By Mary Welch

Aiming to acquire unspecified new technology while developing cancer treatments based on its high-density microparticle (HDM) method, Coulter Cellular Therapies Inc., raised more than $16 million in a private placement.

The Boston-based company plans to expand, move to a renovated facility, add staff and license a new technology that uses HDM for immunotherapy, said Lonnie Moulder, vice president of business development and commercial affairs.

HDM technology, with Coulter's portfolio of monoclonal antibodies, enables the enrichment and immune activation of specific human blood cell populations, as well as the purging of malignant cells from stem cell transplants. Initial products focus on leukemia, lymphoma, multiple myeloma and breast cancer.

HDMs, coupled with monoclonal antibodies specific to antigens prevalent on target blood or immune cells, are mixed with a patient's or donor's blood or bone marrow. They settle rapidly through the cell suspension and attach to the target cells. The particles then fall with their target cells to the bottom of the container, thus effectively depleting the suspension of unwanted cells or capturing desired cells for therapeutic purposes.

Walter Ogier, president and CEO of Coulter, said the HDM method allows for the "straightforward, rapid [and] essentially quantitative capture of target cells while enabling nearly complete — 90 percent — recovery of the desirable cells to be returned to the patient. The processing of samples can be done in approximately an hour, without prior purification of blood or bone marrow and without prolonged incubation and capture procedures."

The company's first product, TCell-HDM, is in a feasibility study in relapsed cancer patients receiving donor leukocyte infusions. The study is evaluating the capability of TCell-HDM to deplete a potentially lethal subpopulation of T-cells that would otherwise be infused along with white blood cells from a healthy donor.

Coulter has several products expected to reach clinical trials later this year.

A new investor, Advanced Technology Ventures, of Waltham, Mass., led the financing round, which also included new investors: Crown Advisors Ltd., of New York; WHC Trust, of Miami; and other private investors. Participants also included InterWest Partners, of Menlo Park, Calif.; Brinson Partners Inc., of Chicago; and MedVentures Associates, of Orinda, Calif. *