Exhibit 4.5

Dated [·] 2026

SCANCELL HOLDINGS PLC

WARRANT INSTRUMENT

relating to

the issue of warrants entitling the holder(s)
to subscribe for shares in the capital of
Scancell Holdings PLC

Hogan Lovells Cadwalader International LLP
Atlantic House
50 Holborn Viaduct
London, EC1A 2FG

Tel: +44 (0) 20 7296 2000
Fax: +44 (0) 20 7296 2001

TABLE OF CONTENTS

Page

This Warrant instrument is executed and entered into on [●] 2026 (this “instrument”) by:

SCANCELL HOLDINGS PLC, a company incorporated in England and Wales with registration number 06564638 whose registered office is at Bellhouse Building Sanders Road, Oxford Science Park, Oxford, England, OX4 4GD (the “Company”).

BACKGROUND:

IT IS AGREED:

“2026 Fundraising” means the (i) private placement of Shares pursuant to Section 4(a)(2) of the U.S. Securities Act of 1933; and (ii) a UK placing and retail offer of Shares, as announced by the Company on 23 July 2026;

“Adjustment Event” means any or all of the following, at any time, or by reference to any record date, when any Subscription Rights remain unexercised:

“Affiliates” means in respect of a company, any business entity from time to time directly or indirectly controlling, controlled by, or under common control with, a shareholder of such a company;

“Aggregate Cash Settlement Value” means the product of: (i) the total number of Warrant Shares the Warrantholder would otherwise have been entitled to subscribe for pursuant to the exercise of all remaining Subscription Rights; and (ii) the value per Warrant Share as calculated based on the USD equivalent of the Fair Market Value immediately upon the occurrence or following the relevant Cash Settlement Event;

“Aggregate Subscription Price” has the meaning given in clause 6.2(b)(i);

“Allotted Shares” has the meaning given in clause 7.1(a);

“Anti-Corruption Laws” means the UK Bribery Act 2010, the US Foreign Corrupt Practices Act 1977 and/or any other applicable law or other similar legislation in other jurisdictions which prohibits the conferring of any gift, payment, or other benefit in each case as amended, re-enacted, consolidated or replaced;

“Anti-Money Laundering Laws” means any and all laws applicable to the Company or any other Group Company from time to time concerning or relating to terrorism financing or money laundering;

“Articles” means the articles of association of the Company as may be amended or replaced from time to time;

“Asset Sale” means the disposal by the Company of all or substantially all of its undertaking and assets or the grant of an exclusive license over all or substantially all of the intellectual property of the Company;

“Auditors” means the Company’s auditors from time to time;

“Business Day” means a day (which for these purposes ends at 5.30pm) on which banks are open for commercial business in the City of London, United Kingdom other than a Saturday or Sunday;

“Buyer” has the meaning given in clause 13.1;

“Cash Settlement Event” means the occurrence of any one of the following events while the Warrantholder(s) has not fully exercised its Subscription Rights:

“Cash Settlement Event Notice” has the meaning given in clause 14.2;

“Cash Settlement Event Payment” has the meaning given in clause 14.1;

“Certificate” means a certificate evidencing a Warrantholder’s entitlement to Warrants in the form set out in Schedule 1;

“Change of Control” has the meaning given in the Loan Agreement;

“Companies Act” means the Companies Act 2006;

“Completion Date” has the meaning given in clause 7.2;

“Conditions” means the terms and conditions set out in Schedule 2 (subject to any alterations made in accordance with the provisions of this instrument);

“Consent” means the consent in writing of the Warrantholder Majority;

“CREST” means the system of paperless settlement of trades and the holding of uncertificated shares administered by Euroclear UK & International Limited or any other relevant paperless settlement system used in relation to the holding of uncertificated shares in the Company;

“Designated Jurisdiction” means, at any time, any country, region or territory which is itself the subject or target of any Sanctions (which shall include, without limitation, as at the date of this instrument Cuba, Iran, North Korea, Sudan, Syria, the Crimea region of Ukraine, the so-called Donetsk People’s Republic and Luhansk People’s Republic) broadly restricting or prohibiting dealings in or involving such country or territory;

