# EDGAR Filing Document

**Accession Number:** 0000894158
**File Stem:** 0001104659-25-102103
**Filing Date:** 2025-10
**Character Count:** 194340
**Document Hash:** aefccd9ca6d99e5ce6ecb3dfdcbc3597
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-102103.hdr.sgml**: 20251024

**ACCESSION NUMBER**: 0001104659-25-102103

**CONFORMED SUBMISSION TYPE**: 424B5

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20251024

**DATE AS OF CHANGE**: 20251024

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Theriva Biologics, Inc.
- **CENTRAL INDEX KEY:** 0000894158
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 133808303
- **STATE OF INCORPORATION:** NV
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 424B5
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-279077
- **FILM NUMBER:** 251415923

**BUSINESS ADDRESS:**
- **STREET 1:** 9605 MEDICAL CENTER DRIVE
- **STREET 2:** SUITE 270
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850
- **BUSINESS PHONE:** (734) 332-7800

**MAIL ADDRESS:**
- **STREET 1:** 9605 MEDICAL CENTER DRIVE
- **STREET 2:** SUITE 270
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Synthetic Biologics, Inc.
- **DATE OF NAME CHANGE:** 20120305

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ADEONA PHARMACEUTICALS, INC.
- **DATE OF NAME CHANGE:** 20081027

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PIPEX PHARMACEUTICALS, INC.
- **DATE OF NAME CHANGE:** 20061214

**Filed Pursuant to Rule 424(b)(5)**

**Registration Statement No. 333-279077**

**Prospectus Supplement No. 2**

**(To Prospectus dated September 25, 2024)**

![](tm2529425d1_424b5img01.jpg)

**Up to $4,019,597 of Shares**

**Common Stock**

We have entered into an Amended and Restated At Market Issuance Sales Agreement, dated February 9, 2021, as amended by Amendment No. 1 thereto, dated May 3, 2021, as further amended by Amendment No. 2 thereto, dated May 2, 2024 (the "Sales Agreement"), with A.G.P./Alliance Global Partners ("AGP" or the "Sales Agent"), relating to the sale of shares of our common stock, par value $0.001 per share (the "common stock"), offered by this prospectus supplement and the accompanying base prospectus. During the year ended December 31, 2024 through the date hereof, we sold through the Sales Agreement approximately 12,016,073 shares of our common stock and received net proceeds of approximately $6.1 million.

On October 21, 2025, the last reported sale price of our common stock on the NYSE American LLC was $0.2998 per share.

Sales of our common stock, if any, under this prospectus supplement will be made by any method permitted that is deemed an "at the market offering" as defined in Rule 415 under the Securities Act of 1933, as amended (the "Securities Act"). The Sales Agent is not required to sell any specific amount but will act as our Sales Agent using commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed terms between the Sales Agent and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The Sales Agent will be entitled to compensation at a commission rate equal to up to 3.0% of the gross sales price per share sold. In connection with the sale of the common stock on our behalf, the Sales Agent will be deemed to be an "underwriter" within the meaning of the Securities Act and the compensation of the Sales Agent will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to the Sales Agent with respect to certain liabilities, including liabilities under the Securities Act.

As of the date of this prospectus, the aggregate market value of our outstanding common stock held by non-affiliates is approximately $19,659,047, which is calculated based on 23,403,628 shares of our outstanding common stock held by non-affiliates and a price of $0.84 per share, the closing price of our common stock on October 15, 2025, which is the highest closing sale price of our common stock on the NYSE American LLC within the prior 60 days of this prospectus. During the prior twelve calendar month period that ends on and includes the date hereof, we have offered and sold approximately $2,533,373.88 of shares of our common stock pursuant to General Instruction I.B.6 to Form S-3. As a result, pursuant to General Instruction I.B.6 to Form S-3 and in accordance with the terms of the Sales Agreement, we may offer and sell through this prospectus supplement and the accompanying base prospectus additional shares of our common stock having an aggregate offering price of up to $4,019,597 from time to time through or to the Sales Agent.

If our public float increases such that we may sell additional amounts under the Sales Agreement and the registration statement of which this prospectus supplement is a part, we will file a prospectus supplement prior to making additional sales. In no event will we sell securities in public primary offerings on Form S-3 with a value exceeding more than one-third of our public float (as defined by General Instruction I.B.6 to Form S-3) in any 12 calendar month period so long as our public float remains below $75 million.

**Investing in our common stock involves a high degree of risk. Before making an investment decision, please read the information under the heading "Risk Factors" beginning on page S-4 of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement, and the accompanying base prospectus.**

**Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying base prospectus. Any representation to the contrary is a criminal offense.**

**A.G.P.**

The date of this prospectus supplement is October 24, 2025

**TABLE OF CONTENTS**

**PROSPECTUS SUPPLEMENT**

---

| | |
|:---|:---|
|  | **Page** |
| [ABOUT THIS PROSPECTUS SUPPLEMENT](#a_001) | [S-ii](#a_001) |
| [INDUSTRY AND MARKET DATA](#a_002) | [S-iv](#a_002) |
| [PROSPECTUS SUPPLEMENT SUMMARY](#a_003) | [S-1](#a_003) |
| [THE OFFERING](#a_004) | [S-3](#a_004) |
| [RISK FACTORS](#a_005) | [S-4](#a_005) |
| [SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS](#a_006) | [S-7](#a_006) |
| [USE OF PROCEEDS](#a_007) | [S-8](#a_007) |
| [DIVIDEND POLICY](#a_008) | [S-9](#a_008) |
| [DILUTION](#a_009) | [S-10](#a_009) |
| [PLAN OF DISTRIBUTION](#a_010) | [S-11](#a_010) |
| [LEGAL MATTERS](#a_011) | [S-13](#a_011) |
| [EXPERTS](#a_012) | [S-13](#a_012) |
| [WHERE YOU CAN FIND MORE INFORMATION](#a_013) | [S-13](#a_013) |
| [INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE](#a_014) | [S-13](#a_014) |

---

**PROSPECTUS**

---

| | |
|:---|:---|
|  | **Page** |
| [About this Prospectus](#ATP_015) | [ii](#ATP_015) |
| [Prospectus Summary](#PS_016) | [1](#PS_016) |
| [Risk Factors](#RF_017) | [6](#RF_017) |
| [Forward-Looking Statements](#FLS_018) | [7](#FLS_018) |
| [Use of Proceeds](#UOP_019) | [8](#UOP_019) |
| [Description of Capital Stock](#DOCS_020) | [9](#DOCS_020) |
| [Description of Debt Securities](#DODS_021) | [14](#DODS_021) |
| [Description of Warrants](#DOW_022) | [20](#DOW_022) |
| [Description of Units](#DOU_023) | [22](#DOU_023) |
| [Legal Ownership of Securities](#LOS_024) | [23](#LOS_024) |
| [Plan of Distribution](#POD_025) | [26](#POD_025) |
| [Legal Matters](#LM_026) | [28](#LM_026) |
| [Experts](#E_027) | [28](#E_027) |
| [Where You Can Find More Information](#WTCFMI_028) | [28](#WTCFMI_028) |
| [Incorporation of Certain Information by Reference](#IOCBR_029) | [28](#IOCBR_029) |

---

**ABOUT THIS PROSPECTUS SUPPLEMENT**

This prospectus supplement and the accompanying base prospectus are part of a "shelf" registration statement on Form S-3 (File No. 333-279077) that we filed with the U.S. Securities and Exchange Commission (the "SEC") on May 2, 2024, as amended by Amendment No. 1 thereto filed with the SEC on September 11, 2024 and was declared effective on September 25, 2024.

This prospectus supplement describes the specific terms of this offering and also adds to and updates information contained in the accompanying base prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying base prospectus. The accompanying base prospectus, including the documents incorporated by reference, provides more general information. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in the accompanying base prospectus or in any document incorporated by reference that was filed with the SEC before the date of this prospectus supplement, on the other hand, you should rely on the information in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date — for example, a document incorporated by reference in the accompanying base prospectus — the statement in the document having the later date modifies or supersedes the earlier statement. You should read this prospectus supplement and the accompanying base prospectus, including the information incorporated by reference and any free writing prospectus that we have authorized for use in connection with this offering, in their entirety before making an investment decision.

You should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying base prospectus, along with the information contained in any free writing prospectus that we have authorized for use in connection with this offering. We have not authorized anyone to provide you with different or additional information. You should assume that the information appearing in this prospectus supplement, the accompanying base prospectus, the documents incorporated by reference in this prospectus supplement and the accompanying base prospectus, and in any free writing prospectus that we have authorized for use in connection with this offering is accurate only as of the respective dates of those documents. Our business, financial condition, results of operations and prospects may have changed since those dates.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference in this prospectus supplement or the accompanying base prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties and covenants were accurate only as of the date when made; therefore, such representations, warranties and covenants should not be relied on as accurate representations of the current state of our affairs.

Unless we have indicated otherwise, or the context otherwise requires, references in this prospectus supplement and the accompanying base prospectus to "Theriva," the "Company," "we," "us" and "our" refer to Theriva Biologics, Inc. and its subsidiaries.

This prospectus supplement, the accompanying base prospectus and the information incorporated by reference includes trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included or incorporated by reference into this prospectus supplement or the accompanying base prospectus are the property of their respective owners.

We are offering to sell, and are seeking offers to buy, the common stock only in jurisdictions where such offers and sales are permitted. No action has been or will be taken in any jurisdiction by us or the Sales Agent that would permit a public offering of the common stock or the possession or distribution of this prospectus supplement and the accompanying base prospectus in any jurisdiction, other than in the United States. Persons outside the United States who come into possession of this prospectus supplement and the accompanying base prospectus must inform themselves about, and observe any restrictions relating to, the offering of the common stock and the distribution of this prospectus supplement and the accompanying base prospectus outside the United States. This prospectus supplement and the accompanying base prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying base prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

This prospectus supplement and the accompanying prospectus is part of a registration statement that we have filed with the SEC utilizing a "shelf" registration process. Under the shelf registration process, we may offer shares of our common stock having an aggregate offering price of up to $200,000,000 under the accompanying base prospectus. Under this prospectus supplement and the accompanying base prospectus, we may offer shares of our common stock having an aggregate offering price of up to $4,019,597 from time to time at prices and on terms to be determined by market conditions at the time of offering.

S-ii

We provide information to you about this offering of shares of our common stock in two separate documents that are bound together: (1) this prospectus supplement, which describes the specific details regarding this offering; and (2) the accompanying base prospectus, which provides general information, some of which may not apply to this offering. Generally, when we refer to this "prospectus," we are referring to both documents combined. If information in this prospectus supplement is inconsistent with the accompanying base prospectus, you should rely on this prospectus supplement. However, if any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in this prospectus supplement—the statement in the document having the later date modifies or supersedes the earlier statement as our business, financial condition, results of operations and prospects may have changed since the earlier dates. This prospectus supplement, the accompanying base prospectus and the documents incorporated into each by reference include important information about us, the securities being offered and other information you should know before investing in our securities. You should also read and consider information in the documents we have referred you to in the section of this prospectus supplement and the accompanying base prospectus entitled "Where You Can Find More Information."

