UNDERWRITING AGREEMENT — COMPILED EXECUTED SIGNATURE PAGES

UNDERWRITING AGREEMENT — COMPILED EXECUTED SIGNATURE PAGES
Underwriting Agreement dated October 12, 2023
Selling-Stockholder Secondary Offering of 6,250,000 Shares of Common Stock Par Value $0.001 Per Share of PENTERRA PHARMACEUTICALS CORP.
Public Offering Price: $41.60 per share Aggregate Offering Size (Base): $260,000,000
Prepared by: Calderwood & Harkness LLP One Liberty Plaza, 52nd Floor New York, NY 10006 Telephone: (212) 558-4000 Facsimile: (212) 558-3588
The following pages constitute the compiled executed signature pages to the Underwriting Agreement dated as of October 12, 2023 (the "Underwriting Agreement"), among Penterra Pharmaceuticals Corp., a Delaware corporation (the "Company" or the "Issuer"), the Selling Stockholders named therein, and the several Underwriters named in Schedule I thereto, for which Ridgeline Securities LLC is acting as the Representative of the several Underwriters. This compilation has been prepared by Calderwood & Harkness LLP, counsel to the Company, in connection with the closing of the secondary offering of 6,250,000 shares of common stock, par value $0.001 per share (the "Shares"), of the Company at a public offering price of $41.60 per share. The Underwriting Agreement, together with the Schedules attached thereto, sets forth the terms and conditions governing the purchase by the several Underwriters, severally and not jointly, of the Shares from the Selling Stockholders. Each signature page reproduced herein has been executed by the applicable party and delivered to Calderwood & Harkness LLP on or before the date of the Underwriting Agreement.
All capitalized terms used but not otherwise defined herein shall have the meanings ascribed to such terms in the Underwriting Agreement.
SIGNATURE PAGE 1 — ISSUER
PENTERRA PHARMACEUTICALS CORP.
As Issuer
The undersigned, duly authorized to act on behalf of Penterra Pharmaceuticals Corp., a Delaware corporation (the "Company"), hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of the Company set forth in the Underwriting Agreement are true and correct as of the date hereof.
Company Address:
Penterra Pharmaceuticals Corp. 400 Meridian Parkway, Suite 1200 Princeton, NJ 08540
Attention: Lisa Hargrove, Chief Financial Officer
Telephone: (609) 555-3200
Email: lhargrove@penterra.com
PENTERRA PHARMACEUTICALS CORP.
By: /s/ Lisa Hargrove
________________________________________
Name: Lisa Hargrove
Title: Chief Financial Officer
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Penterra Pharmaceuticals Corp. (Issuer)]
SIGNATURE PAGE 2 — SELLING STOCKHOLDER
SELLING STOCKHOLDERS
The undersigned Selling Stockholder hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of such Selling Stockholder set forth in the Underwriting Agreement are true and correct as of the date hereof, including without limitation the representations and warranties relating to such Selling Stockholder's ownership of, and authority to sell, the Shares set forth opposite such Selling Stockholder's name in Schedule II to the Underwriting Agreement.
Base Shares to be offered by this Selling Stockholder: 3,000,000 shares of Common Stock
Over-Allotment Shares subject to option: Up to 450,000 additional shares of Common Stock
/s/ Dr. Elena Castellano
________________________________________
Name: Dr. Elena Castellano
Capacity: Individually, as Selling Stockholder
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Dr. Elena Castellano (Selling Stockholder)]
SIGNATURE PAGE 3 — SELLING STOCKHOLDER
SELLING STOCKHOLDERS (continued)
The undersigned Selling Stockholder hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of such Selling Stockholder set forth in the Underwriting Agreement are true and correct as of the date hereof, including without limitation the representations and warranties relating to such Selling Stockholder's ownership of, and authority to sell, the Shares set forth opposite such Selling Stockholder's name in Schedule II to the Underwriting Agreement.
Base Shares to be offered by this Selling Stockholder: 2,500,000 shares of Common Stock
Over-Allotment Shares subject to option: Up to 375,000 additional shares of Common Stock
/s/ Dr. Riccardo Castellano
________________________________________
Name: Dr. Riccardo Castellano
Capacity: Individually, as Selling Stockholder
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Dr. Riccardo Castellano (Selling Stockholder)]
SIGNATURE PAGE 4 — SELLING STOCKHOLDER
SELLING STOCKHOLDERS (continued)
The undersigned Selling Stockholder hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of such Selling Stockholder set forth in the Underwriting Agreement are true and correct as of the date hereof, including without limitation the representations and warranties relating to such Selling Stockholder's ownership of, and authority to sell, the Shares set forth opposite such Selling Stockholder's name in Schedule II to the Underwriting Agreement.
