Pfizer (NYSE:PFE), the world's largest research-based pharmaceutical company, delivered a mixed fourth-quarter report before the opening bell this morning, highlighting an adjusted EPS increase of 22% to $0.56 at the expense of a 2% decline in reported revenue to $13.56 billion.

On an operation basis, Pfizer's biggest drag came from its primary care and specialty care segments, where revenue declined 8% and 5%, respectively. Primary care revenue was negatively affected by ongoing patent expirations of LDL cholesterol-lowering medication Lipitor in developed markets, while its specialty care segment suffered from the end of a three-year collaboration agreement for rheumatoid arthritis medication Enbrel.

If there was one bright spot, it was Pfizer's oncology division, which saw revenue climb 26% on an operating basis due to a 126% year-over-year increase in Inlyta sales, and a 105% rise in Xalkori sales, excluding the negative effects of currency translation. Unfortunately, Pfizer's oncology division accounts for just 3.5% of total revenue.

Lower expenses were one of the reasons Pfizer was able to boost its adjusted EPS by 22% over the previous year as research and development expenses dipped $94 million, or 5%, from the year-ago quarter. However, the simple fact that Pfizer repurchased $4.6 billion worth of common stock, and $16.3 billion during the course of 2013, certainly helped its EPS rise as well since there are fewer shares now outstanding. Including one-time costs, and the fact that Pfizer recognized a sizable gain last year from the discontinuation of reporting results from its animal health division, Zoetis, which was spun off in February 2013, net income fell by 59%.

Looking ahead, Pfizer anticipates delivering $49.2 billion to $51.2 billion in revenue for the full year in 2014 -- a 2.7% decline from 2013 at the midpoint -- with an adjusted EPS forecast of $2.20 to $2.30, which is essentially flat from the adjusted $2.22 it reported in 2013. This forecast, according to commentary from Pfizer CFO Frank D'Amelio is based on the expected negative impact of $3 billion from increased generic competition and higher R&D expenses, but it should be counteracted by the anticipated repurchase of $5 billion in common stock in 2014.

Pfizer shares were up around 2% as of midday trading.