* Adjusted profit beats street by 1 cent
* Prevnar sales see bigger-than-expected fall
* Co narrows 2017 adjusted profit forecast (Adds analyst comment, updates shares)
Aug 1 (Reuters) - Pfizer Inc's quarterly revenue missed Wall Street estimates on Tuesday, hurt by falling demand for its blockbuster pneumonia vaccine Prevnar as well as older drugs.
Sales of Prevnar declined 8.2 percent to $1.15 billion, largely due to the timing of government purchases for the pediatric indication.
Sales of its copycat generics and biosimilars fell 13.5 percent in the quarter to $5.23 billion.
"Pfizer's ambition of stabilizing this book of business looks some way off," Berenburg analysts said in a note.
Revenue from its patent-protected drugs rose about 8 percent to $7.67 billion in the quarter.
Sales of its key drugs, including rheumatoid arthritis treatment Xeljanz and breast cancer treatment Ibrance beat analyst estimates.
However, overall revenue fell to $12.9 billion in the second quarter from $13.15 billion, below the analysts' estimate of $13.08 billion, according to Thomson Reuters I/B/E/S.
"These results show that Pfizer's growth drivers are still insufficient to drive meaningful sales growth against the backdrop of generic erosion," Berenberg analysts said in a note.
Net income attributable to the largest U.S. drugmaker rose to $3.07 billion, or 51 cents per share, from $2.05 billion, or 33 cents per share, a year earlier.
Excluding items, Pfizer earned 67 cents per share, beating the average analysts' estimate by a cent.
Looming patent expirations on Pfizer's sexual dysfunction treatment Viagra, pain drug Lyrica and falling Prevnar sales has pushed analysts to prescribe deals to resuscitate the company's growth.
"Over the next five years, we project the potential for approximately 25 to 30 approvals, of which up to 15 have the potential to be blockbusters," Chief Executive Ian Read said in a statement on Tuesday.
Last year, Pfizer acquired drugmaker Medivation for $14 billion and decided against splitting itself into two companies, one housing its patent-protected drug business and the other its generics business.
The drugmaker also narrowed its 2017 adjusted earnings forecast to a range of $2.54 per share to $2.60 per share. It had previously forecast a range of $2.50 per share to $2.60 per share.
The company's shares were marginally down at $33.10 before the bell on Tuesday. (Reporting by Natalie Grover in Bengaluru; Editing by Arun Koyyur)