NEW YORK (TheStreet) -- Stocks drifted lower on Monday afternoon with the Nasdaq gapping from record highs set on Friday as the biotech sector declined. Investors were also showing their nerves in anticipation of Apple's (AAPL) earnings after the bell and the kickoff to the Federal Reserve's two-day meeting on Tuesday.

The S&P 500 was down 0.25%, the Dow Jones Industrial Average slid 0.12%, and the Nasdaq fell 0.58%. 

Biotech companies weighed on the Nasdaq, following the lead of Mylan (MYL) and Teva Pharmaceuticals (TEVA). The two were lower after Mylan rejected a $40 billion bid from Teva. 

"The fact that they broke off negotiations -- obviously that's impacting the market here," Peter Cardillo, chief market economist at Rockwell Global Capital, told CNBC

Celldex (CLDX), Biogen (BIIB) and Celgene (CELG) were all lower, while the Health Care SPDR ETF (XLV) declined 1.7% and the iShares Nasdaq Biotechnology Index ETF (IBB) fell 4.1%. Biotech company Celladon (CLDN) tanked nearly 81% after a trial of its heart failure treatment missed its primary and secondary endpoints.

Crude oil dropped below $57 a barrel again on Monday as infighting in Yemen continued to create waves on commodity markets. West Texas Intermediate crude fell 0.3% to $56.99 a barrel. 

"The crude complex is having a soft start to the week, stuck between trying to weigh up a potential supply disruption due to the escalating unrest in Yemen, and a stronger dollar," said Matt Smith, commodity analyst at Schneider Electric. "As Saudi Arabia deploys ground troops to its southern borders, markets remain jittery about the prospect of contagion in the Middle East."

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