Vital Therapies Inc. will sell an additional 1,312,500 common shares in its underwritten public offering of 8,750,000 shares due to the full exercise of the underwriters' overallotment option.

Including the option exercise, Vital Therapies will issue 10,062,500 shares at $4 apiece for gross proceeds of about $40.3 million, before deducting underwriting discounts and commissions and offering expenses.

The sale of the optional shares is expected to close March 31.

Vital Therapies intends to use the net proceeds to continue the clinical development of the ELAD System, working capital and other general corporate purposes.

Raymond James & Associates Inc. is acting as the sole book-running manager of the issue, with National Securities Corp. acting as the co-manager.