Supplemental Prospectus (Form 424B4)

Filed Pursuant to Rule 424(b)(4)

Registration No.: 333-297386

PROSPECTUS

 

2,158,274 Shares of Common Stock Issuable Upon Exercise of Warrant

11,157,549 Shares of Common Stock Issuable Upon Conversion of Promissory Note

This prospectus relates to the resale, from time to time, of up to 13,315,823 shares (the "Shares") of our common stock, $0.00033 par value per share ("Common Stock"), by the Selling Stockholder (as defined below). The Shares covered by this prospectus consist of (x) 2,158,274 shares of Common Stock issuable upon exercise of the Warrant (as defined below) and (y) up to 11,157,549 shares of Common Stock issuable upon conversion of the Promissory Note (as defined below), in each case, issued to the Selling Stockholder in a private placement as described in this prospectus.

On April 30, 2026, PDS Biotechnology Corporation (the "Company") entered into a Securities Purchase Agreement (the "Securities Purchase Agreement") with YA II PN, LTD., a Cayman Islands exempt limited company (the "Selling Stockholder"). Pursuant to the Securities Purchase Agreement, on June 15, 2026 (the "Closing Date"), the Company issued and sold to the Selling Stockholder and the Selling Stockholder purchased from the Company (i) a promissory note (the "Promissory Note") in an aggregate principal amount of $6,000,000 and (ii) a warrant to purchase up to 2,158,274 shares of Common Stock at an exercise price of $1.1824 per share (the "Warrant"), subject to adjustments as set forth in the Warrant. In connection with the Securities Purchase Agreement, on the Closing Date, the Company and the Selling Stockholder entered into a Registration Rights Agreement (the "Registration Rights Agreement"), pursuant to which the Company is obligated to file a registration statement to register the shares of Common Stock issuable upon conversion of the Promissory Note and exercise of the Warrant. We will not receive any proceeds from the sale of the Shares by the Selling Stockholder under this prospectus. We will, however, receive proceeds from any portion of the Warrant that is exercised through the payment of the exercise price in cash. We intend to use the proceeds, if any, for general corporate purposes. The Selling Stockholder will bear all commissions and discounts, if any, attributable to the sale of the Shares. We will bear all costs, expenses and fees in connection with the registration of the Shares.

The Selling Stockholder may offer such shares from time to time as it may determine through public or private transactions or through other means described in the section entitled "Plan of Distribution" at prevailing market prices, at prices related to prevailing market prices or at privately negotiated prices. This prospectus does not necessarily mean that the Selling Stockholder will offer or sell the Shares. We cannot predict when or in what amounts the Selling Stockholder may sell any of the Shares offered by this prospectus. Any shares of Common Stock subject to resale hereunder will have been issued by us and acquired by the Selling Stockholder prior to any resale of such shares pursuant to this prospectus.

Our Common Stock is listed on The Nasdaq Capital Market under the symbol "PDSB." On July 20, 2026, the closing price of our Common Stock was $0.7173 per share.

We are a "smaller reporting company" as defined under the federal securities laws and, as such, have elected to comply with certain reduced reporting requirements for this prospectus and may elect to do so in future filings.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading "Risk Factors" on page 5 of this prospectus as well as those contained in any 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.

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 July 21, 2026.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or the SEC, using a "shelf" registration process. Under the shelf registration process, the Selling Stockholder may, from time to time, offer and sell the Shares described in this prospectus in one or more offerings. Information about the Selling Stockholder may change over time. We will not receive any of the proceeds from the sale of our Common Stock by the Selling Stockholder under this prospectus, although we will receive proceeds from any portion of the Warrant that is exercised through the payment of its respective exercise price in cash.

We may also file a prospectus supplement or post-effective amendment to the registration statement of which this prospectus forms a part that may contain material information relating to these offerings. The prospectus supplement or post-effective amendment may also add, update, or change information contained in this prospectus with respect to that offering. If there is any inconsistency between the information in this prospectus and the applicable prospectus supplement or post-effective amendment, you should rely on the prospectus supplement or post-effective amendment, as applicable. Before purchasing any securities, you should carefully read this prospectus, any post-effective amendment, and any applicable prospectus supplement, together with the additional information described under the heading "Where You Can Find More Information" and "Incorporation of Certain Information by Reference." We incorporate by reference important business and financial information about us into this prospectus and any prospectus supplement or any free writing prospectus we may authorize to be delivered to you. You may obtain the information incorporated by reference into this prospectus without charge by following the instructions under "Where You Can Find More Information." All references in this prospectus to "PDS Biotech", "PDS," the "Company," "we," "us" or "our" mean PDS Biotechnology Corporation, unless we state otherwise or the context otherwise requires.

