By Karen Pihl-Carey

Campath appears to be effective and safe in the treatment of advanced B-cell chronic lymphocytic leukemia (CLL), the kind resistant to available therapies, researchers said Tuesday at the American Society of Hematology meeting in New Orleans.

The drug is a monoclonal antibody, developed through a 50-50 joint venture of San Antonio-based Ilex Oncology Inc. and LeukoSite Inc., of Cambridge, Mass. The two companies expect to file a biologics license application for the product in the CLL indication by year's end.

In the Phase II trial data presented at ASH, Campath reversed the course of disease progression or prevented progression in 93 percent of the study's patients, according to a principal investigator of the study, Michael Keating, of the University of Texas M.D. Anderson Cancer Center in Houston.

The study included 93 patients who were administered Campath intravenously for two hours on an outpatient basis. They received the drug at a target dose of 30 mg three times a week for four to 12 weeks. At a one-year follow-up period, median survival had not been reached, Keating said.

Campath works in CLL patients by depleting the malignant B cells that bear the CD52 antigen. The Phase II trial sought to establish the drug's level of activity against these cells in CLL patients who previously received alkylating agents and failed therapy with fludarabine, the only approved drug to treat patients not successfully treated with alkylating agents. Life expectancy for these patients was less than nine months.

In August, Ilex and LeukoSite granted exclusive marketing and distribution rights for Campath to Schering AG, of Berlin. (See BioWorld Today, Aug. 25, 1999, p. 1.)

Ilex's stock (NASDAQ:ILXO) closed Tuesday at $17, up 75 cents. LeukoSite's stock (NASDAQ:LKST) gained $2.56 to close at $47.187. LeukoSite is merging with Cambridge-based Millennium Pharmaceuticals Inc.

In other news at ASH:

¿ AltaRex Corp., of Waltham, Mass., said early results from an OvaRex open-label Phase II ovarian cancer study indicate that nine of the 11 patients evaluated to date had a significant increase in immune response levels. Three of 12 patients, who received multiple injections, remained free of disease progression for more than 230 days. The study is ongoing and includes 13 patients with late-stage ovarian cancer that has relapsed.

¿ BioTransplant Inc., of Charlestown, Mass., and the Massachusetts General Hospital reported on scientific advances in modifying bone marrow transplantation recipients' immune systems to achieve acceptance of donor cells or organs. In a clinical proof-of-concept study using mixed chimerism to treat chemotherapy-refractory hematologic malignancies, eight patients experienced complete antitumor responses and six experienced partial responses, out of 21 patients receiving matched donor bone marrow transplants. The company and hospital also highlighted methods to create long-term tolerance to xenogenic transplants and the development of animal models to study the mechanisms involved in tolerance induced by mixed hematopoietic chimerism.

¿ Celgene Corp., of Warren, N.J., said in a preliminary analysis of Thalomid (thalidomide) to treat the bone marrow disorder myelodysplastic syndrome, researchers observed hematologic improvements in 50 percent of the 20 evaluable patients. Three long-standing, transfusion-dependent patients were able to discontinue transfusions altogether. A total of 33 patients were enrolled in the study.

¿ CytRx Corp., of Atlanta, said administration of its investigational agent Flocor in an experimental transgenic mouse model of acute chest syndrome suppressed development of ACS and significantly reduced mortality. Survival in mice treated with Flocor was more than double that of the control animals. Flocor is in an ongoing Phase I trial in ACS, and results from a Phase III trial of Flocor for acute sickle cell crisis will be available in January.

¿ Fred Hutchinson Cancer Research Center, of Seattle, said an experimental agent, CMA-676, part of an antibody-targeted chemotherapy technology to fight acute myeloid leukemia, induced remission in a significant proportion of patients with few serious side effects. In a pivotal Phase II trial in the U.S., CMA-676 given alone produced remission among 34 percent of patients.

¿ Immunomedics Inc., of Morris Plains, N.J., said its radioactive version of Epratuzumab, its second product to treat non-Hodgkin's lymphoma (NHL), demonstrated complete and partial remissions in half of treated NHL patients who failed high-dose chemotherapy in addition to regimens of conventional chemotherapy and antibody therapy with Rituxan. Researchers did not observe any immune reaction to the product.

¿ NeoRx Corp., of Seattle, said 12 patients out of 27 whose response evaluation has been determined experienced complete disappearance of all evidence of myeloma cancer tumors in an ongoing Phase II trial of the company's Skeletal Targeted Radiotherapy. Of those who achieved complete response, many had failed to respond to initial chemotherapy or had relapsed after responding. The therapy appeared to show no serious toxicity in the 45 patients treated to date.

¿ Nexell Therapeutics Inc., of Irvine, Calif., said researchers at the National Institutes of Health corrected a rare blood disorder, chronic granulomatous disease, using a mini-transplant conditioning regimen incorporating Isolex stem cell selection technology to purge donor T cells from the stem cell graft. The approach reduced both conditioning-related toxicity and the severity of graft-vs.-host disease.

¿ SuperGen Inc., of San Ramon, Calif., said results of a Phase I study of its proprietary cancer drug Nipent (pentostatin) in combination with cyclophosphamide in patients with chronic lymphocytic leukemia (CLL) show all three patients responded to the therapy. Two of the patients displayed a response superior to that achieved with their initial therapy. The company said the combination therapy was well tolerated and extremely active in previously treated patients with CLL.

¿ The Liposome Co. Inc., of Princeton, N.J., said its novel liposomal gene delivery system successfully delivers genes without toxic side effects associated with viral delivery efforts. The company uses compounds called fusogenic and anionic liposomes.

¿ Theratechnologies, of Montreal, said a purging process of chronic myeloid leukemia cells could be applied to several forms of cancers invading the bone marrow and diseases involving immunoreactive cells. The process uses a newly synthesized photosensitive agent, a dibromo rhodamine derivative (TH 9402), which has a propensity to accumulate in malignant cells. It kills the cells when activated with an adequate wavelength of light. Theratechnologies developed both the photosensitive agent and the light source.