Contract analysis

I. PURPOSE AND BACKGROUND A. Purpose of This Memorandum This memorandum establishes the independence protocol and information barrier policy (the "Protocol") governing the evaluation by the Special Committee (defined below) of the Board of Directors (the "Board") of Penterra Pharmaceuticals Corp. (NYSE: PPHR), a Delaware corporation headquartered at 400 Innovation Drive, Suite 1200, Princeton, NJ 08540 (the "Company"

II. DEFINITIONS As used in this Protocol, the following terms shall have the meanings set forth below. Terms defined elsewhere in this Protocol and not listed below shall have the meanings assigned to them where defined. "Caliston" means Caliston BioSciences, Inc., a Delaware corporation with principal offices at 88 Harbor Point Road, Cambridge, MA 02142. "Caliston Counsel" means Whitfield Graves LLP, One Federal Str

III. EXCLUDED PERSONS — IDENTIFICATION AND RECUSAL REQUIREMENTS A. Identification of Excluded Persons The following individuals have been identified as Excluded Persons by reason of the conflicts of interest described in Section I.B above. Each Excluded Person is subject to the recusal and information barrier obligations set forth in this Section III and in Section IV below.

1. Dr. Marcus Hale — Chairman and Chief Executive Officer of Penterra Pharmaceuticals Corp. Dr. Hale holds a twenty-eight and one-half percent (28.5%) equity interest in Caliston BioSciences, Inc., acquired through personal investment of approximately $42 million across Caliston's Seed, Series A, and Series B financing rounds. Dr. Hale has served as a board observer (non-voting) at Caliston since 2018, attending four

2. Angela Whitmore — Non-independent director of Penterra and Executive Vice President, Commercial Operations. Ms. Whitmore is the spouse of Dr. Evan Whitmore, who serves as Head of Clinical Development at Caliston and as a member of Caliston's board of directors. By reason of this spousal relationship, Ms. Whitmore has a material interest in the outcome of the Proposed Transaction and lacks independence for purposes

3. Raymond Tusk — Non-independent director of Penterra. Mr. Tusk was appointed to the Board at the recommendation of Dr. Hale. Mr. Tusk lacks independence for purposes of the Special Committee by reason of his longstanding personal and professional relationship with Dr. Hale, which the Board has determined would impair Mr. Tusk's ability to exercise independent judgment with respect to the Proposed Transaction. The i

1. No Attendance or Participation. Excluded Persons shall not attend, participate in, or observe any meeting or deliberation of the Special Committee, whether held in person, by telephone, by videoconference, or by any other means of communication. This prohibition applies to formal meetings, informal discussions, and any other gathering at which the Special Committee's work in connection with the Proposed Transactio

2. No Access to Materials. Excluded Persons shall not receive, review, or have access to any materials, memoranda, analyses, correspondence, presentations, draft agreements, term sheets, valuation models, due diligence reports, board books, or other documents prepared for, by, or at the direction of the Special Committee or the Special Committee Advisors in connection with the Proposed Transaction. This prohibition e

3. No Summaries or Updates. Excluded Persons shall not receive or be provided any oral or written summaries, reports, briefings, or updates regarding the substance of the Special Committee's deliberations, analyses, findings, or conclusions, except as expressly authorized in Section VI below (Board Reporting Protocol). Permissible communications under the Board Reporting Protocol are limited to procedural and ministe

4. No Communications Regarding Substance. Excluded Persons shall not communicate with any Special Committee Member, any member of the Special Committee Advisors, or any Penterra employee or agent acting at the direction of the Special Committee regarding the substance of the Special Committee's evaluation, negotiation strategy, valuation analysis, legal advice received, or deliberations. This prohibition applies to a

5. No Influence. Excluded Persons shall not attempt to influence, directly or indirectly, the Special Committee's evaluation, recommendation, or decision-making with respect to the Proposed Transaction. This prohibition encompasses, without limitation, any effort to pressure, persuade, lobby, threaten, incentivize, or otherwise attempt to shape the outcome of the Special Committee's process, whether through communica

6. Voting and Recusal Agreement. Dr. Hale has executed a separate Voting and Recusal Agreement dated June 2, 2023, formalizing the foregoing obligations and providing that Dr. Hale shall abstain from voting on any matter related to the Proposed Transaction when the matter comes before the full Board. Ms. Whitmore and Mr. Tusk are required to recuse themselves from voting on the Proposed Transaction pursuant to the Bo