You should rely only on this prospectus supplement, the accompanying base prospectus and the information incorporated or deemed to be incorporated by reference therein. We have not and the Sales Agent has not authorized anyone to provide you with information that is in addition to or different from that contained or incorporated by reference in this prospectus supplement and the accompanying base prospectus. If anyone provides you with different or inconsistent information, you should not rely on it. We are not offering to sell these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained or incorporated by reference in this prospectus supplement or the accompanying base prospectus is accurate as of any date other than as of the date of this prospectus supplement or the accompanying base prospectus, as the case may be, or in the case of the documents incorporated by reference, the date of such documents regardless of the time of delivery of this prospectus supplement and the accompanying base prospectus or any sale of our securities. Our business, financial condition, liquidity, results of operations and prospects may have changed since those dates.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference in the accompanying base prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

No action has been or will be taken in any jurisdiction by us or the Sales Agent that would permit a public offering of the common stock or the possession or distribution of this prospectus supplement and the accompanying base prospectus in any jurisdiction, other than in the United States. Persons outside the United States who come into possession of this prospectus supplement and the accompanying base prospectus must inform themselves about, and observe any restrictions relating to, the offering of the common stock and the distribution of this prospectus supplement and the accompanying base prospectus outside the United States. This prospectus supplement and the accompanying base prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying base prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

S-iii

**INDUSTRY AND MARKET DATA**

We obtained the industry and market data in this prospectus supplement from our own research as well as from industry and general publications, surveys and studies conducted by third parties. These data involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the industry in which we operate is necessarily subject to a high degree of uncertainty and risk due to a variety of factors, including those described in "Risk Factors" and elsewhere in this prospectus supplement and in the documents incorporated by reference in this prospectus supplement. These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

S-iv

**PROSPECTUS SUPPLEMENT SUMMARY**

*This summary highlights information contained elsewhere in this prospectus supplement, the accompanying prospectus or incorporated by reference in this prospectus supplement. This summary does not contain all the information you should consider before investing in our common stock. You should read the following summary together with the more detailed information appearing in this prospectus supplement, the accompanying prospectus and the information incorporated by reference in their entirety, including our consolidated financial statements and related notes as well as the section entitled "Risk Factors" herein and in the documents incorporated by reference, before making any investment decision.*

**The Company**

*Overview*

We are a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need. As a result of the acquisition in March 2022 of Theriva Biologics, S.L. ("VCN", formerly named VCN Biosciences, S.L.), described in more detail below (the "Acquisition"), we transitioned our strategic focus to oncology through the development of VCN's new oncolytic adenovirus platform designed for intravenous and intravitreal delivery to trigger tumor cell death, to improve access of co-administered cancer therapies to the tumor, and to promote a robust and sustained anti-tumor response by the patient's immune system. Our lead product candidate, VCN-01, a clinical stage oncolytic human adenovirus that is modified for tumor-selective replication and to express an enzyme, PH20 hyaluronidase, has been evaluated in a Phase 2b clinical study for the treatment of pancreatic cancer ("VIRAGE"), and has recently been used to treat patients in a Phase 1 clinical study for the treatment of retinoblastoma, and Phase 1 clinical studies for the treatment of other solid tumors including head and neck squamous cell carcinoma.

Prior to the Acquisition, our focus was on developing therapeutics designed to treat gastrointestinal (GI) diseases which included our clinical development candidates: (1) SYN-004 (ribaxamase) which is designed to degrade certain commonly used intravenous (IV) beta-lactam antibiotics within the GI tract to prevent microbiome damage, thereby preventing overgrowth and infection by pathogenic organisms such as *Clostridioides difficile* infection (CDI) and vancomycin resistant Enterococci (VRE), and reducing the incidence and severity of acute graft-versus-host-disease (aGVHD) in allogeneic hematopoietic cell transplant (HCT) recipients, and (2) SYN-020, a recombinant oral formulation of the enzyme intestinal alkaline phosphatase (IAP) produced under cGMP conditions and intended to treat both local GI and systemic diseases. As part of our strategic transformation into an oncology focused company, we are exploring value creation options for our SYN-004 and SYN-020 assets, including out-licensing or partnering.

**Our Current Product Pipeline**

***\*Based on management's current beliefs and expectations***

**aGVHD** acute graft-versus host disease. **allo-HCT** allogeneic hematopoietic cell transplant. **CSR** clinical study report. **HNSCC** head and neck squamous cell carcinoma. **IV** intravenous. **IVit** intravitreal. For other abbreviations see the text.

¹Additional products with preclinical proof-of-concept include SYN-006 (carbapenemase) to prevent aGVHD, CDI, and microbiome damage in patients treated with carbapenem antibiotics and SYN-007 (ribaxamase) DR to prevent antibiotic associated diarrhea with oral β-lactam antibiotics.

²Depending on funding/partnership. SYN-004 may enter a U.S. Food and Drug Administration ("FDA")-agreed Phase 3 clinical trial for the treatment of CDI.

**Corporate Information**

Our predecessor, Sheffield Pharmaceuticals, Inc., was incorporated in 1986, and in 2006 engaged in a reverse merger with Pipex Therapeutics, Inc., a publicly-traded Delaware corporation formed in 2001. After the reverse merger, we changed our name to Pipex Pharmaceuticals, Inc., and in October 2008 we changed our name to Adeona Pharmaceuticals, Inc. On October 15, 2009, we engaged in a merger with a wholly owned subsidiary for the purpose of reincorporating in the State of Nevada. On February 15, 2012, we changed our name to Synthetic Biologics, Inc. On August 10, 2018, we effected a one for thirty-five reverse stock split of our authorized, issued and outstanding common stock. On July 15, 2022, we effected a one for ten reverse stock split of our authorized, issued and outstanding common stock. On October 12, 2022, we changed our name to Theriva Biologics, Inc. On August 26, 2024, we effected a one for twenty-five reverse stock split of our authorized, issued and outstanding common stock (the "Reverse Stock Split").

Our principal executive offices are located at 9605 Medical Center Drive, Suite 270, Rockville, Maryland 20850, and our telephone number is (301) 417-4367. Our website address is *www.therivabio.com*. Information contained on our website is intended for informational purposes only and is not incorporated by reference into this prospectus, and it should not be considered to be part of this prospectus or the registration statement of which this prospectus forms a part. The SEC maintains an internet site that contains reports, proxy and information statements, and other information regarding issuers like us that file documents electronically with the SEC. The address of the SEC website is *www.sec.gov*.

**Smaller Reporting Company**

We are a "smaller reporting company" as defined in the Securities Exchange Act of 1934, as amended (the "Exchange Act"). As a result, we may take advantage of certain reduced disclosure obligations available to smaller reporting companies, including the exemption from compliance with the auditor attestation requirements pursuant to the Sarbanes-Oxley Act of 2022, reduced disclosure about our executive compensation arrangements and the requirements to provide only two years of audited financial statements in our annual reports and registration statements. We will continue to be a "smaller reporting company" as long as (1) we have a public float (i.e., the market value of our common stock held by non-affiliates) less than $250 million calculated as of the last business day of our most recently completed second fiscal quarter, or (2) our annual revenues are less than $100 million for our previous fiscal year and we have either no public float or a public float of less than $700 million as of the end of that fiscal year's second fiscal quarter. Decreased disclosures in our SEC filings due to our status as a "smaller reporting company" may make it harder for investors to analyze our results of operations and financial prospects.

**THE OFFERING**

*All share information presented herein reflects a 1-for-25 reverse stock split of our common stock, which we effected on August 26, 2024.*

---

| | |
|:---|:---|
| **Common stock offered by us pursuant to this prospectus supplement** | Shares of our common stock having an aggregate offering price of up to $4,019,597. |
| **Common stock to be outstanding after this offering<sup>(1)</sup>** | Up to 36,821,223 shares, assuming sales of 13,407,595 shares of our common stock in this offering at an offering price of $0.2998 per share, which was the last reported sale price of our common stock on the NYSE American on October 21, 2025. The actual number of shares issued will vary depending on the sales price under this offering. |
| **Manner of offering** | "At the market offering" that may be made from time to time on the NYSE American or other market for our common stock in the United States through or to the Sales Agent. See the section entitled "Plan of Distribution" on page S-11 of this prospectus supplement for additional information. |
| **Use of proceeds** | We currently intend to use the net proceeds from this offering primarily for working capital and general corporate purposes, including for research and development and manufacturing scale-up. We may also use a portion of the net proceeds to invest in or acquire other products, businesses or technologies, although we have no commitments or agreements with respect to any such investments or acquisitions as of the date of this prospectus. See "Use of Proceeds" on page S-8 of this prospectus supplement for additional information. |
| **Risk factors** | You should read the "Risk Factors" section of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement for a discussion of factors to consider before deciding to purchase shares of our common stock. |
| **NYSE American symbol** | Our common stock is listed on the NYSE American under the symbol "TOVX" |

---

(1) Based on 23,413,628 shares of our common stock outstanding as of October 22, 2025 and excludes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· 1,116,101 shares of common stock issuable upon the exercise of outstanding stock options with a weighted average exercise price of $5.09 per share;

· 16,339,060 shares
 of common stock issuable upon the exercise of outstanding warrants to purchase common stock with a weighted average exercise price
 of $0.55 per share; and

· 3,391,465 additional shares of the common stock reserved for future issuance under our equity incentive plans.

**RISK FACTORS**

*Investing in our common stock involves a high degree of risk. This prospectus supplement does not describe all of those risks. You should consider the risk factors described in this prospectus supplement under the caption "Risks Related to This Offering and Our Securities" below, as well as the those described under the caption "Risk Factors" in the documents incorporated by reference herein, including our most recent Annual Report on Form 10-K, any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K, and all other information contained or incorporated by reference into this prospectus supplement and the accompanying base prospectus before deciding whether to purchase any of the common stock being offered under this prospectus supplement. Each of the risks described below could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our common stock, and the occurrence of any of these risks might cause you to lose all or part of your investment. Moreover, the risks described below are not the only ones that we face. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations. Please also read carefully the section below titled "Special Note Regarding Forward-Looking Statements."*

**Risks Relating to the Offering**

***Our management team may invest or spend the proceeds of this offering in ways with which you may not agree or in ways which may not yield a significant return.***

Our management will have broad discretion over the use of proceeds from this offering. The net proceeds from this offering will be used primarily for general corporate purposes, which may include, among other things, for clinical trials for our product candidates, paying general and administrative expenses and accounts payable, increasing our working capital, funding research and development and funding capital expenditures. We may also use a portion of the net proceeds for licensing or acquiring intellectual property to incorporate into our products and product candidates or our research and development programs and to in-license, acquire or invest in other businesses or products, although we have no commitments or agreements with respect to any such licenses, acquisitions or investments as of the date of this prospectus supplement. Our management will have considerable discretion in the application of the net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. The net proceeds may be used for corporate purposes that do not increase our operating results or enhance the value of our common stock. The failure of our management to use these funds effectively could have a material adverse effect on our business, cause the market price of our common stock to decline and impair the commercialization of our products and/or delay the development of our product candidates. Pending their use, we may invest the net proceeds from this offering in short-term, investment-grade, interest-bearing instruments and U.S. government securities. These investments may not yield a favorable return to our stockholders.

***If you purchase shares of our common stock sold in this offering, you will experience immediate and substantial dilution in the net tangible book value of your shares. In addition, we may issue additional equity or convertible debt securities in the future, which may result in additional dilution to investors.***

The price per share of our common stock being offered may be higher than the net tangible book value per share of our outstanding common stock prior to this offering. Assuming that an aggregate of 13,407,595 shares of our common stock are sold at a price of $0.2998 per share, the last reported sale price of our common stock on the NYSE American on October 21, 2025, new investors in this offering will incur immediate dilution of $0.2598 per share. For a more detailed discussion of the foregoing, see the section entitled "Dilution" below. To the extent outstanding stock options or warrants are exercised, there will be further dilution to new investors.

***You may experience future dilution as a result of future equity offerings.***

In order to raise additional capital, we may in the future offer additional shares of our common stock or other securities convertible into or exchangeable for our common stock at prices that may not be the same as the price per share in this offering. We may sell shares or other securities in any other offering at a price per share that is less than the price per share paid by investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders. The price per share at which we sell additional shares of our common stock, or securities convertible or exchangeable into common stock, in future transactions may be higher or lower than the price per share paid by investors in this offering.

***Because we do not intend to declare cash dividends on our shares of common stock in the foreseeable future, stockholders must rely on appreciation of the value of our common stock for any return on their investment.***

We have never declared or paid cash dividends on our common stock. We currently anticipate that we will retain future earnings for the development, operation and expansion of our business and do not anticipate declaring or paying any cash dividends on our common stock in the foreseeable future. In addition, the terms of any future preferred stock or debt agreements may preclude us from paying dividends. As a result, we expect that only appreciation of the price of our common stock, if any, will provide a return to investors in this offering for the foreseeable future.

***Resales of our common stock in the public market during this offering by our stockholders may cause the market price of our common stock to fall.***

We may issue common stock from time to time in connection with this offering. This issuance from time to time of these new shares of our common stock, or our ability to issue these shares of common stock in this offering, could result in resales of our common stock by our current stockholders concerned about the potential dilution of their holdings. In turn, these resales could have the effect of depressing the market price for our common stock.

