X0306 4 2021-02-05 0 0001785345 Landos Biopharma, Inc. LABP 0001678736 Poukalov Konstantin C/O LANDOS BIOPHARMA, INC. 1800 KRAFT DRIVE, SUITE 216 BLACKSBURG VA 24060 1 0 1 0 Common Stock 2021-02-05 4 P 0 27453 11.14 A 14647181 I By funds Common Stock 2021-02-08 4 P 0 34611 11.38 A 14681792 I By funds Common Stock 2021-02-08 4 P 0 86671 12.53 A 14768463 I By funds Common Stock 2021-02-08 4 P 0 1771 13.10 A 14770234 I By funds Common Stock 2021-02-09 4 P 0 64730 13.80 A 14834964 I By funds Common Stock 2021-02-09 4 P 0 34951 14.60 A 14869915 I By funds The prices reported in Column 4 are weighted average prices. The reporting person undertakes 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 ranges of the prices reported on this Form 4. These shares were purchased in multiple transactions at prices ranging from $11.05 to $11.75, inclusive. Securities are held by Perceptive Life Sciences Master Fund, Ltd. ("PLSMF"), Perceptive Xontogeny Venture Fund, LP ("PXVF"), and PX Venture (A), LLC ("PXV"). Perceptive Advisors, LLC ("Perceptive Advisors") serves as the investment manager to PLSMF, PXVF, and PXV. The Reporting Person is a managing director of Perceptive Advisors. The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein. These shares were purchased in multiple transactions at prices ranging from $10.96 to $11.93, inclusive. These shares were purchased in multiple transactions at prices ranging from $11.96 to $12.95, inclusive. These shares were purchased in multiple transactions at prices ranging from $13.09 to $13.10, inclusive. These shares were purchased in multiple transactions at prices ranging from $13.17 to $14.16, inclusive. These shares were purchased in multiple transactions at prices ranging from $14.17 to $15.20, inclusive. /s/ Eric W. Blanchard, Attorney-in-Fact 2021-02-09