Amgen's ( AMGN) shares were strengthening after a published report said a potential competitor to the company's valuable anemia drugs might be delayed by two years before reaching the market. Reuters reported Wednesday that Switzerland's Roche plans to seek U.S. approval for Cera, a drug for treating anemia caused by chemotherapy, in 2009. The report said the drug would then be targeted to go on sale in 2010, as much as two years beyond the date investors were expecting. Shares of Amgen were gaining $3.91, or 5.4%, to $76.80. Volume at midday was more than triple the average for a full session during the last three months. The stock was as high as $80.03 earlier in the trading day. According to the news report, Roche still expects to seek approval in the U.S. this year to sell Cera for anemia associated with kidney disease, putting the possible launch next year. Amgen sells the anemia drugs Epogen and Aranesp, which together had sales of $5.8 billion last year. Amgen is the world's biggest biotech company by market capitalization, sporting a value of $94.7 billion. Genentech ( DNA) is second, with a market cap of $90.8 billion.