* Company gives no reason for departure
* H1 adj net profit down 20 pct, matching expectations
* H1 sales down 8 pct, worse than forecast
FRANKFURT, Aug 12 (Reuters) - German generic-drugs maker
Stada Arzneimittel
In a surprise release the evening before the scheduled date, the world's fifth-largest generic drug maker said its earnings were hurt by competition and weak currencies in its main foreign markets Russia and Serbia.
Chief Financial Officer Wolfgang Jeblonski would leave with immediately "by mutual consent," the company said on Wednesday, declining to elaborate on his departure.
Chief Executive Hartmut Retzlaff and fellow executive board member Christof Schumann would take over Jeblonski's responsibilities on an interim basis, Stada added.
Jeblonski, with Stada since 1991, had a contract set to expire in August 2011.
Full-year sales and earnings could still beat last year's levels, the world's fifth-largest generics maker said, repeating an earlier assessment.
Stada also reiterated that 2009 adjusted earnings before interest, tax, depreciation and amortisation should amount to at least 250 million euros, down as much as 15 percent from the year before.
First-half net profit, adjusted for one-offs including currency and interest-rate hedging, fell to 52.1 million euros ($73.60 million), dragged lower by a 2.5 million writedown on irrecoverable receivables from some Serbian drug distributors.
Stada's first-half group sales fell 8 percent to 755.2 million euros, less than the 771 million euros expected by analysts on average.
Sales in Germany, its largest market, slid 5 percent as health insurers increasingly tendered bulk procurement deals of generic drugs at a discount, leaving Stada grappling for contracts and weighing on prices.
The company said it planned to step up its cost-cutting measures, aiming for a double-digit million euro contribution to annual earnings from next year.
Germany's largest health insurer AOK is spearheading a move by insurers towards bulk procurement deals to cut the cost of off-patent drugs, upsetting generic makers' marketing strategy that used to be targeted at doctors.
Stada derives more than a third of group sales from Germany, with Russia and Serbia accounting for about 10 percent each.
The shares trade at 10.2 times estimated 12-months forward earnings, slightly below the healthcare sector's average multiple, according to StarMine, which weights estimates according to analysts' track record. (Reporting by Ludwig Burger and Patricia Gugau. Editing by Robert MacMillan)