* Allergan Ligand Retinoid Therapeutics Inc. (ALRT), of San Diego, Tuesday effected a unit separation that turned 3.25 million publicly traded units into their component parts. Priced originally at $10, each unit consisted of one share of callable common stock and two warrants, each to purchase one share of common stock of Ligand Pharmaceuticals Inc. at a price of $7.12. The ALRT common stock will trade on NASDAQ under the symbol ALRI, and the Ligand warrants will trade on the same market under the symbol LGNDW.

* ImClone Systems Inc., of New York, received a milestone payment of $500,000 from corporate partner Merck KGaA for ImClone's pilot-scale manufacturing run of BEC-2, a small cell lung cancer treatment that is the company's lead therapeutic compound. The achievement also triggered the first in a series of eight quarterly support payments totaling $4.7 million. An anti-idiotypic monoclonal antibody, BEC-2 is a cancer vaccine designed to mimic GD3, a glycolipid antigen found on the surface of some tumor cells.

* Immunex Corp., of Seattle, reported that its Flt3 cytokine ligand safely increased numbers of the immune system's stem and dendritic cells. The company plans to follow up this first human test of the ligand with studies to investigate possible use as an antitumor agent.

* Matrix Pharmaceutical Inc., of Fremont, Calif., has won a recommendation for marketing authorization for its AccuSite Injectable Gel in six European countries -- Belgium, Denmark, Finland, Ireland, Luxembourg and the Netherlands -- through the European Union's mutual recognition process. Approved by the U.K. but still under review by the FDA and various European regulatory agencies, AccuSite is a sustained-released fluorouracil/ epinephrine treatment for external genital warts.

* Micro Therapeutics Inc., of San Clemente, Calif., and the department of radiological sciences at the University of California, Los Angeles, School of Medicine have won conditional FDA approval of an investigational device exemption application for the Embolyx Liquid Embolic System, under development for endovascular treatment of arteriovenous malformations in the brain. The company and university will initiate human clinical studies once UCLA's institutional review board approves.

* NeoTherapeutics Inc., of Irvine, Calif., reported interim results on its Canadian Phase I/II trial of AIT-082 in Alzheimer's disease patients. The drug was well tolerated with no adverse reactions, and was absorbed into the patients' bloodstream. Analysis of cognitive function will be made after all the patients have completed their dosage regimen. AIT-082 is a small molecule designed to cross the blood-brain barrier and enhance nerve cell function by increasing neurotrophic factors in damaged or degenerating neurons.

* Neurobiological Technologies Inc., of Richmond, Calif., has tested the Xerecept brain injury product in three animal models and found it reduces brain water content and significantly improves neurological recovery during the month following injury. Xerecept is a synthetic preparation of Corticotropin-releasing factor, an endogenous peptide hormone. The company plans to develop the product for treatment of traumatic brain injury and peritumoral brain edema. Pivotal Phase III clinical trials are planned for the fourth quarter.

* PRIZM Pharmaceuticals Inc., of San Diego, has signed a collaborative research agreement with Chiron Technologies' Center for Gene Therapy, a business of Emeryville, Calif.-based Chiron Corp. The companies will combine PRIZM's Directin targeting technology with a proprietary Chiron gene-delivery vector as a potential treatment for cancers and other diseases.

* Quintiles Transnational Corp., of Research Triangle Park, N.C., has acquired Raleigh-based Butler Communications Inc. and its affiliated companies, including Butler Clinical Recruitment Inc., which specializes in communication programs to accelerate the recruitment of patients for clinical trials. Quintiles exchanged 214,000 shares of stock in a pooling of interest transaction and assumed approximately $2.8 million in existing Butler Clinical Recruitment debt.

* Transkaryotic Therapies Inc., of Cambridge, Mass., has received a $2.5 million milestone payment from Bridgewater, N.J.-based Hoechst Marion Roussel Inc. The payment was triggered when Hoechst accepted for development Transkaryotic's human cell line, capable of producing large quantities of a target protein. The next steps in the collaboration call for a review and refinement of the manufacturing process and detailed preclinical testing as a precursor to an investigational new drug application filing with the FDA. To date, Transkaryotic Therapies has earned $29 million from this collaboration, with the possibility of an additional $38 million.