PARIS - Immuno-Designed Molecules (IDM) reported "very encouraging" results from a Phase II clinical trial of a therapy for ovarian cancer. The trial, which started in December 1997, was carried out at centers in France and Belgium.

Paris-based IDM presented the results last week at the 36th annual meeting of the American Society of Clinical Oncology in New Orleans.

The therapy, known as IDM-1, is composed of macrophage-activated killer (MAK) cells associated with a bispecific anti-HER-2/neu antibody, MDX-210 - developed by Medarex Inc. - and is designed to boost the capacity of the patient's immune system to recognize and destroy cancer cells. It was tested on 17 patients suffering from advanced ovarian cancer who already had been treated with surgery and chemotherapy and in whom secondary exploratory surgery had discovered residual tumor cells.

Each patient received six doses of a version of IDM-1 that was prepared with her own monocytes and injected over a one-month period. It proved possible to evaluate the efficacy of the treatment on 14 of the patients, in eight of whom the tumor cells disappeared altogether and/or there was a significant reduction (of over 50 percent) in CA-125, the biological marker of ovarian cancer.

On the strength of these results, the company decided at the end of 1999 to terminate the Phase II trial and start a Phase III trial that would include a control group and be based on clinical efficacy criteria. That trial is being carried out in several European countries, including France and the UK, as well as Canada and the U.S. and is expected to take three and a half years.

IDM CEO Jean-Loup Romet-Lemonne told BioWorld International that the first of a planned cohort of 280 patients had recently been recruited. He said the object of the trial was to "show that treatment with IDM-1 significantly prolongs the complete clinical remission obtained by surgery and chemotherapy."

IDM-1 issues from one of two families of "cell drug" therapies being developed by IDM to treat different cancers. One is based on the use of MAK cells, the basic version of which does not involve the use of antibodies and is currently in Phase II trials in bladder cancer. The bispecific antibody version, now known as IDM-1, but previously designated MAK-BAb, could subsequently be tested in breast and prostate cancer as well as ovarian cancer. Another variant, MAK cells with monoclonal antibodies (MAK-MAb), is in Phase II clinical development for the treatment of chronic lymphoid leukemia.

The company's other therapeutic approach is based on the use of macrophage-dendritic (MAC-DC) cells that are reinjected as a cellular vaccine to initiate a powerful immune response. This therapy entered clinical development in 1998, and two Phase II trials currently are under way, one in prostate cancer and the other in melanoma. All of IDM's Phase II trials are being conducted in France and Belgium, where it has its own laboratories. In addition to the five products in Phase II and Phase III trials, IDM has a further 10 products at an advanced stage of preclinical development. The company supplies its therapies to clinicians in the form of integrated processors (or kits), so they are technically medical devices and not medicines.

Romet-Lemonne also disclosed that IDM would announce the signing of its first co-development agreement with a pharmaceutical company within the next two weeks, adding that the deal would include a commercialization option. As well as its agreement with Medarex for the supply of antibodies, IDM has entered into a collaboration with the British company Oxford Biomedica, from which it obtains antigens and to which it provides assistance in the conduct of ex vivo clinical studies.