The market's fixation on biotech continued Tuesday with ImClone Systems ( IMCL) taking its place among the session's volume leaders. After vaulting to a 52-week high of $81.05 in early trading, ImClone shares drifted lower and ended the session down $3.15, or 4.3%, to $69.94, on almost 21 million shares traded, or more than 9 times its normal trading volume. The company said first-quarter earnings came in at 76 cents a share on revenue of $109.6 million, both well ahead of consensus estimates. The biopharmaceutical company saw a jump in licensing and milestone revenue related to its cancer drug Erbitux, which was cleared for sale by the Food and Drug Administration in the first quarter. But the shares pulled back after executives told a conference call that although 2004 would be profitable, subsequent quarters' income wouldn't match numbers put up in the first quarter. Also doing big volume for a second consecutive session was OSI Pharmaceuticals ( OSIP), which skyrocketed Monday on word of clinical success in a small-cell lung cancer trial. OSI ended the day down $6.85, or 7.5%, to $84.25, with almost 23 million shares changing hands. Moving lower in heavy trading was Conexant Systems ( CNXT), which posted earnings that beat estimates last night but guided its fiscal third quarter lower. Shares of Conexant traded down 81 cents, or 14%, to $4.96, on volume of more than 55 million shares, which was almost five times its normal daily volume. Other names joining the list of Nasdaq high-volume leaders included Microsoft ( MSFT), Intel ( INTC), Cisco ( CSCO), Sirius ( SIRI) and Oracle ( ORCL). NYSE volume was led by Lucent ( LU), General Electric ( GE), Motorola ( MOT), Nortel ( NT) and EMC ( EMC).