HYBRIDON’s GEM 91 ANTISENSE AIDS THERAPEUTIC IND APPROVAL EXPECTED "SHORTLY," FIRM TELLS BIOEAST; RIBOZYME, ANTIVIRALS, INNOVIR, TARGETECH IN ANTISENSE RACE
Hybridon is awaiting FDA approval of an IND for its antisense AIDS treatment GEM 91 and expects to begin clinical trials "very shortly," Hybridon VP-Research Kirk Field, PhD, told the BioEast conference Jan. 25 in Washington, D.C. Privately held Hybridon filed an IND for the Gene Expression Modulation (GEM) compound in November, Field said. The research start-up plans to conduct initial Phase I trials at the National Institute of Allergy and Infectious Diseases, Field said. Expanded trials will be conducted by the ANRS, the AIDS research group in France, he added. GEM 91 is a 25-base oligonucleotide targeted against the "g-a- g" structural protein on the AIDS virus, Field said. "This is an area [where] there is very little genetic drift in strains of HIV," he maintained. Hybridon has not seen resistant strains of the virus develop in vitro, Field said. Hybridon is developing the compound in conjunction with National Cancer Institute Laboratory of Tumor Cell Biology Director Robert Gallo, the Worcester Foundation for Experimental Biology and the University of Massachusetts Medical Center. The company had been forecasting clinical trials of an AIDS antisense agent since early 1991 ("The Pink Sheet" Jan. 14, 1991, T&G-7). After a management change in mid-1991, the company pushed its projection back ("The Pink Sheet" Aug. 26, 1991, T&G-3). Short-term cell culture data shows that GEM 91 can "keep the virus at bay...so that no infectious virus is being shed," Field maintained. Upon removal of GEM 91, HIV production returns, Field noted, so GEM 91 cannot be considered a "cure." Post- treatment, the virus appears to retain susceptibility to GEM 91, he added. Hybridon is also exploring the use of GEM 91 in conjunction with other antiviral agents like AZT (Burroughs Wellcome's Retrovir). Hybridon has "a strong patent position" in the antisense/AIDS arena, Field maintained. Hybridon has three issued and three allowed patents as well as 28 applications on file, Field said. One of the issued patents, licensed from the Worcester Foundation, "broadly covers the use of antisense oligonucleotides to control the replication of HIV," a corporate backgrounder declares. The backgrounder maintains that Hybridon's "patent counselors have been hard-pressed to understand how other companies believe they can market antisense oligonucleotide-based drugs against AIDS without directly infringing on the patent already issued and licensed to Hybridon." Isis has an issued patent for "antisense inhibitors" of HIV; several other antisense firms are pursuing HIV as a target. Hybridon could file two more antisense INDs in 1993, the company said. One is for a second AIDS therapeutic, GEM 92. Hybridon is also developing an antisense influenza A treatment. Earlier-stage research projects for the company include herpes simplex virus, cystic fibrosis, Alzheimer's, cancer and organ transplant rejection, Field said. Worcester, Mass.-based Hybridon was founded in 1990 with seed funding from Harvard Medical School's Medical Science Partners venture fund. The firm raised $27.6 mil. in 1992. Hybridon has negotiated two agreements with "large international pharmaceutical houses," Field said. "These collaborations are pending final approvals and are expected to be signed and commenced during the first quarter of 1993," the firm said. Hybridon currently has a staff of 56 with plans to expand to 70 during 1993. The Jan. 25 workshop at the BioEast '93 biotechnology conference included presentations by a number of other privately held firms conducting research under the expanding rubric "antisense." Antivirals, Inc. President Denis Burger, PhD, said his company is pursuing "third generation" antisense technology. The Portland, Oregon company was founded in 1980 and describes itself as the "pioneer" company "in the antisense field." Antivirals, Inc. characterizes attempts to use natural genetic material for gene inactivation as "first generation" antisense. Modified DNA, such as the phosphorothioates like GEM 91, constitute "second generation" antisense, the company maintains. In 1989, Antivirals, Inc. developed its first "third generation" antisense