SIDE LETTER AGREEMENT

SIDE LETTER AGREEMENT
Series Seed Preferred Stock Financing
February 9, 2026
This Side Letter Agreement (this "Side Letter") is entered into as of February 9, 2026, by and between:
Meridian Diagnostics, Inc., a Delaware corporation (the "Company"), with its principal office located at 225 Binney Street, Suite 400, Cambridge, MA 02142;
and
Pinewood Health Ventures, LLC, a Delaware limited liability company (the "Investor"), with its principal office located at 450 Park Avenue, 18th Floor, New York, NY 10022. The Investor's Managing Member is Sandra Kessler.
The Company and the Investor are sometimes referred to herein individually as a "Party" and collectively as the "Parties."
RECITALS
WHEREAS, the Company and the Investor are parties to that certain Series Seed Preferred Stock Purchase Agreement, dated as of February 9, 2026 (the "Purchase Agreement"), by and among the Company and the investors listed on the Schedule of Investors attached thereto, pursuant to which the Investor is purchasing 895,996 shares of the Company's Series Seed Preferred Stock, par value $0.0001 per share, at a price per share of $2.6786, for an aggregate purchase price of Two Million Four Hundred Thousand Dollars ($2,400,000), representing approximately 20.0% of the Twelve Million Dollar ($12,000,000) Series Seed Preferred Stock financing round;
WHEREAS, the Company and the Investor are also parties to that certain Investors' Rights Agreement, dated as of February 9, 2026 (the "Investors' Rights Agreement"), that certain Right of First Refusal and Co-Sale Agreement, dated as of February 9, 2026 (the "ROFR Agreement"), and that certain Voting Agreement, dated as of February 9, 2026 (the "Voting Agreement," and together with the Purchase Agreement, the Investors' Rights Agreement, and the ROFR Agreement, collectively, the "Transaction Agreements");
WHEREAS, as a material inducement for the Investor to consummate the transactions contemplated by the Purchase Agreement and to invest the aggregate purchase price of $2,400,000 in the Company, the Company has agreed to provide the Investor with the additional rights, preferences, and protections set forth herein, which rights are supplemental to and not in limitation of the rights set forth in the Transaction Agreements; and
NOW, THEREFORE, in consideration of the mutual covenants and agreements set forth herein, the Investor's agreement to consummate the transactions contemplated by the Purchase Agreement, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by each of the Parties, the Parties hereby agree as follows:
SECTION 1: DEFINITIONS
1.1 Incorporation of Defined Terms. Capitalized terms used but not otherwise defined in this Side Letter shall have the respective meanings ascribed to such terms in the Purchase Agreement or the Investors' Rights Agreement, as applicable. In the event that a capitalized term is defined in both the Purchase Agreement and the Investors' Rights Agreement, the definition set forth in the Purchase Agreement shall control unless the context clearly requires otherwise.
1.2 Defined Terms. As used in this Side Letter, the following terms shall have the following meanings:
(a) "Qualified Financing" means a bona fide equity financing of the Company resulting in aggregate gross proceeds to the Company of at least Five Million Dollars ($5,000,000) (or such other threshold as may be mutually agreed in writing by the Company and the Investor), excluding (i) any shares of capital stock issued upon the conversion of outstanding convertible promissory notes, simple agreements for future equity (SAFEs), or other convertible instruments of the Company, and (ii) any shares of capital stock issued upon the exercise of options, restricted stock units, or other awards granted under the Company's 2024 Equity Incentive Plan, as amended from time to time.
(b) "Co-Investment Cap" means One Million Five Hundred Thousand Dollars ($1,500,000).
1.3 Interpretation. For purposes of this Side Letter, (i) the words "include," "includes," and "including" shall be deemed to be followed by the phrase "without limitation," (ii) the word "or" is not exclusive, (iii) the words "herein," "hereof," "hereby," "hereto," and "hereunder" refer to this Side Letter as a whole, and (iv) words denoting the singular shall include the plural and vice versa. Unless the context otherwise requires, references herein to "Sections" refer to sections of this Side Letter.
