Results from a recent clinical trial indicate that rubitecan (Orathecin™), an oral chemotherapy agent, may be effective for the treatment of refractory pancreatic cancer.
The pancreas is an organ that is surrounded by the stomach, small intestine, bile ducts (tubes that connect the liver to the small intestine), gallbladder, liver and spleen. The pancreas helps the body to break down food and produces hormones, such as insulin, to regulate the body’s storage and use of food. Standard treatment for pancreatic cancer includes surgery, chemotherapy (typically including Gemzar®) and/or radiation. Refractory pancreatic cancer refers to cancer that has stopped responding to standard therapies. Patients with refractory pancreatic cancer are considered incurable and current treatment is aimed at extending survival time and improving a patient’s quality of life by alleviating symptoms caused by pancreatic cancer, including pain and extreme weight loss.
Rubitecan is a novel chemotherapy agent that can be taken orally. It is classified as a topoisomerase I inhibitor and belongs to the same group of chemotherapy agents as Camptosar® and Hycamptin®. Rubitecan works by inhibiting the replication of cells by inhibiting DNA replication. DNA is the genetic material found in all cells. When cells are not replicating or producing proteins, the DNA within a cell is wound tightly upon itself. Topoisomerases are enzymes (proteins) that unwind DNA so that DNA can be replicated and then re-wind DNA to its stable form after replication. Rubitecan inhibits topoisomerase I so that DNA cannot be unwound and therefore, cannot replicate. Since cancer cells replicate at a higher rate than normal cells, they are more vulnerable to rubitecan than normal cells.
Results from the recent clinical trial included 45 patients with refractory pancreatic cancer. Over 90% of patients had stopped responding to Gemzar® and more than 70% had stopped responding to two or more chemotherapy agents. Over the course of treatment with rubitecan, 22% of patients had an anti-cancer response. Cancer size was decreased by at least 50% in three patients and cancer had stopped growing and/or decreased in size by up to 50% in seven patients.
These results indicate that rubitecan may produce anti-cancer responses in patients who have stopped responding to standard therapies. Rubitecan is now in the final phase of clinical trials prior to approval by the Food and Drug Administration (FDA). Patients with refractory pancreatic cancer may wish to speak with their physician about the risks and benefits or participating in a clinical trial further evaluating rubitecan or other novel therapeutic approaches.