File: Attachment OpenSesame News Release re Subscription Receipt Offering.pdf

NOT FOR DISTRIBUTION TO U.S. NEWSWIRE SERVICES OR FOR DISSEMINATION IN THE UNITED STATES. ANY FAILURE TO COMPLY WITH THIS RESTRICTION MAY CONSTITUTE

A VIOLATION OF U.S. SECURITIES LAWS

OPENSESAME PROVIDES UPDATE ON THE TERMS OF THE SUBSCRIPTION RECEIPT OFFERING

March 17, 2026 TSXV OPEN.P

OpenSesame Acquisition Corp. (the "Company") [TSXV: OPEN.P] is pleased to provide an update on its proposed business combination (the "Transaction") with Vector Science and Therapeutics Inc. ("Vector") which is intended to be the Company's qualifying transaction (as such term is defined in Policy 2.4 Capital Pool Companies ("Policy 2.4") of the TSX Venture Exchange (the "TSXV") Corporate Finance Manual.

In connection with the Transaction, OpenSesame US Corp. ("Open US"), a wholly-owned subsidiary of the Company, is conducting an offering of subscription receipts (the "Subscription Receipts") at a price of CAD$0.10 per Subscription Receipt, for minimum aggregate proceeds of CAD$2,000,000 and maximum aggregate proceeds of CAD$3,000,000 (the "Offering").

As previously announced on October 6, 2025, pursuant to the terms of the Transaction, the Company will acquire all of the issued and outstanding securities of Vector, which will constitute an arm's length reverse takeover transaction of the Company.

Details of the Transaction

Pursuant to an acquisition agreement to be entered among the Company, Vector and Open US (the "Acquisition Agreement"), the Company will acquire all of the currently 11,585,538 issued and outstanding shares of Class A common stock in the capital of Vector (each, a "Vector Share") and outstanding share purchase warrants to acquire 5,971,973 Vector Shares ("Vector Warrants") from the shareholders of Vector in exchange for the issuance of common shares of the Company (each, a "Company Share") and warrants to acquire Company Shares ("Company Warrants"). To effect the proposed Transaction, it is intended that Open US will merge with and into Vector, with Vector being the surviving entity and becoming a wholly-owned subsidiary of the Company (the "Merger"). As part of the merger, the holders of Vector Shares will exchange their Vector Shares and Vector Warrants for Company Shares and Company Warrants on the basis of 10 Company Shares and Warrants for each 1 Vector Share and Warrant. Following the completion of the Transaction, it is intended that Vector (after giving effect to the Merger) will become a wholly-owned subsidiary of the Company and the Company will continue the business of Vector.

As part of the Transaction, the Company intends to change its name to "Vector Science and Therapeutics Corp.", or such other name as determined by Vector and acceptable to applicable regulators. As used herein, "Resulting Issuer" refers to the Company following the completion of the Transaction.

Details of the Offering

The gross proceeds from the Offering will be held in escrow pending, among other things, receipt of the approval from the TSXV for the listing (the "Listing") of the common shares of the Resulting Issuer (contemplated by this Offering) on the TSXV. Farris LLP will act as escrow agent in connection with the Offering. Upon satisfaction of certain escrow release conditions set out in the subscription agreement for

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the Offering on or before June 30, 2026 (as such deadline may be extended in accordance with the terms and conditions of a subscription receipt escrow agreement to be entered into between Open US and Farris LLP), each Subscription Receipt will automatically convert into a unit of Open US (a "Unit") on a 1:1 basis and the proceeds from the Offering will be released from escrow to Open US. Each Unit will consist of one (1) common share of Open US (an "Open US Share") and one (1) common share purchase warrant (a "Warrant"), with each Warrant exercisable into one additional Open US Share (a "Warrant Share") until June 27, 2028, at a price of CAD$0.25 per Warrant Share.

The Subscription Receipts will be subject to a statutory indefinite hold period in Canada. The securities of the Resulting Issuer issued upon exchange of the Open US Shares and the Warrants will not be subject to any statutory hold or restricted period.

Subject to applicable securities laws and TSXV approval, the Company may pay a finder's fee or commission, which may include cash and/or Warrants to certain persons, subject to securities laws and Exchange approval. For certainty, no finder's fee will be payable in respect of Subscription Receipts sold pursuant to Section 4(a)(2) of the U.S. Securities Act and Rule 506 of Regulation D to a finder who is not registered as a broker-dealer under the United States Securities Exchange Act of 1934, as amended, and applicable state securities laws, or unless such finder is exempt from such registration requirements.