***The shares of common stock offered under this prospectus supplement and the accompanying base prospectus may be sold in "at the market offerings", and investors who buy shares at different times will likely pay different prices.***

Investors who purchase shares under this prospectus supplement and the accompanying base prospectus at different times will likely pay different prices, and so may experience different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices, and numbers of shares sold, and there is no minimum or maximum sales price. Investors may experience declines in the value of their shares as a result of share sales made at prices lower than the prices they paid.

***The actual number of shares we will issue under the Sales Agreement at any one time or in total, is uncertain.***

Subject to certain limitations in the sales agreement and compliance with applicable law, we have the discretion to deliver placement notices to the Sales Agent at any time throughout the term of the sales agreement. The number of shares that are sold by the Sales Agent as our Sales Agent after we deliver a placement notice will fluctuate based on the market price of the common stock and the trading volume of our common stock during the sales period and limits we set with the Sales Agent.

***The market price of our common stock has been and may continue to be volatile and adversely affected by various factors.***

Our stock price has fluctuated in the past, has recently been volatile and may be volatile in the future. By way of example, on October 21, 2025, the price of our common stock closed at $0.2998 per share while on October 22, 2024, our stock price closed at $1.45 per share with no discernable announcements or developments by us or third parties. We may incur rapid and substantial decreases in our stock price in the foreseeable future that are unrelated to our operating performance or prospects. In addition, the outbreak of the novel strain of coronavirus (COVID-19) has caused broad stock market and industry fluctuations. The stock market in general and the market for biotechnology and pharmaceutical companies in particular have experienced extreme volatility that has often been unrelated to the operating performance of particular companies. As a result of this volatility, investors may experience losses on their investment in our common stock. The market price of our common stock could fluctuate significantly in response to various factors and events, including:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· investor reaction to our business strategy;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the success of competitive products or technologies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· our continued compliance with the listing standards of the NYSE American;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· regulatory or legal developments in the United States and other countries, especially changes in laws or regulations applicable to our products;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· results of our clinical trials;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· actions taken by regulatory agencies with respect to our products, clinical studies, manufacturing process or sales and marketing terms;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· variations in our financial results or those of companies that are perceived to be similar to us;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the success of our efforts to acquire or in-license additional products or product candidates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· developments concerning our collaborations or partners;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· developments or disputes concerning patents or other proprietary rights, litigation matters and our ability to obtain patent protection for our products;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· our ability or inability to raise additional capital and the terms on which we raise it;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· declines in the market prices of stocks generally;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· trading volume of our common stock;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· sales of our common stock by us or our stockholders;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· general economic, industry and market conditions; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· other events or factors, including those resulting from such events, or the prospect of such events, including war, terrorism and other international conflicts, such as the conflict in the Middle East, the conflict between Russia and the Ukraine, public health issues including health epidemics or pandemics, such as the outbreak of the novel coronavirus (COVID-19), and natural disasters such as fire, hurricanes, earthquakes, tornados or other adverse weather and climate conditions, whether occurring in the United States or elsewhere, could disrupt our operations, disrupt the operations of our suppliers or result in political or economic instability.

These broad market and industry factors may seriously harm the market price of our common stock, regardless of our operating performance. Further, recent increases are significantly inconsistent with any improvements in actual or expected operating performance, financial condition or other indicators of value. Since the stock price of our common stock has fluctuated in the past, has been recently volatile and may be volatile in the future, investors in our common stock could incur substantial losses. In the past, following periods of volatility in the market, securities class-action litigation has often been instituted against companies. Such litigation, if instituted against us, could result in substantial costs and diversion of management's attention and resources, which could materially and adversely affect our business, financial condition, results of operations and growth prospects. There can be no guarantee that our stock price will remain at current prices or that future sales of our common stock will not be at prices lower than those sold to investors.

Additionally, recently, securities of certain companies have experienced significant and extreme volatility in stock price due to short sellers of shares of common stock, known as a "short squeeze." These short squeezes have caused extreme volatility in those companies and in the market and have led the price per share of those companies to trade at a significantly inflated rate that is disconnected from the underlying value of the company. Many investors who have purchased shares in those companies at an inflated rate face the risk of losing a significant portion of their original investment as the price per share has declined steadily as interest in those stocks have abated. While we have no reason to believe our shares would be the target of a short squeeze, there can be no assurance that we won't be in the future, and you may lose a significant portion or all of your investment if you purchase our shares at a rate that is significantly disconnected from our underlying value.

**SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS**

This prospectus supplement and the accompanying base prospectus and the documents we file with the SEC that are incorporated by reference herein and therein contain "forward-looking statements" within the meaning of Section 27A of the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), these statements reflect our current views with respect to our ongoing and planned clinical trials, business strategy, business plan, financial performance and other future events. These statements include forward-looking statements both with respect to us, specifically, and the biotechnology sector, in general. We make these statements pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Statements that include the words "expect," "intend," "plan," "believe," "project," "estimate," "may," "should," "anticipate," "will" and similar statements of a future or forward-looking nature identify forward-looking statements for purposes of the federal securities laws or otherwise.

All forward-looking statements involve inherent risks and uncertainties, and there are or will be important factors that could cause actual results to differ materially from those indicated in these statements. We believe that these factors include, but are not limited to, those factors set forth under the caption "Risk Factors" in this prospectus supplement and in the accompanying base prospectus and under the captions "Risk Factors," "Business," and "Management's Discussion and Analysis of Financial Condition and Results of Operations," in our most recent Annual Report on Form 10-K and our subsequent Quarterly Reports on Form 10-Q, all of which you should review carefully. Please consider our forward-looking statements in light of those risks as you read this prospectus supplement and the accompanying base prospectus. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. Given these uncertainties, you should not place undue reliance on these forward-looking statements.

You should not assume that the information contained in this prospectus supplement is accurate as of any date other than the date on the front of this prospectus supplement, or that any information incorporated by reference into this prospectus supplement is accurate as of any date other than the date of the document so incorporated by reference. Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in these forward-looking statements, even if new information becomes available in the future. Thus, you should not assume that our silence over time means that actual events are bearing out as expressed or implied in such forward-looking statements.

If one or more of these or other risks or uncertainties materializes, or if our underlying assumptions prove to be incorrect, actual results may vary materially from what we anticipate. All subsequent written and oral forward-looking statements attributable to us or individuals acting on our behalf are expressly qualified in their entirety by this Note. Before purchasing any shares of common stock, you should consider carefully all of the factors set forth or referred to in this prospectus supplement and in the accompanying base prospectus that could cause actual results to differ.

**USE OF PROCEEDS**

We may issue and sell shares of our common stock having aggregate gross proceeds of up to $4,019,597 from time to time under this prospectus supplement and the documents incorporated by reference herein and therein. Because there is no minimum offering amount required as a condition to close this offering, the actual total offering amount, commissions and proceeds to us, if any, are not determinable at this time. The amount of proceeds from this offering will depend upon the number of shares of our common stock sold and the market price at which they are sold. There can be no assurance that we will be able to sell any shares of our common stock under or fully utilize the Sales Agreement with the Sales Agent as a source of financing.

We intend to use the net proceeds, if any, from the sales of shares of our common stock offered by this prospectus supplement for working capital and general corporate purposes, including, to acquire, license or invest in assets, businesses, technologies, product candidates or other intellectual property, to make milestone payments and to repurchase securities. We have broad discretion in determining how the proceeds of this offering will be used, and our discretion is not limited by the aforementioned possible uses. Our Board of Directors believes the flexibility in application of the net proceeds is prudent.

As of the date of this prospectus supplement, we cannot specify with certainty all of the particular uses for the net proceeds to be received from this offering. The amounts and timing of our actual expenditures will depend on numerous factors including our operating costs and the amount of funding, if any, received from grants. Accordingly, our management will have broad discretion in the application of the net proceeds, and investors will be relying on the judgment of management regarding the application of the net proceeds from the offering. We may find it necessary or advisable to reallocate the net proceeds of this offering; however, any such reallocation would be substantially limited to the categories set forth above as we do not intend to use the net proceeds for other purposes. Pending such uses set forth above, we plan to invest the net proceeds in government securities and other short-term investment grade, marketable securities.

**DIVIDEND POLICY**

We have never declared or paid any cash dividends on our common stock and we do not currently intend to pay any cash dividends on our common stock in the foreseeable future. We expect to retain all available funds and future earnings, if any, to fund the development and growth of our business. Any future determination to pay dividends, if any, on our common stock will be at the discretion of our board of directors and will depend on, among other factors, the terms of any outstanding preferred stock, our results of operations, financial condition, capital requirements and contractual restrictions.

**DILUTION**

If you invest in our common stock, your interest will be diluted immediately to the extent of the difference between the offering price and the adjusted net tangible book value per share of our common stock after this offering.

Our net tangible book value as of June 30, 2025 was approximately $(9.0) million, or $(0.99) per share, based on 9,059,232 shares of our common stock outstanding as of June 30, 2025. "Net tangible book value per share" is determined by dividing our total tangible assets, less total liabilities, by the number of shares of our common stock outstanding as of June 30, 2025. Dilution with respect to net tangible book value per share represents the difference between the amount per share paid by purchasers of shares of common stock in this offering and the net tangible book value per share of our Common Stock immediately after this offering.

Our pro forma net tangible book value as of June 30, 2025 was $(2.3) million or approximately $(0.098) per share. Pro forma net tangible book value per shares represents our total tangible assets as adjusted to take into account our issuance of the following securities subsequent to June 30, 2025: (i) 5,723,396 shares of our common stock in our at-the-market offering and our receipt of approximately $2.4 million in net proceeds, (ii) 8,092,280 shares of our common stock upon the exercise of warrants in a warrant inducement offering and our receipt of approximately $4.3 million in net proceeds, and (iii) an aggregate of 538,720 shares of common stock in connection with the cashless exercise of a pre-funded warrant.

After giving effect to the (i) pro forma adjustments set forth above and (ii) the assumed sale of 13,407,595 shares of our common stock in this offering at an assumed public offering price of $0.2998 per share, which represents the closing price of our common stock on the NYSE American on October 21, 2025 and after deducting Sales Agent fees and estimated offering expenses payable by us, our pro forma as adjusted net tangible book value as of June 30, 2025 would have been approximately $1.5 million, or approximately $0.04 per share.

This represents an immediate increase in pro forma net tangible book value of $0.138 per share to existing stockholders and immediate dilution of $0.2598 in net tangible book value per share to new investors purchasing shares of common stock in this offering compared to the assumed public offering price per share in this offering.

The following table illustrates the per share dilution to investors purchasing shares in an offering using this prospectus supplement:

---

| | | |
|:---|:---|:---|
| Assumed public offering price per share |  | $0.2998 |
| &nbsp;&nbsp;&nbsp;Pro forma net tangible book value per share as of June 30, 2025 | $(0.098) |  |
| &nbsp;&nbsp;&nbsp;Increase in pro forma net tangible book value per share attributable to new investors purchasing our common stock in this offering | $0.138 |  |
| Pro forma as adjusted net tangible book value per share after giving effect to this offering |  | $0.04 |
| Dilution per share to investors purchasing our common stock in this offering |  | $0.2598 |

---

(1) Based on 9,059,232 shares of our common stock outstanding as of June 30, 2025 and excludes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· 1,126,430 shares of common stock issuable upon the exercise of outstanding stock options with a weighted average exercise price of $5.18 per share;

· 8,786,686 shares of common stock issuable upon the exercise of outstanding warrants to purchase common stock with a weighted average exercise price of $1.18 per share; and

· 1,381,136 additional shares of the common stock reserved for future issuance under our equity incentive plans.

The above illustration of dilution per share to investors participating in this offering assumes no exercise of outstanding options to purchase our common stock or outstanding warrants to purchase shares of our common stock. To the extent that any of these outstanding options or warrants are exercised or we issue additional shares under our equity incentive plans, there will be further dilution to new investors. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

**PLAN OF DISTRIBUTION**

This prospectus supplement relates to the offer and sale of up to $4,019,597 shares of our common stock pursuant to the Sales Agreement. The sales of shares of our common stock, if any, under this prospectus supplement will be made at market prices by any method deemed to be an "at the market offering" as defined in Rule 415(a)(4) under the Securities Act. During the year ended December 31, 2024 through the date hereof, we sold through the Sales Agreement approximately 12,016,073 shares of our common stock and received net proceeds of approximately $6.1 million.

