According to results presented at the Chemotherapy Foundation Symposium XXI, the anticancer agent rubitecan (Orathecin™) appears to provide a treatment alternative to patients with recurrent 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 not yet approved by the FDA but is in the last phases of clinical trials prior to FDA approval. Rubitecan 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.
Researchers recently conducted a clinical trial to further evaluate rubitecan for treatment of refractory pancreatic cancer. This trial was a phase III trial, which is the last phase of clinical trials prior to FDA review. Over 400 patients were involved in this trial, the majority of whom had received at least 2 prior chemotherapy regimens. One group of patients was treated with rubitecan and the other group of patients was treated with the “best care” option for their individual situation. “Best care” recipients were typically treated with a chemotherapy agent such as Gemzar®, 5-fluorouracil, mitomycin C, capecitabine, or docetaxel. Patients who did not respond to, or stopped responding to “best care” were allowed to receive treatment with rubitecan. Anti-cancer responses, including complete or partial disappearances of cancer or disease stabilization occurred in 28% of patients treated with rubitecan, compared with only 13% of patients treated with “best care”. In the group of patients who demonstrated an anti-cancer response to rubitecan, the average time to cancer progression was 269 days and the average overall survival time was 338 days. Treatment with rubitecan was generally well tolerated.
The researchers concluded that rubitecan may provide a treatment alternative for patients with refractory pancreatic cancer. Patients with refractory pancreatic cancer may wish to speak with their physician about the risks and benefits of participating in a clinical trial further evaluating rubitecan or other promising therapeutic approaches.
Reference: SuperGen. Independent review of Orathecin™ Phase III trial supports drug’s activity in pancreatic cancer patients who failed prior treatments Data presented at “Innovative Cancer Therapy for Tomorrow” symposium to be used as basis for registrational filing with FDA. Available at: http://www.supergen.com/subpages/asp/viewdoc.asp?id=277. Accessed November 26, 2003.