Base Shares to be offered by this Selling Stockholder: 500,000 shares of Common Stock
Over-Allotment Shares subject to option: Up to 75,000 additional shares of Common Stock
/s/ Dr. Marco Castellano
________________________________________
Name: Dr. Marco Castellano
Capacity: Individually, as Selling Stockholder
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Dr. Marco Castellano (Selling Stockholder)]
SIGNATURE PAGE 5 — SELLING STOCKHOLDER (ENTITY)
CASTELLANO FAMILY HOLDINGS LLC
As Selling Stockholder
The undersigned, duly authorized to act on behalf of Castellano Family Holdings LLC, a Delaware limited liability company, in its capacity as Selling Stockholder, hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of such Selling Stockholder set forth in the Underwriting Agreement are true and correct as of the date hereof, including without limitation the representations and warranties relating to such Selling Stockholder's ownership of, and authority to sell, the Shares set forth opposite such Selling Stockholder's name in Schedule II to the Underwriting Agreement.
Base Shares to be offered by this Selling Stockholder: 250,000 shares of Common Stock
Over-Allotment Shares subject to option: Up to 37,500 additional shares of Common Stock
Entity Address:
Castellano Family Holdings LLC c/o Penterra Pharmaceuticals Corp. 400 Meridian Parkway, Suite 1200 Princeton, NJ 08540
CASTELLANO FAMILY HOLDINGS LLC
By: /s/ Dr. Marco Castellano
________________________________________
Name: Dr. Marco Castellano
Title: Manager
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Castellano Family Holdings LLC (Selling Stockholder)]
SIGNATURE PAGE 6 — UNDERWRITERS (REPRESENTATIVE)
UNDERWRITERS
RIDGELINE SECURITIES LLC as Representative of the several Underwriters named in Schedule I to the Underwriting Agreement and on behalf of itself
The undersigned, on behalf of itself and as Representative of the several Underwriters named in Schedule I to the Underwriting Agreement, hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of the Underwriters, and of the Representative on behalf of the several Underwriters, set forth in the Underwriting Agreement are true and correct as of the date hereof. By executing this Underwriting Agreement as Representative, the undersigned confirms its authority to act on behalf of each of the several Underwriters listed in Schedule I to the Underwriting Agreement, each of which has authorized the Representative to execute and deliver the Underwriting Agreement on its behalf.
Address for notices:
Ridgeline Securities LLC 383 Madison Avenue New York, NY 10017
Attention: Equity Capital Markets — Syndicate Desk
Telephone: (212) 555-7000 Facsimile: (212) 555-7001
RIDGELINE SECURITIES LLC as Representative of the several Underwriters
By: /s/ Jonathan Pryce-Hall
________________________________________
Name: Jonathan Pryce-Hall
Title: Managing Director
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Ridgeline Securities LLC (Lead Left Book-Running Manager, as Representative of the Several Underwriters)]
SIGNATURE PAGE 7 — UNDERWRITERS (JOINT BOOK-RUNNING MANAGER)
BROADMARK CAPITAL INC.
Joint Book-Running Manager
The undersigned, on its own behalf and as one of the several Underwriters named in Schedule I to the Underwriting Agreement, hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of the Underwriters set forth in the Underwriting Agreement, to the extent applicable to the undersigned, are true and correct as of the date hereof. The undersigned acknowledges and agrees that the Representative is authorized to act on its behalf in connection with the transactions contemplated by the Underwriting Agreement.
Address for notices:
Broadmark Capital Inc. 200 Park Avenue New York, NY 10166
Attention: Equity Capital Markets
Telephone: (212) 555-4500 Facsimile: (212) 555-4501
BROADMARK CAPITAL INC.
By: /s/ Samuel Okonkwo
________________________________________
Name: Samuel Okonkwo
Title: Managing Director
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Broadmark Capital Inc. (Joint Book-Running Manager)]
SIGNATURE PAGE 8 — UNDERWRITERS (CO-MANAGER)
LINDEN GROVES & CO.
Co-Manager
The undersigned, on its own behalf and as one of the several Underwriters named in Schedule I to the Underwriting Agreement, hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of the Underwriters set forth in the Underwriting Agreement, to the extent applicable to the undersigned, are true and correct as of the date hereof. The undersigned acknowledges and agrees that the Representative is authorized to act on its behalf in connection with the transactions contemplated by the Underwriting Agreement.