compounds, Burger said. These compounds, called NEU-GENEs, use a novel morpholino-type backbone which has shown higher binding affinity and specificity in vitro than phosphorothioates, Burger said. A major advantage of NEU-GENEs, Burger maintained, is reduced cost. The company estimates that morpholino-type compounds may offer up to a 10-fold savings in production costs compared to phosphorothioates. Antivirals, Inc.'s research is focusing on HIV, hepatitis B and C, herpes simplex virus, human papilloma virus, cytomegalovirus, malaria and an "ultra-broad spectrum antibacterial," Burger said. The company also has an anti- inflammatory research program, with projects focusing on interleukins and intracellular adhesion molecules in collaboration with Tanabe Research Labs in San Diego. Five NEU-GENE patents have issued, Burger said. The firm employs 25 and plans to double its staff in 1993, he added. Ribozyme Pharmaceuticals, Inc. CEO Ralph Christoffersen, formerly a SmithKline Beecham senior VP, told the workshop that his company is developing ribozymes (RNA molecules that act as enzymes) to treat HIV, herpes simplex virus and restenosis. The firm holds five patents, Christoffersen said. The Boulder, Colo. company collaborates with Tom Cech, PhD, University of Colorado, who shared the 1989 Nobel Prize for his discovery of ribozymes. RPI was founded in February 1992 by U.S. Biochemical ("The Pink Sheet" Jan. 27, 1992, In Brief) and has raised $18 mil. in venture capital. The company plans to focus on human pharmaceuticals, with partners for specific diseases, and outlicense non-human uses, he said. U.S. Biochemical retains rights to reagent uses of the technology. Ribozyme has 30 employees and expects to double in size during 1993. Innovir Labs Chief Science Officer Allan Goldberg, PhD, outlined his firm's approach to harnessing ribozymes for therapeutic use. New York City-based Innovir, founded in 1989, collaborates with Sidney Altman, PhD, Yale University, who shared the 1989 Nobel Prize with Cech. One approach being pursued by Innovir is the use of small RNA segments called External Guide Sequences (EGSs) to direct a naturally occurring ribozyme, RNase P, to cut new targets. Innovir is also developing a gene therapy delivery system to allow continuous delivery of ribozymes. The company has a patent on a vector employing the hepatitis delta virus with ribozymes introduced into the genome. The company's initial disease targets include hepatitis B and acute promyelocytic leukemia. Johnson & Johnson is conducting research on the vector-based delivery of ribozymes in plants, R.W. Johnson-Australia Research Director Wayne Gerlach, PhD, told BioEast '93. J&J said it is exploring the application of ribozymes to human therapeutics for dermatologic indications such as acne and psoriasis. TargeTech is developing Gene Drugs for gene therapy and antisense applications, CEO Henry Nordoff said. Each Gene Drug consists of a protein ligand targeted for a specific receptor on the liver, a linker and a gene. The genetic material is not inserted in the genome, thereby avoiding the safety concerns raised by retroviral-vector-based gene therapy, Nordoff said. The company is focusing initially on gene therapy for hemophilia A and hypercholesterolemia and on antisense therapy for hepatitis B. TargeTech has one issued patent covering its "core technology for the injectable delivery of DNA into the liver," the firm said. It has 28 patent applications pending. The Meriden, Ct. firm was founded in 1989 and acquired by Immune Response in November for $3 mil. in cash and 1.3 mil. shares. The firm has 17 employees in Meriden and 13 at the University of Connecticut laboratory of founders George Wu, MD/PhD, and Catherine Wu, PhD. Paris-based GenSet is currently establishing a laboratory in La Jolla, Calif., Research Director Marc Vasseur told the BioEast meeting. The firm is developing both antisense and "sense" compounds, he said. Founded in 1989, the firm has raised more than $10 mil. in venture funding and is actively selling DNA for research use. GenSet began a trial of a chronic myelogenous leukemia antisense agent in Paris in December. The firm has collaborations with French research agencies and Moscow State University, Vasseur said.
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