Note 1 - Organization and Significant Accounting Policies	6 Months Ended
Jun. 30, 2026
Notes to Financial Statements
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	1. Organization and Significant Accounting Policies *Nature of Operations* Phio Pharmaceuticals Corp. (“Phio” or the “Company”) is a clinical stage biopharmaceutical company whose proprietary INTASYL® self-delivering small interfering RNAi(siRNA) technology is designed to make immune cells more effective in killing tumor cells. The Company is developing therapeutics that are designed to leverage INTASYL to precisely target specific proteins that reduce the body’s ability to fight cancer, without the need for specialized formulations or drug delivery systems. The Company is committed to discovering and developing innovative cancer treatments for patients by creating new pathways toward a cancer-free future. Phio was incorporated in the state of Delaware in 2011 as RXi Pharmaceuticals Corporation. On November 19, 2018, the Company changed its name to Phio Pharmaceuticals Corp., to reflect its transition from a platform company to one that is fully committed to developing groundbreaking immuno-oncology therapeutics. *Basis of Presentation* The accompanying condensed consolidated financial statements are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). Certain information and footnote disclosures that are included in the Company’s annual consolidated financial statements, but that are not required for interim reporting purposes, have been condensed or omitted. In the opinion of management, the interim condensed consolidated financial statements reflect all adjustments necessary for a fair presentation of results for the periods presented. These statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s most recent Annual Report on Form 10-K for the year ended December 31, 2025, as filed with the Securities and Exchange Commission (the “SEC”) on March 5, 2026 (the “2025 Form 10-K”). Interim results are not necessarily indicative of results for a full year. *Principles of Consolidation* The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, MirImmune, LLC. All material intercompany accounts have been eliminated in consolidation. *Segments* The Company operates as one operating segment and all assets are located in the United States. *Use of Estimates* The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The areas subject to significant estimates and judgment include, among others, those related to the fair value of equity awards, accruals for research and development expenses, useful lives of property and equipment, and the valuation allowance on the Company’s deferred tax assets. On an ongoing basis the Company evaluates its estimates and bases its estimates on historical experience and other relevant assumptions that the Company believes are reasonable under the circumstances. Actual results could differ materially from these estimates. *Liquidity* The Company has reported recurring losses from operations since its inception and expects to continue to have negative cash flows from operations for the foreseeable future. Historically, the Company’s primary source of funding has been from sales of its securities. The Company’s ability to continue to fund its operations is dependent on obtaining funding from third parties, such as proceeds from the issuance of debt, sale of equity, or strategic opportunities, in order to maintain its operations. This is dependent on a number of factors, including the market demand or liquidity of the Company’s common stock ("Common Stock"). There is no guarantee that debt, additional equity or other funding will be available to the Company on acceptable terms, or at all. If the Company fails to obtain additional funding when needed, the Company would be forced to scale back or terminate its operations or seek to merge with or to be acquired by another company. Based on current cash flow projections, the Company believes it has sufficient cash and cash equivalents, including net proceeds from its January 2025 Offerings, July 2025 Financing, and November 2025 Financing, (collectively, "the 2025 Financings"), to meet its current planned obligations for at least 12 months from the date these financial statements are issued. The Company has limited cash resources, has incurred recurring operating losses and negative cash flows from its operations since its inception and has not yet recognized any product revenues. These factors have previously raised doubt about the Company’s ability to continue as a going concern. *Summary of Significant Accounting Policies* The Company’s significant accounting policies as of June 30, 2026, are consistent with those described in the Company’s Annual Report on Form 10‑K for the year ended December 31, 2025. There have been no material changes during the current period. *Recent Accounting Pronouncements* In November 2024, the FASB issued ASU 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosure (Subtopic 220-40): Disaggregation of Income Statement Expenses,” which requires additional disclosure about the specific expense categories in the notes to financial statements at interim and annual reporting periods. The amendments in this ASU do not change or remove current expense disclosure requirements but affect where this information appears in the notes to financial statements. This ASU is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027, with early adoption permitted. Upon adoption, the guidance can be applied prospectively or retrospectively. The Company is currently evaluating the impact that ASU 2024-03 will have on its consolidated financial statements. Recent Tax Legislation On July 4, 2025, the One Big Beautiful Bill Act (the “OBBBA”) was enacted in the U.S. The OBBBA includes significant provisions, such as the permanent extension of certain expiring provisions of the Tax Cuts and Jobs Act, modifications to the international tax framework and the restoration of favorable tax treatment for certain business provisions and allows immediate expensing of certain domestic research and experimental expenditures under new Section 174A of the Internal Revenue Code. The Company has not had a material impact from the OBBBA to its consolidated financial statements.

