BASEL, Switzerland (AP) -- Pharmaceutical giant Roche Holding on Wednesday announced plans to buy Arius Research Inc. of Canada for $190.4 million as the latest in a series of purchases of North American biotechnology companies.

Roche said the move would give it access to a new screening platform for antibody therapeutics, FunctionFIRST, which rapidly identifies and selects antibodies based on their ability to affect disease before progressing into clinical development.

"Arius' promising platform and early pipeline of new antibody candidates represent an excellent fit with our own progressing research in the fields of cancer and immunology," said Lee Babiss, head of global research at Roche.

Babiss said FunctionFIRST will enable Roche to strengthen its developmental portfolio, providing it with a large library of antibodies to help identify the best new drug candidates.

A Roche statement said the two companies have signed an agreement for Roche to acquire Arius in an all-cash transaction.

Roche announced Monday a $43.7 billion offer for the remaining shares of the U.S. biotechnology pioneer Genentech Inc. The Swiss company already owns 55.9 percent of the South San Francisco, Calif.-based company, manufacturer of the widely prescribed anticancer drug Avastin and other popular drugs.

On Tuesday Roche said it would buy the U.S. gene therapy company Mirus Bio Corp. for $125 million. The Madison, Wisconsin-based company is developing RNAi, or gene silencing, a technology that uses mechanisms within the body to target and "turn off" certain genes associated with cancer and other diseases.

Last year, Roche acquired rights for the gene-silencing technology of biotechnology company Alnylam Pharmaceuticals Inc. of Cambridge, Mass., as part of a deal potentially worth $1 billion.