BOSTON, Mass. ( TheStreet) -- Look for U.S. pharmaceutical companies to ratchet up acquisition activity -- the target being biotech and specialty drug firms, according to Credit Suisse pharmaceuticals analyst Catherine Arnold, in a research note published Thursday morning. Arnold believes that the cost-saving mega-mergers between Big Pharma are largely done, so now Big Pharma will focus on boosting revenue growth through smaller acquisitions. So, who's going to buy whom, according to Arnold? Appetizing takeover targets include Alexion Pharmaceuticals ( ALXN), Amylin Pharmaceuticals ( AMLN), Vertex Pharmaceuticals ( VRTX), BioMarin ( BMRN), Rigel ( RIGL) and Salix Pharmaceuticals ( SLXP). The potential buyers include Abbott Labs ( ABT), Bristol-Myers Squibb ( BMY), Eli Lilly ( LLY), Johnson & Johnson ( JNJ), Gilead Sciences ( GILD) and Forest Labs ( FRX).