Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) PHIO PHARMACEUTICALS CORP. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Delaware 45-3215903 (I.R.S. Employer Identification No.) 11 Apex Drive, Suite 300A PMB 2006, Marlborough, Massachusetts 01752 ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 ...

For the quarterly period ended September 30, 2023 Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-36304 Phio Pharmaceuticals Corp. (Exact name of registrant as specified in its charter) Delaware 45-3215903 (State o ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-36304 Phio Pharmaceuticals Corp. (Exact name of registrant as specified in its charter) Delaware 45-3215903 (State or oth ...

Table of Contents For the transition period from to Commission File Number: 001-36304 Phio Pharmaceuticals Corp. (Exact name of registrant as specified in its charter) UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Delaware 45-3215903 (State or ot ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-36304 PHIO PHARMACEUTICALS CORP. (Exact name of registrant as specified in its charter) (State or other jurisdictio ...

[Part I — FINANCIAL INFORMATION](index=3&type=section&id=Part%20I%20%E2%80%94%20FINANCIAL%20INFORMATION) [Financial Statements](index=3&type=section&id=ITEM%201.%20FINANCIAL%20STATEMENTS) Phio Pharmaceuticals Corp.'s unaudited condensed consolidated financial statements as of September 30, 2022, show decreased cash and total assets, continued net losses of **$8.7 million**, and stable operating cash usage compared to 2021 [Condensed Consolidated Balance Sheets](index=3&type=section&id=Condensed%20Consolidated%20Balance%20Sheets) Condensed Consolidated Balance Sheet Highlights (in thousands) | Account | Sep 30, 2022 | Dec 31, 2021 | | :--- | :--- | :--- | | Cash | $14,484 | $24,057 | | Total current assets | $15,377 | $24,727 | | Total assets | $15,791 | $25,170 | | Total current liabilities | $2,194 | $3,068 | | Total liabilities | $2,264 | $3,238 | | Total stockholders' equity | $13,527 | $21,932 | [Condensed Consolidated Statements of Operations](index=4&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations) Operating Results for the Three Months Ended September 30 (in thousands, except per share data) | Metric | 2022 | 2021 | | :--- | :--- | :--- | | Research and development | $2,508 | $2,673 | | General and administrative | $1,063 | $1,066 | | Total operating expenses | $3,571 | $3,739 | | Operating loss | $(3,571) | $(3,739) | | Net loss | $(3,576) | $(3,742) | | Net loss per common share (Basic & Diluted) | $(0.26) | $(0.28) | Operating Results for the Nine Months Ended September 30 (in thousands, except per share data) | Metric | 2022 | 2021 | | :--- | :--- | :--- | | Research and development | $5,398 | $6,661 | | General and administrative | $3,334 | $3,400 | | Total operating expenses | $8,732 | $10,061 | | Operating loss | $(8,732) | $(10,061) | | Net loss | $(8,749) | $(9,836) | | Net loss per common share (Basic & Diluted) | $(0.64) | $(0.78) | [Condensed Consolidated Statements of Stockholders' Equity](index=5&type=section&id=Condensed%20Consolidated%20Statements%20of%20Stockholders%27%20Equity) - Total stockholders' equity decreased from **$21.9 million** at December 31, 2021, to **$13.5 million** at September 30, 2022, primarily driven by the net loss of **$8.7 million** for the nine-month period[15](index=15&type=chunk) - In contrast, during the nine months ended September 30, 2021, stockholders' equity increased from **$13.0 million** to **$25.2 million**, largely due to **$19.6 million** in net proceeds from a private placement and a registered direct offering, and **$2.1 million** from warrant exercises[16](index=16&type=chunk) [Condensed Consolidated Statements of Cash Flows](index=6&type=section&id=Condensed%20Consolidated%20Statements%20of%20Cash%20Flows) Cash Flow Summary for the Nine Months Ended September 30 (in thousands) | Cash Flow Activity | 2022 | 2021 | | :--- | :--- | :--- | | Net cash used in operating activities | $(9,424) | $(9,387) | | Net cash used in investing activities | $(121) | $(51) | | Net cash (used in) provided by financing activities | $(28) | $21,723 | | Net (decrease) increase in cash and restricted cash | $(9,573) | $12,285 | | Cash and restricted cash at end of period | $14,534 | $26,579 | [Notes to Condensed Consolidated Financial Statements](index=7&type=section&id=Notes%20to%20Condensed%20Consolidated%20Financial%20Statements) - The company believes its existing cash is sufficient to fund operations for at least the next 12 