* Chiron Corp., of Emeryville, Calif., and its joint business partner, Ortho Diagnostic Systems Inc., of Raritan, N.J., signed an agreement to provide reagents, systems and support to the American Red Cross to screen blood supplies for viral diseases. Ortho Diagnostic is a subsidiary of Johnson & Johnson, of New Brunswick, N.J.

* NeXstar Pharmaceuticals Inc., of Boulder, Colo., will receive $2.4 million a year, a $1.4 million increase, in an extension of a 1993 agreement with Schering AG, of Berlin. The two companies are developing in vivo imaging agents using NeXstar's Selex combinatorial chemistry process. NeXstar's technology creates libraries of oligonucleotides. The nucleotide molecules, called aptamers, are targeted for development as drugs and diagnostics.

* Acorda Therapeutics Inc., of New York, entered an agreement with Elan Corp. plc, of Athlone, Ireland, for use of its drug delivery technology to develop an oral, sustained-release form of fampridine, which is Acorda's compound for treatment of spinal cord injuries. Fampridine, 4-aminopyridine, acts on nerve cells' potassium channels, which when damaged become exposed and short-circuit electrical impulses that control neurological function. Financial terms were not disclosed.

* Alpha-Beta Technology Inc., of Worcester, Mass., entered a collaboration with MycoTox Inc., of Denver, to develop antifungal drugs. Financial terms were not disclosed. In the agreement, Alpha-Beta's small molecule carbohydrate compounds will be screened against MycoTox's library of antifungal targets. Alpha-Beta will retain commercial rights to the drug candidates.

* GalaGen Inc., of Arden Hills, Minn., said results of a Phase I trial of Diffistat-G, a polyclonal antibody for treatment of antibiotic-associated diarrhea, revealed the drug was safe and neutralized toxins produced by Clostridium difficile, the bacteria responsible for the condition.

* Novo Nordisk A/S, of Bagsvaerd, Denmark, began selling Norditropin in the U.S. for treatment of children with growth hormone deficiency. Novo received FDA approval of its growth hormone in May 1995, but was barred from entering the U.S. market by federal court action brought by a competitor, Genentech Inc., of South San Francisco. The two companies' patent battles are ongoing.

* SangStat Medical Corp., of Menlo Park, Calif., said the FDA accepted for review its product license application (PLA) for Thymoglobulin, a rabbit anti-thymocyte polyclonal antibody, for treatment of acute graft rejection in organ transplant patients. The drug is sold in 39 countries by Lyon, France-based Pasteur Merieux Connaught and was licensed to SangStat for marketing in the U.S. and Canada. SangStat submitted the Thymoglobulin PLA in January 1997.