Celgene Corporation (NASDAQ:CELG) reported second-quarter earnings before the bell today, posting an adjusted diluted EPS of $0.90 on a split-adjusted basis, narrowly beating the Street's expectations by $0.01. The company generated $1.873 billion in revenue during the quarter, topping consensus estimates by $23 million. 

The company's flagship cancer drug Revlimid generated worldwide sales of $1.214 billion for the quarter, an increase of 15% year-over-year. Based on these strong results, Celgene increased the upper bound of its 2014 sales guidance for Revlimid to $5.0 billion, from $4.95 billion. 

Abraxane sales also saw a nice uptick for the quarter, rising by 39% to $215 million, compared to the same period a year ago. This dramatic increase was due mainly to the drug's recent label expansion as a treatment for advanced pancreatic cancer. 

Pomalyst sales continued to show promise in the second quarter, increasing by 143% to $161 million, reflecting the company's substantial marketing efforts for the drug. 

Vidaza sales, by contrast, nosedived in the quarter by 28.1% to $152 million, compared to a year ago, as a result of generic azacitidine being introduced into the U.S. market.

Although Celgene posted a healthy 17% increase in revenue year-over-year for the quarter, shares are falling today following this earnings release. My view is that investors were expecting a wider beat based on the company's recent history of posting stellar quarterly results.