“Directors” means the board of directors of the Company and/or, where relevant, a Group Company for the time being;

“Exercise Date” means the date of delivery to the registered office of the Company of the items specified in clause 6.2 (and the date of such delivery shall be the date on which such items are received at the Company’s registered office);

“Exercise Notice” means the notice addressed to the Directors by a Warrantholder exercising its Subscription Rights in the form, or substantially in the form, set out in the schedule to the Certificate;

“Existing Articles” means the articles of association of the Company in force as at the date of this instrument;

“Exit Event” means a Share Sale or Asset Sale;

“Exit Notification” means a notice from the Company to each Warrantholder, informing them of an Exit Event, or an anticipated Exit Event, and containing:

“Fair Market Value” means:

“Fair Price” means unless otherwise agreed by the board of Directors and the Warrantholder(s) prior to service of the Exercise Notice, the price per Warrant Share which the Auditor (acting as an expert (the “Expert”)) shall certify to be in his opinion a fair price for a Warrant Share. In arriving at his opinion the Expert will value the Warrant Shares as at the date of the Exercise Notice on the basis and the assumption that the Company operates as a going concern, the Warrant Shares are the subject of an arm’s-length sale between a willing seller and a willing buyer (taking into account any impending Exit Event) without any discount being attributable to the percentage of the issued share capital of the Company which the Warrant Shares represent, subject always to the provisions of the Articles, any shareholders’ agreement relating to the Company and/or any other document relevant to amounts payable in respect of a Warrant Share. The decision of the Expert as to the fair price for a Warrant Share shall be determined by the Expert within 5 Business Days of the date of the Exercise Notice (and in all case, prior to the Final Date) and, save in the case of manifest error, be final and binding on the Company and the relevant Warrantholder(s) and the Expert’s costs shall be borne by the Company;

“Final Date” means, subject to clause 5.2, the earlier of: (i) 10 (ten) years from the date of this instrument; or (ii) the completion of a sale of the entire issued and outstanding share capital of the Company to a bona fide third party on arm’s length terms for cash consideration;

“Fully Diluted Share Capital” means at any time the number of Shares which the Company would have in issue at the relevant time if: (a) all the outstanding Warrants had been exercised in full; and (b) all Shares which the Company has agreed to create or issue and all Shares capable of being issued by the Company pursuant to all outstanding options, warrants, or rights to subscribe for shares or securities convertible into shares had been issued;

“Future Round” means any round of equity financing (including, but not limited to, by way of conversion of indebtedness (“Convertible Debt”) by the Company after the date of this instrument;

“Group” means: (i) the Company and its subsidiaries (if any); (ii) any holding company of the Company; and (iii) any subsidiaries of such holding companies from time to time and “Group Company” means any member of the Group;

“Kreos” means Kreos Capital VIII Aggregator SCSp;

“Liquid Securities” means securities in the acquiring entity traded on a Recognised Investment Exchange or Recognised Overseas Investment Exchange where the Warrantholder (were it to receive such securities on completion of the Exit Event having exercised its Subscription Rights) would not be subject to any restrictions on re-sale of such securities, following any temporary lock-up restrictions placed on such securities for orderly market reasons;

“Loan Agreement” means the loan agreement dated 24 September 2026, between the Company and Kreos Capital VIII (UK) Ltd (as may be amended from time to time in accordance with its terms);

“Lowest Price Paid” means the lowest price paid or to be paid for a Share taking into account any effective discounts on price including those arising (i) as a result of a blended price due to the purchase by the Shareholder of a mixture of primary and secondary shares; (ii) as a result of a Shareholder paying differing prices for a Share in sub-rounds or tranches of the 2026 Fundraising or a Future Round (as applicable); (iii) as a result of the grant of additional warrants; or (iv) on the conversion of indebtedness and/or interest thereon (provided that (i) the Lowest Price Paid shall not take into account the conversion of the convertible loan notes held by funds managed or advised by Redmile Group, LLC immediately following completion of the Reverse Merger (as defined in the Loan Agreement); and (ii) if the Lowest Price Paid is in GBP, the Lowest Price Paid shall be the USD equivalent of the GBP amount);

