BARCELONA, Spain, March 20, 2002 (PRIMEZONE) -- Dr. Dana Leach, Vice President of Preclinical Development and Immunopharmacology at Pharmexa, today presented the company's HER-2 DNA AutoVac(tm) therapeutic vaccine for the treatment of breast cancer, at the 3rd European Breast Cancer Conference.
Dr. Leach told the news briefing: "The objective of our vaccine, which is in Phase I/II trials in Denmark and the U.K., is to stimulate the patient's own immune system and to see whether we can induce it to launch specific killer cells as well as producing HER-2 specific antibodies. Our first objective is to test the safety of the vaccine, but we also want to make a preliminary evaluation of the vaccine's ability to raise an immune response. There are 27 patients with advanced breast cancer in the trial, which should be completed late this year.
"HER-2 is a protein that is over-expressed in many tumours, but because it is also expressed at low levels in some normal tissues, the immune system does not recognize it as foreign and the immune cells, especially helper T cells that initiate the immune response, are simply not around to launch an attack. So, the vaccine -- AutoVac(tm) -- has been designed to help kick-start the immune response by giving the T cells a foreign agent to recognize and react against. The aim is that the immune system then recognizes the over expressed HER-2 in the cancer cells and attacks them, but ignores the normal tissue because it contains only low levels.
"Animal tests have shown that the vaccine produced a specific immune response and there had been no adverse side effects.
"The vaccine consists of two small inactive fragments derived from tetanus toxin -- the bacterium that causes lockjaw. The researchers included DNA encoding the fragments, into DNA that they had made in the laboratory to code for a portion of the HER-2 molecule. The DNA vaccine is injected and taken up by the cells, which then manufacture the protein, including the inserted tetanus fragments that 'wake up' the immune system and help it to respond to HER-2.
"The company is also planning clinical trials in a variation of this approach. Instead of a DNA vaccine that prompts the body's cells to make the necessary protein, the AutoVac protein will be made beforehand in the laboratory and injected directly as a vaccine into the patient."
"Each approach has potential advantages -- DNA is generally believed to be a good way to get a response from cytotoxic T cells, while protein is better at inducing antibody responses," he said. "We have to look at tackling cancer from as many different approaches as possible because different tumours react in different ways. We know that already from the variable responses to chemotherapy, radiotherapy, endocrine treatment and other immunotherapies. But, as we get better at diagnosis and understanding the genetic make-up of tumours it should become possible to make better predictions about which treatment is best for which patient and to combine treatments that work synergistically to boost effectiveness.
"The success of the drug Herceptin as a treatment has shown that HER-2 is a good target. Although it is early days yet, any time that you can successfully take a new cancer vaccine into the clinic it is an important and exciting event."
Pharmexa expects to announce the results of the Phase I/II trial before the year end.
To the editors
Pharmexa A/S (CSE:PHARMX) is a leading company in the field of therapeutic vaccines for the treatment of serious chronic diseases. Pharmexa's proprietary AutoVac(tm) pharmaccine technology platform is broadly applicable, but the company currently focuses its resources on a number of cancer forms and chronic inflammatory diseases, with research and development programs in breast cancer, rheumatoid arthritis, asthma, osteoporosis and allergy. The Pharmexa Group has 145 employees and has entered into collaborative agreements with Lexigen/Merck KgaA, Ferring, Schering-Plough Animal Health, H. Lundbeck, NeuroSearch and AstraZeneca.
Additional information can be found on www.pharmexa.com.