic was that he was feeling so good, despite being an end-stage cancer patient, that he would come in for his daily injection and then head off to work. And he was not alone in showing progress. Tests indicated that the interior of her tumor was deteriorating, as if it were liquefying and dying.