OrbiMed Discloses Stake in Upstream Bio, Inc.

TL;DR

OrbiMed just filed a 13D on Upstream Bio, Inc. - big pharma investor stake.

AI Summary

On October 15, 2024, OrbiMed Advisors LLC and its affiliates filed a Schedule 13D regarding their beneficial ownership of Upstream Bio, Inc. The filing indicates that OrbiMed Advisors LLC, along with OrbiMed Capital GP VIII LLC, OrbiMed Israel GP II, L.P., and OrbiMed Advisors Israel II Limited, collectively hold a significant stake in Upstream Bio, Inc. The specific percentage of ownership and any recent transactions are detailed within the full filing.

Why It Matters

This filing signals a significant investment or change in control interest by a major healthcare-focused investment firm in Upstream Bio, Inc., potentially impacting the company's strategic direction and valuation.

Risk Assessment

Risk Level: medium — Schedule 13D filings often indicate a significant stake or potential activist interest, which can introduce uncertainty and volatility for the subject company.

Key Players & Entities

• Upstream Bio, Inc. (company) — Subject company
• OrbiMed Advisors LLC (company) — Filing entity
• OrbiMed Capital GP VIII LLC (company) — Affiliated filing entity
• OrbiMed Israel GP II, L.P. (company) — Affiliated filing entity
• OrbiMed Advisors Israel II Limited (company) — Affiliated filing entity
• October 15, 2024 (date) — Date of event

FAQ

Key Financial Figures

• $0.001 — 1,695 shares of common stock, par value $0.001 per share, outstanding of Upstream Bio,
• $17.00 — . The purchase price for each Share was $17.00. As a result of the IPO, the Issuer's t
• $10.00 — 000 Series A Shares, each at a price of $10.00 per Series A Share. In October 2022, A
• $5 m — of offering expenses, of not less than $5 million, in which case the Issuer will be
• $1 m — , net of offering expenses, of at least $1 million, in which case the Issuer will be

Filing Documents

• ss4005698_sc13d.htm (SC 13D) — 132KB
• ss4005698_ex9901.htm (EX-99.1) — 7KB
• 0000947871-24-000805.txt ( ) — 141KB

Security and Issuer

Item 1. Security and Issuer This Statement on Schedule 13D (this " Statement ") relates to the common stock, par value $0.001 per share (the " Shares "), of Upstream Bio, Inc., a corporation organized under the laws of Delaware (the " Issuer "), with its principal executive offices located at 890 Winter Street, Suite 200, Waltham, MA 02451 . The Shares are listed on the NASDAQ Global Select Market under the ticker symbol "UPB". Information given in response to each item shall be deemed incorporated by reference in all other items, as applicable. On October 15, 2024, the Issuer completed its initial public offering pursuant to which the Issuer agreed to issue and sell 15,000,000 Shares to the participants in the offering (the " IPO "). In addition, the Issuer granted the underwriters of the IPO an option to purchase, at the public offering price less any underwriting discounts and commissions, up to an additional 2,250,000 Shares. The purchase price for each Share was $17.00. As a result of the IPO, the Issuer's total number of outstanding Shares increased to 51,341,695 (without giving effect to the additional 2,250,000 shares that may be issued and sold by the Issuer to the underwriters pursuant to the underwriters' option).

Identity and Background

Item 2. Identity and Background (a) This Statement is being filed by OrbiMed Advisors LLC (" OrbiMed Advisors "), OrbiMed Capital GP VIII LLC, (" GP VIII "), OrbiMed Advisors Israel II Limited (" Advisors II "), and OrbiMed Israel GP II, L.P. (" Israel GP ") (collectively, the " Reporting Persons "). (b) — (c), (f) OrbiMed Advisors, a limited liability company organized under the laws of Delaware and a registered investment adviser under the Investment Advisers Act of 1940, as amended, is the managing member or general partner of certain entities as more particularly described in Item 6 below. OrbiMed Advisors has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022. GP VIII, a limited liability company organized under the laws of Delaware, is the general partner of a limited partnership, as more particularly described in Item 6 below. GP VIII has its principal offices at 601 Lexington Avenue, 54th Floor, New York, New York 10022. Advisors II, an exempted company organized under the laws of the Cayman Islands, is the general partner of Israel GP. Advisors II has its principal offices at 5 Hahoshlim Street, Building B, 1st Floor, Herzliya Pituach, Israel. Israel GP, an exempted limited partnership organized under the laws of the Cayman Islands, is the general partner of a limited partnership, as more particularly described in Item 6 below, Israel GP has its principal offices at 5 Hahoshlim Street, Building B, 1st Floor, Herzliya Pituach, Israel. The directors and executive officers of OrbiMed Advisors, GP VIII, Advisors II, and Israel GP are set forth on Schedules I, II, III, and IV, respectively, attached hereto. Schedules I through IV set forth the following information with respect to each such person: (i) name; (ii) business address; (iii) present principal occupation of employment and the name, principal business and address of any corporation or other organization in which such employment is conducted; and (iv) citizens