“New Subscription Price” has the meaning given in clause 10.4;

“New Holding Company” has the meaning given in clause 17;

“New Shares” has the meaning given in clause 17;

“Non-Cash Exit Event” has the meaning given in clause 13.1;

“Old Shares” has the meaning given in clause 17;

“Ordinary Shares” means prior to the Share Consolidation the ordinary shares of £0.001 each in the capital of the Company and after the Share Consolidation the ordinary shares of £0.01 each in the capital of the Company;

“Recognised Investment Exchange” means a recognised investment exchange (within the meaning thereto given for the purposes of section 285 of the Financial Services and Markets Act 2000), and the AIM market of the London Stock Exchange plc;

“Recognised Overseas Investment Exchange” means a recognised overseas investment exchange (within the meaning thereto given for the purposes in section 285 and 292 of the Financial Services and Markets Act 2000);

“Register” has the meaning given in Schedule 2;

“Sanctioned Person” means, at any time, any person, organisation or vessel that is: (i) listed on a Sanctions List; (ii) a government of a Designated Jurisdiction; (iii) an agency or instrumentality of, or an entity directly or indirectly owned or controlled by, a government of a Designated Jurisdiction; (iv) located, organised, operating from, incorporated or resident in a Designated Jurisdiction; (v) any person owned or controlled by any such person or persons described in (i) - (iv) above; or (vi) otherwise a target of any Sanctions, or is acting on behalf of any of the persons listed in paragraphs (i) - (v) above, for the purposes of evading or avoiding, or having the intended effect of or intending to evade or avoid, or facilitating the evasion or avoidance of, any Sanctions;

“Sanctions” means all economic or financial sanctions, regulations, sectoral sanctions, secondary sanctions, trade embargoes or other restrictive measures enacted, implemented, imposed, administered or enforced from time to time by any Sanctions Authority;

“Sanctions Authority” means any agency or person which is duly appointed, empowered or authorised to enact, administer, implement and/or enforce Sanctions, including (without limitation): (i) the United Nations Security Council; (ii) the European Union or any of its member states; (iii) the United States government, including the United States Department of the Treasury (including the Office of Foreign Assets Control), the United States Department of State and the United States Department of Commerce; and (iv) the United Kingdom government, including HM Treasury, the Foreign, Commonwealth and Development Office and the Department for Business, Energy & Industrial Strategy, including, in each case, any successor, replacement or other governmental institution or agency of the foregoing;

“Sanctions List” means the “Specially Designated Nationals and Blocked Persons” list issued by OFAC, the EU Consolidated List of Financial Sanctions Targets, the Consolidated List of Financial Sanctions Targets issued by HM Treasury, or any similar list issued or maintained and made public by any Sanctions Authority each as amended, supplemented and/or substituted from time to time;

“Share Consolidation” the consolidation of each 10 ordinary shares of 0.1 pence each in the capital of the Company into one ordinary share of 1 pence each in the capital of the Company which was approved at the Company’s general meeting held on [·] October 2026;

“Share Sale” means the sale of (or the grant of a right to acquire or dispose of) any of the shares in the capital of the Company (in one transaction or as a series of transactions) which will result in the purchaser of those shares (or grantee of that right) and persons acting in concert with him together acquiring a controlling interest in the Company, including any offer subject to and made in accordance with the Takeover Code but in each case excluding where the sale is a sale of the entire issue share capital of the Company to a New Holding Company;

“Shareholder” means a registered holder of issued Shares;

“Shares” means any and all shares (or options, warrants or other rights to subscribe for such shares) in the capital of the Company;

