BioWorld International Correspondent

SYDNEY, Australia - Prima Biomed Ltd. is planning a Phase I/II trial after a successful Phase I trial indicating that the company's means of stimulating the body's own immune system against tumors is causing immune activity.

Tests on eight of the 10 patients who took part in the Phase I trial show increased levels of T cells being generated in response to the tumor molecule MUC1, with the results of the remaining two patients yet to be released.

Prima CEO Marcus Clarke said that the patients had not yet been checked for their clinical response to the treatment - whether symptoms have been relieved or the cancer has regressed or stabilized - but the tests showed that the immune systems of the patients are responding to the treatment.

He said that the patients will undergo follow-up tests during the rest of the year, including assessment of their condition, as well as further tests on the response of their immune systems.

In the meantime, the results are sufficiently encouraging for Melbourne-based Prima to run a Phase I/II trial to investigate the potential clinical efficiency of the company's immune stimulant and immunizing process, it said.

Clarke said that no details are available on the Phase I/II trials, but the company expects that the design will be complete by July. He also said the company has held discussions with major pharmaceutical companies, but is waiting to see if there is a clinical response.

Prima's treatment, developed at the Austin Research Institute in Melbourne 10 years ago, is keyed to Mucin 1, a glycoprotein expressed by tumors in a range of cancers, including breast, bowel, ovarian, pancreatic and lung. The treatment, which is complex, involves first extracting some of the patient's immune-stimulating cells, which then are cultured and treated with hormones and growth factors to produce dendritic cells (cells that enable the body to recognize foreign proteins).

The dendritic cells then are treated with a combination of Mannan, a complex mannose sugar molecule, and recombinant MUC1. The Mannan combines with a receptor on the dendritic cell and carries the recombinant MUC1 into the cell. The result should then be a dendritic cell that would stimulate the immune system to produce T cells specific for MUC1. Those are injected into the patient.