Neither we nor the Selling Stockholder has authorized anyone to provide you with any information or to make any representations other than those contained in or incorporated by reference into this prospectus, any post-effective amendment, or any applicable prospectus supplement prepared by or on behalf of us or to which we have referred you. We and the Selling Stockholder take no responsibility for and can provide no assurance as to the reliability of any other information that others may give you. The Selling Stockholder will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus, any post-effective amendment and any applicable prospectus supplement to this prospectus is accurate only as of the date on its respective cover. Our business, financial condition, results of operations and prospects may have changed since those dates. This prospectus contains, and any post-effective amendment or any prospectus supplement may contain, market data and industry statistics and forecasts that are based on independent industry publications and other publicly available information. We believe this information is reliable as of the applicable date of its publication, however, we have not independently verified the accuracy or completeness of the information included in or assumptions relied on in these third-party publications. In addition, the market and industry data and forecasts that may be included in or incorporated by reference into this prospectus, any post-effective amendment or any prospectus supplement may involve estimates, assumptions and other risks and uncertainties and are subject to change based on various factors, including those discussed under the heading "Risk Factors" contained in this prospectus, any post-effective amendment, the applicable prospectus supplement and otherwise incorporated by reference herein. Accordingly, investors should not place undue reliance on this information.

An investment in our securities involves certain risks that should be carefully considered by prospective investors. See "Risk Factors."

PROSPECTUS SUMMARY

Overview

We are a clinical-stage immunotherapy company developing a growing pipeline of targeted cancer and infectious disease immunotherapies based on our Versamune® T cell activator and Versamune® in combination with our interleukin 12 (IL-12) fused anti-body drug conjugate (ADC), PDS01ADC. In addition, we are developing the Infectimune® T cell-activator in infectious diseases.

We believe our investigational targeted immunotherapies have the potential to overcome limitations of current immunotherapy approaches through effective conversion of the immune suppressive tumor to an immunogenic microenvironment in addition to the induction of the right type, potency and quantity of tumor-targeting killer (CD8) T cells. Our Versamune® immunotherapies and Versamune® in combination with PDS01ADC, are being developed for treatments in oncology, and Infectimune® is being developed for preventive vaccines against infectious agents. When paired with an antigen, which is a disease-related protein that is recognizable by the immune system, Versamune® and Infectimune® have both been shown to induce, in-vivo, large quantities of high-quality, highly potent polyfunctional disease-specific CD4 helper and CD8 killer T cells, a specific sub-type of T cell that has shown potential to be more effective at killing infected or target cells. Infectimune® is also designed to promote the induction of disease-specific neutralizing antibodies. PDS01ADC is an investigational tumor targeting IL-12 that we believe may enhance the proliferation, potency and longevity of T cells in the tumor microenvironment and reduces the prevalence of immune suppressive cells and components within the tumor.

We believe our proprietary combinations of Versamune® and PDS01ADC together with immune checkpoint inhibitors or other standards of care, may enhance the proliferation, potency and longevity of antigen specific multifunctional CD8 T cells in the tumor microenvironment and work synergistically to inhibit or treat cancer.

For more information about our business, please see our most recent Annual Report on Form 10-K, as supplemented and updated by subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K that we have filed or will file with the SEC, and in other documents which are incorporated by reference into this prospectus.

Recent Developments

On April 30, 2026, the Company entered into the Securities Purchase Agreement with the Selling Stockholder. Pursuant to the Securities Purchase Agreement, on the Closing Date, the Company issued and sold to the Selling Stockholder (i) the Promissory Note and (ii) the Warrant, for a total purchase price of $5,760,000, reflecting an original issue discount of 4%.

The Promissory Note has an aggregate principal amount of $6,000,000, a maturity date of the twelve-month anniversary of the Closing Date and bears interest at a rate of 10% per annum, payable monthly beginning on the 60-day anniversary of the Closing Date. The Promissory Note is convertible into shares of Common Stock at the option of the Selling Stockholder, but only upon the occurrence and during the continuance of a payment event of default.

The Warrant is exercisable beginning on the six-month anniversary of the Closing Date and expires on the date that is 60 months after the Closing Date, subject to certain beneficial ownership and exchange cap limitations.

In connection with the Securities Purchase Agreement, on the Closing Date, PDS Operating Corporation, a Delaware corporation and wholly owned subsidiary of the Company (the "Guarantors"), entered into a Guaranty Agreement (the "Guaranty Agreement") in favor of the Selling Stockholder.

