By Toni Clarke

BOSTON (Reuters) - For foreign drugmakers seeking to expand in the United States, the prospects could hardly look better.

The weak U.S. dollar is a boon to those seeking U.S. pharma assets, and it is particularly beneficial at a time U.S. drugmakers are mired in cost-cutting efforts and drug safety concerns.

"It's like the Manhattan real estate market," said David Webster, president of Webster Consulting Group, which advises pharmaceuticals companies. "What keeps it afloat are the Japanese and Europeans or whoever seems to be making money worldwide and whoever has a strong currency."

Last week, Takeda Pharmaceutical Co Ltd (4502.T: Quote, Profile, Research), Japan's biggest pharmaceuticals company, agreed to acquire Millennium Pharmaceuticals Inc MLNM.O, one of the few profitable U.S. biotechnology companies, for $8.8 billion.

The deal is the latest in a series of transactions by foreign drugmakers.

Japan's Eisai Co Ltd (4523.T: Quote, Profile, Research) recently acquired MGI Pharma Inc for $3.9 billion. Anglo-Swedish drugmaker AstraZeneca Plc (AZN.L: Quote, Profile, Research) bought biotechnology company MedImmune Inc for $15.6 billion.

Switzerland's Roche Holding AG (ROG.VX: Quote, Profile, Research) acquired Ventana Medical Systems Inc VMSI.O for $3.4 billion; GlaxoSmithKline Plc (GSK.L: Quote, Profile, Research) of Britain bought Reliant Pharmaceuticals for $1.65 billion; and Swiss drugmaker Novartis AG (NOVN.VX: Quote, Profile, Research) just agreed to pay up to $39 billion for a 77 percent stake in eye care company Alcon Inc (ACL.N: Quote, Profile, Research).

CURRENCY BENEFIT