Contract analysis

I. Purpose and Authorization This letter confirms that Calderwood & Harkness LLP ("C&H") has been engaged as outside tax counsel to represent Penterra Pharmaceuticals Corp. ("PPC") in connection with the examination of PPC's federal income tax returns (Forms 1120) for the tax years ending December 31, 2017, December 31, 2018, December 31, 2019, and December 31, 2020 (collectively, the "Examination"). We write in resp

1. Leonard Cross, Responsible Partner, Tax Department, Calderwood & Harkness LLP (admitted to practice in the States of New York and New Jersey, and the District of Columbia);

2. Sylvia Hartwell, Billing Partner, Tax Department, Calderwood & Harkness LLP (admitted to practice in the State of New York and the District of Columbia);

3. Garrett Simmons, Lead Associate, Tax Department, Calderwood & Harkness LLP (admitted to practice in the State of New York); and

4. Leila Nazari, Working Associate, Tax Department, Calderwood & Harkness LLP (admitted to practice in the States of New York and New Jersey). A copy of the executed Form 2848, as filed on June 8, 2022, is enclosed with this letter for your reference and records. We respectfully request that all future communications regarding the Examination—including, without limitation, all Information Document Requests ("IDRs"),

II. Confirmation of Opening Conference We write to confirm our understanding that an opening conference for the Examination is to be scheduled in the near term. C&H proposes that the opening conference be held during the week of June 27 through July 1, 2022, or at such other date and time as may be convenient for the Examination team. We are prepared to accommodate the team's scheduling preferences, and we ask that y

III. Identification of Taxpayer and Returns Under Examination For the record and to facilitate the efficient administration of the Examination, we set forth below certain identifying information regarding the taxpayer and the returns under examination: Taxpayer: Penterra Pharmaceuticals Corp. Employer Identification Number (EIN): 22-3741856 Entity Type: Corporation organized under the laws of the State of Delaware; p

IV. Key PPC Contacts The primary client contact for the Examination on behalf of PPC is: Marcus Whitfield Vice President of Global Tax Penterra Pharmaceuticals Corp. 2200 Independence Boulevard Princeton Junction, NJ 08550 Mr. Whitfield oversees PPC's internal tax function and will serve as the principal liaison between PPC's in-house tax department and C&H throughout the course of the Examination. PPC's General Coun

V. Preliminary Matters and Cooperation C&H and PPC are fully committed to cooperating with the Internal Revenue Service throughout the Examination process. PPC recognizes its obligations as a taxpayer under examination and intends to respond promptly, thoroughly, and in good faith to all IDRs and other requests issued by the Examination team. All such responses will be coordinated and submitted through C&H. In order

VI. Contact Information For purposes of the Examination, the primary contacts at C&H are as follows: Leonard Cross Partner, Tax Department Calderwood & Harkness LLP 1735 Market Street, Suite 3100 Philadelphia, PA 19103 Direct Telephone: (215) 574-8042 Email: leonard.cross@calderwoodharkness.com Garrett Simmons Lead Associate, Tax Department Calderwood & Harkness LLP 1735 Market Street, Suite 3100 Philadelphia, PA 191

VII. Closing We appreciate the IRS Examination team's cooperation and professionalism in connection with the opening of this Examination, and we are grateful for the team's willingness to schedule the opening conference at a mutually convenient time. We look forward to a productive, professional, and constructive examination process and are committed to working collaboratively with the Examination team toward the eff