Mission Viejo-based Aeolus Pharmaceuticals Inc. has raised $26.7 million and plans to use the money to help cover expenses as it works on developing its lead biodefense drug compound.

Aeolus filed papers with the Securities and Exchange Commission this week that “relates to the offer and sale from time to time” of up to 88.7 million shares of its common stock.

Chief Executive John McManus said that the S-1 filing, similar to a shelf registration by larger companies, was triggered by a financing deal that Aeolus completed in February.

“The financing’s really been done,” McManus said. “It’s not a sale of stock by the company to investors. The S-1 allows the investors the right, if they choose, to be able to resell their stock.”

Aeolus develops cancer and biodefense drugs, and has yet to produce a commercial product. The company currently has a five-year, $118 million research and development contract with the Biomedical Advanced Research and Development Authority, a division of the U.S. Department of Health and Human Services, covering its AEOL 10150 compound.

The company moved to raise the additional money to cover about $100,000 of monthly expenses that aren’t reimbursed under its federal government contract, McManus said.