In connection with the Securities Purchase Agreement, the Company and the Selling Stockholder entered into the Registration Rights Agreement on the Closing Date, pursuant to which the Company is obligated to file a registration statement to register the shares of Common Stock issuable upon conversion of the Promissory Note and exercise of the Warrant within 30 days after the Closing Date.

The foregoing descriptions of the terms of the Securities Purchase Agreement, Promissory Note, Guaranty Agreement, Warrant, and Registration Rights Agreement do not purport to be complete and are qualified in their entirety by the full text of the Securities Purchase Agreement (Exhibit 10.1), form of Promissory Note (Exhibit 4.1), form of Guaranty Agreement (Exhibit 10.3), form of Warrant (Exhibit 4.2), and form of Registration Rights Agreement (Exhibit 10.2), each of which is incorporated herein by reference.

On the Closing Date, the Company also entered into the Sales Agreement with Yorkville Securities, LLC, an affiliate of the Selling Stockholder, and B. Riley Securities, Inc., with respect to an at-the-market offering program

under which the Company may offer and sell, from time to time at its sole discretion, shares of its Common Stock through or to the Agents, as sales agents or principals. For more information see the section entitled "Private Placement of Securities."

Corporate Information

Information concerning our company is contained in the documents that we file with the SEC as a reporting company under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), which are accessible at www.sec.gov, and on our website at www.pdsbiotech.com. The information contained on, or that can be accessed through, our website is not a part of this prospectus. Investors should not rely on any such information in deciding whether to purchase our Common Stock. We have included our website address in this prospectus solely as an inactive textual reference. Information on our website is not, and should not be considered, part of this prospectus.

Our principal executive offices are located at 303A College Road East, Princeton, NJ 08540, and our telephone number is (800) 208-3343.

Implications of Being a Smaller Reporting Company

We are a "smaller reporting company," meaning that the market value of our Common Stock held by non-affiliates is less than $700 million and our annual revenue was less than $100 million during our most recently completed fiscal year. We may continue to be a smaller reporting company if either (i) the market value of our Common Stock held by non-affiliates is less than $250 million or (ii) our annual revenue was less than $100 million during the most recently completed fiscal year and the market value of our Common Stock held by non-affiliates is less than $700 million. For so long as we remain a smaller reporting company, we are permitted and intend to rely on exemptions from certain disclosure and other requirements that are applicable to other public companies that are not smaller reporting companies. We have taken advantage of some reduced reporting burdens in this prospectus and the documents incorporated by reference herein. Accordingly, the information that we provide to our stockholders may be different than you might receive from other public companies in which you hold equity interests.

THE OFFERING

Shares of Common Stock offered by the Selling Stockholder

Up to 13,315,823 Shares.

Shares of Common Stock outstanding prior to this offering

55,921,806 Shares as of July 2, 2026

Use of proceeds

We will not receive any proceeds from the resale of the Shares by the Selling Stockholder in this offering. We will, however, receive proceeds from any portion of the Warrant that is exercised through the payment of its respective exercise price in cash. For additional information, refer to the section entitled "Use of Proceeds."

Terms of this offering

The Selling Stockholder may sell, transfer or otherwise dispose of any or all of the Shares offered by this prospectus from time to time on the Nasdaq Capital Market or any other stock exchange, market or trading facility on which the Shares are traded, or in private transactions. The Shares may be offered and sold or otherwise disposed of by the Selling Stockholder at fixed prices, market prices prevailing at the time of sale, prices related to prevailing market prices, or privately negotiated prices. See the section entitled "Plan of Distribution."

Risk factors

An investment in our Common Stock involves a high degree of risk. See "Risk Factors" beginning on page 5 of this prospectus, the "Risk Factors" section in our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports filed on Form 10-Q, and any amendment or update thereto reflected in subsequent filings with the SEC, which are incorporated by reference herein, and other information included this prospectus, any prospectus supplement, and the documents incorporated by reference in this prospectus for a discussion of factors you should carefully consider before deciding to invest in our Common Stock.

Market for our Common Stock

Our Common Stock is traded on the Nasdaq Capital Market under the symbol "PDSB."