months from the date of the financial statements' release[23](index=23&type=chunk) - In February 2021, the Small Business Administration approved the full forgiveness of the company's Paycheck Protection Program (PPP) loan, resulting in a recognized gain on debt extinguishment of **$233,000** for the nine months ended September 30, 2021[39](index=39&type=chunk) - In March 2021, the company entered into a clinical co-development collaboration with AgonOx, Inc., committing to future payments of up to **$4.0 million** to reimburse AgonOx for clinical trial expenses, with no expenses incurred under this agreement as of September 30, 2022[56](index=56&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=14&type=section&id=ITEM%202.%20MANAGEMENT%27S%20DISCUSSION%20AND%20ANALYSIS%20OF%20FINANCIAL%20CONDITION%20AND%20RESULTS%20OF%20OPERATIONS) Management discusses the company's focus on developing immuno-oncology therapeutics, with lead candidate PH-762 in Phase 1b trials and PH-894 IND-enabling studies nearing completion, noting decreased operating expenses and sufficient cash for the next 12 months [Overview](index=14&type=section&id=Overview) - Phio is developing therapeutics using its INTASYL™ self-delivering RNAi technology to target tumor and immune cells, aiming to strengthen the immune system and weaken tumor defenses[61](index=61&type=chunk) - Lead product candidate PH-762 is in a Phase 1b clinical trial for advanced melanoma, with top-line data from the first group of subjects anticipated in Q1 2023[65](index=65&type=chunk)[67](index=67&type=chunk) - Second product candidate PH-894 is designed to silence the epigenetic protein BRD4, with IND-enabling studies expected to be finalized in Q4 2022[68](index=68&type=chunk)[69](index=69&type=chunk) - The company is collaborating with AgonOx, Inc. to develop T cell-based therapies using PH-762 and AgonOx's DP TIL technology, with a clinical trial expected to start in Q4 2022[74](index=74&type=chunk) [Results of Operations](index=18&type=section&id=Results%20of%20Operations) Operating Expenses Comparison (in thousands) | Expense Category | 3 Months Ended Sep 30, 2022 | 3 Months Ended Sep 30, 2021 | 9 Months Ended Sep 30, 2022 | 9 Months Ended Sep 30, 2021 | | :--- | :--- | :--- | :--- | :--- | | Research and development | $2,508 | $2,673 | $5,398 | $6,661 | | General and administrative | $1,063 | $1,066 | $3,334 | $3,400 | | **Total operating expenses** | **$3,571** | **$3,739** | **$8,732** | **$10,061** | - R&D expenses for the nine months ended Sep 30, 2022 decreased by **19%** YoY, primarily due to lower manufacturing and preclinical study costs for PH-762 in the prior year, partially offset by increased costs for PH-894 preclinical studies in the current year[87](index=87&type=chunk) - General and administrative expenses remained relatively flat for both the three and nine-month periods compared to the prior year[89](index=89&type=chunk)[90](index=90&type=chunk) [Liquidity and Capital Resources](index=19&type=section&id=Liquidity%20and%20Capital%20Resources) - As of September 30, 2022, the company had cash of **$14.5 million**, compared to **$24.1 million** at December 31, 2021[92](index=92&type=chunk) - Management believes that existing cash is sufficient to fund operations for at least the next 12 months[93](index=93&type=chunk) - Net cash used in operating activities was **$9.4 million** for the nine months ended September 30, 2022, consistent with the prior year period[97](index=97&type=chunk)[98](index=98&type=chunk) - Net cash from financing activities decreased significantly from **$21.7 million** provided in the first nine months of 2021 (from capital raising and warrant exercises) to **$28,000** used in the same period of 2022[100](index=100&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=21&type=section&id=ITEM%203.%20QUANTITATIVE%20AND%20QUALITATIVE%20DISCLOSURES%20ABOUT%20MARKET%20RISK) As a smaller reporting company, Phio Pharmaceuticals is not required to provide quantitative and qualitative disclosures about market risk - As a smaller reporting company, Phio Pharmaceuticals is not required to provide quantitative and qualitative disclosures about market risk[101](index=101&type=chunk) [Controls and Procedures](index=21&type=section&id=ITEM%204.