Each time that we wish to issue and sell shares of our common stock under the Sales Agreement, we will provide the Sales Agent with a placement notice describing the amount of shares to be sold, the time period during which sales are requested to be made, any limitation on the amount of shares of our common stock that may be sold in any single day, any minimum price below which sales may not be made or any minimum price requested for sales in a given time period and any other instructions relevant to such requested sales. Upon receipt of a placement notice, the Sales Agent, acting as our sales agent, will use commercially reasonable efforts, consistent with its normal trading and sales practices and applicable state and federal laws, rules and regulations and the rules of the NYSE American, to sell shares of our common stock under the terms and subject to the conditions of the placement notice and the sales agreement. We or the Sales Agent may suspend the offering of shares of our common stock pursuant to a placement notice upon notice.

Settlement for sales of shares of common stock, unless the parties agree otherwise, will occur on the first trading day following the date on which any sales are made in return for payment of the net proceeds to us. There are no arrangements to place any of the proceeds of this offering in an escrow, trust or similar account. Sales of shares of our common stock as contemplated in this prospectus supplement will be settled through the facilities of The Depository Trust Company or by such other means as we and the Sales Agent may agree upon.

The Sales Agent will be entitled to compensation at a fixed commission rate of up to 3.0% of the gross proceeds from the sale of shares of our common stock on our behalf pursuant to the Sales Agreement. Pursuant to the terms of the Sales Agreement, we agreed to reimburse the Sales Agent for the documented fees and costs of its legal counsel reasonably incurred in connection with entering into the transactions contemplated by the Sales Agreement in an amount not to exceed $50,000 in the aggregate, in addition to up to $10,000 annually for the Sales Agent's counsel's fees and any incidental expenses to be reimbursed by us. We will report at least quarterly the number of shares of common stock sold through the Sales Agent under the Sales Agreement, the net proceeds to us and the compensation paid by us to the Sales Agent in connection with the sales of common stock.

We estimate that the total expenses for this offering, excluding compensation payable to the Sales Agent and certain expenses reimbursable to the Sales Agent under the terms of the Sales Agreement, will be approximately $111,000. The remaining sales proceeds, after deducting any expenses payable by us and any transaction fees imposed by any governmental, regulatory, or self-regulatory organization in connection with the sales, will equal our net proceeds for the sale of such shares of common stock.

Because there are no minimum sale requirements as a condition to this offering, the actual total public offering price, commissions and net proceeds to us, if any, are not determinable at this time. The actual dollar amount and number of shares of common stock we sell through this prospectus will be dependent, among other things, on market conditions and our capital raising requirements.

In connection with the sale of shares of common stock on our behalf, the Sales Agent will be deemed to be an "underwriter" within the meaning of the Securities Act, and the compensation of the Sales Agent will be deemed to be underwriting commissions or discounts. We have agreed to provide indemnification and contribution to the Sales Agent against certain civil liabilities, including liabilities under the Securities Act.

The Sales Agent will not engage in any market making activities involving shares of our common stock while the offering is ongoing under this prospectus if such activity would be prohibited under Regulation M or other anti-manipulation rules under the Securities Act. As our sales agent, the Sales Agent will not engage in any transactions that stabilizes shares of our common stock.

The offering pursuant to the Sales Agreement will terminate upon the earlier of (i) the sale of all shares of common stock subject to the Sales Agreement and (ii) termination of the Sales Agreement as permitted therein. We may terminate the Sales Agreement in our sole discretion at any time by giving one (1) day's prior notice to the Sales Agent. The Sales Agent may terminate the Sales Agreement under the circumstances specified in the sales agreement and in its sole discretion at any time by giving five (5) days' prior notice to us.

This prospectus supplement in electronic format may be made available on websites maintained by the Sales Agent and the Sales Agent may distribute this prospectus supplement electronically.

**Other Activities and Relationships**

The Sales Agent and certain of its affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. The Sales Agent and certain of its affiliates have, from time to time, performed, and may in the future perform, various commercial and investment banking and financial advisory services for us and our affiliates, for which they received or will receive customary fees and expenses.

*September 2024 Offering*

For example, on September 27, 2024 we consummated a public offering (the "September 2024 Offering") of an aggregate of (i) 918,600 shares (the "Shares") of common stock, (ii) pre-funded warrants ("Pre-Funded Warrants") to purchase up to 510,000 shares of common stock (the "Pre-Funded Warrant Shares"), and (iii) common stock purchase warrants ("Common Warrants") to purchase up to 1,428,600 shares of common stock (the "Common Warrant Shares"). Each Share and associated Common Warrant to purchase one (1) Common Warrant Share was sold at a combined public offering price of $1.75. Each Pre-Funded Warrant and associated Common Warrant to purchase one (1) Common Warrant Share was sold at a combined public offering price of $1.7499. The Company received aggregate gross proceeds from the September 2024 Offering of approximately $2.5 million, before deducting placement agent fees and other offering expenses.

In connection with the September 2024 Offering, on September 26, 2024, we entered into a placement agency agreement (the "Placement Agency Agreement") with AGP, pursuant to which AGP agreed to act as placement agent on a "reasonable best efforts" basis in connection with the September 2024 Offering. We paid AGP an aggregate fee equal to 7.0% of the gross proceeds raised in the September 2024 Offering. Further, we agreed to reimburse AGP up to an aggregate of $100,000 for accountable legal fees, other reasonable and documented out-of-pocket expenses, and non-accountable expenses.

*May 2025 Offering*

On May 8, 2025, we consummated a public offering (the "May 2025 Offering") of an aggregate of (i) 1,990,900 shares of our common stock, (ii) pre-funded warrants to purchase up to 4,827,280 shares of common stock, and (iii) common stock purchase warrants to purchase up to 6,818,180 shares of common stock. Each share and associated common stock warrant to purchase one shares of common stock was sold at a combined public offering price of $1.10 and each pre-funded warrant and associated common warrant to purchase one (1) shares of common stock was sold at a combined public offering price of $1.099. We received aggregate gross proceeds from the May 2025 Offering of approximately $7.5 million, before deducting placement agent fees and other offering expenses.

In connection with the May 2025 Offering, on May 7, 2025, we entered into a placement agency agreement (the "Placement Agency Agreement") with AGP, pursuant to which AGP agreed to act as placement agent on a "reasonable best efforts" basis in connection with the May 2025 Offering. We paid AGP an aggregate fee equal to 7.0% of the gross proceeds raised in the May 2025 Offering. Further, we agreed to reimburse AGP up to an aggregate of $100,000 for accountable legal fees, other reasonable and documented out-of-pocket expenses, and non-accountable expenses.

*October 2025 Warrant Inducement*

On October 16, 2025, we entered into a warrant inducement agreement (the "Inducement Agreement") with certain holders named therein (the "Holders") of existing common stock purchase warrants to purchase up to an aggregate of 8,092,280 shares of common stock, consisting of (i) common stock purchase warrants to purchase up to an aggregate of 1,345,000 shares of common stock issued on September 27, 2024 (the "September Warrants") and (ii) common stock purchase warrants to purchase up to an aggregate of 6,747,280 shares of common stock issued on May 8, 2025 (the "May Warrants" and, together with the September Warrants, the "Existing Warrants"). Pursuant to and in accordance with the Inducement Agreement, the Holders exercised for cash the Existing Warrants at a reduced exercise price of $0.54 per share and we issued to the Holders new common stock purchase warrants to purchase up to an aggregate of 16,184,560 shares of common stock (the "Warrant Exercise"). We received aggregate gross proceeds of approximately $4.4 million for the exercise of the Existing Warrants, before deducting financial advisor fees and other expenses payable by us.

AGP served as our exclusive financial advisor in connection with the Warrant Exercise and other transactions described in the Inducement Agreement. Pursuant to the terms of an engagement letter, dated October 16, 2025, by and between us and AGP (the "Engagement Letter"), the Company agreed to pay to AGP a cash fee equal to 7.0% of the aggregate gross proceeds received from the Holder upon exercise of the Existing Warrants and reimbursement of certain expenses.

In the ordinary course of its various business activities, the Sales Agent and certain of its affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for its own account and for the accounts of its customers, and such investment and securities activities may involve securities and/or instruments issued by us and our affiliates. If the Sales Agent or its affiliates have a lending relationship with us, they routinely hedge their credit exposure to us consistent with their customary risk management policies. The Sales Agent and its affiliates may hedge such exposure by entering into transactions that consist of either the purchase of credit default swaps or the creation of short positions in our securities or the securities of our affiliates, including potentially the Common Stock offered hereby. Any such short positions could adversely affect future trading prices of the Common Stock offered hereby. The Sales Agent and certain of its affiliates may also communicate independent investment recommendations, market color or trading ideas and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

**LEGAL MATTERS**

Blank Rome LLP, New York, New York is representing us in connection with the offering. The validity of the shares of common stock offered hereby will be passed upon for us by Parsons Behle & Latimer, Reno, Nevada. Duane Morris LLP, New York, New York is acting as counsel for the Sales Agent in connection with this offering.

As of the date of this prospectus supplement, an attorney of Blank Rome LLP beneficially owns securities exercisable to purchase shares of common stock that represent less than 1% of our outstanding shares of common stock.

**EXPERTS**

The consolidated financial statements of Theriva Biologics, Inc. as of December 31, 2024 and 2023 and for each of the two years in the period ended December 31, 2024 incorporated by reference in this prospectus supplement and in the registration statement of which this prospectus supplement forms a part have been so incorporated in reliance on the report of BDO USA, P.C, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting. The report on the consolidated financial statements contains an explanatory paragraph regarding the Company's ability to continue as a going concern.

**WHERE YOU CAN FIND MORE INFORMATION**

This prospectus supplement is part of a registration statement on Form S-3 (File No. 333-279077) we filed with the SEC. This prospectus supplement does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus supplement, we refer you to the registration statement, the base prospectus and the exhibits and schedules filed as a part of the registration statement. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus supplement, regardless of the time of delivery of this prospectus supplement or any sale of the securities offered by this prospectus supplement.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public at the SEC's website at *www.sec.gov*. Our SEC filings are also available on our website, *www.therivabio.com* under the heading "Investor Relations—SEC Filings." The reference to our website is an inactive textual reference only, the information contained in, and that can be accessed through our website, is not incorporated into and is not a part of this prospectus. We make available on our website our SEC filings as soon as reasonably practicable after those reports are filed with the SEC.

**INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE**

The SEC allows us to "incorporate by reference" information from other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus supplement. Information in this prospectus supplement supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus supplement.

We incorporate by reference into this prospectus supplement, the accompanying base prospectus and the registration statement of which this prospectus supplement is a part the information or documents listed below that we have filed with the SEC (Commission File No. 001-12584):

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· [Our Annual Report on Form 10-K for the fiscal year ended December 31, 2024 filed with the SEC on March 6, 2025;](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000141057825000285/tmb-20241231x10k.htm)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· [Our Quarterly Report on Form 10-Q for the quarter ended March 31, 2025 filed with the SEC on May 14, 2025;](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000141057825001242/tmb-20250331x10q.htm)

· [Our Quarterly Report on Form 10-Q for the quarter ended June 30, 2025 filed with the SEC on August 11, 2025;](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000141057825001654/tmb-20250630x10q.htm)

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· Our Current Reports on Form 8-K filed with the SEC on [March 31, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925029654/tm2510883d1_8k.htm) (other than as set forth therein), [May 7, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925045309/tm2514050d1_8k.htm) (other than as set forth therein), [May 8, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925046170/tm2514447d1_8k.htm) , [June 2, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925055181/tm2516499d1_8k.htm) (other than as set forth therein), [June 20, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925061203/tm2518362d1_8k.htm) , [June 25, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925062559/tm2518991d1_8k.htm) , [September 4, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925087465/tm2525057d1_8k.htm) , [October 2, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925096047/tm2527561d1_8k.htm) , [October 6, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925096946/tm2528055d1_8k.htm) (other than as set forth therein), [October 8, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925097739/tm2528131d1_8k.htm) , [October 14, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925098882/tm2528558d1_8k.htm) (other than as set forth therein), [October 17, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925100468/tm2528131d2_8k.htm) and [October 20, 2025](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465925100608/tm2529071d1_8k.htm) ;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· The
 description of our common stock set forth in (i) our registration statements on [Form 8-A12B, filed with the SEC on June 20, 2007 (File No. 001-12584)](http://www.sec.gov/Archives/edgar/data/894158/000089016307000379/s11-7491_8a.htm) and (ii) [Exhibit 4.2](https://www.sec.gov/Archives/edgar/data/894158/000141057824000293/tmb-20231231xex4d3.htm) —Description of Securities of
 Theriva Biologics, Inc. to our Annual Report on Form 10-K for the fiscal year ended December 31, 2024.