RISK FACTORS

Before you invest in our securities, in addition to the other information, documents or reports included or incorporated by reference in this prospectus and in any prospectus supplement, you should carefully consider the risk factors set forth in the section entitled "Risk Factors" in any prospectus supplement as well as in "Part I, Item 1A. Risk Factors" in our most recent annual report on Form 10-K and in "Part II, Item 1A. Risk Factors" in our quarterly reports on Form 10-Q filed subsequent to such Form 10-K, which are incorporated by reference into this prospectus and any prospectus supplement in their entirety, as the same may be updated from time to time by our future filings under the Exchange Act. Each of the risks described in these sections and documents could materially and adversely affect our business, financial condition, results of operations and prospects and the market price of our shares and any other securities we may issue. Moreover, the risks and uncertainties discussed in the foregoing documents are not the only risks and uncertainties that we face, and our business, financial condition, results of operations and prospects and the market price of our shares and any other securities we may issue could be materially adversely affected by other matters that are not known to us or that we currently do not consider to be material risks to our business.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated herein by reference contain forward-looking statements (including within the meaning of Section 21E of the Exchange Act and Section 27A of the United States Securities Act of 1933, as amended (the "Securities Act")), and we anticipate that the applicable prospectus supplement will contain forward-looking statements. These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results to be materially different from any future results expressed or implied by the forward-looking statements. In some cases, you can identify forward-looking statements by the use of words such as "believe," "anticipate," "intend," "plan," "estimate," "may," "could," "anticipate," "predict," or "expect" and similar expressions. You should not place undue reliance on forward-looking statements since they involve known and unknown risks, uncertainties and other factors that are, in many cases, beyond our control. Forward-looking statements are not guarantees of future performance. Actual events or results may differ materially from those discussed in the forward-looking statements as a result of various factors. Except as required by applicable law, we do not undertake any obligation to publicly update any forward-looking statements, whether as a result of new information, future developments or otherwise.

Important factors that could cause actual results to differ materially from those reflected in our forward-looking statements include, among others:

All written and verbal forward-looking statements attributable to us or any person acting on our behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this section. We caution investors not to rely too heavily on the forward-looking statements we make or that are made on our behalf.

In addition, you should refer to the documents we have incorporated by reference for a discussion of other important factors that may cause our actual results to differ materially from those expressed or implied by our forward-looking statements. As a result of these factors, we cannot assure you that the forward-looking statements will prove to be accurate. Furthermore, if our forward-looking statements prove to be inaccurate, the inaccuracy may be material. In light of the significant uncertainties in these forward-looking statements, you should not regard these statements as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified time frame, or at all.

We may discuss certain of these risks and uncertainties in greater detail in any prospectus supplement under the heading "Risk Factors." Additional cautionary statements or discussions of risks and uncertainties that could affect our results or the achievement of the expectations described in forward-looking statements may also be contained in the documents we incorporate by reference into this prospectus, including our most recent Annual Report on Form 10-K and our Quarterly Report on Form 10-Q filed with the SEC.

USE OF PROCEEDS

All proceeds from the resale of the Shares of Common Stock offered by this prospectus will belong to the Selling Stockholder. We will not receive any proceeds from the resale of the Shares of Common Stock by the Selling Stockholder. We will, however, receive proceeds from any portion of the Warrant that is exercised through the payment of its respective exercise price in cash. We intend to use the proceeds, if any, for general corporate purposes.

The Selling Stockholder will pay any underwriting fees, discounts, selling commissions, stock transfer taxes and certain legal expenses incurred by the Selling Stockholder in disposing of its Shares of Common Stock, and we will bear all other costs, fees and expenses incurred in effecting the registration of the securities covered by this prospectus, including, without limitation, all registration and filing fees, Nasdaq listing fees and fees and expenses of our counsel and our independent registered public accountants.

DIVIDEND POLICY

We have never paid any cash dividends on our Common Stock to date. We currently intend to retain all of our future earnings, if any, to fund the development and growth of our business and do not anticipate paying any cash dividends for at least the next five years, if ever. Any future determination as to the payment of cash dividends on our Common Stock will be at our board of directors' discretion and will depend on our financial condition, operating results, capital requirements and other factors that our board of directors considers to be relevant.

DESCRIPTION OF CAPITAL STOCK

The following is a summary of all material characteristics of our capital stock as set forth in our certificate of incorporation and bylaws, as amended. Copies of these documents are filed or incorporated by reference as exhibits to the registration statement, of which this prospectus forms a part.

DESCRIPTION OF COMMON STOCK

We are presently authorized to issue 150,000,000 shares of Common Stock, par value $0.00033 per share. As of July 2, 2026, there were 55,921,806 shares of Common Stock issued and outstanding.

We have one class of Common Stock. Holders of our Common Stock are entitled to one vote per share on all matters to be voted upon by stockholders and do not have cumulative voting rights in the election of directors. Holders of shares of Common Stock are entitled to receive on a pro rata basis such dividends, if any, as may be declared from time to time by our board of directors in its discretion from funds legally available for that use, subject to any preferential dividend rights of outstanding preferred stock. They are also entitled to share on a pro rata basis in any distribution to our common stockholders upon our liquidation, dissolution or winding up, subject to the prior rights of any outstanding preferred stock. Common stockholders do not have preemptive rights to subscribe to any additional stock issuances by us, and they do not have the right to require the redemption of their shares or the conversion of their shares into any other class of our stock. The rights, preferences and privileges of holders of Common Stock are subject to, and may be adversely affected by, the rights of the holders of any series of preferred stock that we may designate and issue in the future.

