With its important multiple sclerosis business facing off against growing competition, Biogen plans to get further involved in an "attractive value creation" prospect: a biosimilars joint venture with Samsung.

The company plans to scoop up more stake in Samsung Bioepis, CFO Jeff Capello said on this week's first-quarter conference call. According to Pulse News in Korea, the biotech intends to raise its stake to up to 49.9%, while Biogen didn't immediately disclose the number of shares it plans to purchase or the total expected cost. Biogen representatives didn't immediately respond to a request for comment.

Currently, Biogen holds 5.4% of the joint venture, according to Pulse, while Samsung owns the other 94.6%. 

The companies have had success with their biosims partnership so far. The business contributed $128 million to Biogen's top liacine in the first quarter—93% more than during the same period last year. 

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On the conference call, Biogen CEO Michel Vounatsos said the European biosim business is now tracking at $500 million in sales per year. The partners' Humira biosim is set to launch there in October under an agreement with AbbVie. 

In Europe, the companies also market Benepali, a biosim to Amgen's Enbrel, and Flixabi, a biosim to Johnson & Johnson and Merck's Remicade.

The move comes as Biogen's stalwart multiple sclerosis franchise—anchored by Tecfidera—operates in an increasingly competitive field. This week, Roche executives said their new launch, Ocrevus, is among the best ever in the disease area. 

RELATED: Roche's Ocrevus is one of the best MS launches ever, but Tecentriq in I-O? Not so much

For the first quarter, Tecfidera revenues grew 3% to $987 million. Biogen is somewhat protected against the Ocrevus threat, however, as the company collects royalties on the med. In the first quarter, Ocrevus royalties represented $77 million in revenue for Biogen.