Address for notices:
Linden Groves & Co. 745 Fifth Avenue New York, NY 10151
Attention: Capital Markets Group
Telephone: (212) 555-8800 Facsimile: (212) 555-8801
LINDEN GROVES & CO.
By: /s/ Authorized Signatory
________________________________________
Name: ________
Title: Managing Director
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Linden Groves & Co. (Co-Manager)]
SIGNATURE PAGE 9 — UNDERWRITERS (CO-MANAGER)
HARBORVIEW PARTNERS LLC
Co-Manager
The undersigned, on its own behalf and as one of the several Underwriters named in Schedule I to the Underwriting Agreement, hereby executes and delivers this Underwriting Agreement as of the date set forth below, and confirms that all representations, warranties, covenants, and agreements of the Underwriters set forth in the Underwriting Agreement, to the extent applicable to the undersigned, are true and correct as of the date hereof. The undersigned acknowledges and agrees that the Representative is authorized to act on its behalf in connection with the transactions contemplated by the Underwriting Agreement.
Address for notices:
Harborview Partners LLC 1 Federal Street Boston, MA 02110
Attention: Equity Syndicate
Telephone: (617) 555-2200 Facsimile: (617) 555-2201
HARBORVIEW PARTNERS LLC
By: /s/ Authorized Signatory
________________________________________
Name: ________
Title: Managing Director
Date: October 12, 2023
[Signature Page to Underwriting Agreement — Harborview Partners LLC (Co-Manager)]
SCHEDULE I
UNDERWRITERS AND THEIR RESPECTIVE COMMITMENTS
The following table sets forth the names of the several Underwriters and the number of Base Shares that each has severally agreed to purchase from the Selling Stockholders pursuant to Section 2 of the Underwriting Agreement, at a purchase price to the Underwriters of $40.56 per share (the public offering price of $41.60 per share less the underwriting discount of $1.04 per share), subject to the terms and conditions set forth in the Underwriting Agreement.
Pricing Summary:
Over-Allotment Option:
The Selling Stockholders have granted to the several Underwriters an option, exercisable for a period of 30 days from the date of the Prospectus, to purchase up to an additional 937,500 shares of Common Stock (the "Option Shares") at the price to the Underwriters set forth above, solely to cover over-allotments, if any. If the over-allotment option is exercised in full or in part, the Option Shares shall be allocated among the several Underwriters pro rata in accordance with the percentage allocations set forth above, as follows:
In the event of a partial exercise of the over-allotment option, the Option Shares to be purchased by each Underwriter shall be determined by the Representative, provided that each Underwriter's allocation shall be approximately proportional to its percentage allocation set forth in the table above.
SCHEDULE II
SELLING STOCKHOLDERS AND THEIR RESPECTIVE SHARE ALLOCATIONS
The following table sets forth, with respect to each Selling Stockholder: (i) the number of shares of Common Stock beneficially owned by such Selling Stockholder immediately prior to the offering; (ii) the number of Base Shares to be sold by such Selling Stockholder in the offering; (iii) the maximum number of Option Shares that may be sold by such Selling Stockholder upon exercise of the over-allotment option; and (iv) the number of shares of Common Stock to be beneficially owned by such Selling Stockholder immediately following the completion of the offering (assuming full exercise of the over-allotment option).
Notes to Schedule II:
1.  Beneficial ownership is determined in accordance with Rule 13d-3 under the Securities Exchange Act of 1934, as amended. The number of shares beneficially owned by each Selling Stockholder includes shares held directly by such Selling Stockholder and shares over which such Selling Stockholder has sole or shared voting or dispositive power, but does not include any shares issuable upon the exercise of stock options or the vesting of restricted stock units that are not exercisable or do not vest within 60 days of the date of the Underwriting Agreement.
2.  Dr. Marco Castellano serves as the Manager of Castellano Family Holdings LLC. The shares listed as beneficially owned by Dr. Marco Castellano in the table above do not include the shares beneficially owned by Castellano Family Holdings LLC. Dr. Marco Castellano disclaims beneficial ownership of the shares held by Castellano Family Holdings LLC, except to the extent of his pecuniary interest therein.
3.  In the event the over-allotment option is not exercised or is exercised only in part, the number of shares owned post-offering by each Selling Stockholder will be greater than the amounts shown in the "Shares Owned Post-Offering (Full Exercise)" column by the number of Option Shares not sold by such Selling Stockholder.
