[8-K] Phio Pharmaceuticals Corp. Reports Material Event

Rhea-AI Filing Summary

Phio Pharmaceuticals (PHIO) reported early clinical signals in its Phase 1b dose‑escalation trial of INTASYL PH‑762 for cutaneous squamous cell carcinoma. The company announced Day 36 outcomes in the fifth and final dose cohort: 100% tumor clearance (Complete Response) in one patient, greater than 90% (Near Complete Response) in a second, and greater than 50% (Partial Response) in a third.

Phio also stated that the Safety Monitoring Committee issued a favorable review of safety data at the maximum dose. These updates come from the ongoing Phase 1b dose escalation study (NCT 06014086).

Insights

Biotech clinical analyst

Early Phase 1b signals with favorable safety at max dose.

Phio disclosed patient-level responses at Day 36 in a Phase 1b dose-escalation cohort for PH‑762: one Complete Response (100%), one Near Complete Response (> 90%), and one Partial Response (> 50%). The Safety Monitoring Committee provided a favorable safety review at the maximum dose, supporting continued development.

Because this is an early-stage, small-sample readout, outcomes are preliminary. Dose-escalation cohorts primarily assess safety and tolerability, with efficacy observations considered exploratory at this stage.

The filing references the ongoing trial (NCT 06014086) and notes Day 36 assessments on November 3, 2025 disclosures. Subsequent filings may provide broader cohort data, durability, and additional safety updates.

false 0001533040 0001533040 2025-11-03 2025-11-03

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported):  November 3, 2025

PHIO PHARMACEUTICALS CORP.

(Exact name of registrant as specified in its charter)

Delaware	001-36304	45-3215903
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

411 Swedeland Road, Suite 23-1080
King of Prussia, PA	19406
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (610) 947-0251

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class:		Trading Symbol(s):		Name of each exchange on which registered:
Common Stock, par value $0.0001 per share		PHIO		The Nasdaq Capital Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01. Other Events.

On November 3, 2025, Phio Pharmaceuticals Corp. ("Phio”) issued a press release announcing (i) 100% tumor clearance (Complete Response) in one patient, greater than 90% (Near Complete Response) in second patient and greater than 50% (Partial Response) in third patient at Day 36 with cutaneous squamous cell carcinoma and (ii) that the Safety Monitoring Committee has issued a favorable review of safety data at the maximum dose of INTASYL PH-762. These patients completed treatment in the fifth and final dose cohort of Phio’s ongoing Phase 1b dose escalation clinical trial (NCT 06014086).

The full text of the press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description
99.1		Press release issued by the Company on November 3, 2025.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	PHIO PHARMACEUTICALS CORP.
Date: November 3, 2025	By:	/s/ Robert J. Bitterman
		Robert J. Bitterman President & Chief Executive Officer

3

FAQ

What did PHIO announce in its 8-K?

Phio reported Day 36 outcomes in a Phase 1b cohort of PH‑762: 100% Complete Response in one patient, >90% Near Complete in a second, and >50% Partial in a third.

Which trial and indication are referenced for PHIO?

The announcement relates to the ongoing Phase 1b dose escalation trial of INTASYL PH‑762 (NCT 06014086) in cutaneous squamous cell carcinoma.

What did the Safety Monitoring Committee conclude?

The Safety Monitoring Committee issued a favorable review of safety data at the maximum dose of PH‑762.

What timeline is associated with the patient responses?

Responses were assessed at Day 36 for patients in the fifth and final dose cohort.

How many patients with responses were highlighted by PHIO?

Three patients were highlighted: one with Complete Response, one with Near Complete Response, and one with Partial Response.

What is the dosing context for these results?

These patients completed treatment in the fifth and final dose cohort of the Phase 1b dose escalation.