Provisions of our eighth amended and restated certificate of incorporation, as amended, and third amended and restated bylaws may delay or discourage transactions involving an actual or potential change of control or change in our management, including transactions in which stockholders might otherwise receive a premium for their shares, or transactions that our stockholders might otherwise deem to be in their best interests. Therefore, these provisions could adversely affect the price of our Common Stock. Among other things, our eighth amended and restated certificate of incorporation, as amended, and third amended and restated bylaws:

In addition, we are subject to the provisions of Section 203 of the General Corporation Law of Delaware. Section 203 prohibits a publicly held Delaware corporation from engaging in a "business combination" with an "interested stockholder" for a period of three years after the date of the transaction in which the person became an interested stockholder, unless the business combination is approved in a prescribed manner. A "business combination"

includes mergers, asset sales and other transactions resulting in a financial benefit to the interested stockholder. Subject to specified exceptions, an "interested stockholder" is a person who, together with affiliates and associates, owns, or within three years did own, 15% or more of the corporation's voting stock.

The transfer agent and registrar of our Common Stock is Computershare Trust Company, N.A. The address of our transfer agent and registrar is 1290 Avenue of the Americas, 9th Floor, New York, NY 10104, and its telephone number is (212) 805-7100.

Our Common Stock is traded on The Nasdaq Capital Market under the symbol "PDSB."

DESCRIPTION OF PREFERRED STOCK

We have authority to issue 5,000,000 shares of preferred stock, par value $0.00033 per share. As of July 2, 2026, we did not have any shares of preferred stock issued or outstanding.

Under our certificate of incorporation, our board of directors has the authority, without further action by stockholders, to designate one or more series of preferred stock and to fix the voting powers, designations, preferences, limitations, restrictions and relative rights granted to or imposed upon the preferred stock, including dividend rights, conversion rights, voting rights, rights and terms of redemption, liquidation preference and sinking fund terms, any or all of which may be preferential to or greater than the rights of the Common Stock.

Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of the Common Stock. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring or preventing a change in our control and may adversely affect the market price of the Common Stock and the voting and other rights of the holders of Common Stock.

We will describe in a prospectus supplement relating to any series of preferred stock being offered the following terms:

Unless we specify otherwise in the applicable prospectus supplement, the preferred stock will rank, relating to dividends and upon our liquidation, dissolution or winding up:

PRIVATE PLACEMENT OF SECURITIES

On April 30, 2026, the Company entered into the Securities Purchase Agreement with the Selling Stockholder. Pursuant to the Securities Purchase Agreement, on the Closing Date, the Company issued and sold to the Selling Stockholder (i) the Promissory Note and (ii) the Warrant, for a total purchase price of $5,760,000. The Securities Purchase Agreement contains customary representations, warranties and covenants.

Promissory Note

The Promissory Note has an aggregate face value of $6,000,000 and was issued on the Closing Date for a purchase price of $5,760,000. The Promissory Note has a maturity date of the twelve-month anniversary of the Closing Date and an interest rate of 10% per annum (subject to increase upon the occurrence and during the continuance of an Event of Default (as defined in the Promissory Note)), payable monthly beginning on the 60-day anniversary of the Closing Date and on each monthly anniversary thereafter.

The Company may redeem the Promissory Note at any time in full or in part, without prepayment penalty, by paying an amount equal to (a) the outstanding principal balance being redeemed by the Company plus (b) all accrued and unpaid interest on the outstanding principal balance being redeemed as of the date of such redemption. Beginning on September 15, 2026, the holder of the Promissory Note may elect to accelerate up to $1,600,000 by increasing aggregate principal amortization payments, provided that any monthly principal amortization payment may not be increased by more than $700,000, by providing written notice to the Company. Prior to the first installment date, and thirty days prior to each subsequent installment date, 100% of any net cash proceeds received from sales of Common Stock pursuant to the Sales Agreement after the Closing Date shall be applied by the Company against the amortization payment due on the next installment date. If net cash proceeds received from sales of Common Stock pursuant to the Sales Agreement exceed the amortization payment due on the installment date, 60% of such net cash proceeds shall be applied against subsequent amortization payments in reverse chronological order and 40% of such net cash proceeds may be retained by the Company.

