Stimulating the Body's Defenses for Fight Cancer

Comediennes such as Gilda Radner and Madeline Kahn, Oscar-winning actresses like Loretta Young and Sandy Dennis, singers Laura Nyro and Dinah Shore, actor Pierce Brosnan's wife Cassandra Harris, actress Jessica Tandy, former Connecticut governor Ella Grasso, and Martin Luther King's wife Coretta Scott King all died of ovarian cancer. It's not just celebrities, politicians or movie stars, who are stricken with ovarian cancer. One in every 55 U.S. women is at risk for ovarian cancer. The American Cancer Society estimates about 22,000 new cases of ovarian cancer will be diagnosed. It is the leading cause of death from gynecologic malignancies, and the fifth leading cause of cancer deaths among women.Family doctors often fail to properly diagnose "The Silent Killer" until it is too late. A British survey discovered 75 percent of family doctors believed symptoms are only present during the advanced stages of the cancer. By the time women are diagnosed for ovarian cancer, 40 to 50 percent of the patients are in the advanced stage, where there is little hope for survival.Less than one-half the women diagnosed with ovarian cancer will live five years. The general public is often unaware of the side effects ovarian cancer patients suffer during chemotherapy. In mid March, the U.S. Food and Drug Administration criticized the safety profile of Eli Lilly's Gemzar for ovarian cancer patients, saying the 2.8 months increased survival seen in studies of patients taking the drug wasn't enough to offset the treatment's increased toxicity which included anemia, neutropenia (a blood disorder) and thrombocytopenia (reduced platelets in the blood).Presently used first-line treatments for ovarian cancer patients include Cisplatin, with associated side effects such as nerve, kidney and/or ear damage, Carboplatin (side effects: nerve damage in the arms and/or legs, joint pain, and/or thrombocytopenia), Paclitaxel (neurotoxicity), or Melphalan, with side effects which include irreversible bone marrow failure, bone marrow suppression).A woman stricken with ovarian cancer faces first surgery, then chemotherapy. Recent widespread press heralding a new development in treating ovarian cancer, intra-abdominal or intraperitoneal chemotherapy, is just that: more chemotherapy. According to Dr. Robert Edwards, research director of the Magee-Women's Gynecologic Cancer in Pittsburgh, "Many women don't feel well enough to work for the duration of the intra-abdominal (therapy)." Some patients, such as Cindy Pakalnis of Marshall (Pennsylvania) have called the treatments "grueling."While some life extension has been proven, the patient's life deteriorates. Many patients struggle with balancing the loss in quality of life with the rigors of the therapy. Researchers are actively pursuing new directions that may some day provide new hope for the ovarian cancer patient. Minnesota cancer researcher Dr. Levi Downs explained, "It prevents the tumor from making new blood vessels. Without new blood vessels, the tumor can't sufficiently feed new cells, so the cancer can't grow." New Hope for Ovarian Cancer Patients?One promising technology that has been developed over the past decade is OvaRex® MAb. It was developed by ViRexx Medical Corp., an Edmonton-based company, which trades on the American Stock Exchange (ticker symbol: REX) and on the Toronto Stock Exchange (ticker symbol: VIR). Now licensed to Unither Pharmaceuticals, a wholly owned subsidiary of United Therapeutics (NASDAQ: UTHR), OvaRex® MAb is currently undergoing two identical Phase III trials at about 64 research centers across the United States. One trial has completed enrollment, according to a mid December news release issued by ViRexx Medical Corp."OvaRex® MAb is our lead candidate for the treatment of ovarian cancer, and is an intravenous infusion of a monoclonal antibody," he said. Monoclonal antibodies are a new breed of biotech drugs that are extremely specific; that is, each antibody binds to only one particular antigen. In the case of OvaRex® MAb, it is a monoclonal antibody that binds specifically to the CA-125 antigen. Dr. Tyrrell talked about the current Phase III studies, "The trials are ongoing. It is in this phase that we treat the patients with OvaRex® MAb with the hopes of increasing the time to disease relapse." Tyrrell noted, "In the original study, the average time to relapse was delayed by about 14 months. What makes OvaRex® MAb different from other immunotherapeutic treatments is, instead of attacking the body's cancerous cells directly, the monoclonal antibody targets the cancerous antigen in circulation. Some believe it helps retrain the body's immune system to fight the ovarian cancer cells. The mechanism that reportedly has made OvaRex® MAb effective is how it alerts the body to recognize and fight the CA-125.ViRexx has addressed the "tolerance problem" a body suffers when it has become inflicted with a malignant tumor. Introducing a foreign antibody, in this case the mouse antibody against CA125, the body's defense systems are awakened to the ovarian cancer cells. This begins a chain reaction alerting the immune system to battle the invading antibody CA125 complex. As with many pioneering scientific breakthroughs, serendipity is what lies behind the OvaRex® MAb story. As one technology was being developed, another - the murine monoclonal antibody treatment for ovarian cancer - came about by accident. We talked to its inventor, Dr. Antoine Noujaim, about the biotech drug's roots. In the early 1980s, biotech companies, such as Immunomedics and Cytomedics were researching tumors and using antibodies to image the tumors so they could be evaluated in a cancer patient's body. "I worked with Dr. Mike Longenecker and we established a company called Biomira (Toronto: BRA) in 1984," Dr. Noujaim recalled. "We developed antibodies against a mucin, which is really a glycopeptide," explained Dr. Noujaim. "It's a peptide that has a lot of sugars on it present in the ascitis fluid from ovarian cancer patients." That is how Dr. Noujaim and his team developed the very early antibody which is now used for OvaRex® MAb. "We sent some of these antibodies to Professor Richard Baum in Germany for imaging of ovarian cancer patients," Noujaim remembered. "Dr. Baum phoned back, after some time, and told me, 'The patients I was imaging here had advanced ovarian cancer and some of them seem to have done quite well after we gave them a couple of shots (of the B43.13 antibody, the clinical name for OvaRex® MAb) to image the tumor.' "Richard was imaging patients that were in the last stages of the disease," he pointed out. Baum urged Noujaim to investigate this further. I've seen hundreds of patients, but nothing like this." From this encouragement, Noujaim began formulating the potential mechanism of how this monoclonal antibody would work. We were using foreign antibodies, a small amount of foreign antibodies." How in the world did Noujaim know to use murine (mouse) antibodies? The serious effort to develop the antibodies began in 1996. Having conducted trials in Canada and Europe, it was a "massive undertaking" Noujaim told us. "We had over 500 patients injected with the murine monoclonal antibody." He extrapolated beyond OvaRex® MAb, saying, "We've proven completely the mechanism of action on this, how it works. Noujaim believes it can apply to breast, ovarian, prostate and pancreatic cancer. Indeed, BrevaRex® MAb for breast cancer and multiple myeloma patients has completed Phase 1 trials, and ProstaRex® MAb for prostate cancer patients is at the pre-clinical stage.While the company has licensed, under a royalty agreement, the OvaRex® MAb technology to United Therapeutics, through that company's subsidiary, Unither Pharmaceuticals, ViRexx has retained rights to most member nations of the European Union and certain other countries.

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