* Hybridon Inc., of Cambridge, Mass., will ask shareholders at a special meeting Nov. 18 to approve a five-for-one reverse stock split in order to maintain a listing on the Nasdaq National Market. If approved, the split will convert the company's 25.3 million shares outstanding to 5.06 million shares.

* Viragen Inc., of Plantation, Fla., said genital herpes will be its primary disease target for Omniferon, the company's second-generation natural alpha interferon. A recent study by the Centers for Disease Control (CDC), in Atlanta, estimated that only nine percent of the 45 million infected Americans know they have genital herpes. Recent patents issued to Viragen in Japan, Korea, the United Kingdom, Germany, Italy and Israel are related to the company's topical treatments for genital herpes.

* Palatin Technologies Inc., of Princeton, N.J., submitted to the FDA an investigational new drug application for LeuTech, the company's kit-packaged, radiolabeled infection imaging system. Injected intravenously, LeuTech binds with white blood cells at infection sites within the body, allowing such sites to be imaged using conventional planar imaging techniques.

* Myriad Genetics Inc., of Salt Lake City, in collaboration with 20 U.S. cancer institutions, has developed a statistical model to enable physicians to assess the probability that a breast or ovarian cancer patient carries a BRCA1 gene mutation. Published in the Oct. 15 issue of the Journal of the American Medical Association, the findings suggest that women should be considered for genetic testing if they have been diagnosed with breast cancer and also have two relatives who have been diagnosed with breast cancer or ovarian cancer.

* Accorda Therapeutics Inc., of New York, received a $2 million Advanced Technology Program grant from the U.S. Department of Commerce to fund a three-year project to develop therapeutic products for regenerating nerves and restoring neurological function to people paralyzed by spinal cord injury or other neurological conditions. These products consist of naturally occurring nerve-growth promoters bonded to synthetic polymer fibers, which are designed to guide growth across regions of scar formation and overcome growth inhibitors normally present in the spinal cord.

* Advanced Tissue Sciences Inc., of La Jolla, Calif., received a three-year Advanced Technology Program grant totaling $2 million from the National Institute of Standards and Technology. In collaboration with the Department of Bioengineering at the University of California, in San Diego, the company will design, construct and evaluate tissue-engineered vascular grafts produced from cells grown on a biocompatible scaffold.

* Alexion Pharmaceuticals Inc., of New Haven, Conn., reported positive preliminary Phase I/II and Phase IIa results for its lead drug candidate, the C5 inhibitor 5G1.1-SC. Results of the trial in cardiopulmonary bypass patients were presented at the annual meeting of the American Society of Anesthesiologists. The study, according to the company, confirms that the anti-inflammatory drug "potently and selectively inhibits the generation of pathologic complement byproducts."

* Aronex Pharmaceuticals Inc., of The Woodlands, Texas, received two Phase II Small Business Innovation Research grants totaling $1.1 million from the National Institute of Allergy and Infectious Diseases. The company will use the funds to further development of Zintevir, an HIV integrase inhibitor now in a Phase I/II trial.

* ArQule Inc., of Medford, Mass., and Acacia Biosciences Inc., of Richmond, Calif., have agreed to collaborate on drug discovery in the field of cholesterol biosynthesis and metabolism. Researchers will use Acacia's Genome Reporter Matrix to screen ArQule's Mapping Array library of compounds. If leads are identified, the companies will use ArQule's Directed Array program to optimize them.

* Biosite Diagnostics Inc., of San Diego, received 510(k) clearance from the FDA to market the Triage Cardiac Panel in the U.S. Used in combination with the Triage Meter, the cardiac panel measures three biochemical markers for myocardial infarction: creatinin kinase, myoglobin and troponin I.

* CEL-SCI Corp., of Alexandria, Va., dropped a patent infringement lawsuit against ImmunoRx, of Sarasota, Fla., and John Hadden. The company initiated legal proceedings in February 1996, alleging Hadden, a former consultant to CEL-SCI, and Immuno-Rx, the company he co-founded after leaving CEL-SCI, illegally exported a CEL-SCI-patented drug to Mexico for the purpose of conducting clinical trials. CEL-SCI said a May FDA warning letter to Immuno-Rx had likely resolved the matter.

* Microbial Insights Inc., of Rockford, Tenn., launched a urine test for disseminated candidiasis, a test the company says can detect the disease as early as 20 days before a blood test would. The test costs $55.

* OraVax Inc., of Cambridge, Mass., received a Phase II Small Business Innovation Research grant totaling $690,000 from the National Institutes of Health to develop vaccines and immunoglobulin products to prevent and treat Clostridium difficile associated diseases.

* Pharmacyclics Inc., of Sunnyvale, Calif., presented encouraging interim trial results for Gd-Tex (gadolinium texaphyrin) at the American Society for Therapeutic Radiology and Oncology meeting in Orlando. In a Phase Ib/II trial in patients with brain metastases, a low dose produced median survival of 66 days, while a higher dose produced median survival of 363 days. Gd-Tex is a synthetic molecule that captures and focuses medically useful forms of energy, such as X-rays, which are used in the radiation therapy of cancer.