X0609 4 2026-06-15 0002114044 Hemab Therapeutics Holdings, Inc. COAG 0001346824 RA CAPITAL MANAGEMENT, L.P. false 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 false false true false 0001315082 RA Capital Healthcare Fund LP false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 1 0 0001384859 Kolchinsky Peter false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 1 0 0001619841 Shah Rajeev M. false C/O RA CAPITAL MANAGEMENT, L.P. 200 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 1 0 0 Common Stock 2026-06-15 4 P 0 6146 24.89 A 6383114 I See footnotes Common Stock 2026-06-16 4 P 0 61523 24.98 A 6444637 I See footnotes Common Stock 1009052 I See footnotes Common Stock 354938 I See footnotes The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $24.55 to $25.00 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote. RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus II Fund, L.P. (the "Nexus Fund II") and RA Capital Nexus IV Fund, L.P. (the "Nexus Fund IV"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, the Fund, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein. Held directly by the Fund. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $24.65 to $25.00 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote. Held directly by Nexus Fund II. Held directly by Nexus Fund IV. /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 2026-06-17 /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC the General Partner of RA Capital Healthcare Fund, L.P. 2026-06-17 /s/ Peter Kolchinsky, individually 2026-06-17 /s/ Rajeev Shah, individually 2026-06-17