Several major biotech and pharma companies will be reporting first quarter results this week as we head into the peak of the earnings season. Overall, about 183 S&P 500 members are scheduled to report this week and by the end of the week, more than 60% of the index’s total membership will have reported their results.According to our Earnings Trend report, the results so far show more positive earnings and revenue surprises as well as fewer negative revisions to second quarter estimates. However, despite the better-than-expected performance so far, total Q1 earnings and revenues are still expected to decline from the year-ago period thereby representing the 4th quarter in a row of earnings declines for the index.What’s in Store for Drug Stocks?Medical is one of the sectors expected to perform well in the first quarter with earnings expected to grow 2% on revenue growth of 9%. Johnson & Johnson kicked off the earnings season for pharma stocks with a beat and an improved outlook. Abbott followed suit with an earnings beat and a raised outlook.Among biotech companies, Biogen, famous for its multiple sclerosis treatments, reported better-than-expected earnings. But the majority of pharma and biotech companies are yet to report results. This week, we expect to see a flurry of earnings reports with companies like Eli Lilly and Company LLY, GlaxoSmithKline plc GSK, Vertex Pharmaceuticals Incorporated VRTX, Bristol-Myers Squibb Company BMY and AbbVie Inc. ABBV slated to report in the first half of the week.Let’s see how these players are poised ahead of the scheduled announcements.Lilly is set to report first quarter 2016 earnings results on Apr 26 before the market opens. This Zacks Rank #2 (Buy) company has a negative Earnings ESP, which makes it difficult to conclusively predict an earnings beat this quarter. While products like Trulicity, Cyramza, Humalog, and Trajenta should continue performing well, Alimta could continue to experience some softening in later lines of therapy (second line and beyond) reflecting the launch of Cyramza in the second-line setting as well as competition from immuno-oncology agents (read more: Will Currency & Competition Hurt Lilly's Q1 Earnings?). U.K.-based Glaxo will be reporting first quarter results on Apr 27. Glaxo’s Zacks Rank #3 (Hold) and Earnings ESP of 0.00% make it difficult to conclusively predict an earnings beat this quarter. Several products are facing generic competition and the Consumer Healthcare business is expected to be sluggish in the first quarter due to the year-over-year comparison in Flonase’s performance. But new products should help drive growth in the Pharma segment this year while currency will be a tailwind (read more: Glaxo Q1 Earnings: What's in Store for the Stock?). Vertex, known for its strong presence in the cystic fibrosis (CF) market, will be reporting on Apr 27 as well. Once again, it is difficult to conclusively predict an earnings beat for Vertex this quarter given the company’s Zacks Rank #3 and Earnings ESP of 0.00%. First quarter sales could be impacted by some inventory stocking in the fourth quarter. Operating expenses will also shoot up as Vertex develops its pipeline and works on expanding Kalydeco's and Orkambi’s labels and continues to invest in the Orkambi launch (read more: Vertex to Report Q1 Earnings: Is a Surprise in Store?). Bristol-Myers, which has a very strong earnings track record, is scheduled to report first-quarter 2016 results on Apr 28. However, with the company sporting a Zacks Rank #2 and a negative Earnings ESP, it is difficult to conclusively predict an earnings beat this quarter. So while cancer drugs in the company’s portfolio should continue performing well, the HIV and HCV businesses will remain under competitive pressure (read more: Bristol-Myers Q1 Earnings: Can the Stock Surprise?). AbbVie is also reporting first quarter results on Apr 28. This company, which is best known for its flagship product, Humira, is expected to beat earnings expectations – AbbVie has a Zacks Rank #3 and an Earnings ESP of +1.77%. Strong Imbruvica and Humira sales should drive performance (read more: AbbVie Likely to Beat on Q1 Earnings: Stock to Gain?). Stay Tuned! Check later on our full write-up on earnings releases of these stocks.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report BRISTOL-MYERS (BMY): Free Stock Analysis Report LILLY ELI & CO (LLY): Free Stock Analysis Report GLAXOSMITHKLINE (GSK): Free Stock Analysis Report VERTEX PHARM (VRTX): Free Stock Analysis Report ABBVIE INC (ABBV): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research