IMMUNEX RECOMBINANT GM-CSF PHASE II/III STUDIES

IMMUNEX RECOMBINANT GM-CSF PHASE II/III STUDIES will begin shortly in bone marrow transplant patients at the Fred Hutchinson Institute in Seattle and the University of Minnesota, according to the company. At a Jan. 11-13 healthcare conference sponsored by Hambrecht & Quist, Immunex President Stephen Duzan said that GM-CSF (granulocyte-macrophage colony stimulating factor) "Phase II/III trials are expected to begin imminently." Immunex is co-managing the U.S. trials with its development partner, Hoechst's Behringwerke subsidiary. Commenting on the results of Phase I studies with GM-CSF, Duzan reported that "white blood cell counts were restored in eight patients with myelodysplasic syndrome, [and] counts increased two to 70-fold in 25 patients with malignancy and/or bone marrow failure." In addition, "platelet counts were increased two to ten-fold in seven of 16 patients, and five bone marrow patients demonstrated marked acceleration in post-transplant white blood cell counts," Duzan said. Duzan noted that "all of the data for GM-CSF was extremely encouraging. We did not encounter at efficacious doses any kind of significant side effect problems or toxicity." Immunex' GM-CSF is also being tested by the National Institutes of Health as adjunct therapy for neutropenia in cancer patients who undergo chemotherapy. The neutropenia indication, according to Duzan, "is the most important therapeutic indication for this product." Immunex plans to start trials in the first quarter of the year with GM-CSF in pediatric bone marrow transplant patients. Two other products being developed in the U.S. for Behringwerke, interleukin-3 and G-CSF, will enter the clinic in 1988. Interleukin-3 "will enter clinical trials in both Europe and the United States -- Europe in January and the U.S. in April -- [for] white blood cell restoration in immune suppressed conditions," Duzan reported. "We will also be taking a G-CSF product into the clinic. The master drug file for that is scheduled to be completed in March of this year, and clinical testing will begin in June . . . in the area of white blood cell restoration," Duzan said. Immunex' Interleukin-4, under development by Kodak's Eastman Pharmaceuticals division, is expected to begin Phase I studies in the first half of 1988. "The IND will be filed by Eastman Pharmaceuticals in this quarter of 1988 as a treatment for cancer and B cell deficiencies," Duzan said. Development and marketing rights for interleukin-4 were acquired by Eastman Pharmaceuticals from Immunology Ventures, a joint venture between Immunex and Kodak ("The Pink Sheet" Nov. 9, "In Brief"). Immunology Ventures retains manufacturing rights and will receive royalties from sales. Immunex also has four interleukin-1s slated for the clinic in 1988, two that it is developing on its own and two in conjunction with Syntex. Immunex is self-developing interleukin-1 as a vaccine adjuvant and as a wound healing agent. Duzan predicted that trials would start with interleukin-1 as a wound healing agent "in the second quarter of this year." Immunex is developing interleukin-1 (alpha) as a vaccine adjuvant for both animals and humans. Duzan reported that field trials in cattle, dogs and cats have begun and that the firm plans to use that data "as the basis for the filing of the IND." Clinical trials are targeted for mid-1988 with interleukin-1 (beta) as a radioprotective agent. Describing preclinical results, Duzan noted: "If you pretreat a mouse with interleukin-1, in 85% of the cases, the mouse will survive . . . a lethal dose of radiation because there is not a bone marrow failure." Preclinical results, Duzan added, "led us and Syntex to the conclusion that there is potential for this therapeutic as a pretreatment for cancer patients undergoing radiation therapy for their tumors, and that it could permit both higher doses and longer regimens of radiation therapy." Syntex and Immunex plan to "piggyback" on the Phase I radioprotection trials for an IND for rheumatoid arthritis, which will be filed in late 1988, Duzan predicted.