Current Report

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): May 15, 2026

TONIX PHARMACEUTICALS HOLDING CORP.

(Exact name of registrant as specified in its charter)

Nevada

001-36019

26-1434750

(State or Other Jurisdiction

of Incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

200 Connell Drive, Berkeley Heights, New Jersey, 07922

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (862) 799-8599

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	TNXP	The NASDAQ Global Select 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 7.01

Regulation FD Disclosure.

On May 15, 2026, Tonix Pharmaceuticals Holding Corp. (the “Company”) presented certain data from the Phase 1 trial for its TNX-4800 product candidate for protection against Lyme disease at the Global Lyme Alliance. A copy of the presentation is attached hereto as Exhibit 99.01.

The information in this Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.01 attached hereto, shall not be deemed “filed” for purposes of Section 18 of the United States Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall they be deemed incorporated by reference in any filing under the United States Securities Act of 1933 or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing.

Item 8.01

Other Events.

On May 15, 2026, the Company presented the following analysis of pharmacokinetic data from the Phase 1 trial for TNX-4800 at the Global Lyme Alliance in connection with the proposed adaptive Phase 2 field study for TNX-4800, planned for the first half of 2027, pending agreement by the U.S. Food and Drug Administration:

•

Simulation of a two-dose regimen (350 mg subcutaneous administration on Day 1 and 56 Days) of TNX-4800 were presented that predict mean serum levels for participants in the field study. Predictions were quantified for the time in days for serum levels to decrease below four serum levels, referred to as Minimum Effective Concentrations (“MECs”), of 10 µg/mL , 15 µg/mL, 20 µg/mL and 5 µg/mL. Days to MEC were: MEC₁ (10 µg/mL): 196 days; MEC₂ (15 µg/mL): 161 days; MEC₃ (20 µg/mL): 136 days; MEC₄ (5 µg/mL): 265 days.

•

The simulations and predictions support the feasibility of a two-dose 350 mg regimen maintaining a minimal mean serum level above MEC 10 µg/mL for six months following the initial dose, the proposed primary endpoint for the field study.

Forward-Looking Statements

This Current Report on Form 8-K contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and Private Securities Litigation Reform Act, as amended, including those relating to the Company’s product development, clinical trials, clinical and regulatory timelines, market opportunity, competitive position, possible or assumed future results of operations, business strategies, potential growth opportunities and other statement that are predictive in nature. These forward-looking statements are based on current expectations, estimates, forecasts and projections about the industry and markets in which we operate and management’s current beliefs and assumptions.

These statements may be identified by the use of forward-looking expressions, including, but not limited to, “expect,” “anticipate,” “intend,” “plan,” “believe,” “estimate,” “potential,” “predict,” “project,” “should,” “would” and similar expressions and the negatives of those terms. These statements relate to future events or our financial performance and involve known and unknown risks, uncertainties, and other factors which may cause actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Such factors include those set forth in the Company’s filings with the SEC. Prospective investors are cautioned not to place undue reliance on such forward-looking statements, which speak only as of the date of this press release. The Company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise.

Item 9.01

Financial Statements and Exhibits.

(d)

Exhibit

No.

Description.

99.01

TNX-4800: A Long-Acting, Bactericidal, Human Monoclonal Antibody to Prevent Lyme Disease in the U.S.

104

Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURE

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

	TONIX PHARMACEUTICALS HOLDING CORP.

Date: May 15, 2026	By:	/s/ Bradley Saenger
		Bradley Saenger
		Chief Financial Officer

Tonix Pharmaceuticals Holding Corp. filed SEC Form 8-K: Regulation FD Disclosure, Other Events, Financial Statements and Exhibits