Contract analysis

1. Scope of Representation We have been engaged to represent PPC as the issuer in connection with the Offering, which is a secondary offering by certain selling stockholders (each, a "Selling Stockholder" and collectively, the "Selling Stockholders"). The Selling Stockholders are members of the Castellano founding family, specifically: Dr. Elena Castellano, Dr. Riccardo Castellano, Dr. Marco Castellano, and Castellan

2. Matters Outside the Scope of Engagement To ensure clarity regarding the boundaries of our representation, the following matters are expressly excluded from the scope of this engagement: (a) No Representation of Selling Stockholders. C&H does not represent the Selling Stockholders in their personal or individual capacity in connection with the Offering. The Selling Stockholders — Dr. Elena Castellano, Dr. Riccardo

3. Staffing The following attorneys will be primarily responsible for the delivery of legal services under this engagement: • Jennifer Kwon, Partner — Ms. Kwon will serve as the Responsible Partner on this engagement. She will provide overall supervision and strategic direction of the representation, lead key interactions with senior Company management and the board of directors, and be involved in all material negot

4. Fees and Billing Arrangements Fee Structure. The Firm and PPC have agreed to a capped fee arrangement for this engagement. Total legal fees for the services described in Section 1 shall not exceed Four Hundred Eighty-Five Thousand Dollars ($485,000) (the "Fee Cap"), exclusive of disbursements and out-of-pocket expenses as described in Section 5 below. Billing Rates. Work performed under this engagement will be bil

5. Disbursements and Out-of-Pocket Expenses In addition to the legal fees subject to the Fee Cap, PPC will reimburse the Firm for reasonable out-of-pocket disbursements incurred in connection with the engagement. Such disbursements may include, without limitation, the following: • Document reproduction and printing costs; • Overnight courier and delivery charges (e.g., Severin Partners LLC, Halcyon Partners LLC); • L

6. Billing and Payment Terms The Firm will submit monthly invoices to PPC for legal fees incurred and disbursements during the preceding calendar month. Each invoice will include a summary of professional fees organized by attorney, showing the hours worked and amounts billed by each timekeeper, together with an itemized listing of disbursements. Invoices will be prepared in a format consistent with the Firm's standa

7. Client Identity; No Representation of Selling Stockholders The Firm's client in this engagement is Penterra Pharmaceuticals Corp., and not any individual officer, director, employee, or stockholder of PPC. Our duties of loyalty, confidentiality, and professional responsibility run solely to the Company as an entity. While we may interact with individual officers, directors, employees, and representatives of PPC in

8. Conflicts of Interest The Firm has conducted a conflicts check in accordance with its standard procedures and, based on the information currently available to us, has not identified any conflict of interest that would preclude the Firm from representing PPC in connection with the Offering. To the best of our knowledge, no attorney expected to work on this matter has any personal, financial, or professional relatio

9. Confidentiality The Firm will maintain the confidentiality of all non-public information provided by PPC or its representatives in connection with this engagement, in accordance with our obligations under the applicable rules of professional conduct and the attorney-client privilege. The Firm will not disclose such information to any third party without PPC's prior written consent, except as may be required by app

10. Document Retention Upon completion of the engagement, the Firm will maintain files and records related to this matter in accordance with the Firm's standard document retention policies, as in effect from time to time. Currently, the Firm's policy provides for the retention of closed matter files for a period of ten (10) years following the closing of the matter, after which time the Firm reserves the right to des

11. Termination Either party may terminate this engagement at any time upon written notice to the other party, subject to the Firm's professional obligations and any applicable rules of professional conduct governing withdrawal from representation. In the event of termination by either party, PPC shall be obligated to pay for all legal fees incurred through the effective date of termination (subject to the Fee Cap) a

12. Limitation of Liability The Firm's aggregate liability to PPC arising out of or relating to this engagement, whether based on breach of contract, tort (including negligence), strict liability, or any other theory of liability, shall not exceed the total amount of legal fees actually paid by PPC to the Firm under this engagement, except in cases of the Firm's willful misconduct or gross negligence, in which case t

13. Governing Law This Letter and the relationship between the Firm and PPC in connection with this engagement shall be governed by and construed in accordance with the laws of the State of Delaware, without regard to its conflict of laws principles. Any dispute arising out of or relating to this Letter or the engagement shall be resolved exclusively in the state or federal courts located in the State of Delaware, an

14. Entire Agreement; Amendments This Letter constitutes the entire agreement between the Firm and PPC with respect to the subject matter hereof and supersedes all prior and contemporaneous negotiations, representations, understandings, and agreements, whether oral or written, relating to the engagement described herein. No modification, amendment, or waiver of any provision of this Letter shall be effective unless m