IMMUNOMEDICS IMMURAID-CEA IMAGING AGENT SHOWS "VERY LOW" HAMA INDUCTION

IMMUNOMEDICS IMMURAID-CEA IMAGING AGENT SHOWS "VERY LOW" HAMA INDUCTION rate after multiple injections, the Morris Plains, N.J. cancer R&D firm concludes. An abstract of an Immunomedics study to be presented at the Society of Nuclear Medicine meeting in Toronto June 8-9 states that in 15 patients tested up to three months after a second injection of the murine monoclonal antibody-based technetium (Tc99m) imaging agent, "none have developed" a human anti-mouse antibody (HAMA) response. The HAMA study is the latest in a series of Phase III clinical trials of the murine MAb-based imaging agent that Immunomedics has submitted to FDA to add to the April 1991 PLA registration for ImmuRAID-CEA for the detection of colorectal cancer. The PLA initially contained data on about 170 patients, but Immunomedics subsequently has submitted data on "several hundred more," the company said. The development of HAMA has been a consideration in the approval of MAb-based therapies and imaging agents where repeated use may be required in patients. For example, labeling for Cytogen's OncoScint CR/OV for colorectal and ovarian cancers, the first monoclonal antibody- based imaging agent approved, includes a patient information section discussing the risks of HAMA ("The Pink Sheet" Jan. 11, T&G-7). Phase III trials of OncoScint showed a HAMA response in 40% of patients ("The Pink Sheet" Jan. 4, p. 12). At a meeting of the New York Society of Security Analysts May 26, Immunomedics President David Ortlieb declared: "We're submitting additional patient data to the FDA. We believe that these data will support the broad claims that we are seeking concerning the product's safety, its efficacy and utility, and eventually secure the kind of labeling for product usage that we desire." ImmuRAID-CEA will be distributed in North America by Adria Labs under a licensing deal announced in December 1991. As Immunomedics awaits FDA action on ImmuRAID-CEA, the company is also focusing on ImmuRAID-MN3, which is currently in Phase III and on schedule for a PLA filing projected for mid-1994. As reported by the firm last September (The Pink Sheet" Oct. 5, 1992, T&G-10), ImmuRAID-MN3 is being studied at 10 clinical centers with 10 more to come. Indications being sought for the agent, which attaches itself to granulocytes, are the detection of infected prostheses, bone infections and soft tissue infections. ImmuRAID-MN3 is "easy to use," Ortlieb told NYSSA. "Preliminary results suggest that useful images can be obtained within one hour of injection, and in addition the product does not involve handling the patient's blood -- greatly reducing the risk of exposure for hospital workers to infectious agents like HIV and hepatitis B viruses," he explained. Immunomedics hopes to move ImmuRAID-CEA into Phase III trials for the detection of breast and lung cancer by the end of this year. Other Immunomedics imaging products include ImmuRAID-LL2 for B-cell lymphoma, which also is projected to enter Phase III by the end of this year; and ImmuRAID-AFP for liver and germ cell cancers, currently in Phase II. ImmuRAID-CEA, ImmuRAID-LL2 and ImmuRAID-AFP all have therapeutic counterparts (ImmuRAIT) -- the same antibody linked with a therapeutic isotope -- in Phase I/II trials. Immunomedics reported a net loss of $2.2 mil. and revenues of $1.2 mil. during the third quarter ended March 31. Company VP- Finance and Administration Amy Factor reported at the NYSSA meeting that Immunomedics has "$43 mil. in the bank and virtually no debt." On June 3, Immunomedics increased the size of its board of directors to seven with the election of Merck VP-Public Affairs Albert Angel.