We also incorporate by reference any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items unless such Form 8-K expressly provides to the contrary) made with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including those made on or after the date of this prospectus supplement but prior to the termination of the offering (i.e., until the earlier of the date on which all of the securities registered hereunder have been sold or the registration statement of which this prospectus supplement forms a part has been withdrawn). Information in such future filings updates and supplements the information provided in this prospectus supplement. Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements.

We will furnish without charge to each person, including any beneficial owner, to whom a prospectus is delivered, upon written or oral request, a copy of any or all of the documents incorporated by reference into this prospectus supplement but not delivered with the prospectus supplement, including exhibits that are specifically incorporated by reference into such documents. You should direct any requests for documents to:

**Theriva Biologics, Inc.**

**9605 Medical Center Drive, Suite 270**

**Rockville, Maryland 20850**

**Telephone: (301) 417-4364**

**Attention: Corporate Secretary**

You may also access these documents, free of charge, on the SEC's website at *www.sec.gov* or on our website at *https://ir.therivabio.com/sec-filings*. The information contained in, or that can be accessed through, our website is not incorporated by reference in, and is not part of, this prospectus supplement and the accompanying base prospectus.

In accordance with Rule 412 of the Securities Act, any statement contained in a document incorporated by reference herein shall be deemed modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement.

You should rely only on information contained in, or incorporated by reference into, this prospectus supplement and the accompanying base prospectus. We have not authorized anyone to provide you with information different from that contained in this prospectus supplement or incorporated by reference into this prospectus supplement. We are not making offers to sell the securities in any jurisdiction in which such an offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make such an offer or solicitation.

**PROSPECTUS**

**$200,000,000**

![](tm2529425d1_424b5img01.jpg)

**THERIVA BIOLOGICS, INC.**

**Common Stock**

**Preferred Stock**

**Debt Securities**

**Warrants**

**Units**

We may, from time to time, offer and sell up to $200,000,000 of any combination of our common stock, par value $0.001 (the "common stock"), preferred stock, par value $0.001 (the "preferred stock"), debt securities, warrants or units described in this prospectus, either individually or in combination with other securities, at prices and on terms described in one or more supplements to this prospectus. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock, or debt securities upon the exercise of warrants.

This prospectus provides you with a general description of the securities that we may offer. Each time we offer and sell securities, we will provide a supplement to this prospectus that contains specific information about the offering and the amounts, prices and terms of the securities. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as the documents incorporated by reference, before buying any of the securities being offered.

Securities may be sold by us to or through underwriters or dealers, directly to purchasers or through agents designated from time to time. For additional information on the methods of sale, you should refer to the section entitled "Plan of Distribution" in this prospectus and in the applicable prospectus supplement. If any underwriters, dealers or agents are involved in the sale of any of the securities, their names and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, in the applicable prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement. No securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such securities.

Our common stock is listed on the NYSE American LLC under the symbol "TOVX." On September 23, 2024, the last reported sale price of our common stock on the NYSE American LLC was $3.42 per share. The applicable prospectus supplement will contain information, where applicable, as to any other listing, if any, on any securities market or other exchange of the specific security covered by such prospectus supplement.

As of the date of this prospectus, the aggregate market value of our outstanding common stock held by non-affiliates is approximately $9,806,578, which is calculated based on 1,353,565 shares of our outstanding common stock held by non-affiliates and a price of $7.245 per share, the closing price of our common stock on July 24, 2024, which is the highest closing sale price of our common stock on the NYSE American LLC within the prior 60 days of this prospectus. During the prior twelve calendar month period that ends on and includes the date hereof, we have offered and sold approximately $3,738,514 of shares of our common stock pursuant to General Instruction I.B.6 to Form S-3.

**Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading "Risk Factors" beginning on page 6 of this prospectus and contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the other documents that are incorporated by reference into this prospectus.**

**Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.**

**The date of this prospectus is September 25, 2024.**

**TABLE OF CONTENTS**

---

| | |
|:---|:---|
|  | **Page** |
| [About this Prospectus](#ATP_015) | [ii](#ATP_015) |
| [Prospectus Summary](#PS_016) | [1](#PS_016) |
| [Risk Factors](#RF_017) | [6](#RF_017) |
| [Forward-Looking Statements](#FLS_018) | [7](#FLS_018) |
| [Use of Proceeds](#UOP_019) | [8](#UOP_019) |
| [Description of Capital Stock](#DOCS_020) | [9](#DOCS_020) |
| [Description of Debt Securities](#DODS_021) | [14](#DODS_021) |
| [Description of Warrants](#DOW_022) | [20](#DOW_022) |
| [Description of Units](#DOU_023) | [22](#DOU_023) |
| [Legal Ownership of Securities](#LOS_024) | [23](#LOS_024) |
| [Plan of Distribution](#POD_025) | [26](#POD_025) |
| [Legal Matters](#LM_026) | [28](#LM_026) |
| [Experts](#E_027) | [28](#E_027) |
| [Where You Can Find More Information](#WTCFMI_028) | [28](#WTCFMI_028) |
| [Incorporation of Certain Information by Reference](#IOCBR_029) | [28](#IOCBR_029) |

---

i

**ABOUT THIS PROSPECTUS**

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission (the "SEC") using a "shelf" registration process. Under this shelf registration statement, we may sell from time to time in one or more offerings up to a total dollar amount of $200,000,000 of shares of common stock, preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or as units in combination with other securities as described in this prospectus. Each time we sell any type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change any of the information contained in this prospectus or in the documents we have incorporated by reference into this prospectus. To the extent that any statement that we make in a prospectus supplement is inconsistent with statements made in this prospectus, the statements made in this prospectus will be deemed modified or superseded by those made in a prospectus supplement. You should carefully read both this prospectus and the applicable prospectus supplement and any related free writing prospectus, together with the additional information described under "Where You Can Find More Information," before buying any of the securities being offered.

**THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT**

Neither we, nor any agent, underwriter or dealer has authorized any person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus prepared by or on behalf of us or to which we have referred you. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus, any applicable supplement to this prospectus or any related free writing prospectus does not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor does this prospectus, any applicable supplement to this prospectus or any related free writing prospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction.

You should not assume that the information contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus, any applicable prospectus supplement or any related free writing prospectus is delivered, or securities are sold, on a later date.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the section entitled "Where You Can Find More Information."

Except as otherwise indicated herein or as the context otherwise requires, references in this prospectus to "Theriva," "the Company," "we," "us," "our" and similar references refer to Theriva Biologics, Inc., an entity incorporated under the laws of the State of Nevada, and where appropriate our consolidated subsidiaries.

This prospectus and the information incorporated herein by reference include trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included or incorporated by reference into this prospectus, any applicable prospectus supplement or any related free writing prospectus are the property of their respective owners.

ii

**PROSPECTUS SUMMARY**

*The following summary highlights information contained elsewhere in this prospectus or incorporated by reference herein and does not contain all the information that may be important to purchasers of our securities. Prospective purchasers of our securities should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading "Risk Factors" contained in this prospectus, the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. Prospective purchasers of our securities should also carefully read the information incorporated by reference into this prospectus, including our financial statements, and the exhibits to the registration statement of which this prospectus is a part.*

**Overview**

We are a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need. As a result of the acquisition in March 2022 (the "Acquisition") of Theriva Biologics, S.L. ("VCN", formerly named VCN Biosciences, S.L.), we began transitioning our strategic focus to oncology, which is now our primary focus, through the development of VCN's new oncolytic adenovirus platform designed for intravenous and intravitreal delivery to trigger tumor cell death, to improve access of co-administered cancer therapies to the tumor, and to promote a robust and sustained anti-tumor response by the patient's immune system. Our lead product candidate, VCN-01, a clinical stage oncolytic human adenovirus that is modified for tumor-selective replication and to express an enzyme, PH20 hyaluronidase, is currently being evaluated in a Phase 2 clinical study for the treatment of pancreatic cancer ("Virage"), and has recently been used to treat patients in a Phase 1 clinical study for the treatment of retinoblastoma, and Phase 1 clinical studies for the treatment of other solid tumors including head and neck squamous cell carcinoma.

Prior to the Acquisition, our focus was on developing therapeutics designed to treat gastrointestinal (GI) diseases which included our clinical development candidates: (1) SYN-004 (ribaxamase) which is designed to degrade certain commonly used intravenous (IV) beta-lactam antibiotics within the GI tract to prevent microbiome damage, thereby preventing overgrowth and infection by pathogenic organisms such *Clostridioides difficile* infection (CDI) and vancomycin resistant Enterococci (VRE), and reducing the incidence and severity of acute graft-versus-host-disease (aGVHD) in allogeneic hematopoietic cell transplant (HCT) recipients, and (2) SYN-020, a recombinant oral formulation of the enzyme intestinal alkaline phosphatase (IAP) produced under cGMP conditions and intended to treat both local GI and systemic diseases. As part of our strategic transformation into an oncology focused company, we are exploring value creation options for our SYN-004 and SYN-020 assets, including out-licensing or partnering.

**Our Current Product Pipeline**

![](tm2529425d1_424b5img02.jpg)

***\*Based on management's current beliefs and expectations***

**allo-HCT** allogeneic hematopoietic cell transplant. **CPI** immune checkpoint inhibitor. **CSR** clinical study report. **FTD** Fast Track Designation. **HNSCC** head and neck squamous cell carcinoma. **IV** intravenous. **IVit** intravitreal. **ODD** Orphan Drug Designation. For other abbreviations see the text.

¹ Additional products with preclinical proof-of-concept include SYN-006 (carbapenemase) to prevent aGVHD and infection by carbapenem resistant enterococci and SYN-007 (ribaxamase) DR to prevent antibiotic associated diarrhea with oral β-lactam antibiotics.

² Depending on funding/partnership. SYN-004 may enter an FDA-agreed Phase 3 clinical trial for the treatment of CDI.

**Recent Developments**

***Reverse Stock Split***

On August 26, 2024, we effected a reverse stock split of our authorized, issued and outstanding shares of common stock at a ratio of one (1) share of common stock for every twenty-five (25) shares of common stock (the "Reverse Stock Split") and the common stock began trading on the NYSE American on a post-split basis when the market opened on August 26, 2024.

As a result of the Reverse Stock Split, each twenty-five (25) shares of common stock outstanding automatically combined into one (1) new share of common stock without any action on the part of the holders, and the number of outstanding shares common stock was reduced from 25,131,230 shares to 1,005,249 shares (subject to rounding of fractional shares).

No fractional shares were issued in connection with the Reverse Stock Split. Stockholders who otherwise would be entitled to receive fractional shares because they hold a number of pre-Reverse Stock Split shares of common stock not evenly divisible by 25 ware, in lieu of a fractional share, automatically be entitled to receive an additional fractional share of the common stock to round up to the next whole number.

The Reverse Stock Split was effected to meet the per share price requirements of the NYSE American, the securities exchange on which the common stock is listed.

After the Reverse Stock Split, the trading symbol for the common stock continued to be "TOVX." The new CUSIP number for the common stock following the Reverse Stock Split is 87164U 508.

**Corporate Information**

Our predecessor, Sheffield Pharmaceuticals, Inc., was incorporated in 1986, and in 2006 engaged in a reverse merger with Pipex Therapeutics, Inc., a publicly-traded Delaware corporation formed in 2001. After the reverse merger, we changed our name to Pipex Pharmaceuticals, Inc., and in October 2008 we changed our name to Adeona Pharmaceuticals, Inc. On October 15, 2009, we engaged in a merger with a wholly owned subsidiary for the purpose of reincorporating in the State of Nevada. On February 15, 2012, we changed our name to Synthetic Biologics, Inc. On August 10, 2018, we effected a one for thirty-five reverse stock split of our authorized, issued and outstanding common stock. On July 15, 2022, we effected a one for ten reverse stock split of our authorized, issued and outstanding common stock. On October 12, 2022, we changed our name to Theriva Biologics, Inc. On August 26, 2024, we effected the Reverse Stock Split.

