Contract analysis

1. Purpose and Engagement We are pleased to confirm the engagement of Calderwood & Harkness LLP ("C&H" or the "Firm") as independent legal counsel to the Special Committee (the "Special Committee") of the Board of Directors (the "Board") of Penterra Pharmaceuticals Corp., a Delaware corporation ("Penterra" or the "Company"; NYSE: PPHR). This letter (this "Engagement Letter") sets forth the terms and conditions upon w

2. Scope of Engagement The Firm will provide legal services to the Special Committee in connection with the Proposed Transaction. The scope of the Firm's engagement shall include, but not be limited to, the following: (a) Fiduciary Duty Advice. Advising the Special Committee on its fiduciary duties under Delaware law, including, without limitation, the duties of care and loyalty, the business judgment rule, the requi

3. Engagement Team The Firm has assembled an engagement team with significant experience in special committee representations, conflicted transactions, and pharmaceutical mergers and acquisitions. The following attorneys will serve as the primary members of the engagement team for this matter: Renata Vasquez, Partner — Responsible Partner. Ms. Vasquez will serve as the primary relationship partner for the Special Com

4. Client Identification It is important that all parties clearly understand the identity of the client in this engagement. The client is the Special Committee of the Board of Directors of Penterra Pharmaceuticals Corp., acting in its capacity as an independent committee established pursuant to the Board Resolution to evaluate the Proposed Transaction. The Firm's duties of loyalty, confidentiality, and zealous repres

5. Fees and Billing 5.1 Hourly Rates Legal services rendered by the Firm in connection with this engagement will be billed on an hourly basis at the Firm's standard rates for the professionals assigned to the matter. As of the date of this Engagement Letter, the applicable blended hourly rates are as follows: The foregoing rates reflect the Firm's standard rates for engagements of this nature and complexity. The Firm

6. Conflicts of Interest The Firm has conducted a comprehensive conflicts check in accordance with its internal procedures and the applicable Rules of Professional Conduct. Based on that review, the Firm confirms that, as of the date of this Engagement Letter, it has no existing or prior client relationships with any of the following persons or entities that would create a conflict of interest with respect to this en

7. Confidentiality All information provided to the Firm by or on behalf of the Special Committee in connection with this engagement, including, without limitation, documents, memoranda, communications (whether oral or written), deliberations, analyses, strategies, and work product (collectively, "Confidential Information"), will be treated by the Firm as strictly confidential and privileged. The Firm will take all re

8. Independence and Information Barriers The Firm acknowledges the critical importance of its independence as counsel to the Special Committee. The independence of the Special Committee and its advisors is a foundational element of the process by which the Special Committee will evaluate the Proposed Transaction, and is essential to establishing the procedural protections necessary to withstand judicial scrutiny unde

9. Termination Either the Special Committee or the Firm may terminate this engagement at any time, with or without cause, upon written notice to the other party. In the case of a termination initiated by the Firm, the Firm will take such steps as are reasonably necessary to protect the Special Committee's interests during the transition period, including facilitating the transfer of the engagement to successor counse

10. Document Retention The Firm will maintain engagement files, including electronic and paper records, in accordance with its standard document retention policies, which provide for the retention of closed-matter files for a period of not less than ten (10) years following the conclusion of the engagement, subject to applicable law and ethical obligations. Upon the conclusion of the engagement, the Special Committee

11. Limitation of Engagement The Firm's engagement is limited to the matters described in Section 2 (Scope of Engagement) of this Engagement Letter. Without limiting the generality of the foregoing, the Special Committee acknowledges and agrees as follows: (a) The Firm is not engaged to provide tax advice to the Special Committee, the Company, or any stockholder of the Company or Caliston. The Firm may, in the course

12. Governing Law This Engagement Letter shall be governed by and construed in accordance with the laws of the Commonwealth of Pennsylvania, without regard to conflict-of-laws principles that would require the application of the laws of any other jurisdiction. Any dispute arising out of or relating to this Engagement Letter or the Firm's engagement hereunder shall be resolved in accordance with the applicable rules a

13. Acceptance and Execution We are grateful for the Special Committee's confidence in retaining Calderwood & Harkness LLP for this important engagement, and we look forward to working with you throughout the evaluation of the Proposed Transaction. We are committed to providing the highest quality legal services and to supporting the Special Committee in the discharge of its fiduciary duties. Please confirm the Speci

1. Conflicts Clearance Memorandum (dated June 1, 2023)

2. W-9 and Wire Transfer Instructions for Retainer Payment cc: Bernard Crawford, Calderwood & Harkness LLP cc: Sophie Tremblay, Calderwood & Harkness LLP cc: Daniel Obi, Calderwood & Harkness LLP Timekeeper Category | Blended Hourly Rate Partners | $1,025.00 Associates | $625.00