Earnings season continues in full swing this week as pharmaceutical giants Pfizer Inc., Merck & Co. Inc. and Bristol-Myers Squibb Co. are among 40 Standard & Poor's 500 companies reporting quarterly results Tuesday. Of the S&P 500 companies that have already released results this earnings season, around 77 percent have beaten profit projections, while 49 percent have topped revenue estimates, Bloomberg data show. 

Here's a deeper look into pharmaceutical companies reporting Tuesday. 

Pfizer 

Shares of Pfizer (NYSE:PFE) edged up 0.5 percent to $34.77 in morning trading Monday after the New York company posted a 4 percent drop in quarterly revenue and cut its full-year forecast due to a stronger U.S. dollar. However, the drugmaker, which has a market capitalization of $217 billion, topped Wall Street’s earnings expectations, driven by demand for its vaccines and cancer drugs.

The drugmaker reported first-quarter net income of $2.38 billion, or earnings per share of 38 cents, on revenue of $10.86 billion, compared with a profit of $2.33 billion, or earnings per share of 36 cents, on sales of $11.3 billion a year ago. Wall Street had expected Pfizer to report first-quarter net income of $2.32 billion, or earnings per share of 46 cents, on revenue of $10.7 billion, analysts polled by Thomson Reuters said.

Pfizer now expects full-year earnings in the range of $1.95 to $2.05 per share, with revenue in the range of $44 billion to $46 billion.

Shares of Pfizer have gained more than 10 percent this year, and are up 14 percent in the last 12 months.

Merck

Shares of Merck (NYSE:MRK) jumped nearly 5 percent Tuesday to $59.90 after the drugmaker reported stronger-than-expected quarterly earnings and revenue, helped by sales of its Januvia diabetes drug and its animal health products.

Merck, which has a market value of $163 billion, saw sales of Januvia rise 4 percent to $1.4 billion last quarter from $1.3 billion a year earlier, after recording a 1.8 percent decline in sales in 2014. Meanwhile, sales of its animal health products rose 2 percent to $829 million from $813 million during the same period a year ago.

The Kenilworth, New Jersey, company turned in first-quarter net income of $953 million, or earnings per share of 33 cents, on revenue of $9.43 billion, compared with a profit of $1.71 billion, or earnings per share of 57 cents, on sales of $10.3 billion a year ago. Analysts had expected Merck to report first-quarter net income of $834.7 million, or earnings per share of 29 cents, on revenue of $9.1 billion.

Shares of Merck have dipped 0.16 percent this year, and have lost nearly 1 percent in the last 12 months.

Bristol-Myers Squibb

Shares of the biopharmaceutical company Bristol-Myers Squibb (NYSE:BMY) dropped 2 percent to $63.90 in morning trading, despite beating Wall Street’s quarterly profit and revenue estimates. Sales last quarter were boosted by higher estimates of royalties owed the company from sales of its Abilify schizophrenia treatment and sales from Orencia, a biologic drug approved for the treatment of moderate to severe rheumatoid arthritis.

Sales of Abilify rose 3 percent to $554 million from a year earlier, while revenue from Orencia jumped 10 percent to $400 million. The New York company’s strong earnings come just days after it announced its experimental drug cured hepatitis C in more than 90 percent of patients in a late-stage study.

Bristol-Myers Squibb, which has a market cap of $108 billion, reported first-quarter net income of $1.19 billion, or earnings per share of 71 cents, on revenue of $4.04 billion, compared with a profit of $937 million, or earnings per share of 56 cents, on sales of $3.8 billion a year ago. Meanwhile, Bristol-Myers boosted its outlook this year after the company's quarterly revenue rose 6 percent, boosted on strength from its cancer immunotherapy drug Yervoy, whose sales 20 percent to $325 million from a year ago. 

Shares of Bristol-Myers Squibb have gained more than 9 percent this year, and have soared nearly 31 percent in the last 12 months.