Chemical and Pharmaceutical company Bayer AG slid to an enormous 4.4% fall in Frankfurt trading because of a slump at the German drug and chemical maker's plastics unit.

Bayer, based in Leverkusen, fell by 1.41 Euros to 47.98 Euros. The stock was the biggest loser in Germany's benchmark DAX Index of 30 biggest companies, which gained 0.8%.

The worst slump in 35 years drove 2009 earnings at the Material Science unit down by 59%. Bayer aims to increase group underlying earnings toward 7 Billion Euros and expects to see revenue rising more than 5%.

"The guidance for 2010 for sales was okay, but adjusted Ebitda was below expectations -- though I think it's conservative", said Daniel Wendorff, a Frankfurt-based Analyst for Commerzbank AG.

Marijn Dekkers, the former CEO of Thermo Fisher Scientific Inc. will replace the current Chief Executive Officer Werner Wenning, 63, who has led Germany's largest drug maker since April 2002 and has spent more than 40 years at the company.

Bayer plans to reply to the U. S. Food and Drug Administration's letter on ant clotting drug Xarelto for patients undergoing hip or knee replacement surgery in the later months of the year and plans first filings for its use in preventing stroke in patients with atrial fibrillation.

Wenning said that he was optimistic and expected the adjusted sales grew by more than 5%.