Our principal executive offices are located at 9605 Medical Center Drive, Suite 270, Rockville, Maryland 20850, and our telephone number is (301) 417 - 4367. Our website address is *www.therivabio.com*. Information contained on our website is intended for informational purposes only and is not incorporated by reference into this prospectus, and it should not be considered to be part of this prospectus or the registration statement of which this prospectus forms a part. The SEC maintains an internet site that contains reports, proxy and information statements, and other information regarding issuers like us that file documents electronically with the SEC. The address of the SEC website is *www.sec.gov*.

**Smaller Reporting Company**

We are a "smaller reporting company" as defined in the Securities Exchange Act of 1934, as amended (the "Exchange Act"). As a result, we may take advantage of certain reduced disclosure obligations available to smaller reporting companies, including the exemption from compliance with the auditor attestation requirements pursuant to the Sarbanes-Oxley Act of 2022, reduced disclosure about our executive compensation arrangements and the requirements to provide only two years of audited financial statements in our annual reports and registration statements. We will continue to be a "smaller reporting company" as long as (1) we have a public float (i.e., the market value of our common stock held by non-affiliates) less than $250 million calculated as of the last business day of our most recently completed second fiscal quarter, or (2) our annual revenues are less than $100 million for our previous fiscal year and we have either no public float or a public float of less than $700 million as of the end of that fiscal year's second fiscal quarter. Decreased disclosures in our SEC filings due to our status as a "smaller reporting company" may make it harder for investors to analyze our results of operations and financial prospects.

**Risks Associated with our Business**

Our business is subject to numerous risks, as described under the heading "Risk Factors" contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the documents that are incorporated by reference into this prospectus.

**The Securities We May Offer**

We may offer shares of our common stock, preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or as units in combination with other securities, with a total value of up to $200,000,000 from time to time under this prospectus at prices and on terms to be determined at the time of any offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· designation or classification;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· aggregate principal amount or aggregate offering price;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· maturity;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· original issue discount;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· rates and times of payment of interest or dividends;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· redemption, conversion, exercise, exchange or sinking fund terms;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· ranking;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· restrictive covenants;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· voting or other rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· conversion or exchange prices or rates and, if applicable, any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· a discussion of material United States federal income tax considerations, if any.

The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents, underwriters or dealers reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through agents, underwriters or dealers, we will include in the applicable prospectus supplement:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the names of those agents, underwriters, or dealers;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· applicable fees, discounts and commissions to be paid to them;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· details regarding over-allotment options, if any; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the net proceeds to us.

The following is a summary of the securities we may offer with this prospectus.

*Common Stock*

We may issue shares of our common stock from time to time. Each holder of our common stock is entitled to one vote for each share on all matters submitted to a vote of the stockholders, including the election of directors. Under our articles of incorporation, as amended (the "Articles of Incorporation") and second amended and restated bylaws (the "Bylaws"), our stockholders do not have cumulative voting rights. Subject to preferences that may be applicable to any then-outstanding preferred stock, holders of common stock are entitled to receive ratably those dividends, if any, as may be declared from time to time by the board of directors out of legally available funds. In the event of our liquidation, dissolution or winding up, holders of common stock are entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities and the satisfaction of any liquidation preference granted to the holders of any then-outstanding shares of preferred stock. Holders of shares of our common stock do not have preemptive, subscription, redemption, or conversion rights and there are no redemption or sinking fund provisions applicable to the common stock. The rights, preferences and privileges of the holders of common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of preferred stock that we may designate in the future.

*Preferred Stock*

We may issue shares of our preferred stock from time to time, in one or more series. Our board of directors will determine the designations, voting powers, preferences and rights of the preferred stock, as well as the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, preemptive rights, terms of redemption or repurchase, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series. Convertible preferred stock will be convertible into our common stock or exchangeable for other securities. Conversion may be mandatory or at the holder's option and would be at prescribed conversion rates. If we sell any series of preferred stock under this prospectus, we will fix the designations, voting powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock.

We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

*Debt Securities*

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock or other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

Any debt securities issued under this prospectus will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. A form of indenture has been filed as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

*Warrants*

We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or as units in combination with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. In this prospectus, we have summarized certain general features of the warrants.

We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of warrants being offered, as well as any warrant agreements and warrant certificates that contain the terms of the warrants. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants.

Any warrants issued under this prospectus may be evidenced by warrant certificates. Warrants also may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

*Units*

We may issue units consisting of any combination of the other types of securities offered under this prospectus in one or more series. We may evidence each series of units by unit certificates that we will issue under a separate agreement. We may enter into unit agreements with a unit agent. Each unit agent will be a bank or trust company that we select. We will indicate the name and address of the unit agent in the applicable prospectus supplement relating to a particular series of units.

In this prospectus, we have summarized certain general features of the units under "Description of Units." We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to the series of units being offered, as well as the complete unit agreement that contains the terms of the units. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the specific unit agreement that contains the terms of the particular series of units we are offering, before the issuance of such units.

**RISK FACTORS**

Investing in our securities involves a high degree of risk. Before deciding whether to invest in our securities, you should consider carefully the risks and uncertainties described under the heading "Risk Factors" contained in the applicable prospectus supplement and any related free writing prospectus, and discussed under the section entitled "Risk Factors" contained in our most recent Annual Report on Form 10-K, our most recent Quarterly Reports on Form 10-Q, as such filings may be updated by subsequent annual, quarterly and other reports that are incorporated by reference into this prospectus in their entirety. The risks described in these documents are not the only ones we face, but those that we consider to be material. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. Past financial performance may not be a reliable indicator of future performance, and historical trends should not be used to anticipate results or trends in future periods. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also read carefully the section below entitled "Forward-Looking Statements."

**FORWARD-LOOKING STATEMENTS**

This prospectus, including the documents that we incorporate by reference herein, contains, and any applicable prospectus supplement or free writing prospectus including the documents we incorporate by reference therein may contain, forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act") and Section 21E of the Exchange Act, including statements regarding our future financial condition, business strategy and plans and objectives of management for future operations. Forward-looking statements include all statements that are not historical facts. In some cases, you can identify forward-looking statements by terminology such as "believe," "will," "may," "estimate," "continue," "anticipate," "intend," "should," "plan," "might," "approximately," "expect," "predict," "could," "potentially" or the negative of these terms or other similar expressions. Forward-looking statements include statements regarding our intentions, beliefs, projections, outlook, analyses or current expectations.

Discussions containing these forward-looking statements may be found, among other places, in the sections entitled "Business," "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" contained in the documents incorporated by reference herein, including our most recent Annual Report on Form 10-K and our Quarterly Reports on Form 10-Q and our Current Reports on Form 8-K, as well as any amendments thereto.

These statements relate to future events or our future financial performance and involve known and unknown risks, uncertainties and other factors that could cause our actual results, levels of activity, performance or achievement to differ materially from those expressed or implied by these forward-looking statements. We discuss in greater detail, and incorporate by reference into this prospectus in their entirety, many of these risks and uncertainties under the heading "Risk Factors" contained in the applicable prospectus supplement, in any free writing prospectus we may authorize for use in connection with a specific offering, and in the documents incorporated by reference herein. These statements reflect our current views with respect to future events and are based on assumptions and subject to risks and uncertainties. We undertake no obligation to revise or publicly release the results of any revision to these forward-looking statements, except as required by law. Given these risks and uncertainties, readers are cautioned not to place undue reliance on such forward-looking statements. All forward-looking statements are qualified in their entirety by this cautionary statement.

**USE OF PROCEEDS**

We will retain broad discretion over the use of the net proceeds from the sale of the securities offered hereby. Except as described in any prospectus supplement or in any related free writing prospectus that we may authorize to be provided to you, we currently intend to use the net proceeds from the sale of the securities offered by us hereunder primarily for working capital and general corporate purposes. We will set forth in the applicable prospectus supplement or free writing prospectus our intended use for the net proceeds received from the sale of any securities sold pursuant to the prospectus supplement or free writing prospectus.

**DESCRIPTION OF CAPITAL STOCK**

*The following is a description of the material terms of our capital stock. This is a summary only and does not purport to be complete. It is subject to and qualified in its entirety by reference to our Articles of Incorporation and our Bylaws, each of which are incorporated by reference as an exhibit to the registration statement of which this prospectus forms a part. We encourage you to read our Certificate of Incorporation, our Bylaws and the applicable provisions of the Nevada Revised Statute (the "NRS"), for additional information.*

Our authorized capital stock consists of:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· 14,000,000 shares of common stock, par value $0.001 per share; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· 10,000,000 shares of preferred stock, par value $0.001 per share.

**Common Stock**

*Outstanding Shares*. As of September 9, 2024, there were 1,353,565 shares of our common stock outstanding.

*Voting Rights*. The holders of the common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders, including the election of directors, and do not have cumulative voting rights. Accordingly, the holders of a majority of the shares of the common stock entitled to vote in any election of directors can elect all of the directors standing for election.

*Dividend Rights*. Subject to preferences that may be applicable to any then outstanding preferred stock, the holders of common stock are entitled to receive dividends, if any, as may be declared from time to time by our board of directors out of legally available funds.

*Liquidation Rights*. In the event of our liquidation, dissolution or winding up, holders of the common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities, subject to the satisfaction of any liquidation preference granted to the holders of any then outstanding shares of preferred stock.

*Other Rights and Preferences*. The holders of the common stock have no preemptive, conversion or subscription rights, and there are no redemption or sinking fund provisions applicable to the common stock. The rights, preferences and privileges of the holders of the common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of our preferred stock that we may designate and issue in the future.

*Fully Paid and Nonassessable*. All of our outstanding shares of common stock are fully paid and nonassessable.

**Preferred Stock**

The following summary of terms of our preferred stock is not complete. We will file as an exhibit to the registration statement of which this prospectus is a part or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Our board of directors may, without further action by our stockholders, fix the rights, preferences, privileges and restrictions of up to an aggregate of 10,000,000 shares of preferred stock in one or more series and authorize their issuance. There are no shares of preferred stock designated or outstanding. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of our common stock.

Our board of directors will fix the designations, voting powers, preferences and rights of the preferred stock of each series we issue under this prospectus, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will describe in the applicable prospectus supplement the terms of the series of preferred stock being offered, including, to the extent applicable:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the title and stated value;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the number of shares we are offering;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the liquidation preference per share;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the purchase price;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the dividend rate, period and payment date and method of calculation for dividends;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the procedures for any auction and remarketing;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the provisions for a sinking fund;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· any listing of the preferred stock on any securities exchange or market;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· whether the preferred stock will be convertible into our common stock, and, if applicable, the conversion price, or how it will be calculated, and the conversion period;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· whether the preferred stock will be exchangeable into debt securities, and, if applicable, the exchange price, or how it will be calculated, and the exchange period;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· voting rights of the preferred stock;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· preemptive rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· restrictions on transfer, sale or other assignment;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· whether interests in the preferred stock will be represented by depositary shares;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· a discussion of material United States federal income tax considerations applicable to the preferred stock;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· any limitations on the issuance of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· any other specific terms, preferences, rights or limitations of, or restrictions on, the preferred stock.

**Anti-Takeover Effects of Nevada Law**

The provisions of NRS, our Articles of Incorporation and our Bylaws described below may have the effect of delaying, deferring or discouraging another party from acquiring control of us.

***Business Combinations***

The "business combination" provisions of Sections 78.411 to 78.444, inclusive, of the NRS generally prohibit a Nevada corporation with at least 200 stockholders from engaging in various "combination" transactions with any interested stockholder for a period of two years after the date of the transaction in which the person became an interested stockholder, unless the transaction is approved by the board of directors prior to the date the interested stockholder obtained such status or the combination is approved by the board of directors and thereafter is approved at a meeting of the stockholders by the affirmative vote of stockholders representing at least 60% of the outstanding voting power held by disinterested stockholders, and extends beyond the expiration of the two-year period, unless:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the combination was approved by the board of directors prior to the person becoming an interested stockholder or the transaction by which the person first became an interested stockholder was approved by the board of directors before the person became an interested stockholder or the combination is later approved by a majority of the voting power held by disinterested stockholders; or

· if the consideration to be paid by the interested stockholder is at least equal to the highest of: (a) the highest price per share paid by the interested stockholder within the two years immediately preceding the date of the announcement of the combination or in the transaction in which it became an interested stockholder, whichever is higher, (b) the market value per share of common stock on the date of announcement of the combination and the date the interested stockholder acquired the shares, whichever is higher, or (c) for holders of preferred stock, the highest liquidation value of the preferred stock, if it is higher.

