Study – CAP7.1

CAP7.1 is an inactive version of an existing anticancer agent called etoposide, which becomes active in the body via specific enzymes. It works by targeting an enzyme in the body called topoisomerase II, which cuts strands of DNA in the cancer cells and so stops them replicating. CAP7.1 is currently being investigated in a randomized, multicenter, proof-of-concept phase II study in adults with refractory biliary tract carcinomas. Clinical studies are conducted to ensure that a new drug is safe and effective before, if approval is granted, being available to a wider patient population.

In the study, patients receive either CAP7.1 or the best supportive care according to the standard practice of each participating institution. When progressive disease is seen in the supportive care group, a change to the CAP7.1 study arm is possible.
Primary efficacy of the study is defined as the disease control rate RECIST criteria:

• complete remission
• partial remission
• no disease progression

Etoposide release following CAP7.1 administration

It is believed that the biochemical mechanism of etoposide release following CAP7.1 administration is responsible for positive effects in the treatment of advanced tumours seen in previous clinical studies. The enzyme, carboxylesterase, responsible for the conversion of CAP7.1 to the active agent is found in particularly high concentrations in the liver. A high dose of ‘undisguised’ etoposide is therefore probably released site-specifically and can more easily target biliary tract carcinoma cancer cells.

Patients with biliary tract carcinomas and other gastrointestinal cancers from previous studies appear to have benefited from treatment with CAP7.1.