The FDA signed off on Baxalta's ($BXLT) twice-weekly upgrade on the top-selling Advate, adding another hemophilia A treatment to the company's portfolio as it faces buyout pressure from Shire ($SHPG).

The treatment, to be marketed as Adynovate, replaces the missing coagulation protein to blame for certain types of hemophilia, stopping dangerous bleeds for patients with the rare disease. The injection is a long-acting version of Advate, the world's most prescribed Factor VIII-replacement therapy and a cornerstone of Baxalta's multibillion-dollar hemophilia franchise.

Adynovate, developed as BAX 855, is a key product for Baxalta as it fights to maintain its position in the competitive hemophilia market. Rival Biogen ($BIIB) launched the first long-acting Factor VIII therapy last year with Eloctate, which can be dosed every three to 5 days. Meanwhile, Bayer is awaiting FDA approval for the twice-a-week BAY 81-8973, to be sold as Kovaltry, and Novo Nordisk ($NVO) is in Phase III with a similar treatment.

Baxalta CEO Ludwig Hantson

And maintaining growth in Baxalta's hemophilia franchise, which brought in $3.7 billion for ex-parent Baxter ($BAX) last year, would help management shake free of M&A pressure from Shire, which has maintained its interest in buying the company for about $30 billion in stock.

That buyout offer, tendered just days after Baxalta spun out from Baxter, has been repeatedly refused by CEO Ludwig Hantson. In an effort to defend itself, Baxalta has laid out plans to launch 20 new therapies by 2020, growing its annual revenue to $8.5 billion in the process.

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