Source and Amount of Funds or Other Consideration

Item 3. Source and Amount of Funds or Other Consideration In October 2021, Advisors II and Israel GP, pursuant to their authority under the limited partnership agreement of OrbiMed Israel Partners II, L.P. (" OIP II "), as more particularly described in Item 6 below, caused OIP II to purchase 275,000 shares of the Issuer's Series A redeemable convertible preferred stock (" Series A Shares ") and OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OrbiMed Private Investments VIII, L.P. (" OPI VIII "), as more particularly described in Item 6 below, caused OPI VIII to purchase 1,100,000 Series A Shares, each at a price of $10.00 per Series A Share. In October 2022, Advisors II and Israel GP, pursuant to their authority under the limited partnership agreement of OIP II, and OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OPI VIII, caused OIP II and OPI VIII to purchase 225,000 and 900,000 Series A Shares, respectively, at a price of $10.00 per Series A Share. In June 2023, Advisors II and Israel GP, pursuant to their authority under the limited partnership agreement of OIP II, and OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OPI VIII, caused OIP II and OPI VIII to purchase 47,058 and 188,235 shares of the Issuer's Series B redeemable convertible preferred stock (" Series B Shares "), respectively, at a price of $17.00 per Series B Share. In April 2024, Advisors II and Israel GP, pursuant to their authority under the limited partnership agreement of OIP II, and OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OPI VIII, caused OIP II and OPI VIII to purchase 141,176 and 564,705 Series B Shares, respectively, at a price of $17.00 per Series B Share. Each Series A Share and Series B Share automatically converted into Shares on a one-for-1.049 basis immediately

Purpose of Transaction

Item 4. Purpose of Transaction This Statement relates to the acquisition of Shares by the Reporting Persons. The Shares acquired by the Reporting Persons were acquired for the purpose of making an investment in the Issuer and not with the intention of acquiring control of the Issuer's business on behalf of the Reporting Persons' respective advisory clients. The Reporting Persons from time to time intend to review their investment in the Issuer on the basis of various factors, including the Issuer's business, financial condition, results of operations and prospects, general economic and industry conditions, the securities markets in general and those for the Issuer's Shares in particular, as well as other developments and other investment opportunities. Based upon such review, the Reporting Persons will take such actions in the future as the Reporting Persons may deem appropriate in light of the circumstances existing from time to time. If the Reporting Persons believe that further investment in the Issuer is attractive, whether because of the market price of Shares or otherwise, they may acquire Shares or other securities of the Issuer either in the open market or in privately negotiated transactions. Similarly, depending on market and other factors, the Reporting Persons may determine to dispose of some or all of the Shares currently owned by the Reporting Persons or otherwise acquired by the Reporting Persons either in the open market or in privately negotiated transactions. Except as set forth in this Schedule 13D, the Reporting Persons have not formulated any plans or proposals which relate to or would result in: (a) the acquisition by any person of additional securities of the Issuer or the disposition of securities of the Issuer, (b) an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Issuer or any of its subsidiaries, (c) a sale or transfer of a material amount of the assets of the Issuer or any of its su