At the election of the Selling Stockholder, for so long as the Company's failure to pay to the Selling Stockholder any amounts when and as due under the Promissory Note within five (5) business days after such payment is due has occurred and is continuing, the Promissory Note is convertible, in whole or in part, at any time and from time to time at a conversion price of (i) 95% of the lowest daily VWAP of the Common Stock during the five (5) consecutive trading days immediately prior to the conversion date, or (ii) 92% of the closing price on the trading day immediately prior to the conversion date, but in no event lower than 20% of the Minimum Price under 5635(d) as of the Closing Date. The Selling Stockholder shall not have the right to convert any portion of the Promissory Note to the extent that after giving effect to such conversion, the Selling Stockholder, together with any affiliate thereof, would beneficially own (as determined in accordance with Section 13(d) of the Exchange Act and the rules promulgated thereunder) in excess of 4.99% of the number of shares of Common Stock outstanding immediately after giving effect to such conversion. In addition, the Promissory Note will limit conversions such that the number of shares issuable upon conversion may not exceed 19.99% of the Company's outstanding Common Stock as of the date of the Securities Purchase Agreement, unless stockholder approval is obtained in accordance with Nasdaq rule 5635(d).

In addition, for as long as the Promissory Note remains outstanding, the Company is generally restricted from entering into any agreement, arrangement or transaction in or of which the terms thereof would materially restrict, materially delay, conflict with or materially impair the ability of the Company to perform its obligations under the Promissory Note or amending any material term of its organizational documents so as to adversely affect any rights of the Selling Stockholder. In addition, so long as the Promissory Note remains outstanding, the Securities Purchase Agreement provides that the Company and each of its subsidiaries may not effect, enter into or agree to enter into any "Variable Rate Transaction" other than (i) the Sales Agreement or (ii) with the Selling Stockholder.

The Promissory Note also sets forth certain customary events of default after which the Promissory Note may be declared immediately due and payable, including certain types of bankruptcy or insolvency events of default involving the Company and its significant subsidiaries.

Security Agreement and Subsidiary Guarantees

In connection with the Securities Purchase Agreement, on the Closing Date, PDS Operating Corporation, a Delaware corporation and wholly owned subsidiary of the Company (together with any other entity that may become a party thereto) (the "Guarantors"), and the Selling Stockholder entered into a Guaranty Agreement (the "Guaranty

Agreement"), pursuant to which the Guarantors guaranteed all of the Company's obligations under the Securities Purchase Agreement and the Promissory Note and related obligations.

Warrant

The Warrant was issued on the Closing Date and is exercisable beginning on the six (6) month anniversary of the Closing Date and for five years after the Closing Date, at an exercise price of $1.1824 per share subject, with certain exceptions, to adjustments in the event of stock splits, dividends, and certain fundamental transactions, as more fully described in the Warrant. The Selling Stockholder shall not have the right to exercise any portion of the Warrant to the extent that after giving effect to such exercise, the Selling Stockholder, together with any affiliate thereof, would beneficially own (as determined in accordance with Section 13(d) of the Exchange Act and the rules promulgated thereunder) in excess of 4.99% of the number of shares of Common Stock outstanding immediately after giving effect to such exercise. In addition, the Warrant limits exercises such that the number of shares issuable upon exercise may not exceed 19.99% of the Company's outstanding Common Stock as of the date of the Securities Purchase Agreement, unless stockholder approval is obtained in accordance with Nasdaq rule 5635(d).

If, at the time the Selling Stockholder exercises the Warrant, there is no effective registration statement available for an issuance of the shares underlying the Warrant to the Selling Stockholder, then in lieu of making the cash payment otherwise contemplated to be made to the Company upon the exercise of the Warrant, the Selling Stockholder may elect to receive upon exercise (either in whole or in part) on a cashless basis the net number of shares of Common Stock determined according to a specified formula (as set forth in the Warrant).

Registration Rights Agreement

In connection with the Securities Purchase Agreement, the Company and the Selling Stockholder entered into the Registration Rights Agreement on the Closing Date, pursuant to which the Company is obligated to file a registration statement to register the shares of Common Stock issuable upon conversion of the Promissory Note and exercise of the Warrant within 30 days after the Closing Date (the "Filing Deadline"). If the Company fails to meet the Filing Deadline or maintain the effectiveness of the registration statement for the required effectiveness period, subject to certain permitted exceptions, the Company will be deemed to be in default under the Promissory Note. The Company also agreed, among other things, to indemnify the selling holders under the registration statement from certain liabilities and to pay all fees and expenses incident to the Company's performance of or compliance with the Registration Rights Agreement.