%20CONTROLS%20AND%20PROCEDURES) Management concluded the company's disclosure controls and procedures were effective as of September 30, 2022, with no material changes to internal control over financial reporting during the quarter - Management concluded that the company's disclosure controls and procedures were effective at the reasonable assurance level as of the end of the period covered by the report[103](index=103&type=chunk) - There were no changes in internal control over financial reporting during the quarter ended September 30, 2022, that have materially affected, or are reasonably likely to materially affect, internal controls[104](index=104&type=chunk) [Part II — OTHER INFORMATION](index=22&type=section&id=Part%20II%20%E2%80%94%20OTHER%20INFORMATION) [Legal Proceedings](index=22&type=section&id=ITEM%201.%20LEGAL%20PROCEEDINGS) The company is not currently a party to any actual or threatened material legal proceedings - To the company's knowledge, it is not currently a party to any actual or threatened material legal proceedings[107](index=107&type=chunk) [Risk Factors](index=22&type=section&id=ITEM%201A.%20RISK%20FACTORS) The company faces a new risk factor regarding non-compliance with Nasdaq's minimum bid price requirement, with an extension granted until February 20, 2023, to regain compliance and avoid delisting - On February 25, 2022, the company received a notice from Nasdaq for non-compliance with the minimum bid price requirement of **$1.00** per share[110](index=110&type=chunk) - On August 25, 2022, Nasdaq granted an additional **180-day** period, until February 20, 2023, for the company to regain compliance[111](index=111&type=chunk) - Failure to regain compliance could lead to delisting, which would adversely impact the liquidity and market price of the company's common stock and its ability to raise future financing[112](index=112&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=22&type=section&id=ITEM%202.%20UNREGISTERED%20SALES%20OF%20EQUITY%20SECURITIES%20AND%20USE%20OF%20PROCEEDS) The company reports no previously undisclosed sales or issuances of unregistered equity securities - No previously undisclosed sales or issuances of unregistered securities occurred[113](index=113&type=chunk) [Defaults Upon Senior Securities](index=22&type=section&id=ITEM%203.%20DEFAULTS%20UPON%20SENIOR%20SECURITIES) The company reports no defaults upon senior securities - None[114](index=114&type=chunk) [Mine Safety Disclosures](index=22&type=section&id=ITEM%204.%20MINE%20SAFETY%20DISCLOSURES) This item is not applicable to the company - Not applicable[115](index=115&type=chunk) [Other Information](index=22&type=section&id=ITEM%205.%20OTHER%20INFORMATION) The company reports no other information - None[116](index=116&type=chunk) [Exhibits](index=23&type=section&id=ITEM%206.%20EXHIBITS) This section lists exhibits filed with the Form 10-Q, including Sarbanes-Oxley certifications and Inline XBRL documents - The report includes an index of exhibits filed, such as Sarbanes-Oxley Act certifications (31.1, 32.1) and Inline XBRL data files[119](index=119&type=chunk)

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-36304 Phio Pharmaceuticals Corp. (Exact name of registrant as specified in its charter) Delaware 45-3215903 (State of inc ...

Part I [Financial Statements (Unaudited)](index=3&type=section&id=Item%201.%20Financial%20Statements) Presents Phio Pharmaceuticals Corp.'s unaudited condensed consolidated financial statements, showing reduced net loss and sufficient cash [Condensed Consolidated Balance Sheets](index=3&type=section&id=Condensed%20Consolidated%20Balance%20Sheets) The balance sheet reflects a decrease in total assets and stockholders' equity, primarily due to reduced cash balances Condensed Consolidated Balance Sheet Highlights (in thousands) | Account | March 31, 2022 | December 31, 2021 | | :--- | :--- | :--- | | **Assets** | | | | Cash | $20,459 | $24,057 | | Total current assets | $21,667 | $24,727 | | **Total assets** | **$22,162** | **$25,170** | | **Liabilities & Equity** | | | | Total current liabilities | $2,573 | $3,068 | | **Total liabilities** | **$2,711** | **$3,238** | | **Total stockholders' equity** | **$19,451** | **$21,932** | [Condensed Consolidated Statements of Operations](index=4&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations) The company reported a reduced net loss for the quarter, primarily driven by decreased research and development expenses Condensed Consolidated Statements of Operations (in thousands, except per share data) | Metric | Three Months Ended March 31, 2022 | Three Months Ended March 31, 2021 | | :--- | :--- | :--- | | Research and development | $1,586 | $2,429 | | General and administrative | $1,054 | $1,209 | | **Total operating expenses** | **$2,640** | **$3,638** | | **Operating loss** | **($2,640)** | **($3,638)** | | **Net