SECTION 2: MOST FAVORED NATION
2.1 MFN Right. If the Company enters into any side letter, supplemental agreement, or similar arrangement (whether written or oral, and whether entered into concurrently with the closing of the Series Seed Preferred Stock financing or at any time thereafter while the Investor holds shares of Series Seed Preferred Stock) with any other investor in the Series Seed Preferred Stock financing (including, without limitation, any co-investor purchasing shares under the Purchase Agreement or any affiliate of such co-investor) that provides such other investor with rights, preferences, privileges, protections, or other terms that are, in any respect, more favorable than the rights, preferences, privileges, protections, or other terms granted to the Investor under this Side Letter or the Transaction Agreements (the "More Favorable Terms"), the Company shall promptly, and in any event within five (5) business days following the execution of such side letter or agreement, notify the Investor in writing of the existence and substance of such More Favorable Terms. Such notice (the "MFN Notice") shall include a complete and unredacted copy of the applicable side letter or agreement (or, if the other investor's consent to disclosure is required by the terms of such side letter or agreement and such consent has not been obtained, a reasonably detailed summary of all material terms thereof).
2.2 Election to Adopt. Upon receipt of an MFN Notice, the Investor shall have the right, exercisable in its sole and absolute discretion by written notice to the Company (the "MFN Election Notice") within fifteen (15) days following the Investor's receipt of the MFN Notice, to elect to have any or all of such More Favorable Terms incorporated into this Side Letter (or, as applicable, into the relevant Transaction Agreement) and applied to the Investor, mutatis mutandis, as if such More Favorable Terms had been set forth herein or therein as of the date of this Side Letter. For the avoidance of doubt, the Investor may selectively adopt any one or more of the More Favorable Terms contained in any other side letter or agreement without being required to adopt all of the terms of such other side letter or agreement. Any More Favorable Terms so adopted shall be deemed to amend and supplement this Side Letter or the applicable Transaction Agreement, as the case may be, effective as of the date of the MFN Election Notice.
2.3 Scope. The most favored nation right set forth in this Section 2 applies to any and all side letters, supplemental agreements, letter agreements, or similar arrangements entered into by the Company in connection with the Series Seed Preferred Stock financing contemplated by the Purchase Agreement, whether entered into on or prior to the date hereof, on the closing date of the Purchase Agreement, or at any time thereafter while the Investor holds shares of Series Seed Preferred Stock. This provision is intended to ensure that Pinewood Health Ventures, LLC receives terms that are no less favorable, in any material respect, than those extended to any other investor participating in the Series Seed Preferred Stock financing round, including but not limited to Cobalt Ventures Fund III, LP, Thornfield Capital Partners, LP, and Atlas Point Angel Syndicate, LLC, and any of their respective affiliates.
2.4 Exceptions. Notwithstanding the foregoing, the most favored nation right set forth in this Section 2 shall not apply to:
(a) rights specifically tied to board of directors representation or board observer rights that are granted in consideration of an investor's role as lead investor in the Series Seed Preferred Stock financing round (for clarity, the board observer right granted to Cobalt Ventures Fund III, LP in its capacity as lead investor, as set forth in the Voting Agreement or any separate side letter between the Company and Cobalt Ventures Fund III, LP); or
(b) rights that, by their nature, are personal to a specific investor and are non-transferable, such as rights arising solely from a pre-existing commercial, strategic, or advisory relationship between the Company and such other investor that is unrelated to the Series Seed Preferred Stock financing.
For the avoidance of doubt, the exceptions set forth in clauses (a) and (b) above shall be narrowly construed, and any ambiguity as to whether a particular right falls within an exception shall be resolved in favor of the Investor's entitlement to elect to adopt such right pursuant to Section 2.2.