Company Shareholder Approval

The Transaction is not a Non-Arm's Length Qualifying Transaction (as defined in the Policy 2.4) and, accordingly, the Company is not required to obtain the approval of its shareholders for the Transaction.

The Merger will require approval of the shareholders of Vector.

Conditions Precedent and TSXV Matters

Completion of the Transaction is subject to a number of conditions, including, but not limited to, execution of the Acquisition Agreement, completion by the parties of satisfactory due diligence, satisfaction by the parties of all applicable filing and listing requirements pursuant to Policy 2.4, closing of the Offering and acceptance and receipt of all applicable regulatory, corporate and shareholder approvals, including the approval of the TSXV. There can be no assurance that the Transaction will be completed as proposed or at all.

Investors are cautioned that, except as disclosed in the filing statement to be submitted to the TSXV and filed under the Company's profile at www.sedarplus.ca in connection with the Transaction, any information released or received with respect to the Transaction may not be accurate or complete and should not be relied upon. Trading in the securities of a capital pool company should be considered highly speculative.

The TSX Venture Exchange Inc. has in no way passed upon the merits of the Offering or the proposed Transaction and has neither approved nor disapproved the contents of this press release.

Neither the TSXV nor its Regulation Services Provider (as that term is defined in the policies of the TSXV) accepts responsibility for the adequacy or accuracy of this release.

All information provided in this press release relating to Vector has been provided by management of Vector and has not been independently verified by management of the Company.

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FOR FURTHER INFORMATION PLEASE CONTACT:

Scott Kelly, CEO, CFO and Corporate Secretary OpenSesame Acquisition Corp. (T) 604-671-0918 E-mail: scottkelly.ca@gmail.com

Cautionary Note Regarding Forward-Looking Information

This press release contains statements that constitute "forward-looking information" (collectively, "forward-looking statements") within the meaning of the applicable Canadian securities legislation. All statements, other than statements of historical fact, are forward-looking statements and are based on expectations, estimates and projections as at the date of this news release. Any statement that discusses predictions, expectations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as "expects", or "does not expect", "is expected", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking statements. Forward-looking statements contained in this press release include, without limitation, statements regarding: the completion of the Merger, the Offering and the Transaction, the change of the Company's name and proposed terms of the Offering. In making the forward-looking statements contained in this press release, the Company has made certain assumptions, including that: due diligence will be satisfactory; a definitive agreement in respect of the Transaction will be completed and executed; the parties will satisfy all applicable filing and listing requirements pursuant to Policy 2.4; the closing of the Offering; and all applicable shareholder and regulatory approvals related to the Transaction will be received. Although the Company believes that the expectations reflected in forward-looking statements are reasonable, it can give no assurance that the expectations of any forward-looking statements will prove to be correct. Known and unknown risks, uncertainties, and other factors which may cause the actual results and future events to differ materially from those expressed or implied by such forward-looking statements. Such factors include, but are not limited to: results of due diligence; availability of financing; delay or failure to receive board, shareholder or regulatory approvals; and general business, economic, competitive, political and social uncertainties and economic risks associated with domestic and international market conditions. Accordingly, readers should not place undue reliance on the forward-looking statements and information contained in this press release. Except as required by law, the Company disclaims any intention and assumes no obligation to update or revise any forward-looking statements to reflect actual results, whether as a result of new information, future events, changes in assumptions, changes in factors affecting such forward-looking statements or otherwise.

UNITED STATES ADVISORY. The securities referred to herein have not been and will not be registered under the United States Securities Act of 1933, as amended (the "U.S. Securities Act"), have been offered and sold outside the United States to eligible investors pursuant to Regulation S promulgated under the U.S. Securities Act, and may not be offered, sold, or resold in the United States or to, or for the account of or benefit of, a U.S. Person (as such term is defined in Regulation S under the United States Securities Act) unless the securities are registered under the U.S. Securities Act, or an exemption from the registration requirements of the U.S. Securities Act is available. Hedging transactions involving the securities must not be conducted unless in accordance with the U.S. Securities Act. This press release shall not constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in the state in the United States in which such offer, solicitation or sale would be unlawful.

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