X0202 SCHEDULE 13G 0001906837 XXXXXXXX LIVE Common Stock, $0.0001 par value 06/30/2026 0001657677 Parabilis Medicines, Inc. 698955101 30 Acorn Park Drive Cambridge MA 02140 Rule 13d-1(d) ARCH Venture Fund XII, L.P. DE 0 6412780 0 6412780 6412780 N 5.3 PN ARCH Venture Partners XII, L.P. DE 0 6412780 0 6412780 6412780 N 5.3 PN ARCH Venture Partners XII, LLC DE 0 6412780 0 6412780 6412780 N 5.3 OO Robert Nelsen X1 0 6412780 0 6412780 6412780 N 5.3 IN Keith Crandell X1 0 6412780 0 6412780 6412780 N 5.3 IN Kristina Burow X1 0 6412780 0 6412780 6412780 N 5.3 IN Steven Gillis X1 0 6412780 0 6412780 6412780 N 5.3 IN Parabilis Medicines, Inc. 30 Acorn Park Drive, Cambridge, MA 02140 ARCH Venture Fund XII, L.P. ("AVF XII"); ARCH Venture Partners XII, L.P. ("AVP XII LP"); ARCH Venture Partners XII, LLC ("AVP XII LLC") (collectively, the "Reporting Entities" and individually, each a "Reporting Entity"); and Keith Crandell ("Crandell"), Robert Nelsen ("Nelsen"), Kristina Burow ("Burow") and Steven Gillis ("Gillis") (collectively, the "Investment Committee" and individually, each a "Committee Member"). The Reporting Entities and the Committee Members collectively are referred to as the "Reporting Persons." The Reporting Persons are filing this report with respect to shares of Common Stock, par value $0.0001 per share (the "Common Stock") of Parabilis Medicines, Inc. (the "Issuer"). The business address of each of the Reporting Persons is 8755 West Higgins Road, Suite 1025, Chicago, IL, 60631. AVF XII and AVP XII LP are limited partnerships organized under the laws of the State of Delaware. AVP XII LLC is a limited liability company organized under the laws of the State of Delaware. Each Committee Member is a US citizen. Y AVF XII is the record owner of 6,412,780 shares of Common Stock (the "Record Shares") as of June 30, 2026. AVP XII LP, as the sole general partner of AVF XII, may be deemed to beneficially own the Record Shares. AVP XII LLC, as the sole general partner of AVP XII, may be deemed to beneficially own the Record Shares. As Committee Members of AVP XII LLC, each Committee Member may also be deemed to share the power to direct the disposition and vote of the Record Shares. Each Reporting Person disclaims beneficial ownership of such shares of Common Stock except for the shares, if any, such Reporting Person holds of record. The information required by Item 4(b) is incorporated by reference to Row 11 of the cover pages hereto. The percentages set forth on the cover sheet for each Reporting Person are based upon 121,952,030 shares of Common Stock outstanding as of August 10, 2026, as reported by the Issuer in its Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 13, 2026. See row 5 of the cover pages. See row 6 of the cover pages. See row 7 of the cover pages. See row 8 of the cover pages. Y Y Y Y Y Y Exhibit 1 - Joint Filing Agreement ARCH Venture Fund XII, L.P. ARCH Venture Partners XII, L.P. 08/14/2026 ARCH Venture Partners XII, LLC 08/14/2026 /s/ Mark McDonnell* 08/14/2026 ARCH Venture Partners XII, L.P. ARCH Venture Partners XII, LLC 08/14/2026 /s/ Mark McDonnell* 08/14/2026 ARCH Venture Partners XII, LLC /s/ Mark McDonnell* 08/14/2026 Robert Nelsen /s/ Mark McDonnell* 08/14/2026 Keith Crandell /s/ Mark McDonnell* 08/14/2026 Kristina Burow /s/ Mark McDonnell* 08/14/2026 Steven Gillis /s/ Mark McDonnell* 08/14/2026 This Schedule 13G was executed by Mark McDonnell pursuant to a Power of Attorney filed as Exhibit 24 to the Form 3 relating to the beneficial ownership of shares of Neumora Therapeutics, Inc. by the Reporting Persons filed with the Securities and Exchange Commission on September 14, 2023 and incorporated herein in its entirety by reference.