The drug whose packaging is allegedly being imitated is Sankyo's Mevalotin, one of the company's best sellers.
Sankyo began marketing Mevalotin in 1989 and the basic patent on it expired last October, unleashing the release of generic versions by about 30 pharmaceutical firms, starting in July this year.
But exports to and sales in overseas markets showed strong growth, led by its cholesterol-restraining drug Mevalotin
, Sankyo said.
Moody's said sales of Sankyo's cholesterol reducer, Mevalotin
, sold as Pravachol in the United States, are likely to decline due to price-cutting and stronger competition from new drugs.
Group sales came to 545.07 billion yen, down 7.6% on reduced prices for prescription drugs subject to medical insurance, a decline in sales of its mainline anti-hyperlipidemic agent Mevalotin
amid intensified competition and the halt of the sale of the diabetes treatment agent.