Hemispherx Biopharma Inc. said today it narrowed its first-quarter loss to $5.1 million, or 7 cents a share, from $5.9 million, or 10 cents a share, in the same quarter a year ago.

The Philadelphia biotechnology company attributed the improvement to lower general and administrative costs, primarily in employee stock-option expenses, lower interest and non-cash financing costs, and an increase in interest and other income on short-term investments.

The firm said it spent $746,000 more on research and drug development in the quarter compared to the same period last year for its experimental immune-system stimulant, Ampligen.

As of March 31, Hemispherx Biopharma said it had cash and short-term investments of $24.6 million, which was a 12 percent increase, or $2.6 million, over cash reserves as of Dec. 31.

Shares were up 2 cents to $1.60 on the American Stock Exchange.