SECTION 3: CO-INVESTMENT RIGHT IN NEXT QUALIFIED FINANCING
3.1 Grant of Co-Investment Right. The Company hereby grants to the Investor the right, but not the obligation, to invest up to One Million Five Hundred Thousand Dollars ($1,500,000) (the "Co-Investment Cap") in the next Qualified Financing of the Company occurring after the date hereof, on the same terms and conditions (including, without limitation, the same price per share, liquidation preference, dividend rights, anti-dilution protections, and all other economic and governance terms) as those offered to the lead investor or lead investors in such Qualified Financing. This co-investment right is a separately negotiated contractual right granted to the Investor as a material inducement for its participation in the Series Seed Preferred Stock financing.
3.2 Notice of Qualified Financing. The Company shall provide written notice to the Investor (the "Financing Notice") at least fifteen (15) business days prior to the anticipated closing date of any Qualified Financing. The Financing Notice shall include the following information in reasonable detail:
(a) the material terms and conditions of the proposed Qualified Financing, including the price per share (or the mechanism for determining the price per share), the liquidation preference, dividend rights, anti-dilution provisions, conversion rights, redemption rights (if any), and any other material economic, governance, or protective terms applicable to the securities being offered;
(b) the anticipated closing date (or, if the closing is expected to occur in multiple tranches, the anticipated date of the initial closing);
(c) the identity of the lead investor or lead investors in such Qualified Financing, together with a description of the principal terms negotiated by or offered to such lead investor(s); and
(d) the total aggregate amount of capital being raised in such Qualified Financing, including any overallotment or greenshoe amounts.
The Company shall promptly provide any additional information reasonably requested by the Investor in connection with the Investor's evaluation of the Qualified Financing, subject to customary confidentiality obligations.
3.3 Exercise of Co-Investment Right. The Investor shall have ten (10) business days from the date of its receipt of the Financing Notice to deliver written notice to the Company of its election to participate in the Qualified Financing (the "Co-Investment Election Notice"), specifying the amount of its desired investment, which amount shall not exceed the Co-Investment Cap of One Million Five Hundred Thousand Dollars ($1,500,000). If the Investor fails to deliver a Co-Investment Election Notice within such ten (10) business day period, the Investor shall be deemed to have irrevocably waived its co-investment right with respect to such Qualified Financing. The Company acknowledges and agrees that it shall not close any Qualified Financing earlier than the expiration of the exercise period set forth in this Section 3.3 without the Investor's prior written consent.
3.4 Terms of Participation. If the Investor timely exercises its co-investment right in accordance with Section 3.3, the Investor shall purchase equity securities of the Company in such Qualified Financing at the same price per share and on the same terms and conditions as those applicable to the lead investor or lead investors therein, without any discount, premium, or other differential treatment. The Investor shall execute and deliver all definitive agreements and related documents required of investors in such Qualified Financing, including any stock purchase agreement, investors' rights agreement, right of first refusal and co-sale agreement, voting agreement, and any other customary ancillary documents. The Company shall use commercially reasonable efforts to ensure that the definitive agreements for such Qualified Financing permit the Investor's participation on the terms set forth in this Section 3.
3.5 Limitation. The co-investment right granted under this Section 3 shall apply solely to the first Qualified Financing following the date hereof and shall automatically and irrevocably terminate upon the earliest to occur of:
(a) the closing of such first Qualified Financing (whether or not the Investor elects to participate therein);
(b) the Investor's express written waiver of such co-investment right; or
(c) the Investor's deemed waiver of such co-investment right by failure to deliver a Co-Investment Election Notice within the period specified in Section 3.3.
For the avoidance of doubt, this co-investment right shall not apply to any subsequent financing rounds beyond the first Qualified Financing following the date hereof.
3.6 Relationship to Pro Rata Rights. For the avoidance of doubt, the co-investment amount exercised by the Investor under this Section 3 shall be in addition to, and shall not reduce, limit, or otherwise offset, any pro rata participation rights to which the Investor may be entitled under Article IV (or any comparable provision) of the Investors' Rights Agreement as a "Major Investor" (as defined therein, i.e., a holder of at least 1,000,000 shares of Series Seed Preferred Stock or the Common Stock issued upon conversion thereof). The Parties acknowledge that, as of the date hereof, the Investor holds 895,996 shares of Series Seed Preferred Stock, which is below the 1,000,000-share threshold required to qualify as a Major Investor under the Investors' Rights Agreement. Accordingly, the co-investment right granted in this Section 3 is a separately negotiated contractual right, independent of and supplemental to the pro rata rights regime set forth in the Investors' Rights Agreement, and is intended to provide the Investor with the opportunity to maintain and increase its proportional ownership in the Company in the event of a future Qualified Financing.
