CellAct's first clinical drug candidate is a small molecule compound, named CAP7.1, which targets Topoisomerase II. CAP7.1 has completed a Phase I study in adults with endstage cancer disease and is currently in clinical Phase II studies for the treatment of therapy-refractory solid tumors, such as lung-and biliary cancer diseases.

In Phase I, CAP7.1 showed promising safety and tolerability following administration in adults with heavily pretreated solid tumors. In addition, signs of efficacy of CAP7.1 treatment were observed in the majority of treated patients, thereby indicating overall survival prolongation for patients with cancers of lung, hypopharnyx, ovarian, testicular, stomach, esophageal, biliary tract and neuroendocrine tumor of skin. Stable disease in this study was reported in 68% of patients, compared to a median of 30% in comparable cancer studies.

Topoisomerases - The topoisomerases are a class of enzymes that are used in the body to maintain control of cell transcription and replication. They act by transiently cutting one or both strands of DNA. Topoisomerase type I cuts one strand whereas topoisomerase type II cuts both strands of DNA. Topoisomerase-active antitumor drugs interfere with the natural cutting and rejoining of DNA strands. The high cellular level of topoisomerase II in some tumors may partly explain the high therapeutic index of this class of antitumor drugs.