A "combination" is generally defined to include mergers or consolidations or any sale, lease exchange, mortgage, pledge, transfer, or other disposition, in one transaction or a series of transactions, with an "interested stockholder" having: (a) an aggregate market value equal to 5% or more of the aggregate market value of the assets of the corporation, (b) an aggregate market value equal to 5% or more of the aggregate market value of all outstanding shares of the corporation, (c) 10% or more of the earning power or net income of the corporation, and (d) certain other transactions with an interested stockholder or an affiliate or associate of an interested stockholder.

In general, an "interested stockholder" is a person who, together with affiliates and associates, owns (or within two years, did own) 10% or more of a corporation's voting stock. The statute could prohibit or delay mergers or other takeover or change in control attempts and, accordingly, may discourage attempts to acquire our company even though such a transaction may offer our stockholders the opportunity to sell their stock at a price above the prevailing market price.

***Control Share Acquisitions***

The "control share" provisions of Sections 78.378 to 78.3793, inclusive, of the NRS apply to "issuing corporations" that are Nevada corporations with at least 200 stockholders, including at least 100 stockholders of record who are Nevada residents, and that conduct business directly or indirectly in Nevada. The control share statute prohibits an acquirer, under certain circumstances, from voting its shares of a target corporation's stock after crossing certain ownership threshold percentages, unless the acquirer obtains approval of the target corporation's disinterested stockholders. The statute specifies three thresholds: one-fifth or more but less than one-third, one-third but less than a majority, and a majority or more, of the outstanding voting power. Generally, once an acquirer crosses one of the above thresholds, those shares in an offer or acquisition and acquired within 90 days thereof become "control shares" and such control shares are deprived of the right to vote until disinterested stockholders restore the right. These provisions also provide that if control shares are accorded full voting rights and the acquiring person has acquired a majority or more of all voting power, all other stockholders who do not vote in favor of authorizing voting rights to the control shares are entitled to demand payment for the fair value of their shares in accordance with statutory procedures established for dissenters' rights.

A corporation may elect to not be governed by, or "opt out" of, the control share provisions by making an election in its articles of incorporation or bylaws, provided that the opt-out election must be in place on the 10th day following the date an acquiring person has acquired a controlling interest, that is, crossing any of the three thresholds described above. We have not opted out of the control share statutes, and will be subject to these statutes if we are an "issuing corporation" as defined in such statutes.

The effect of the Nevada control share statutes is that the acquiring person, and those acting in association with the acquiring person, will obtain only such voting rights in the control shares as are conferred by a resolution of the stockholders at an annual or special meeting. The Nevada control share law, if applicable, could have the effect of discouraging takeovers of our company.

*Articles of Incorporation and Bylaws*

Our Articles of Incorporation and Bylaws provide that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the authorized number of directors is determined by our board of directors;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· directors may be removed only by the affirmative vote of the holders of at least a majority of our voting stock, whether for cause or without cause;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· our Bylaws may be amended or repealed by our board of directors or by the affirmative vote of our stockholders;

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| | |
|:---|:---|
| · | special meetings of the stockholders may be called by Chairman of the board, if any, the Vice Chairman of the board, if any, or the President or upon request of stockholders owning a majority of the outstanding shares |
|  | our board of directors may fill vacancies on the board of directors; |
| · | our board of directors will be authorized to issue, without stockholder approval, preferred stock, the rights of which will be determined at the discretion of the board of directors and that, if issued, could operate as a "poison pill" to dilute the stock ownership of a potential hostile acquirer to prevent an acquisition that our board of directors does not approve; |

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· our stockholders do not have cumulative voting rights, and therefore our stockholders holding a majority of the shares of common stock outstanding will be able to elect all of our directors; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· our stockholders must comply with advance notice provisions to bring business before or nominate directors for election at a stockholder meeting.

*Potential Effects of Authorized but Unissued Stock*

We have shares of common stock available for future issuance without stockholder approval. We may utilize these additional shares for a variety of corporate purposes, including future public offerings to raise additional capital, to facilitate corporate acquisitions or payment as a dividend on the capital stock.

The existence of unissued and unreserved common stock may enable our board of directors to issue shares to persons friendly to current management.

**Limitations of Director Liability and Indemnification of Directors, Officers and Employees**

NRS 78.138 provides that directors of a corporation is not individually liable to the corporation or its stockholders or creditors for any damages as a result of any act or failure to act in his or her capacity as a director or officer unless: (a) the presumption that directors and officers acted in good faith on an informed basis with a view toward the best interest of the corporation has been rebutted and (b) it is proven that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· The director's or officer's act or failure to act constituted a breach of his or her fiduciary duties as a director or officer; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· such breach involved intentional misconduct, fraud or a knowing violation of law.

Our Articles of Incorporation and Bylaws provide that we will indemnify our directors and officers to the fullest extent permitted by law and may indemnify employees and other agents. Our Articles of Incorporation also provide that we are obligated to advance expenses incurred by a director or officer in advance of the final disposition of any action or proceeding.

We have obtained a policy of directors' and officers' liability insurance.

We have entered into separate indemnification agreements with our directors and officers. These agreements, among other things, require us to indemnify our directors and officers for any and all expenses (including reasonable attorneys' fees, retainers, court costs, transcript costs, fees of experts, witness fees, travel expenses, duplicating costs, printing and binding costs, telephone charges, postage, delivery service fees) judgments, fines and amounts paid in settlement actually and reasonably incurred by such directors or officers or on his or her behalf in connection with any action or proceeding arising out of their services as one of our directors or officers, or any of our subsidiaries or any other company or enterprise to which the person provides services at our request provided that such person follows the procedures for determining entitlement to indemnification and advancement of expenses set forth in the indemnification agreement. We believe that these bylaw provisions and indemnification agreements are necessary to attract and retain qualified persons as directors and officers.

The limitation of liability and indemnification provisions in our Articles of Incorporation and Bylaws may discourage stockholders from bringing a lawsuit against directors for breach of their fiduciary duties. They may also reduce the likelihood of derivative litigation against directors and officers, even though an action, if successful, might provide a benefit to us and our stockholders. Our results of operations and financial condition may be harmed to the extent we pay the costs of settlement and damage awards against directors and officers pursuant to these indemnification provisions.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or persons controlling us, we have been informed that, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

At present, there is no pending litigation or proceeding involving any of our directors or officers as to which indemnification is required or permitted, and we are not aware of any threatened litigation or proceeding that may result in a claim for indemnification.

**Listing of the Common Stock on the NYSE American LLC**

Our common stock is listed for trading on the NYSE American LLC under the symbol "TOVX."

**Transfer Agent and Registrar**

The transfer agent and registrar for our common stock is Equiniti Trust Company.

**Stock Options**

As of September 9, 2024, we had options outstanding to purchase an aggregate of 175,191 shares of common stock that were issued under our equity compensation plans. As of September 9, 2024, there were 112,640 shares of common stock reserved for future issuance under our equity incentive plan.

**Preferred Stock**

As of September 9, 2024, there are no shares of preferred stock outstanding.

**DESCRIPTION OF DEBT SECURITIES**

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended (the "Trust Indenture Act"). We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplement and any related free writing prospectus related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.

**General**

The indenture will not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.

We may issue the debt securities issued under the indenture as "discount securities," which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with "original issue discount," or OID, for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the title of the series of debt securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· any limit upon the aggregate principal amount that may be issued;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the maturity date or dates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the form of the debt securities of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the applicability of any guarantees;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination thereof, and the terms of any subordination;

· if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt securities that is convertible into another security or the method by which any such portion shall be determined;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· our right, if any, to defer payment of interest and the maximum length of any such deferral period;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· if applicable, the date or dates after which, or the period or periods during which, and the price or prices at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder's option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· whether the debt securities of the series shall be issued in whole or in part in the form of a global security or securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the holders' option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· if other than the full principal amount thereof, the portion of the principal amount of debt securities of the series which shall be payable upon declaration of acceleration of the maturity thereof;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· additions to or changes in the covenants applicable to the particular debt securities being issued, including, among others, the consolidation, merger or sale covenant;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· additions to or changes in the events of default with respect to the securities and any change in the right of the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· additions to or changes in the provisions relating to satisfaction and discharge of the indenture;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;· additions to or changes in the provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;

● the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;

● whether interest will be payable in cash or additional debt securities at our or the holders' option and the terms and conditions upon which the election may be made;

● the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if any and principal amounts of the debt securities of the series to any holder that is not a "United States person" for federal tax purposes;

● any restrictions on transfer, sale or assignment of the debt securities of the series; and

● any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.

**Conversion or Exchange Rights**

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

**Consolidation, Merger or Sale**

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.

**Events of Default under the Indenture**

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

● if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of interest for this purpose;

● if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;

● if we fail to observe or perform any other covenant or agreement contained in the debt securities or the indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same to be remedied and stating that such is a notice of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

● if specified events of bankruptcy, insolvency or reorganization occur.

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:

● the direction so given by the holder is not in conflict with any law or the applicable indenture; and

● subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:

● the holder has given written notice to the trustee of a continuing event of default with respect to that series;

● the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request,

● such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities to be incurred by the trustee in compliance with the request; and

● the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.

**Modification of Indenture; Waiver**

We and the trustee may change an indenture without the consent of any holders with respect to specific matters:

● to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;

● to comply with the provisions described above under "Description of Debt Securities—Consolidation, Merger or Sale;"

● to provide for uncertificated debt securities in addition to or in place of certificated debt securities;

● to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred upon us in the indenture;

● to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

● to make any change that does not adversely affect the interests of any holder of debt securities of any series in any material respect;

● to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided above under "Description of Debt Securities—General" to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;

● to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or

● to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act.

In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

● extending the fixed maturity of any debt securities of any series;

● reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any series of any debt securities; or

● reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.

**Discharge**

Each indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

● provide for payment;

● register the transfer or exchange of debt securities of the series;

● replace stolen, lost or mutilated debt securities of the series;

● pay principal of and premium and interest on any debt securities of the series;

● maintain paying agencies;

● hold monies for payment in trust;

● recover excess money held by the trustee;

● compensate and indemnify the trustee; and

● appoint any successor trustee.

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.

**Form, Exchange and Transfer**

We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company, or DTC, or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating such securities will be set forth in the applicable prospectus supplement.

At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

● issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

● register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

**Information Concerning the Trustee**

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indenture at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

**Payment and Paying Agents**

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

**Governing Law**

The indenture and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

**DESCRIPTION OF WARRANTS**

The following description, together with the additional information we may include in any applicable prospectus supplement and in any related free writing prospectus, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be offered independently or in combination with common stock, preferred stock or debt securities offered by any prospectus supplement. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The following description of warrants will apply to the warrants offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The applicable prospectus supplement for a particular series of warrants may specify different or additional terms.

We have filed or will file forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants that may be offered as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant and/or the warrant agreement and warrant certificate, as applicable, that contain the terms of the particular series of warrants we are offering, and any supplemental agreements, before the issuance of such warrants. The following summaries of material terms and provisions of the warrants are subject to, and qualified in their entirety by reference to, all the provisions of the form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements applicable to a particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplement related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectus, and the complete form of warrant and/or the warrant agreement and warrant certificate, as applicable, and any supplemental agreements, that contain the terms of the warrants.

**General**

We will describe in the applicable prospectus supplement the terms of the series of warrants being offered, including, to the extent applicable:

● the offering price and aggregate number of warrants offered;

● the currency for which the warrants may be purchased;

● the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

● the date on and after which the warrants and the related securities will be separately transferable;

● in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

● in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;

● the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;

● the terms of any rights to redeem or call the warrants;

● any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

● the dates on which the right to exercise the warrants will commence and expire;

● the manner in which the warrant agreements and warrants may be modified;

● a discussion of material United States federal income tax consequences of holding or exercising the warrants;

● the terms of the securities issuable upon exercise of the warrants; and

● any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

● in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or, payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any; or

● in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture.