IV. INFORMATION BARRIER POLICY A. Establishment of Information Barrier An information barrier (the "Wall") is hereby established, effective as of June 2, 2023, separating the Inside Group from the Outside Group. The Wall is designed to prevent the flow of confidential information relating to the Special Committee's work—including its analyses, strategy, deliberations, and conclusions—from the Inside Group to the Outs

1. Project Coriander Workspace All documents, memoranda, analyses, correspondence, draft agreements, term sheets, presentations, meeting materials, minutes, notes, and other records created, received, or maintained in connection with the Special Committee's evaluation of the Proposed Transaction (collectively, "Special Committee Materials") shall be stored exclusively in the Project Coriander Workspace on Penterra's

2. Physical Documents Physical copies of Special Committee Materials shall be maintained under the custody of Calderwood & Harkness LLP at its offices at 1700 Market Street, Suite 3400, Philadelphia, PA 19103. Calderwood & Harkness LLP shall maintain such physical materials in a secure location within its offices, with access limited to the members of the Calderwood & Harkness LLP engagement team identified herein. T

3. Separate Email and Communication Channels Special Committee-related communications shall be conducted through dedicated, segregated communication channels to prevent inadvertent disclosure of Special Committee Materials or deliberation content to Excluded Persons or other unauthorized persons. The following protocols shall govern electronic communications: (a) Calderwood & Harkness LLP shall establish a dedicated

1. Scheduling. Meetings shall be scheduled by Independent Counsel in coordination with the Chair. Notice of each meeting shall be provided to all Special Committee Members and Special Committee Advisors through the Project Coriander Distribution Group or another secure communication channel. Meeting notices shall not be distributed through Penterra's regular board portal or administrative systems if such systems are

2. Location. Meetings shall be held at Calderwood & Harkness LLP's offices at 1700 Market Street, Suite 3400, Philadelphia, PA 19103; by secure videoconference using a platform designated by Calderwood & Harkness LLP; or at other locations outside Penterra's headquarters as determined by the Chair in consultation with Independent Counsel. If, for logistical reasons, a meeting must be held at Penterra's offices, the m

3. Attendance. No Excluded Person shall be present at any Special Committee meeting, whether in person or by telephone, videoconference, or any other means. No Excluded Person shall join any call or videoconference of the Special Committee. Attendance at Special Committee meetings shall be limited to: (a) Special Committee Members; (b) members of the Calderwood & Harkness LLP engagement team; (c) representatives of T

4. Minutes. Formal minutes of all Special Committee meetings shall be prepared by Calderwood & Harkness LLP (Daniel Obi, Working Associate) and maintained in the Project Coriander Workspace. Minutes shall document the date, time, location, and attendees of each meeting; the matters discussed and actions taken; any resolutions adopted; and any other matters that Independent Counsel determines should be documented to p

V. COMMUNICATION PROTOCOLS A. Communications Among Inside Group Members Special Committee Members may communicate freely with each other and with Special Committee Advisors regarding any aspect of the Proposed Transaction, including valuation, due diligence findings, negotiation strategy, legal analysis, and the Special Committee's preliminary or final conclusions. There is no restriction on the frequency, subject ma

VI. BOARD REPORTING PROTOCOL A. Permissible Reporting to the Full Board The Special Committee may, at its discretion and in consultation with Independent Counsel, provide periodic status updates to the full Penterra Board, including the Excluded Persons, regarding the progress of the Special Committee's work. Such status updates are intended to keep the full Board apprised of the general status of the evaluation at a

VII. INFORMATION REQUEST PROTOCOL — INTERACTIONS WITH PENTERRA MANAGEMENT A. General Principle The Special Committee recognizes that it may require factual information, data, and operational context from Penterra Management—including, in certain instances, from the Excluded Persons—to conduct a thorough and informed evaluation of the Proposed Transaction. Penterra Management possesses institutional knowledge regardin

VIII. PROCEDURES FOR HANDLING INADVERTENT DISCLOSURES A. Definition of Inadvertent Disclosure An "Inadvertent Disclosure" occurs when any Special Committee Material, deliberation content, negotiation strategy, legal advice, valuation analysis, or other confidential information that is subject to the Wall is disclosed to an Excluded Person or another member of the Outside Group, whether orally, in writing, electronica