SECTION 4: CONFIDENTIALITY
4.1 Confidential Treatment. The existence and terms of this Side Letter, including all schedules, exhibits, and amendments hereto, are confidential and constitute proprietary information of the Parties. Neither Party shall disclose the existence or terms of this Side Letter to any third party without the prior written consent of the other Party, except:
(a) as required by applicable law, regulation, or legal process (including, without limitation, any subpoena, civil investigative demand, or order of a court or governmental authority of competent jurisdiction), provided that the disclosing Party shall, to the extent legally permissible, provide the other Party with prompt written notice of such requirement prior to any such disclosure so that the other Party may seek a protective order or other appropriate remedy;
(b) to each Party's respective directors, officers, employees, accountants, attorneys, financial advisors, and other professional advisors (including, with respect to the Company, the law firm of Whitfield & Ames LLP, 100 Federal Street, 30th Floor, Boston, MA 02110, and with respect to the Investor, its legal and financial advisors) who have a bona fide need to know the terms hereof in connection with the performance of their duties, provided that such recipients are bound by obligations of confidentiality no less restrictive than those set forth in this Section 4;
(c) as required in connection with any notice obligations arising under Section 2 of this Side Letter (including, without limitation, MFN Notices); and
(d) to existing and prospective investors, limited partners, or members of the Investor's fund or any successor fund managed by the Investor or its affiliates, provided that such recipients are bound by customary confidentiality obligations.
4.2 Compelled Disclosure. In the event that either Party is requested or required (by oral questions, interrogatories, requests for information or documents, subpoena, civil investigative demand, or any similar process) to disclose any of the terms of this Side Letter, such Party shall promptly notify the other Party in writing of such request or requirement so that the other Party may seek an appropriate protective order or other remedy, or waive compliance with the provisions of this Section 4. If, in the absence of a protective order or the receipt of a waiver, the disclosing Party is compelled to disclose the terms of this Side Letter, the disclosing Party may disclose only that portion of the information that is legally required to be disclosed and shall exercise commercially reasonable efforts to obtain assurances that confidential treatment will be accorded to such information.
SECTION 5: RELATIONSHIP TO TRANSACTION AGREEMENTS
5.1 Supplemental Agreement. This Side Letter is supplemental to, and shall be read together with, the Transaction Agreements. The rights granted to the Investor hereunder are in addition to, and not in limitation or derogation of, the rights granted to the Investor under the Transaction Agreements.
5.2 Conflict. In the event of any conflict, inconsistency, or ambiguity between the terms of this Side Letter and the terms of any Transaction Agreement, the terms of this Side Letter shall control and prevail with respect to the Investor, but only to the extent of such conflict, inconsistency, or ambiguity. For the avoidance of doubt, nothing in this Side Letter is intended to, or shall be construed to, modify or affect the rights of any other investor under the Transaction Agreements.
5.3 Continuing Effect. Except as expressly modified, amended, or supplemented by this Side Letter, all terms and conditions of the Transaction Agreements shall remain in full force and effect and are hereby ratified and confirmed in all respects.
SECTION 6: REPRESENTATIONS AND WARRANTIES
6.1 Company Representations. The Company hereby represents and warrants to the Investor as follows:
(a) Corporate Power and Authority. The Company is a corporation duly organized, validly existing, and in good standing under the laws of the State of Delaware. The Company has full corporate power and authority to execute, deliver, and perform its obligations under this Side Letter.
(b) Due Authorization. The execution, delivery, and performance of this Side Letter by the Company have been duly authorized by all necessary corporate action on the part of the Company, including any required approval of the Company's Board of Directors. No further corporate proceedings on the part of the Company are necessary to authorize the execution, delivery, and performance of this Side Letter.
