There wasn't much to get excited about the last time Pfizer (NYSE:PFE) reported its quarterly results. While the big pharma company beat analysts' consensus earnings estimate, it also posted a 2% year-over-year revenue decline.

Pfizer announces its third-quarter results before the market opens on Oct. 31. Will the company give investors a Halloween treat -- or a disappointing trick? Here are three key things to watch that will make the difference.

Man with magnifying glass looking at report

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1. Momentum for major growth drivers

The two brightest spots for Pfizer in the second quarter of 2017 were Ibrance and Eliquis. Cancer drug Ibrance generated revenue of $853 million in the quarter, an impressive 66% year-over-year jump. Pfizer and partner Bristol-Myers Squibb co-market anticoagulant Eliquis. Pfizer's share of the drug's sales in the last quarter totaled $605 million, up nearly 50% over the prior-year period. If Ibrance and Eliquis keep their strong momentum going, Pfizer could have a pretty good third quarter.

So far, Ibrance appears to be faring quite well in the face of competition from Novartis' (NYSE:NVS) Kisqali. However, it's still early -- Novartis only won FDA approval for the drug in treating metastatic breast cancer in March. The third quarter could be more revealing as to how much Kisqali could impact sales for Ibrance. 

2. How acquisition assets are paying off

In 2016, Pfizer paid around $14.2 billion to acquire Medivation and close to $5.2 billion to buy Anacor. The third quarter should show some progress for the top assets gained from these transactions: Xtandi and Eucrisa.

In the second quarter, Xtandi sales totaled $300.7 million, $141 million of which went to Pfizer, with the remainder to its partner, Astellas Pharma. There are more urologists prescribing the drug than ever, so Pfizer could see better results in the third quarter. Eucrisa won FDA approval at the end of 2016. In part because of inventory buildups, revenue for the atopic dermatitis drug hasn't grown much yet. However, Pfizer CEO Ian Read said in August that he anticipates stronger revenue growth from Eucrisa in the third quarter. 

3. Improvement for weak links

Pfizer's weakest links right now include its essential health segment, autoimmune disease drug Enbrel, and pneumococcal vaccine Prevnar 13. How weak these are in the third quarter could be critical to the drugmaker's overall performance.

The essential health segment will probably continue to experience declining sales as a result of loss of exclusivity for antidepressant Pristiq earlier this year. Although sales for Pfizer's biosimilars are growing, the company's biosimilar to Remicade hasn't performed up to expectations, in large part due to Johnson & Johnson's effective efforts in making deals with private payers. Meanwhile, Pfizer's own problems with biosimilar competition to Enbrel aren't likely to ease up much. 

Perhaps the biggest question mark will be with Prevnar 13. Despite a revenue decline last quarter, it remains Pfizer's top-selling product. I wouldn't look for much improvement for the vaccine until next year, when Pfizer should lock down more reimbursement arrangements in Europe. However, any hint of stabilization in sales for Prevnar 13 in the third quarter would be good news for the company.

Beyond the numbers

These three areas will be the keys for Pfizer's financial performance in the third quarter. However, investors should also pay close attention to what the company says about other matters that could make a huge difference for its future.

One is pipeline activity. Pfizer has 32 late-stage clinical programs and hopes to win approval for up to 15 new blockbuster drugs over the next five years. Another is business development possibilities. Company executives have stated in the past that they were waiting to see what happens with corporate tax reform in the U.S. The U.S. Senate recently passed a budget resolution, an important prerequisite for tax reform. Although there are several more hurdles, the chances for major tax policy changes appear to be more tangible than ever.

Finally, Pfizer announced earlier this month that it was evaluating the possibility of either selling or spinning off its consumer healthcare business. Don't count on much new information on this front, but pretty much everyone who follows Pfizer will attempt to read between the lines of anything said to get a feel for which direction the company might take.

All in all, there are quite a few ways that Pfizer could generate some excitement -- or some angst -- for investors with its third-quarter update. We'll know on Halloween if the drugmaker delivers a "boo," a "booyah," or just a "blah."

Keith Speights owns shares of Pfizer. The Motley Fool owns shares of and recommends Johnson & Johnson. The Motley Fool has a disclosure policy.