Investors proved cautious ahead of the Federal Reserve's two-day policy meeting that ends on Wednesday.
U.S. stocks ended down on Monday, led by losses in biotech shares after disappointing news from several companies including Amgen.
The Nasdaq Biotech Index sank 4.1 percent, its biggest daily percentage loss since March 25, while the S&P Healthcare index, down 1.8 percent, was the biggest drag on the benchmark S&P 500 index.
Amgen shares led the S&P 500 and Nasdaq's decline, dropping 3.3 percent to $162.38 after U.S. regulators said Amgen's skin cancer immunotherapy cannot be considered for an accelerated review at this time.
