Contract analysis

1. Purpose and Background of Engagement Calderwood & Harkness LLP represents Penterra Pharmaceuticals Corp. ("Penterra" or "PPC"), a Delaware corporation publicly traded on the New York Stock Exchange under the ticker symbol PTPH, with its principal offices located at 480 Overlook Drive, Suite 700, Summit, New Jersey 07901. Penterra is a specialty pharmaceutical company focused on the development and commercializatio

2. Description of the OPDP Inquiry For purposes of establishing context for Whitfield Bauer's engagement, we summarize below the principal allegations set forth in the OPDP inquiry letter. We will provide the full text of the inquiry letter, together with copies of the cited promotional materials, under separate cover in accordance with the privilege protocol described in Section 6 of this letter. 2.1 Promotional Mat

3. Scope of Whitfield Bauer's Engagement Whitfield Bauer is engaged to serve as regulatory co-counsel and will provide services in the areas described below. The scope of this engagement is limited to the matters set forth in this Section 3, and any expansion of the scope of engagement shall require the prior written agreement of C&H and Whitfield Bauer and, as appropriate, the consent of Penterra. 3.1 OPDP Response

4. Staffing The following Whitfield Bauer attorneys are authorized to perform work on this matter: Any additional Whitfield Bauer personnel — whether attorneys, paralegals, or other staff — who may be needed to assist with this matter must be approved in advance by Leonard Cross, Responsible Partner at C&H, and, as necessary and appropriate, by Margaret Tan, EVP and General Counsel of Penterra, prior to commencing an

5. Billing and Fee Arrangements 5.1 Hourly Rates The following hourly rates shall apply to work performed by Whitfield Bauer attorneys on this matter: These rates are effective as of the date of this letter and shall remain in effect for the duration of this engagement unless modified by mutual written agreement of the parties. In the event that Whitfield Bauer implements a firm-wide rate increase during the term of

6. Privilege and Confidentiality The parties acknowledge and agree that all communications between C&H and Whitfield Bauer in connection with this matter are made for the purpose of providing coordinated legal advice to Penterra and are protected by the attorney-client privilege, the work-product doctrine, and the common-interest doctrine. Both firms are engaged to provide legal advice to Penterra with respect to the

7. Conflicts of Interest Whitfield Bauer confirms that it has conducted a thorough conflicts-of-interest check in accordance with its standard conflicts procedures and with the requirements of the applicable Rules of Professional Conduct. Based on that conflicts check, Whitfield Bauer represents and warrants as follows: (a) Whitfield Bauer has identified no conflicts of interest, whether actual or potential, that wou

8. Key Client Contacts The primary client contacts at Penterra Pharmaceuticals Corp. for this matter are as follows: • Margaret Tan, Executive Vice President & General Counsel • Christine Holloway, Vice President, Regulatory Affairs • Dr. Rajeev Anand, M.D., Ph.D., Chief Medical Officer All substantive communications with Penterra personnel regarding the OPDP inquiry or any other aspect of this matter shall be coordi

9. Duration and Termination This engagement shall commence upon the execution of this letter by both parties and shall continue until (a) the matter is resolved to the satisfaction of Penterra and C&H, (b) the engagement is terminated by either C&H or Whitfield Bauer upon written notice to the other party, or (c) Penterra directs the termination of Whitfield Bauer's engagement as co-counsel. In the event of terminati

10. Governing Law This engagement letter shall be governed by and construed in accordance with the laws of the State of New York, without regard to principles of conflicts of law. Both parties consent to the jurisdiction of the courts of the State of New York, and of the federal courts located in the Southern District of New York, for the resolution of any dispute arising out of or relating to this engagement letter.

11. Acceptance We look forward to working with you and your team on this matter. If the foregoing terms are acceptable, please indicate Whitfield Bauer's acceptance of this engagement by signing this letter in the space provided below and returning a signed copy to our offices. An executed copy may be returned by hand, by overnight courier, or by email (as a PDF scan) to Leonard Cross at lcross@calderwoodharkness.com