The foregoing descriptions of the terms of the Securities Purchase Agreement, Promissory Note, Guaranty Agreement, Warrant, the Registration Rights Agreement, and the transactions contemplated thereby do not purport to be complete and are qualified in their entirety by the full text of the Securities Purchase Agreement, form of Promissory Note, form of Guaranty Agreement, form of Warrant, and form of Registration Rights Agreement which are incorporated herein by reference.

SELLING STOCKHOLDER

The Common Stock being offered by the Selling Stockholder is issuable to the Selling Stockholder upon the conversion of the Promissory Note and the exercise of the Warrant. For additional information regarding the issuances of the Promissory Note and the Warrant, see "Private Placement of Securities" above. We are registering the shares of Common Stock in order to permit the Selling Stockholder to offer the shares for resale from time to time.

The table below lists the Selling Stockholder and other information regarding the beneficial ownership of the shares of Common Stock by the Selling Stockholder. The first column lists the number of shares of Common Stock beneficially owned by the Selling Stockholder, based on its ownership of the Promissory Note and Warrant, as of July 2, 2026, assuming the conversion of the Promissory Note and the exercise of the Warrant held by the Selling Stockholder on that date, without regard to any limitations on exercises. The third column lists the shares of Common Stock being offered by this prospectus by the Selling Stockholder.

In accordance with the terms of a Registration Rights Agreement with the Selling Stockholder, this prospectus generally covers the resale of the maximum number of shares of Common Stock issuable upon conversion of the Promissory Note and the exercise of the Warrant, determined as if the outstanding Promissory Note and Warrant were converted or exercised, as applicable, in full as of the trading day immediately preceding the date this registration statement was initially filed with the SEC, each as of the trading day immediately preceding the applicable date of determination and all subject to adjustment as provided in the Registration Rights Agreement, without regard to any limitations on the conversion of the Promissory Note or exercise of the Warrant. The fourth column assumes the sale of all of the shares offered by the Selling Stockholder pursuant to this prospectus.

Under the terms of the Promissory Note and Warrant, the Selling Stockholder may not convert the Promissory Note or exercise the Warrant, as applicable, to the extent such conversion or exercise would cause the Selling Stockholder, together with its affiliates and attribution parties, to beneficially own a number of shares of Common Stock which would exceed 4.99% of our then outstanding Common Stock following such conversion or such exercise, excluding for purposes of such determination shares of Common Stock issuable upon conversion of the Promissory Note or exercise of the Warrant which have not been converted or exercised, as applicable. The number of shares in the second and fourth columns do not reflect this limitation. The Selling Stockholder may sell all, some or none of their shares in this offering. See "Plan of Distribution."

Material Relationships with the Selling Stockholder

On June 15, 2026, the Company entered into a Sales Agreement with the Agents with respect to an at-the-market offering program under which the Company may offer and sell, from time to time at its sole discretion, shares of its Common Stock through or to the Agents, as sales agents or principals, having an aggregate offering price of up to $50,000,000. B. Riley Securities, Inc. is acting as a "qualified independent underwriter" within the meaning of FINRA Rule 5121 in connection with the at-the-market offering. Except for the ownership of the Promissory Note and the Warrant and the Sales Agreement with the Agents, the Selling Stockholder has not had any material relationship with us within the past three years.

PLAN OF DISTRIBUTION

The Selling Stockholder and any of its pledgees, assignees and successors-in-interest may, from time to time, sell any or all of its securities covered hereby on Nasdaq or any other stock exchange, market or trading facility on which the securities are traded or in private transactions. These sales may be at fixed or negotiated prices. The Selling Stockholder may use any one or more of the following methods when selling securities:

The Selling Stockholder may also sell securities under Rule 144 or any other exemption from registration under the Securities Act, if available, rather than under this prospectus.

Broker-dealers engaged by the Selling Stockholder may arrange for other brokers-dealers to participate in sales. Broker-dealers may receive commissions or discounts from the Selling Stockholder (or, if any broker-dealer acts as agent for the purchaser of securities, from the purchaser) in amounts to be negotiated, but, except as set forth in a supplement to this prospectus, in the case of an agency transaction not in excess of a customary brokerage commission in compliance with FINRA Rule 2121; and in the case of a principal transaction a markup or markdown in compliance with FINRA Rule 2121.

In connection with the sale of the securities or interests therein, the Selling Stockholder may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the securities in the course of hedging the positions they assume. The Selling Stockholder may also sell securities short and deliver these securities to close out their short positions, or loan or pledge the securities to broker-dealers that in turn may sell these securities. The Selling Stockholder may also enter into option or other transactions with broker-dealers or other financial institutions or create one or more derivative securities which require the delivery to such broker-dealer or other financial institution of securities offered by this prospectus, which securities such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction).

