First-quarter Kyprolis sales of $68 million helped increase Amgen’s first-quarter sales by 5% compared to the same period last year.

While the biotech saw increased demand and sales for drugs, including bone biologic Prolia and anemia product Epogen, demand and sales declined for some brands, with sales of RA shot Enbrel slipping 5% and kidney drug Aranesp sales falling 2% compared to the same period last year. The company attributed some of this fall-off to inventory draw-down.