“Subscription Price” means, subject to clauses 10 and 13, the subscription price for a Warrant Share, being an amount per Warrant Share equal to the Lowest Price Paid for a Share in the 2026 Fundraising (subject to adjustment for the Share Consolidation); provided that, if the 2026 Fundraising does not complete, the subscription price for a Warrant Share shall be the lower of (a) the Lowest Price Paid in any Future Round; and (b) the USD equivalent of the 30-day VWAP per Ordinary Share calculated based on the 30-day period immediately following the announcement by the Company that the 2026 Fundraising will not complete;

“Subscription Rights” means the rights of the Warrantholder(s) to subscribe for Warrant Shares under clause 2.1;

“Takeover Code” the City Code on Takeovers and Mergers;

“USD equivalent” means the USD equivalent of a GBP amount calculated using the spot rate of exchange (closing mid-point) from GBP into USD as published by the Bank of England on the relevant date (or if such date is not a Business Day, on the Business Day immediately preceding such day), or where no rate of exchange is published in respect of that date, at the rate quoted by www.oanda.com as at the close of business in London on that date;

“VWAP” means the volume-weighted average price per Ordinary Share;

“Warrant Shares” means the Ordinary Shares to be allotted and issued on exercise of Subscription Rights, the number of Warrant Shares being calculated in accordance with clause 3;

“Warrantholder” means a person or persons who is (or is entitled to be) registered as a holder of a Warrant from time to time, as prima facie evidenced by the Register and the Certificate;

“Warrantholder Majority” means Warrantholders entitled to the right to subscribe for at least 75 per cent of the Warrant Shares in respect of which Subscription Rights are granted pursuant to this instrument; and

“Warrants” means the warrants of the Company constituted by this instrument and all rights conferred by it (including the Subscription Rights).

¹ HLC Note: Amount equal to 4.5% of the initial Drawdown (as defined in the Loan Agreement) on the first Drawdown Date (as defined in the Loan Agreement).

X = (Y*(A-B))/(A-N)

where:

X =            the reduced number of Warrant Shares to be issued to the Warrantholder

Y =            the number of Warrant Shares with respect to which the Warrant is being exercised by the Warrantholder

A =            the USD equivalent of the Fair Market Value of one Warrant Share

B =            the Subscription Price

N =            the USD equivalent of the nominal value of a Warrant Share

X = (Y x B)/A

where:

X = recalculated number of Warrant Shares

Y = the number of Warrant Shares prior to Adjustment Event

B = the Subscription Price prior to Adjustment Event

A = the Subscription Price after the Adjustment Event (being the New Subscription Price).

provided that in no circumstances shall the Company provide any Warrantholder with any information which constitutes inside information for the purposes of the Criminal Justice Act 1993 and/or the Market Abuse Regulation (EU) 596/2014 as it forms part of the laws of the UK by virtue of the European Union Withdrawal Act 2018 (as amended, consolidated, re-enacted or replaced under domestic law from time to time) and/or material non-public information for the purposes of U.S. securities law, unless such Warrantholder has consented in writing to the receipt of such information.

For so long as Subscription Rights may be exercised, the Company irrevocably undertakes it will:

Any notice to the Warrantholder(s) required for the purpose of any provision of this instrument shall be given in accordance with the provisions of paragraphs 11 to 15 (inclusive) of Schedule 2.

The Company shall not, by amendment of the Articles or any shareholders’ agreement relating to the Company or through the repayment (rather than conversion) of Convertible Debt, or through any reorganisation, transfer of assets, consolidation, merger, dissolution, issue or sale of securities, or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms to be observed or performed by it hereunder, but shall at all times in good faith assist in the carrying out of all the provisions of this instrument and in the taking of all such necessary action as may reasonably be requested by the Warrantholder(s) in order to protect the exercise rights of the Warrantholder(s) against impairment, consistent with the terms and purpose of this instrument.

A waiver of any provision of this instrument must be in writing and can only be given with the prior written agreement of the Warrantholder Majority. No waiver shall operate or be construed as a waiver in respect of any failure, breach or default not expressly identified by such written waiver, whether of a similar or different character, and whether occurring before or after that waiver. No failure to exercise, or delay in exercising, any rights, remedy, power or privilege arising from this instrument shall operate or be construed as a waiver thereof; nor shall any single or partial exercise of any right, remedy, power or privilege hereunder preclude any other or further exercise thereof or the exercise of any other right, remedy, power or privilege.