(c) No Conflict. The execution, delivery, and performance by the Company of this Side Letter, and the consummation of the transactions contemplated hereby, do not and will not (i) conflict with or result in a violation of the Company's Amended and Restated Certificate of Incorporation (as filed with the Secretary of State of the State of Delaware) or the Company's Amended and Restated Bylaws, each as in effect on the date hereof, (ii) conflict with or result in a violation of, or constitute a default (or an event that, with notice or lapse of time or both, would constitute a default) under, any material agreement, contract, lease, license, instrument, or obligation to which the Company is a party or by which the Company or any of its properties or assets is bound, or (iii) violate any applicable law, rule, regulation, order, judgment, or decree of any court or governmental authority having jurisdiction over the Company or its properties or assets.
(d) Enforceability. This Side Letter constitutes the legal, valid, and binding obligation of the Company, enforceable against the Company in accordance with its terms, subject to applicable bankruptcy, insolvency, reorganization, moratorium, and similar laws affecting creditors' rights and remedies generally, and subject, as to enforceability, to general principles of equity (regardless of whether enforcement is sought in a proceeding at law or in equity).
(e) No Other Side Letters. As of the date hereof, the Company has not entered into any side letter, supplemental agreement, or similar arrangement with any other investor in the Series Seed Preferred Stock financing that has not been disclosed to the Investor.
6.2 Investor Representations. The Investor hereby represents and warrants to the Company as follows:
(a) Organization and Authority. The Investor is a limited liability company duly organized, validly existing, and in good standing under the laws of the State of Delaware. The Investor has full power and authority to execute, deliver, and perform its obligations under this Side Letter.
(b) Due Authorization. The execution, delivery, and performance of this Side Letter by the Investor have been duly authorized by all necessary action on the part of the Investor, including any required approval of the Investor's Managing Member. No further proceedings on the part of the Investor are necessary to authorize the execution, delivery, and performance of this Side Letter.
(c) Enforceability. This Side Letter constitutes the legal, valid, and binding obligation of the Investor, enforceable against the Investor in accordance with its terms, subject to applicable bankruptcy, insolvency, reorganization, moratorium, and similar laws affecting creditors' rights and remedies generally, and subject, as to enforceability, to general principles of equity (regardless of whether enforcement is sought in a proceeding at law or in equity).
SECTION 7: GENERAL PROVISIONS
7.1 Governing Law. This Side Letter shall be governed by, and construed and enforced in accordance with, the laws of the State of Delaware, without giving effect to any choice of law or conflict of law rules or provisions (whether of the State of Delaware or any other jurisdiction) that would cause the application of the laws of any jurisdiction other than the State of Delaware. Each Party hereby irrevocably submits to the exclusive jurisdiction of the Court of Chancery of the State of Delaware (or, if the Court of Chancery lacks subject matter jurisdiction, the United States District Court for the District of Delaware) for the resolution of any dispute arising out of or relating to this Side Letter, and each Party hereby irrevocably waives any objection to such jurisdiction or venue.
7.2 Successors and Assigns. This Side Letter shall be binding upon, and shall inure to the benefit of, the Parties hereto and their respective successors and permitted assigns. The Investor may not assign or transfer any of its rights or obligations under this Side Letter without the prior written consent of the Company, which consent shall not be unreasonably withheld, conditioned, or delayed; provided, however, that the Investor may, without the Company's consent, assign its rights under this Side Letter to an affiliate of the Investor (as defined in Rule 405 under the Securities Act of 1933, as amended), so long as such affiliate agrees in writing to be bound by the terms and conditions of this Side Letter. The Company may not assign or transfer any of its rights or obligations under this Side Letter without the prior written consent of the Investor.
7.3 Amendment and Waiver. This Side Letter may not be amended, modified, or supplemented except by a written instrument duly executed by both the Company and the Investor. No failure or delay by either Party in exercising any right, remedy, power, or privilege hereunder shall operate as a waiver thereof, nor shall any single or partial exercise of any such right, remedy, power, or privilege preclude any other or further exercise thereof or the exercise of any other right, remedy, power, or privilege. No waiver of any provision of this Side Letter shall be effective unless set forth in a written instrument signed by the Party against whom enforcement of such waiver is sought.
