LINDA A. JOHNSONTRENTON, N.J. (AP) ¿ Merck & Co. said Thursday it is making another deal in its strategy to become a top maker of biotech drugs, buying a British company that makes them. Merck, the world's second-biggest drugmaker, said its United Kingdom subsidiary, Merck Sharp & Dohme Ltd., has agreed to acquire Avecia Biologics from its parent holding company. Specific financial terms of the deal were not disclosed, but Merck spokesman Ian McConnell said the value is well below $1 billion. Avecia has been making small amounts of biotech drugs for use in patient tests of experimental treatments for heart disease, blood disorders and cancers for a number of companies since 1998. The drugs are "manufactured" in fermentation tanks containing rapidly reproducing cells including yeast and E. coli, with the active molecule then separated out and purified to produce medication. The company, which is based in Billingham, U.K., and employs 500 people, is making a drug for commercial sale for the first time, for client Dyax Corp. Avecia spokeswoman Bridget Hall said that drug, soon to be launched under the brand name Kalbitor, is for swelling in the extremities. Biologics, or biotech drugs, are grown in mammal, yeast or other cells rather than chemically synthesized like traditional pills. They are one of three areas that Merck, based in Whitehouse Station, N.J., is targeting for growth.