While some of its peers in the pharma sector are starting to recover from a wave of patent expiries on former blockbusters, Pfizer is still feeling the impact and reported lower sales and earnings in the third quarter.

The drugmaker reported net income down 19% to $2.59 billion - shy of consensus analyst estimates - on revenues down 2 per cent to $12.6 billion.

Turnover was held back by the continued impact of generic competition to cholesterol drug Lipitor (atorvastatin) and also the end of a co-promotion arrangement for Boehringer Ingelheim's chronic obstructive pulmonary disease (COPD) treatment Spiriva (tiotropium) in some markets, said chief financial officer Frank D'Amelio.

On the plus side, Pfizer's oncology portfolio put in a good performance with a 26% hike in revenues led by lung cancer drug Xalkori (crizotinib), with sales up 92% to $73 million, and Inlyta (axitinib) for kidney cancer which leaped forward 186% to $83 million.

Meanwhile, Xeljanz (tofacitinib) for arthritis continued to roll out, adding $35 million to the pot despite being rejected for approval in Europe earlier this year. Chief executive Ian Read said the firm was pleased with the launch in the US and other markets with a 53% growth in prescription volume over the second quarter.

Phase III trials of the drug in psoriasis, psoriatic arthritis and ulcerative colitis are also ongoing with results due in 2014 and 2015, he added.

"Our recently launched products are progressing at a measured and steady pace," said D'Amelio, although he pointed out that Pfizer is also facing the end of its co-promotion deal with Amgen's Enbrel (etanercept) in the US and Canada within 36 months from November 1, after which its current high-margin sales will be replaced by a royalty stream.

"These royalty payments will be much less than our current level of Enbrel profits," he noted. Enbrel contributed $932 million in sales outside North America, up 6% year-on-year.

There were also good performances for some established brands such as arthritis treatment Celebrex (celecoxib) which climbed 11% to $752 million in the quarter, as well as Pfizer's biggest-selling product Lyrica (pregabalin) for epilepsy, fibromyalgia and neuropathic pain, which was up 10% to $1.14 billion.

Meanwhile, Pfizer confirmed that from next year it will start reporting separate accounts for its generic medicines or 'value' unit, suggesting it may be following through on plans to spin out the business.

The company trimmed $1 billion of the the upper end of its revenue range forecasts for 2013, saying it now expects sales of S50.8 billion to $51.8 billion and earnings per share of $2.15-$2.20.