Interest in Securities of the Issuer

Item 5. Interest in Securities of the Issuer (a) — (b) The following is based upon 51,341,695 Shares outstanding following the closing of the IPO, as set forth in the Issuer's Rule 424(b)(4) Prospectus filed with the Securities and Exchange Commission on October 11, 2024, without giving effect to an additional 2,250,000 Shares that may be issued and sold by the Issuer to the underwriters pursuant to the underwriters' option. As of the date of this filing, OPI VIII, a limited partnership organized under the laws of Delaware, holds 4,554,873 Shares, constituting approximately 8.9% of the issued and outstanding Shares. GP VIII is the general partner of OPI VIII, pursuant to the terms of the limited partnership agreement of OPI VIII, and OrbiMed Advisors is the managing member of GP VIII, pursuant to the terms of the limited liability company agreement of GP VIII. As a result, OrbiMed Advisors and GP VIII share power to direct the vote and disposition of the Shares held by OPI VIII and may be deemed directly or indirectly, including by reason of their mutual affiliation, to be the beneficial owners of the Shares held by OPI VIII. OrbiMed Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the Shares held by OPI VIII. In addition, OrbiMed Advisors and GP VIII, pursuant to their authority under the limited partnership agreement of OPI VIII, caused OPI VIII to enter into the agreements referred to in Item 6 below. As of the date of this filing, OIP II, an exempted limited partnership organized under the laws of the Cayman Islands, holds 1,138,716 Shares, constituting approximately 2.2% of the issued and outstanding Shares. Israel GP is the general partner of OIP II, pursuant to the terms of the limited partnership agreement of OIP II, and Advisors II is the general partner of Israel GP, pursuant to the terms of the limited part

Contracts, Arrangements, Understandings or Relationships

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, GP VIII is the general partner of OPI VIII, pursuant to the terms of the limited partnership agreement of OPI VIII. Pursuant to this agreement and relationship, GP VIII has discretionary investment management authority with respect to the assets of OPI VIII. Such authority includes the power to vote and otherwise dispose of securities held by OPI VIII. The number of outstanding Shares of the Issuer attributable to OPI VIII is 4,554,873 Shares. GP VIII, pursuant to its authority under the limited partnership agreement of OPI VIII, may be considered to hold indirectly 4,554,873 Shares. In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, OrbiMed Advisors is the managing member of GP VIII, pursuant to the terms of the limited liability company agreement of GP VIII. Pursuant to this agreement and relationship, OrbiMed Advisors and GP VIII have discretionary investment management authority with respect to the assets of OPI VIII. Such authority includes the power of GP VIII to vote and otherwise dispose of securities held by OPI VIII. The number of outstanding Shares attributable to OPI VIII is 4,554,873 Shares. OrbiMed Advisors, pursuant to its authority under the terms of the limited liability company agreement of GP VIII may also be considered to hold indirectly 4,554,873 Shares. In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, Israel GP is the general partner of OIP II, pursuant to the terms of the limited partnership agreement of OIP II, and Advisors II is the general partner of Israel GP, pursuant to the terms of the limited partnership agreement of Israel GP. Pursuant to these agreements and relationships, Advisors II and Israel GP have discretionary investment management

Material to Be Filed as Exhibits

Item 7. Material to Be Filed as Exhibits Exhibit Description 1. Joint Filing Agreement among OrbiMed Advisors LLC, OrbiMed Capital GP VIII LLC, OrbiMed Advisors Israel II Limited, and OrbiMed Israel GP II, L.P. 2. Amended and Restated Investors' Rights Agreement, among the Issuer and certain of its stockholders, dated June 6, 2023 (incorporated by reference to Exhibit 4.2 to the Issuer's Registration Statement on Form S-1/A (File No. 333-282197) filed with the SEC on October 7, 2024). 3. Form of Lock-Up Agreement (incorporated by reference to Exhibit A to Exhibit 1.1 to the Issuer's Registration Statement on Form S-1/A (File No. 333-282197) filed with the SEC on October 7, 2024). Signature After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Dated: October 17, 2024 ORBIMED ADVISORS LLC By: /s/ Carl L. Gordon Name: Carl L. Gordon Title: Member ORBIMED CAPITAL GP VIII LLC By: ORBIMED ADVISORS LLC, its managing member By: /s/ Carl L. Gordon Name: Carl L. Gordon Title: Member of OrbiMed Advisors LLC ORBIMED ADVISORS ISRAEL II LIMITED By: /s/ Carl L. Gordon Name: Carl L. Gordon Title: Director ORBIMED ISRAEL GP II, L.P. By: ORBIMED ADVISORS ISRAEL II LIMITED., its general partner By: /s/ Carl L. Gordon Name: Carl L. Gordon Title: Director of OrbiMed Advisors Israel II Limited SCHEDULE I The names and present principal occupations of each of the executive officers and directors of OrbiMed Advisors LLC are set forth below. Unless otherwise noted, each of these persons is a United States citizen and has a business address of 601 Lexington Avenue, 54 th Floor, New York, NY 10022. Name Position with Reporting Person Principal Occupation Carl L. Gordon Member Member OrbiMed Advisors LLC Sven H. Borho German and Swedish Citizen Member Member OrbiMed Advisors LLC W. Carter Neild Member Member

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View this SC 13D filing on SEC EDGAR