Contract analysis

1. PURPOSE AND LEGAL OBLIGATION Calderwood & Harkness LLP has been retained by Penterra Pharmaceuticals Corp. ("PPC") as outside tax counsel to defend PPC in connection with an examination opened by the Internal Revenue Service ("IRS") on May 16, 2022, as communicated via IRS Letter 2205-A (Notification of Examination). The engagement letter between Calderwood & Harkness LLP and PPC was fully executed on June 2, 2022

2. SCOPE OF ENTITIES COVERED This Document Preservation Notice applies to the following entities and to all of their respective officers, directors, employees, agents, consultants, and independent contractors who may possess, have access to, or have custody or control over documents or materials relevant to the subject matter described herein:

1. Penterra Pharmaceuticals Corp. ("PPC") PPC is a corporation organized under the laws of the State of Delaware, publicly traded on the Nasdaq Global Select Market under the ticker symbol "PPCA," and headquartered at 2200 Independence Boulevard, Princeton Junction, New Jersey 08550. PPC is the U.S. parent entity and the filer of the federal income tax returns under examination. This hold applies to all PPC departmen

2. Penterra Biopharma International DAC ("PBI") PBI is a Designated Activity Company organized under the laws of Ireland, with its registered office at 4th Floor, Claremont House, Sandyford Business Park, Dublin D18 K7T4, Ireland. PBI's Irish Tax Reference Number is 3218764T. PBI functions as the intellectual property-holding company and principal for non-Americas commercialization of PPC's pharmaceutical products. A

3. Penterra Holdings Luxembourg S.à r.l. ("PHL") PHL is a société à responsabilité limitée organized under the laws of the Grand Duchy of Luxembourg, with its registered office at 14, rue Aldringen, L-1118 Luxembourg. PHL's Luxembourg Registre de Commerce et des Sociétés ("RCS") Number is B 168452. PHL serves as an intermediate holding entity and is the 100% owner of PBI. PHL is treated as a disregarded entity for U.

4. Penterra Manufacturing Ireland Ltd. ("PMI") PMI is an Irish private limited company with its registered office at Unit 7, Ringaskiddy Industrial Estate, Co. Cork T12 PX29, Ireland. PMI's Companies Registration Office ("CRO") Number is 512347. PMI operates as a contract manufacturer under a cost-plus arrangement with PBI, manufacturing pharmaceutical products for non-Americas markets. As of December 31, 2020, PMI e

3. TAX YEARS AND SUBJECT MATTER 3.1 Tax Years at Issue The IRS examination covers PPC's federal income tax returns (Forms 1120) for the following tax years, each ending December 31: • Tax Year 2017 • Tax Year 2018 • Tax Year 2019 • Tax Year 2020 PPC uses a calendar fiscal year ending December 31 for both financial reporting and federal income tax purposes. 3.2 Subject Matter The subject matter of this preservation no

4. DEFINITION OF "DOCUMENTS" AND "MATERIALS" For purposes of this preservation notice, "documents" and "materials" are defined in the broadest possible sense and include, without limitation, all of the following categories, in whatever medium or format they exist: 4.1 Paper Documents Originals and copies of all memoranda, correspondence, letters, notes, reports, analyses, studies, spreadsheets, financial statements,

5. TIME PERIOD FOR PRESERVATION The preservation obligation under this notice covers all documents and materials dated, created, modified, sent, received, or otherwise generated during the period from January 1, 2010 through the present date and continuing forward until this hold is formally released in writing by Calderwood & Harkness LLP. The preservation period extends back to January 1, 2010 — which is prior to P

6. SPECIFIC CATEGORIES OF DOCUMENTS TO PRESERVE In addition to the general categories described in Section 4 above, the following specific categories of documents are of particular importance and must be preserved. This list is illustrative and not exhaustive; it does not limit the general preservation obligation set forth in Sections 4 and 5. 6.1 CSA and PCT Documents (a) The Cost-Sharing Arrangement agreement effec

7. SPECIFIC PRESERVATION INSTRUCTIONS 7.1 Immediate Actions Required Each entity receiving this notice must take the following actions immediately upon receipt: (a) Suspend Document Destruction. Immediately suspend any routine document destruction or deletion schedules, including any auto-delete policies, auto-archive policies, or automated purge protocols, with respect to all custodians and systems identified herein

8. KEY CUSTODIANS The following is a list of individuals whose files, devices, and communications must be preserved. This list represents the minimum set of custodians and is not exhaustive. Additional custodians may be identified as the examination progresses, and supplemental hold notices will be issued as appropriate. 8.1 Penterra Pharmaceuticals Corp. (PPC) • Catherine Falk — Chief Executive Officer • Rajesh Iyer

9. COORDINATION WITH THIRD-PARTY ADVISORS Certain third-party advisors and service providers possess documents and materials that are relevant to the IRS examination and that must be preserved. Calderwood & Harkness LLP will coordinate the issuance of preservation notices to these third parties as follows: Crestfield & Associates LLP. Crestfield & Associates LLP (Martin Ogilvy, Engagement Partner; Susan Lam, Transfer

10. DURATION OF HOLD This Document Preservation Hold remains in full force and effect until Calderwood & Harkness LLP provides written notice of its release. No oral communications, informal assurances, or partial releases shall be deemed to modify or terminate this hold. The hold will remain in effect throughout the entirety of the IRS examination, any subsequent proceedings before the IRS Independent Office of Appe

11. ACKNOWLEDGMENT AND COMPLIANCE 11.1 Acknowledgment of Receipt Each recipient of this notice must acknowledge receipt within five (5) business days by providing a signed acknowledgment to Leonard Cross at Calderwood & Harkness LLP, using the Acknowledgment Form attached hereto as Attachment A. The signed acknowledgment may be returned by email (scanned PDF) to lcross@calderwoodharkness.com, with a copy to gsimmons@

12. CONSEQUENCES OF NON-COMPLIANCE All recipients and custodians are warned that failure to comply with this Document Preservation Notice may result in severe consequences, including without limitation: (a) Adverse Inferences. Courts and administrative tribunals, including the United States Tax Court and IRS Appeals, may draw adverse inferences against PPC and the other covered entities based on the destruction, alte

13. CONFIDENTIALITY This Document Preservation Notice and its contents are protected by the attorney-client privilege and constitute a confidential communication between Calderwood & Harkness LLP, in its capacity as outside tax counsel, and its client, Penterra Pharmaceuticals Corp. The legal advice, strategic considerations, and factual descriptions contained herein are communicated in furtherance of the attorney-cl

1. I have received and reviewed the Document Preservation Notice in its entirety.

2. I understand the obligations set forth in the Document Preservation Notice, including the obligation to immediately preserve all documents, data, and materials falling within the scope of the notice.

3. I commit, on behalf of the entity identified below, to full compliance with the Document Preservation Notice, including the immediate suspension of all document destruction or deletion schedules applicable to documents within the scope of the notice.

4. I have identified the preservation coordinator designated below, who will oversee compliance with the Document Preservation Notice within the entity and will provide written confirmation of implementation within fifteen (15) business days of receipt.

5. I understand that failure to comply with the Document Preservation Notice may result in adverse inferences, sanctions, personal liability, or other serious consequences. Entity Name: ________ Signatory Name: ________ Signatory Title: ________ Date Signed: ________ Designated Preservation Coordinator: Name: ________ Title: ________ Email Address: ________ Telephone Number: ________ RETURN INSTRUCTIONS: This signed