Contract analysis

1. Purpose of Memorandum This memorandum documents the conflict check procedures undertaken and the results obtained in connection with the proposed engagement of Calderwood & Harkness LLP ("C&H" or the "Firm") as issuer's counsel to Penterra Pharmaceuticals Corp. ("PPC" or "Penterra") in a registered selling-stockholder secondary offering of shares of PPC common stock (the "Offering"). The Offering will consist of t

2. Conflict Check Methodology The Firm conducted a comprehensive conflict check in accordance with its standard New Matter Intake ("NMI") procedures. The following steps were taken on September 5, 2023, prior to execution of the engagement letter: 2.1 Database Search. All parties, principals, and affiliated entities identified in connection with the proposed engagement were submitted to the Firm's conflicts database

3. Parties Searched and Results Set forth below is a detailed summary of each party searched, including full identifying information, the party's role in the proposed transaction, and the results of the conflict check. 3.1 The Issuer — Penterra Pharmaceuticals Corp. Key Individuals Searched: • Dr. Marco Castellano — Chief Executive Officer • Lisa Hargrove — Chief Financial Officer • David Orenstein — General Counsel

4. Analysis of Potential Issues Although all parties have been cleared through the Firm's conflict check system, three matters warrant additional discussion to ensure that the record is complete and that the responsible partners are informed of circumstances that, while not giving rise to any conflict, merit awareness and documentation. 4.1 Prior Representation of Ridgeline Securities LLC As noted in Section 3.3 abov

5. Clearance Determination Based on the conflict check procedures described in Section 2 and the detailed party-by-party results set forth in Section 3, and taking into account the analysis of potential issues discussed in Section 4, the undersigned has determined the following:

1. All parties identified in connection with the proposed engagement of C&H as issuer's counsel to Penterra Pharmaceuticals Corp. in the selling-stockholder secondary offering have been cleared through the Firm's conflict check system (NMIS).

2. No current client conflict exists within the meaning of NYRPC Rule 1.7. None of the parties on the opposite side of the transaction from PPC — including the underwriters, the Selling Stockholders, or their respective counsel — is a current client of C&H.

3. No former client conflict exists within the meaning of NYRPC Rule 1.9. While C&H previously represented Ridgeline Securities LLC on two unrelated, closed matters, the proposed representation of PPC is not the same as, or substantially related to, either prior matter, and no material adversity exists between PPC and Ridgeline in this transaction.

4. No imputed conflict exists within the meaning of NYRPC Rule 1.10. No member of the proposed deal team has a personal conflict that would be imputed to the Firm.

5. No ethical walls, information barriers, or screening protocols are required or recommended in connection with this engagement.

6. No waivers of conflict or informed consents from any party are required.

7. The matter is cleared to proceed.

6. Recommendation Based on the foregoing analysis, the undersigned recommends as follows: The engagement of Calderwood & Harkness LLP as issuer's counsel to Penterra Pharmaceuticals Corp. in connection with the selling-stockholder secondary offering described herein is approved from a conflicts perspective. No impediment to the Firm's representation of PPC in this transaction has been identified. The engagement lette

7. Certification and Approval This conflict check memorandum was prepared by the undersigned in accordance with the Firm's New Matter Intake procedures and is submitted for review and approval by the responsible partner. Prepared by: BRENDAN WALSH Associate, Capital Markets Group Calderwood & Harkness LLP Signature: ________ Date: September 5, 2023 Reviewed and Approved by: JENNIFER KWON Partner, Capital Markets Grou