Phio Pharmaceuticals Announces Exercise of Warrants for $3.1 Million Gross Proceeds MARLBOROUGH, Massachusetts - (Newsfile Corp.

Phio Pharmaceuticals Announces Exercise of

for $3.1 Million Gross Proceeds

MARLBOROUGH, Massachusetts - (Newsfile

Corp. - July 12, 2024) -- Phio Pharmaceuticals Corp. (Nasdaq: PHIO) (the "Company"), a

clinical stage biotechnology company whose proprietary INTASYL siRNA gene silencing technology is designed to make immune cells more

effective in killing tumor cells, today announced the entry into definitive agreements to exercise certain outstanding warrants to purchase

up to an aggregate of 545,286 shares of common stock of the Company originally issued in February 2020 through December 2023, having exercise

prices between $324.00 and $9.72 per share, at a reduced exercise price of $5.45 per share. The shares of common stock issuable upon exercise

of the warrants are registered pursuant to effective registration statements on Form S-1 (Nos. 333-234032, 333-238204, 333-239779, 333-271521,

333-272526 and 333-276146) and Form S-3 (No. 333-252588). The gross proceeds to the Company from the exercise of the warrants are expected

to be approximately $3.1 million, prior to deducting placement agent fees and estimated offering expenses.

H.C. Wainwright & Co. is acting as the exclusive placement agent

In consideration for the immediate exercise of the warrants for cash

and the payment of additional $0.125 per new unregistered warrant (additional $136,321.50 in the aggregate, which are included in the

gross proceeds to the Company), the exercising holders will receive new unregistered warrants to purchase shares of common stock in a

private placement pursuant to Section 4(a)(2) of the Securities Act of 1933, as amended (the "1933 Act"). The new warrants

will be exercisable for an aggregate of up to 1,090,572 shares of common stock, at an exercise price of $5.45 per share and will be immediately

exercisable upon issuance. 583,098 of the new warrants will have a term of five and one-half years from the issuance date and 507,474

of the new warrants will have a term of eighteen months from the issuance date.

The offering is expected to close on or about July 12, 2024, subject

to satisfaction of customary closing conditions. The Company intends to use the net proceeds from the offering for working capital and

other general corporate purposes.

The new warrants described above were offered in a private placement

pursuant to an applicable exemption from the registration requirements of the 1933 Act and, along with the shares of common stock issuable

upon their exercise, have not been registered under the 1933 Act, and may not be offered or sold in the United States absent registration

with the SEC or an applicable exemption from such registration requirements. The securities were offered only to accredited investors.

The Company has agreed to file a registration statement with the SEC covering the resale of the shares of common stock issuable upon exercise

of the new warrants.

This press release shall not constitute an offer to sell or a solicitation

of an offer to buy nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale

would be unlawful prior to the registration or qualification under the securities laws of any such state or jurisdiction.

About Phio Pharmaceuticals Corp.

Phio Pharmaceuticals Corp. (Nasdaq: PHIO) is a clinical stage biotechnology

company whose proprietary INTASYL siRNA gene silencing technology is designed to make immune cells more effective in killing tumor

cells. INTASYL is the only self-delivering RNAi technology focused on immuno-oncology therapeutics. INTASYL drugs precisely target specific

proteins that reduce the body's ability to fight cancer, without the need for specialized formulations or drug delivery systems.

For additional information, visit the Company's website, www.phiopharma.com.

Forward Looking Statements

This press release contains forward-looking statements within the

meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words such as "intends,"

"believes," "anticipates," "indicates," "plans," "expects," "suggests," "may,"

"would," "should," "potential," "designed to," "will," "ongoing," "estimate,"

"forecast," "target," "predict," "could" and similar references, although not all forward-looking

statements contain these words. Forward-looking statements are neither historical facts nor assurances of future performance and include

statements regarding the ability of INTASYL siRNA gene silencing technology to make immune cells more effective in killing tumor

cells, completion of the offering, the satisfaction of customary closing conditions related to the offering and the anticipated

use of proceeds therefrom. These statements are based only on our current beliefs, expectations and assumptions and are subject to inherent

uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our control. Our actual

results may differ materially from those indicated in the forward-looking statements as a result of a number of important factors, including,

but not limited to, those identified in our Annual Report on Form 10-K for the year ended December 31, 2023 and subsequent Quarterly Reports

on Form 10-Q under the caption "Risk Factors" and in other filings we periodically makes with the SEC. Readers are urged to

review these risk factors and to not act in reliance on any forward-looking statements, as actual results may differ from those contemplated

by our forward-looking statements. We do not undertake to update forward-looking statements to reflect a change in our views, events or

circumstances that occur after the date of this release, except as required by law.

Phio Pharmaceuticals Corp.