Any broker-dealers or agents that are involved in selling the securities may be deemed to be "underwriters" within the meaning of the Securities Act in connection with such sales. In such event, any commissions received by such broker-dealers or agents and any profit on the resale of the securities purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. The Selling Stockholder has informed the Company that it does not have any written or oral agreement or understanding, directly or indirectly, with any person to distribute the securities.

The Company is required to pay certain fees and expenses incurred by the Company incident to the registration of the securities. The Company has agreed to indemnify the Selling Stockholder against certain losses, claims, damages and liabilities, including liabilities under the Securities Act.

We agreed to keep this prospectus effective until the earlier of (i) the date on which the securities may be resold by the Selling Stockholder without registration and without regard to any volume or manner-of-sale limitations by reason of Rule 144, without the requirement for the Company to be in compliance with the current public information under Rule 144 under the Securities Act or any other rule of similar effect or (ii) all of the securities have been sold pursuant

to this prospectus or Rule 144 under the Securities Act or any other rule of similar effect. The resale securities will be sold only through registered or licensed brokers or dealers if required under applicable state securities laws. In addition, in certain states, the resale securities covered hereby may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and is complied with.

Under applicable rules and regulations under the Exchange Act, any person engaged in the distribution of the resale securities may not simultaneously engage in market making activities with respect to the Common Stock for the applicable restricted period, as defined in Regulation M, prior to the commencement of the distribution. In addition, the Selling Stockholder will be subject to applicable provisions of the Exchange Act and the rules and regulations thereunder, including Regulation M, which may limit the timing of purchases and sales of the Common Stock by the Selling Stockholder or any other person. We will make copies of this prospectus available to the Selling Stockholder and have informed them of the need to deliver a copy of this prospectus to each purchaser at or prior to the time of the sale (including by compliance with Rule 172 under the Securities Act).

LEGAL MATTERS

The validity of the Shares has been passed upon by DLA Piper LLP (US), Philadelphia, PA.

EXPERTS

The consolidated financial statements of PDS Biotechnology Corporation as of December 31, 2025 and 2024, and for each of the years in the two-year period ended December 31, 2025, have been incorporated by reference herein and in the registration statement in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We are subject to the information and periodic reporting requirements of the Exchange Act and, in accordance with that act, file periodic reports and other information with the SEC. The SEC maintains an Internet site that contains all reports and other information that we file electronically with the SEC. The address of that website is www.sec.gov.

This prospectus is part of a registration statement on Form S-3 that we have filed with the SEC under the Securities Act for the securities offered under this prospectus (the "Form S-3 Registration Statement"). The Form S-3 Registration Statement, including the exhibits to the Form S-3 Registration Statement, contains additional information about us and the securities offered by this prospectus. The rules and regulations of the SEC allow us to omit from this prospectus certain information that is included in the Form S-3 Registration Statement. For further information about us and our securities, you should review the Form S-3 Registration Statement and the exhibits filed with the Form S-3 Registration Statement.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to incorporate into this prospectus by reference the information we file with it, which means that we can disclose important information to you by referring you to the documents containing that information. The information incorporated by reference is considered to be part of this prospectus, and information that we later file with the SEC will automatically update and, where applicable, modify or supersede that information.

We incorporate by reference the following documents previously filed with the SEC and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (in each case, other than those documents or the portions of those documents not deemed to be filed) until the offering of the securities under the registration statement is terminated or completed:

All documents filed by us pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent to the filing of the Form S-3 Registration Statement, including all such documents we may file with the SEC after the date of the Form S-3 Registration Statement and prior to the effectiveness of the registration statement, and prior to the filing of a post-effective amendment to the Form S-3 Registration Statement which indicates that all securities offered hereby have been sold or which deregisters all such securities then remaining unsold shall be deemed to be incorporated by reference herein and to be a part hereof from the date of filing of such documents. Any statement contained in this prospectus or in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained herein or in any subsequently filed document that is or is deemed to be incorporated by reference herein modifies or supersedes such statement.

Notwithstanding the foregoing, no portion of any document that is "furnished" but not "filed" in accordance with SEC rules under Exchange Act shall be deemed to be incorporated by reference into this prospectus. Any statement contained in this prospectus or in a document incorporated by reference into this prospectus will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or in any other subsequently filed document that is incorporated by reference herein modifies or supersedes the statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

You may request a copy of any of these filings from us at no cost by writing or calling our Corporate Secretary at the following address or telephone number: PDS Biotechnology Corporation, 303A College Road East, Princeton, NJ 08540; Telephone: (800) 208-3343.