4.  The allocation of Option Shares among the Selling Stockholders shall be determined in accordance with Section 2(b) of the Underwriting Agreement, which provides for allocation on a pro rata basis based on each Selling Stockholder's proportion of the total Option Shares, unless otherwise agreed by the Selling Stockholders and the Representative.
5.  Each of the Selling Stockholders listed above has entered into a lock-up agreement with the Representative, dated as of October 12, 2023, restricting the sale or other disposition of shares of Common Stock for a period of 90 days following the date of the Prospectus, subject to certain customary exceptions as set forth in such lock-up agreement.
CERTIFICATION OF COMPILATION
CALDERWOOD & HARKNESS LLP One Liberty Plaza, 52nd Floor New York, NY 10006
I, Brendan Walsh, a partner of Calderwood & Harkness LLP, counsel to Penterra Pharmaceuticals Corp. (Nasdaq: PNTR; CUSIP 70831X 10 5) (the "Company"), hereby certify as follows:
1.  The foregoing pages constitute true and complete copies of all executed signature pages to the Underwriting Agreement dated as of October 12, 2023 (the "Underwriting Agreement"), among Penterra Pharmaceuticals Corp., a Delaware corporation, the Selling Stockholders named therein, and the several Underwriters named in Schedule I thereto, for which Ridgeline Securities LLC acts as the Representative of the several Underwriters.
2.  The Underwriting Agreement governs the offering of 6,250,000 shares of common stock, par value $0.001 per share (the "Shares"), of Penterra Pharmaceuticals Corp. at a public offering price of $41.60 per share, for an aggregate base offering size of $260,000,000. The Selling Stockholders have also granted the Underwriters an over-allotment option to purchase up to an additional 937,500 shares of common stock.
3.  Each executed signature page set forth herein was received by Calderwood & Harkness LLP on or before October 12, 2023, and each such signature page bears the genuine signature of the individual or authorized signatory identified thereon.
4.  The trade date for the offering is October 12, 2023. The settlement date for the offering is October 17, 2023 (T+3), with delivery of the Shares against payment in immediately available funds through the facilities of The Depository Trust Company.
5.  The Underwriting Agreement is governed by, and shall be construed in accordance with, the laws of the State of Delaware, without regard to conflicts of law principles thereof that would result in the application of the law of any other jurisdiction.
6.  This certification is furnished in connection with the closing of the offering and is not intended to, and does not, constitute a legal opinion of Calderwood & Harkness LLP with respect to any matter.
Compiled and certified by:
/s/ Brendan Walsh
________________________________________
Brendan Walsh, Partner Calderwood & Harkness LLP One Liberty Plaza, 52nd Floor New York, NY 10006
Date of Compilation: October 12, 2023
This compilation of executed signature pages is confidential and is furnished solely for the use of the parties to the Underwriting Agreement and their respective counsel in connection with the closing of the offering. This compilation may not be reproduced, distributed, or disclosed to any third party without the prior written consent of Calderwood & Harkness LLP and the Company.
Underwriter | Role | Number of Base Shares | Percentage Allocation
Ridgeline Securities LLC | Lead Left Book-Running Manager / Representative | 2,812,500 | 45.00%
Broadmark Capital Inc. | Joint Book-Running Manager | 1,875,000 | 30.00%
Linden Groves & Co. | Co-Manager | 937,500 | 15.00%
Harborview Partners LLC | Co-Manager | 625,000 | 10.00%
Total | 6,250,000 | 100.00%
Item | Per Share | Total (Base Offering)
Public Offering Price | $41.60 | $260,000,000.00
Underwriting discount (2.50%) | $1.04 | $6,500,000.00
Price to Underwriters (Proceeds to Selling Stockholders) | $40.56 | $253,500,000.00
Underwriter | Maximum Option Shares
Ridgeline Securities LLC | 421,875
Broadmark Capital Inc. | 281,250
Linden Groves & Co. | 140,625
Harborview Partners LLC | 93,750
Total | 937,500
Selling Stockholder | Shares Owned Pre-Offering | Base Shares Offered | Maximum Over-Allotment Shares | Shares Owned Post-Offering (Full Exercise)
Dr. Elena Castellano | 14,200,000 | 3,000,000 | 450,000 | 10,750,000
Dr. Riccardo Castellano | 12,800,000 | 2,500,000 | 375,000 | 9,925,000
Dr. Marco Castellano | 4,500,000 | 500,000 | 75,000 | 3,925,000
Castellano Family Holdings LLC | 8,600,000 | 250,000 | 37,500 | 8,312,500
Total | 40,100,000 | 6,250,000 | 937,500 | 32,912,500