German drugs and chemicals group Bayer plans to invest 4 billion euros ($4.54 billion) in research and development this year, its chief executive told Germany's Bild newspaper.

"That is more than ever before. The development of our new blood thinner Xarelto alone cost 2.2 billion euros," Marijn Dekkers.

Aspirin maker Bayer raised its research and development spending by 5 percent to 3.57 billion euros in 2014, representing 8.5 percent of its sales before special items. It has about 14,000 employees worldwide working in this field.