Coulter Pharmaceuticals Inc., a spin-off of Miami-based CoulterCorp., is going public with two anti-cancer programs based onradioactive monoclonal antibodies and modified cytotoxiccompounds activated by tumor cells.

The Palo Alto, Calif., company registered for an initial publicoffering (IPO) without specifying the number of shares or projectedprice range.

Underwriters are Hambrecht & Quist, of New York, Alex. Brown &Sons Inc., of Baltimore, and Pacific Growth Equities Inc., of SanFrancisco.

Coulter's monoclonal antibodies are designed to bind to the CD20antigen expressed on the surface of immune system B cells corruptedby non-Hodgkin's lymphoma. The disease is a cancer of the bloodand lymph tissues that affects about 225,000 people in the U.S.

The monoclonal antibodies, called B-1, are conjugated withradioactive iodine to kill the cancerous cells.

In the IPO prospectus filed with the Securities and ExchangeCommission, Coulter reported Phase I/II results of the B-1 therapy in40 non-Hodgkin's lymphoma patients whose cancer returned afterreceiving chemotherapy. The company said an "82 percent overallresponse rate and a 45 percent complete response rate" to the tumorshrinking radioimmunotherapy were seen in the study participants.

A Phase II/III trial of the B-1 therapy is under way with non-Hodgkin's lymphoma patients refractory to chemotherapy. Thecompany expects to file a new drug application with the FDA in thesecond half of 1998 for use of the radioactive antibody as a second-line treatment.

Coulter's other approach to fighting cancer involves tumor-activatedpeptide (TAP) pro-drugs, which are chemical modifications ofcytotoxic drugs, such as doxorubicin. The company said the pro-drugis rendered inactive until it reaches the tumor site where it is activatedby enzymes or other chemicals produced by the cancer cells.

Targeting the cytotoxic compound specifically at tumor sites isdesigned to make it more effective in killing cancer cells withoutproducing side effects associated with the death of healthy cells.

Clinical trials of a TAP pro-drug version of doxorubicin are expectedto begin in early 1998.

As of Sept. 30, 1996, Coulter had $18.8 million in cash and reporteda net loss of $10.8 million for the first nine months of this year.

Coulter Pharmaceuticals was formed in April 1995 with financingfrom InterWest Partners, of Menlo Park, Calif.

Coulter Corp. develops blood cell analysis systems. n

-- Charles Craig

(c) 1997 American Health Consultants. All rights reserved.