loss** | **($2,642)** | **($3,407)** | | Net loss per share (Basic & Diluted) | ($0.19) | ($0.32) | [Condensed Consolidated Statements of Stockholders' Equity](index=5&type=section&id=Condensed%20Consolidated%20Statements%20of%20Stockholders%27%20Equity) Stockholders' equity decreased due to the net loss, contrasting with prior year's increase from stock offerings - In Q1 2022, total stockholders' equity decreased by **$2.48 million**, mainly driven by the **$2.64 million net loss**[14](index=14&type=chunk) - In Q1 2021, the company raised a total of **$19.58 million** (net) from a private placement and a registered direct offering, significantly increasing stockholders' equity[15](index=15&type=chunk) [Condensed Consolidated Statements of Cash Flows](index=6&type=section&id=Condensed%20Consolidated%20Statements%20of%20Cash%20Flows) Net cash used in operating activities slightly increased, with no significant financing activities this quarter Condensed Consolidated Statements of Cash Flows (in thousands) | Cash Flow Activity | Three Months Ended March 31, 2022 | Three Months Ended March 31, 2021 | | :--- | :--- | :--- | | Net cash used in operating activities | ($3,469) | ($3,266) | | Net cash used in investing activities | ($104) | ($6) | | Net cash (used in) provided by financing activities | ($25) | $21,723 | | **Net (decrease) increase in cash** | **($3,598)** | **$18,451** | | Cash and restricted cash at end of period | $20,509 | $32,745 | [Notes to Condensed Consolidated Financial Statements](index=7&type=section&id=Notes%20to%20Condensed%20Consolidated%20Financial%20Statements) Notes detail accounting policies, immuno-oncology focus, cash sufficiency, and a clinical co-development - The company is developing therapeutics using its INTASYL™ self-delivering RNAi technology to regulate genes in tumor and immune cells for immuno-oncology applications[20](index=20&type=chunk) - Management believes that existing cash should be sufficient to fund operations for at least the next **12 months** from the date of the financial statement release[44](index=44&type=chunk) - In March 2021, the company entered a clinical co-development agreement with AgonOx Inc. and committed to make future payments of up to **$4.0 million** to reimburse AgonOx for clinical trial expenses[67](index=67&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations (MD&A)](index=16&type=section&id=Item%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses financial condition, business strategy, and operational results, confirming sufficient cash reserves [Overview](index=16&type=section&id=Overview) Phio develops immuno-oncology therapeutics using its INTASYL™ platform, with lead product PH-762 in Phase 1b trials - The company's lead product candidate, PH-762, is being evaluated in a Phase 1b clinical trial for advanced melanoma, with top-line data from the first patient group anticipated in **Q1 2023**[86](index=86&type=chunk) - Phio is collaborating with AgonOx to develop T cell-based therapies using PH-762 and AgonOx's 'double positive' TIL (DP TIL) technology, with a clinical trial expected to start in **Q3 2022**[80](index=80&type=chunk) - The pipeline also includes PH-894 (targeting BRD4), for which IND-enabling studies are expected to be finalized in the **second half of 2022**, and PH-3861, a dual-targeting INTASYL for PD-1 and BRD4[87](index=87&type=chunk)[88](index=88&type=chunk) [Results of Operations](index=20&type=section&id=Results%20of%20Operations) Operating expenses decreased significantly due to lower research and development and general and administrative costs Operating Expenses Comparison (in thousands) | Expense Category | Q1 2022 | Q1 2021 | Dollar Change | | :--- | :--- | :--- | :--- | | Research and development | $1,586 | $2,429 | ($843) | | General and administrative | $1,054 | $1,209 | ($155) | | **Total operating expenses** | **$2,640** | **$3,638** | **($998)** | - The decrease in R&D expenses was mainly due to preclinical studies and manufacturing costs for PH-762 occurring in the prior-year period[96](index=96&type=chunk) - The decrease in G&A expenses was primarily due to lower legal and patent fees[98](index=98&type=chunk) [Liquidity and Capital Resources](index=21&type=section&id=Liquidity%20and%20Capital%20Resources) The company maintains **$20.5 million** in cash, sufficient for **12 months**, primarily funded by security sales - The company had cash of **$20.5 million** at March 31, 2022, and believes this is sufficient to fund operations for at least the next **12 months**[100](index=100&type=chunk)[103](index=103&type=chunk) - Net