DOW JONES NEWSWIRES

Standard & Poor's said online travel agent Priceline.com Inc. (PCLN) will replace Schering-Plough Corp. (SGP) in the S&P 500 index once that pharmaceutical company is being acquired by rival Merck & Co. Inc. (MRK).

Standard & Poor's didn't disclose when the changes would occur, as Schering-Plough's deal with Merck is pending final approval.

Earlier Thursday, the Federal Trade Commission cleared Merck's $41 billion acquisition of Schering-Plough.

The index recently lost another drug maker when Wyeth (WYE) was replaced by thin-film solar panel maker First Solar Inc. (FSLR) because of Wyeth's acquisition by larger rival Pfizer Inc. (PFE).

Priceline shares were up 4.5% to $170 in after-hours trading. The stock has pulled back from its 52-week high hit Monday but remains up nearly quadruple over the past year.

-By Kathy Shwiff, Dow Jones Newswires; 212-416-2357; Kathy.Shwiff@dowjones.com