**Exercise of Warrants**

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants by delivering the warrant or warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent, if applicable, in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of any warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to any warrant agent in connection with the exercise of the warrant.

Upon receipt of payment and the warrant or warrant certificate, as applicable, properly completed and duly executed at the corporate trust office of the warrant agent, if any, or any other office, including ours, indicated in the prospectus supplement, we will, as soon as practicable, issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants (or the warrants represented by such warrant certificate) are exercised, a new warrant or a new warrant certificate, as applicable, will be issued for the remaining warrants.

**Governing Law**

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements, and any claim, controversy or dispute arising under or related to the warrants or warrant agreements, will be governed by and construed in accordance with the laws of the State of New York.

**Enforceability of Rights by Holders of Warrants**

Each warrant agent, if any, will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

**DESCRIPTION OF UNITS**

The following description, together with the additional information we may include in any applicable prospectus supplement and related free writing prospectus, summarizes the material terms and provisions of the units that we may offer under this prospectus. We may issue units consisting of any combination of the other types of securities offered under this prospectus in one or more series. We will issue each unit so that the holder of the unit is also the holder of each security included in the unit. As a result, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date. We may evidence each series of units by unit certificates that we will issue under a separate agreement. We may enter into unit agreements with a unit agent. Each unit agent will be a bank or trust company that we select. We will indicate the name and address of any unit agent in the applicable prospectus supplement relating to a particular series of units. The summary below and that contained in any prospectus supplement is qualified in its entirety by reference to all of the provisions of the unit agreement and/or unit certificate, and depositary arrangements, if applicable. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the units that we may offer under this prospectus, as well as the complete unit agreement and/or unit certificate, and depositary arrangements, as applicable, that contain the terms of the units.

We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of unit agreement and/or unit certificate, and depositary arrangements, as applicable, that contain the terms of the particular series of units we are offering, and any supplemental agreements, before the issuance of such units.

We will describe in the applicable prospectus supplement the terms of the series of units being offered, including:

● the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

● any provisions for the issuance, payment, settlement, transfer, or exchange of the units or of the securities composing the units;

● whether the units will be issued in fully registered or global form; and

● any other terms of the units.

**LEGAL OWNERSHIP OF SECURITIES**

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the "holders" of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as "indirect holders" of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

**Book-Entry Holders**

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary's book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Global securities will be registered in the name of the depositary or its participants. Consequently, for global securities, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a global security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary's book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

**Street Name Holders**

We may terminate a global security or issue securities that are not issued in global form. In these cases, investors may choose to hold their securities in their own names or in "street name." Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any such trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

**Legal Holders**

Our obligations, as well as the obligations of any applicable trustee or third party employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of an indenture, or for other purposes. In such an event, we would seek approval only from the legal holders, and not the indirect holders, of the securities. Whether and how the legal holders contact the indirect holders is up to the legal holders.

**Special Considerations for Indirect Holders**

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are represented by one or more global securities or in street name, you should check with your own institution to find out:

● how it handles securities payments and notices;

● whether it imposes fees or charges;

● how it would handle a request for the holders' consent, if ever required;

● whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

● how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

● if the securities are in book-entry form, how the depositary's rules and procedures will affect these matters.

**Global Securities**

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, The Depository Trust Company, New York, New York, known as DTC, will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under "—Special Situations When a Global Security Will Be Terminated." As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

**Special Considerations for Global Securities**

As an indirect holder, an investor's rights relating to a global security will be governed by the account rules of the investor's financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only as global securities, an investor should be aware of the following:

● an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

● an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

● an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

● an investor may not be able to pledge his or her interest in the global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

● the depositary's policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor's interest in the global security;

● we and any applicable trustee have no responsibility for any aspect of the depositary's actions or for its records of ownership interests in the global security, nor will we or any applicable trustee supervise the depositary in any way;

● the depositary may, and we understand that DTC will, require that those who purchase and sell interests in the global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

● financial institutions that participate in the depositary's book-entry system, and through which an investor holds its interest in the global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

**Special Situations When a Global Security Will Be Terminated**

In a few special situations described below, a global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own names, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, a global security will terminate when the following special situations occur:

● if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

● if we notify any applicable trustee that we wish to terminate that global security; or

● if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the applicable prospectus supplement. When a global security terminates, the depositary, and neither we nor any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

**PLAN OF DISTRIBUTION**

We may sell the securities from time to time pursuant to underwritten public offerings, direct sales to the public, "at the market" offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through one or more underwriters or dealers (acting as principal or agent), through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

● at a fixed price or prices, which may be changed;

● at market prices prevailing at the time of sale;

● at prices related to such prevailing market prices; or

● at negotiated prices.

A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:

● the name or names of the underwriters, dealers, agents or other purchasers, if any;

● the purchase price of the securities or other consideration therefor, and the proceeds we will receive from the sale;

● any option to purchase additional shares or other options under which underwriters, dealers, agents or other purchasers may purchase additional securities from us;

● any agency fees or underwriting discounts to be allowed or paid to the agent or underwriters and other items constituting agents' or underwriters' compensation;

● any public offering price;

● any discounts or concessions allowed or reallowed or paid to dealers; and

● any securities exchange or market on which the securities may be listed.

Only underwriters named in the prospectus supplement will be underwriters of the securities offered by the prospectus supplement. Dealers and agents participating in the distribution of the securities may be deemed to be underwriters, and compensation received by them on resale of the securities may be deemed to be underwriting discounts. If such dealers or agents were deemed to be underwriters, they may be subject to statutory liabilities under the Securities Act.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement other than securities covered by any option to purchase additional shares or other option. If a dealer is used in the sale of securities, we, or an underwriter, will sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale. To the extent required, we will set forth in the prospectus supplement the name of the dealer and the terms of the transaction. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters, dealers or agents with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, dealer or agent, the nature of any such relationship.

We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities, and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, the agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents, dealers and underwriters with indemnification against civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents, dealers or underwriters may make with respect to these liabilities. Agents, dealers and underwriters or their affiliates may engage in transactions with, or perform services for, us in the ordinary course of business.

All securities we may offer, other than common stock, will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum price. Syndicate covering or other short-covering transactions involve purchases of the securities, either through exercise of the option to purchase additional shares or in the open market after the distribution is completed, to cover short positions. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time. These transactions may be effected on any exchange or over-the-counter market or otherwise.

Any underwriters, dealers or agents that are qualified market makers on the NYSE American LLC may engage in passive market making transactions in our common stock on the NYSE American LLC in accordance Regulation M under the Exchange Act, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker's bid, however, the passive market maker's bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

The specific terms of any lock-up provisions in respect of any given offering will be described in the applicable prospectus supplement.

The anticipated date of delivery of offered securities will be set forth in the applicable prospectus supplement relating to each offer.

**LEGAL MATTERS**

The validity of the shares of common stock being offered by this prospectus is being passed upon by Parsons Behle & Latimer, Reno, Nevada. Blank Rome LLP, New York, New York has acted as securities counsel to Theriva Biologics, Inc. Additional legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement. A partner of Blank Rome LLP has options to purchase shares of stock of Theriva Biologics, Inc. that represent less than 1% of the outstanding shares of common stock of Theriva Biologics, Inc.

**EXPERTS**

The consolidated financial statements of Theriva Biologics, Inc. as of December 31, 2023 and 2022 and for each of the two years in the period ended December 31, 2023 incorporated by reference in this prospectus and in the registration statement of which this prospectus forms a part have been so incorporated in reliance on the report of BDO USA, P.C, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting. The report on the consolidated financial statements contains an explanatory paragraph regarding the Company's ability to continue as a going concern.

**WHERE YOU CAN FIND MORE INFORMATION**

This prospectus is part of a registration statement we filed with the SEC. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of the securities offered by this prospectus.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public at the SEC's website at *www.sec.gov*. Our SEC filings are also available on our website, *www.therivabio.com* under the heading "Investor Relations—SEC Filings." The reference to our website is an inactive textual reference only, the information contained in, and that can be accessed through our website, is not incorporated into and is not a part of this prospectus. We make available on our website our SEC filings as soon as reasonably practicable after those reports are filed with the SEC.

**INCORPORATION OF CERTAIN INFORMATION BY REFERENCE**

The SEC allows us to "incorporate by reference" information from other documents that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus.

We incorporate by reference into this prospectus and the registration statement of which this prospectus is a part the information or documents listed below that we have filed with the SEC (Commission File No. 001-12584):

● [Our Annual Report on Form 10-K for the fiscal year ended December 31, 2023 filed with the SEC on March 25, 2024;](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000141057824000293/tmb-20231231x10k.htm)

● [Our Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 2024 filed with the SEC on May 7, 2024;](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000141057824000601/tmb-20240331x10q.htm)

● [Our Quarterly Report on Form 10-Q for the fiscal quarter ended June 30, 2024 filed with the SEC on August 13, 2024;](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000141057824001342/tmb-20240630x10q.htm)

● Our Current Reports on Form 8-K filed with the SEC on [February 7, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924011395/tm245387d1_8k.htm) , [April 22, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924050037/tm2412300d1_8k.htm) (other than as set forth therein), [April 23, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924050307/tm2412300d2_8k.htm) (other than as set forth therein) and [May 2, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924056146/tm2413223d1_8k.htm) , [May 16, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924062270/tm2414630d1_8k.htm) , [May 23, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924064544/tm2415354d1_8k.htm) , (other than as set forth therein) [July 31, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924084159/tm2420486d1_8k.htm) (other than as set forth therein), [August 16, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924090522/tm2421949d1_8k.htm) , [August 26, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924092644/tm2422579d1_8k.htm) and [September 9, 2024](https://www.sec.gov/ix?doc=/Archives/edgar/data/894158/000110465924098225/tm2423567d1_8k.htm) ; and

● The description of our common stock set forth in (i) our registration statements on [Form 8-A12B, filed with the SEC on June 20, 2007 (File No. 001-12584)](https://www.sec.gov/Archives/edgar/data/894158/000089016307000379/s11-7491_8a.htm) and (ii) [Exhibit 4.3](https://www.sec.gov/Archives/edgar/data/894158/000141057824000293/tmb-20231231xex4d3.htm) —Description of Securities to our Annual Report on Form 10-K for the fiscal year ended December 31, 2023.

We also incorporate by reference any future filings (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items unless such Form 8-K expressly provides to the contrary) made with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including those made (i) on or after the date of the filing of the registration statement of which this prospectus forms a part and prior to effectiveness of such registration statement, and (ii) on or after the date of this prospectus but prior to the termination of the offering (i.e., until the earlier of the date on which all of the securities registered hereunder have been sold or the registration statement of which this prospectus forms a part has been withdrawn). Information in such future filings updates and supplements the information provided in this prospectus. Any statements in any such future filings will automatically be deemed to modify and supersede any information in any document we previously filed with the SEC that is incorporated or deemed to be incorporated herein by reference to the extent that statements in the later filed document modify or replace such earlier statements.

We will furnish without charge to each person, including any beneficial owner, to whom a prospectus is delivered, upon written or oral request, a copy of any or all of the documents incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits that are specifically incorporated by reference into such documents. You should direct any requests for documents to:

Theriva Biologics, Inc.

9605 Medical Center Drive, Suite 270

Rockville, Maryland 20850

Telephone (301) 417-4364

Attention: Corporate Secretary

You may also access these documents, free of charge, on the SEC's website at *www.sec.gov* or on our website at *https://ir.therivabio.com/sec-filings*. The information contained in, or that can be accessed through, our website is not incorporated by reference in, and is not part of, this prospectus or any accompanying prospectus supplement.

In accordance with Rule 412 of the Securities Act, any statement contained in a document incorporated by reference herein shall be deemed modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement.

You should rely only on information contained in, or incorporated by reference into, this prospectus and any prospectus supplement. We have not authorized anyone to provide you with information different from that contained in this prospectus or incorporated by reference into this prospectus. We are not making offers to sell the securities in any jurisdiction in which such an offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make such an offer or solicitation.

![](tm2529425d1_424b5img01.jpg)

**Up to $4,019,597 of Shares**

**Common Stock**

**PROSPECTUS SUPPLEMENT**

**A.G.P.**

October 24, 2025