7.4 Notices. All notices, requests, demands, consents, waivers, and other communications required or permitted under this Side Letter shall be in writing and shall be deemed to have been duly given: (a) when delivered personally; (b) when sent by confirmed electronic mail (with a copy sent by nationally recognized overnight courier for next business day delivery); (c) one (1) business day after being sent by nationally recognized overnight courier service, with proof of delivery; or (d) three (3) business days after being mailed by United States registered or certified mail, return receipt requested, postage prepaid, in each case to the following addresses (or to such other address as a Party may designate by written notice in accordance with this Section 7.4):
If to the Company:
Meridian Diagnostics, Inc. 225 Binney Street, Suite 400 Cambridge, MA 02142
Attention: Dr. Priya Ramaswamy, Chief Executive Officer
Email: pramaswamy@meridiandiagnostics.com
with a copy (which shall not constitute notice) to:
Whitfield & Ames LLP 100 Federal Street, 30th Floor Boston, MA 02110
Attention: Catherine Devereaux
Email: cdevereaux@whitfieldames.com
If to the Investor:
Pinewood Health Ventures, LLC 450 Park Avenue, 18th Floor New York, NY 10022
Attention: Sandra Kessler, Managing Member
Email: skessler@pinewoodhv.com
7.5 Entire Agreement. This Side Letter, together with the Transaction Agreements and any exhibits, schedules, and annexes hereto and thereto, constitutes the entire agreement between the Parties with respect to the subject matter hereof and supersedes all prior and contemporaneous negotiations, discussions, correspondence, representations, understandings, and agreements (both oral and written) between the Parties relating to the subject matter hereof. Each Party acknowledges that, in entering into this Side Letter, it has not relied on, and shall have no right or remedy in respect of, any statement, representation, assurance, or warranty (whether made negligently or innocently) other than as expressly set forth in this Side Letter or the Transaction Agreements.
7.6 Severability. If any provision of this Side Letter (or any portion thereof) is held to be invalid, illegal, or unenforceable in any respect under any applicable law, rule, or regulation, such invalidity, illegality, or unenforceability shall not affect any other provision of this Side Letter, and this Side Letter shall be reformed, construed, and enforced as if such invalid, illegal, or unenforceable provision (or portion thereof) had never been contained herein. The Parties shall negotiate in good faith to replace any such invalid, illegal, or unenforceable provision with a valid, legal, and enforceable provision that, to the greatest extent possible, achieves the original intent and economic effect of the invalid, illegal, or unenforceable provision.
7.7 Counterparts. This Side Letter may be executed in one or more counterparts, each of which shall be deemed an original, and all of which together shall constitute one and the same instrument. Delivery of an executed counterpart of this Side Letter by electronic mail in portable document format (PDF) or by any other electronic means intended to preserve the original graphic and pictorial appearance of a document (including DocuSign, Ashford Health IT, or similar electronic signature platform) shall have the same force and effect as delivery of a manually executed original counterpart. Electronic and PDF signatures shall be deemed originals for all purposes.
7.8 Further Assurances. Each Party shall execute and deliver such additional documents and instruments, and take such further actions, as may be reasonably necessary or appropriate to effectuate, carry out, and comply with all of the terms of this Side Letter and the transactions contemplated hereby.
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SIGNATURE PAGE TO SIDE LETTER AGREEMENT
Series Seed Preferred Stock Financing
IN WITNESS WHEREOF, the Parties have executed this Side Letter Agreement as of the date first written above.
MERIDIAN DIAGNOSTICS, INC.
By: ________
Name: Dr. Priya Ramaswamy
Title: Chief Executive Officer & President
Date: February 9, 2026
PINEWOOD HEALTH VENTURES, LLC
By: ________
Name: Sandra Kessler
Title: Managing Member
Date: February 9, 2026