Pfizer's first-quarter net income rose 53% despite growing generic drug competition as the world's second-largest drugmaker benefited from a gain related to a joint venture with China.

But the company's results still fell short of Wall Street's expectations, and Pfizer lowered its 2013 profit forecast by 6 cents to $2.14 to $2.24 per share.

Pfizer said its net income was $2.75 billion, or 38 cents per share, down from $1.79 billion, or 28 cents per share, a year earlier.

Excluding one-time items, adjusted income was 54 cents per share, a cent less than the forecast of analysts surveyed by FactSet.

Results were boosted by a $490m gain from the transfer of some product rights to its joint venture in China.

Pfizer took charges totaling $1.66 billion, for litigation, acquisition and other costs in the same quarter last year.

The company said that revenue in the latest quarter was $13.5 billion, down 9% from $14.89 billion a year earlier and below analysts' expectations of $13.99 billion. Pfizer said unfavourable currency exchange rates reduced revenue by 1%, or four cents per share.

The rest of the drop was due to lower sales due to generic competition of its schizophrenia drug Geodon, which got generic competition in the US last March, and for its cholesterol fighter Lipitor.

After reigning as the world's top-selling drug for nearly a decade, Lipitor got generic competition in the US in November 2011 and then in much of Europe early last year. Sales of Lipitor, which once brought in about $13 billion a year, dropped 55% to $626m in the quarter.

Sales of nearly two dozen other drugs - many former blockbuster medicines with annual sales of $1 billion or more - also declined, mostly due to worsening generic competition.

The bright spots during the quarter were Lyrica, for fibromyalgia and other pain, up 12% at $1.07 billion, and anti-inflammatory pain reliever Celebrex, up 3% at $653m.