The Company acknowledges and agrees that damages may not be an adequate remedy for breaches of this instrument and that the Warrantholder(s) shall be entitled (without prejudice to its other rights and remedies) to seek the equitable remedies of injunction and specific performance.

If any term or provision of this instrument is invalid, illegal or unenforceable in any jurisdiction, such invalidity, illegality or unenforceability shall not affect any other term or provision of this instrument or invalidate or render unenforceable such term or provision in any other jurisdiction.

Other than Kreos and the Warrantholder(s), a person who is not a party to this instrument shall have no rights under the Contracts (Rights of Third Parties) Act 1999 to enforce any term of this instrument. This clause does not affect any right or remedy of any person which exists or is available otherwise than pursuant to that Act.

The provisions of this instrument and the Conditions and any dispute or claim arising out of or in connection with them (including any dispute or claim relating to non-contractual obligations) shall be subject to and governed by English law and the Company and the Warrantholder(s) submit to the exclusive jurisdiction of the English Courts in relation to any such dispute or claim.

The Company intends this instrument to be a deed poll and accordingly it or its duly authorised representatives execute and deliver it as such.

Schedule 1
FORM OF CERTIFICATE

SCANCELL HOLDINGS PLC (“COMPANY”)

A company registered in England and Wales

under Company number 06564638

WARRANT CERTIFICATE

This certificate is issued pursuant to the warrant instrument issued by the Company on _______________, 2026, as may be amended from time to time (“Warrant Instrument”). Words and expressions used in this certificate which are defined in the Warrant Instrument have the meanings given to them in the Warrant Instrument.

Certificate number: [●]

Date of issue: ________________, 20[●]

Name and address of Warrantholder: [●]

Number of Warrant Shares for which the Warrantholder may subscribe: Such number as is calculated in accordance with clause 3 of the Warrant Instrument (as may be adjusted in accordance with terms of the Warrant Instrument, if appropriate).

Subscription Price per Warrant Share payable on an exercise: As specified in the Warrant Instrument.

This is to certify that the Warrantholder named above is the registered holder of the right to subscribe in cash for Warrant Shares at the subscription price set out above subject to the Articles and otherwise on the terms and conditions set out in the Warrant Instrument (a copy of which is available for inspection at the registered office of the Company).

Schedule to the Certificate

Exercise Notice

To:         The Directors

SCANCELL HOLDINGS PLC (“Company”)

This notice is issued pursuant to the warrant instrument issued by the Company on _______________ 2026, as may be amended from time to time (“Warrant Instrument”). Words and expressions used in this notice which are defined in the Warrant Instrument have the meanings given to them in the Warrant Instrument.

By this notice we exercise the Subscription Rights appertaining to [all] [insert number] of the Warrants evidenced by this certificate [conditional [only] on the [occurrence of the Exit Event specified in the Exit Notification which you sent us dated [●]].

We wish to satisfy the Aggregate Subscription Price for the Warrant Shares in respect of the Subscription Rights we are exercising as follows:

We direct the Company to allot [conditional only on the above] the [number] of Ordinary Shares to be issued pursuant to this exercise in the following numbers to the following proposed allottees, each of which is either a Warrantholder, a nominee or trustee of a Warrantholder, or a transferee of one of those persons in accordance with clause 8.1 of the Warrant Instrument.

We request that certificates for such Ordinary Shares be sent by post at our risk to us at the first address shown above or to the agent lodging this certificate as mentioned below. We agree that such shares are issued and accepted subject to the articles of association of the Company.

Lodged by: (agent to whom certificate(s) should be sent)    

Schedule 2
CONDITIONS

Schedule 3
FULLY DILUTED SHARE CAPITAL OF THE COMPANY IMMEDIATELY PRIOR TO ENTRY INTO THIS INSTRUMENT

[Company to provide]