cash used in operating activities increased slightly to **$3.5 million** in Q1 2022, mainly due to prepayments for IND-enabling studies for PH-894 and manufacturing of PH-762[104](index=104&type=chunk)[105](index=105&type=chunk) - Net cash from financing activities was minimal in Q1 2022, compared to **$21.7 million** in net proceeds from capital raising and warrant exercises in Q1 2021[107](index=107&type=chunk) [Quantitative and Qualitative Disclosures About Market Risk](index=22&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) As a smaller reporting company, Phio Pharmaceuticals is not required to provide market risk disclosures - As a smaller reporting company, Phio Pharmaceuticals is not required to provide information on quantitative and qualitative disclosures about market risk[108](index=108&type=chunk) [Controls and Procedures](index=22&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded disclosure controls were effective, with no material changes in internal control - Management concluded that the company's disclosure controls and procedures were effective at the reasonable assurance level as of the end of the period covered by the report[110](index=110&type=chunk) - No changes in internal control over financial reporting occurred during the quarter that have materially affected, or are reasonably likely to materially affect, internal controls[111](index=111&type=chunk) Part II [Legal Proceedings](index=23&type=section&id=Item%201.%20Legal%20Proceedings) The company is not currently involved in any material legal proceedings - The company is not currently involved in any material legal proceedings[114](index=114&type=chunk) [Risk Factors](index=23&type=section&id=Item%201A.%20Risk%20Factors) New risk factors include Nasdaq minimum bid price non-compliance and potential impacts from the Russia-Ukraine conflict - On February 25, 2022, the company received a notice from Nasdaq for failing to meet the minimum bid price requirement of **$1.00 per share**[117](index=117&type=chunk) - The company has until **August 24, 2022**, to regain compliance with the Nasdaq minimum bid price requirement[118](index=118&type=chunk) - The ongoing conflict between Russia and Ukraine may cause global economic instability, disrupt supply chains, and create difficulties in obtaining future funding, which could adversely impact the business[119](index=119&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=24&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) No unregistered sales of equity securities occurred that were not previously reported - No unregistered sales of equity securities occurred that were not previously reported[120](index=120&type=chunk) [Defaults Upon Senior Securities](index=24&type=section&id=Item%203.%20Defaults%20Upon%20Senior%20Securities) The company reports no defaults upon senior securities - None[121](index=121&type=chunk) [Mine Safety Disclosures](index=24&type=section&id=Item%204.%20Mine%20Safety%20Disclosures) This item is not applicable to the company - Not applicable[122](index=122&type=chunk) [Other Information](index=24&type=section&id=Item%205.%20Other%20Information) The company reports no other information - None[123](index=123&type=chunk) [Exhibits](index=25&type=section&id=Item%206.%20Exhibits) This section lists the exhibits filed with the Form 10-Q, including Sarbanes-Oxley certifications - Exhibits filed include Sarbanes-Oxley Act Section 302 and 906 certifications and various Inline XBRL documents[126](index=126&type=chunk) Signatures This section contains the required signatures for the financial report - The report was duly signed on behalf of the registrant on **May 12, 2022**, by Geert Cauwenbergh, Principal Executive and Financial Officer[130](index=130&type=chunk)

3 12 5e05 5e05 anti-PD-1 mAb BP0146 clone RMP1-14 0.1 mg IP 1, 4, 7, 10, 13 4 12 5e05 5e05 PH-894 + anti-PD-1 mAb BP0146 clone RMP1-14 0.5 mg + 0.1 mg IT+ IP 1, 4, 7, 10, 13 Local administration of BRD4-targeting self-delivering RNAi (PH-894) provides abscopal efficacy toward untreated distal tumors and potentiates the efficacy of systemic anti-PD-1 antibody therapy #4237 Benjamin Cuiffo, Melissa Maxwell, Dingxue Yan, Shenghua Zhou, Brianna Rivest, Andrew Boone, James Cardia and Simon P. Fricker Abstract Im ...

FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 For the fiscal year ended December 31, 2021 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number 001-36304 PHIO PHARMACEUTICALS CORP. (Exact name of registrant as specified in its charter) | Title of each class | Tra ...