Frankfurt : German drugmaker Bayer reported a 15.7 percent jump in underlying core earnings for the first quarter, boosted by sales of prescription drugs, such as anti-blindness treatment Eylea and stroke prevention pill Xarelto.

First-quarter profit before interest, taxes, depreciation and amortisation (EBITDA), adjusted for one-off items, rose to 3.4 billion euros ($3.8 billion), bolstered by growth at its farming pesticides and seeds business in North America.

That was above average market expectations for 3.07 billion euros.

"Pharma was driven by a good products performance despite higher investments in R&D (research and development). Crop Science was performing surprisingly well, given the weak seeds market condition," said Peter Spengler, an analyst at DZ Bank.

The shares were seen 1.8 percent higher in pre-market trading at brokerage Lang & Schwarz.

Bayer, the inventor of aspirin and maker of Yasmin birth control pills, said it still expected adjusted EBITDA to increase by a medium single-digit percentage this year, when excluding separately-listed plastics subsidiary Covestro , which it plans to divest on the open market.

The group confirmed its full-year sales forecast, which it said now excludes Covestro, for about 35 billion euros, up from 2015 sales of 34.3 billion. ($1 = 0.8879 euros) (Editing by Victoria Bryan and Louise Heavens)