Note 1 - Organization and Significant Accounting Policies

6 Months Ended

Jun. 30, 2026

Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]

1. Organization and Significant Accounting Policies

Nature of Operations

Phio Pharmaceuticals Corp. (“Phio” or the “Company”) is a clinical stage biopharmaceutical company whose proprietary INTASYL® self-delivering small interfering RNAi(siRNA) technology is designed to make immune cells more effective in killing tumor cells. The Company is developing therapeutics that are designed to leverage INTASYL to precisely target specific proteins that reduce the body’s ability to fight cancer, without the need for specialized formulations or drug delivery systems. The Company is committed to discovering and developing innovative cancer treatments for patients by creating new pathways toward a cancer-free future.

Phio was incorporated in the state of Delaware in 2011 as RXi Pharmaceuticals Corporation. On November 19, 2018, the Company changed its name to Phio Pharmaceuticals Corp., to reflect its transition from a platform company to one that is fully committed to developing groundbreaking immuno-oncology therapeutics.

Basis of Presentation

The accompanying condensed consolidated financial statements are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). Certain information and footnote disclosures that are included in the Company’s annual consolidated financial statements, but that are not required for interim reporting purposes, have been condensed or omitted. In the opinion of management, the interim condensed consolidated financial statements reflect all adjustments necessary for a fair presentation of results for the periods presented.

These statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s most recent Annual Report on Form 10-K for the year ended December 31, 2025, as filed with the Securities and Exchange Commission (the “SEC”) on March 5, 2026 (the “2025 Form 10-K”). Interim results are not necessarily indicative of results for a full year.

Principles of Consolidation

The condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, MirImmune, LLC. All material intercompany accounts have been eliminated in consolidation.

Segments

The Company operates as one operating segment and all assets are located in the United States.

Use of Estimates

The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The areas subject to significant estimates and judgment include, among others, those related to the fair value of equity awards, accruals for research and development expenses, useful lives of property and equipment, and the valuation allowance on the Company’s deferred tax assets. On an ongoing basis the Company evaluates its estimates and bases its estimates on historical experience and other relevant assumptions that the Company believes are reasonable under the circumstances. Actual results could differ materially from these estimates.

Liquidity

The Company has reported recurring losses from operations since its inception and expects to continue to have negative cash flows from operations for the foreseeable future. Historically, the Company’s primary source of funding has been from sales of its securities. The Company’s ability to continue to fund its operations is dependent on obtaining funding from third parties, such as proceeds from the issuance of debt, sale of equity, or strategic opportunities, in order to maintain its operations. This is dependent on a number of factors, including the market demand or liquidity of the Company’s common stock ("Common Stock"). There is no guarantee that debt, additional equity or other funding will be available to the Company on acceptable terms, or at all. If the Company fails to obtain additional funding when needed, the Company would be forced to scale back or terminate its operations or seek to merge with or to be acquired by another company.

Based on current cash flow projections, the Company believes it has sufficient cash and cash equivalents, including net proceeds from its January 2025 Offerings, July 2025 Financing, and November 2025 Financing, (collectively, "the 2025 Financings"), to meet its current planned obligations for at least 12 months from the date these financial statements are issued. The Company has limited cash resources, has incurred recurring operating losses and negative cash flows from its operations since its inception and has not yet recognized any product revenues. These factors have previously raised doubt about the Company’s ability to continue as a going concern.

Summary of Significant Accounting Policies

The Company’s significant accounting policies as of June 30, 2026, are consistent with those described in the Company’s Annual Report on Form 10‑K for the year ended December 31, 2025. There have been no material changes during the current period.

Recent Accounting Pronouncements

In November 2024, the FASB issued ASU 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosure (Subtopic 220-40): Disaggregation of Income Statement Expenses,” which requires additional disclosure about the specific expense categories in the notes to financial statements at interim and annual reporting periods. The amendments in this ASU do not change or remove current expense disclosure requirements but affect where this information appears in the notes to financial statements. This ASU is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027, with early adoption permitted. Upon adoption, the guidance can be applied prospectively or retrospectively. The Company is currently evaluating the impact that ASU 2024-03 will have on its consolidated financial statements.

Recent Tax Legislation

On July 4, 2025, the One Big Beautiful Bill Act (the “OBBBA”) was enacted in the U.S. The OBBBA includes significant provisions, such as the permanent extension of certain expiring provisions of the Tax Cuts and Jobs Act, modifications to the international tax framework and the restoration of favorable tax treatment for certain business provisions and allows immediate expensing of certain domestic research and experimental expenditures under new Section 174A of the Internal Revenue Code. The Company has not had a material impact from the OBBBA to its consolidated financial statements.