* Q2 loss/shr $0.25 vs est loss/shr $0.15
* Q2 rev $23.5 mln vs est $25.6 mln
* Sees FY pro forma oper loss in mid to high $40 mln range
Aug 9 (Reuters) - Isis Pharmaceuticals Inc ISIS.O posted a wider-than-expected quarterly loss, hurt by higher costs, lower investment income and accounting issues at a unit.
The company, however, said it expects financial performance to improve and reduced its operating loss outlook for 2010 by 10 percent to 20 percent to a pro-forma net operating loss in the mid-to-high $40 million range.
The revised outlook includes cash and revenue from its new partnership with GlaxoSmithKline (GSK.N) (GSK.L). In March, Isis and Glaxo entered into an agreement worth up to $1.5 billion to develop treatments for infectious diseases. [ID:nSGE62U0F9]
Second-quarter net loss was $25.2 million, or 25 cents a share, compared with $2.7 million, or 3 cents a share, a year ago. [ID:nASA00MPK]
Revenue for the quarter fell 24 percent to $23.5 million.
Analysts were expecting the company to post a loss of 15 cents a share, on revenue of $25.6 million, according to Thomson Reuters I/B/E/S.
The company, which last week reported positive data from two late-stage studies of its experimental cholesterol drug amidst safety concerns, said it expects to end the year with more than $450 million in cash.
Shares of the company closed at $9.10 Friday on Nasdaq. (Reporting by Krishnakali Sengupta in Bangalore; Editing by Don Sebastian)