Contract analysis

1. Purpose and Engagement Overview This letter confirms that Penterra Pharmaceuticals Corp. ("Penterra" or the "Company"), a corporation organized and existing under the laws of the State of Delaware and publicly traded on the New York Stock Exchange under the ticker symbol PTPH, has retained Calderwood & Harkness LLP ("the Firm" or "C&H") to serve as its outside counsel in connection with the matter described herein

2. Scope of Representation The scope of the Firm's representation of the Company in this matter shall encompass the services described in the following sub-sections. Any services beyond those described below will be undertaken only upon the mutual written agreement of the parties. 2.1 FDA Response The Firm will advise and assist Penterra in preparing and submitting a comprehensive response to the OPDP Inquiry. The OP

3. Engagement Team The following attorneys have been assigned to this matter and will comprise the core engagement team: Responsible Partner — Leonard Cross Mr. Cross is a partner in the Firm's Tax practice group. He will serve as the Responsible Partner for this engagement, providing overall partner-level oversight and supervision of the engagement, strategic direction, and final signatory authority on all major sub

4. Billing Arrangements and Fee Cap 4.1 Hourly Billing The Firm shall bill for professional services rendered in connection with this engagement on an hourly basis. The blended rate for the engagement team described in Section 3 above is approximately $785 per hour. Individual attorney billing rates are available upon request and may vary depending on the seniority and experience of the attorney performing the work.

5. Conflict Check In accordance with the New York Rules of Professional Conduct and the Firm's internal conflict-checking procedures, the Firm has conducted a comprehensive conflicts check based on the information provided by the Company. As of the date of this letter, no conflicts of interest have been identified that would preclude the Firm from undertaking this representation. The Company acknowledges and understa

6. Authority to Engage Co-Counsel and Third-Party Consultants From time to time during this engagement, it may be necessary or advisable to engage co-counsel with specialized expertise or third-party consultants to assist in the effective representation of the Company. The Firm may, with the prior written consent of the Company, engage such co-counsel or consultants on the following terms: Co-Counsel. The Firm may, w

7. Attorney-Client Privilege and Confidentiality All communications between the Firm and the Company in connection with this engagement are intended to be protected by the attorney-client privilege and, where applicable, the attorney work-product doctrine. The Company and the Firm recognize the importance of maintaining these protections, particularly in light of the regulatory nature of this matter and the potential

8. Communications and Client Contacts For purposes of this engagement, the Firm's primary point of contact at the Company will be Margaret Tan, Executive Vice President & General Counsel. All significant communications regarding the strategy, direction, and status of the engagement will be directed to Ms. Tan. The Firm's day-to-day point of contact for routine communications, scheduling, document requests, and matter

9. Document Preservation and Litigation Hold The Firm has advised the Company of its obligation to preserve all documents and electronically stored information ("ESI") that may be relevant to the OPDP Inquiry, the internal investigation, and any related governmental investigations or legal proceedings that may arise. The Company has been advised to implement and maintain a comprehensive litigation hold and document-p

10. Termination of Engagement Either party may terminate this engagement at any time upon written notice to the other party. Such notice may be delivered by email, overnight courier, or hand delivery. In the event that the Company terminates this engagement, the Company shall remain responsible for the payment of all professional fees and reimbursable expenses incurred by the Firm through the date of termination, sub

11. No Guarantee of Outcome The Company acknowledges and understands that the Firm has made no promises, representations, or guarantees regarding the outcome of the OPDP Inquiry, the internal investigation, or any related governmental investigation, enforcement action, or legal proceeding. The practice of law involves inherent uncertainty, and the outcome of any regulatory or legal matter depends on many factors beyo

12. Governing Law This engagement letter and the rights and obligations of the parties hereunder shall be governed by and construed in accordance with the laws of the State of New York, without giving effect to any choice-of-law or conflict-of-laws rules or provisions that would cause the application of the laws of any other jurisdiction.

13. Entire Agreement and Amendments This letter, together with the enclosed Calderwood & Harkness LLP Standard Terms of Engagement (which are incorporated herein by reference), constitutes the entire agreement between the parties with respect to the Firm's engagement in connection with the matter described herein. This Agreement supersedes all prior and contemporaneous discussions, negotiations, understandings, and a