X0306 4 2021-08-27 0 0001785345 Landos Biopharma, Inc. LABP 0001224962 PERCEPTIVE ADVISORS LLC 51 ASTOR PLACE, 10TH FLOOR NEW YORK NY 10003 1 0 1 0 0001249675 PERCEPTIVE LIFE SCIENCES MASTER FUND LTD C/O PERCEPTIVE ADVISORS LLC 51 ASTOR PLACE, 10TH FLOOR NEW YORK NY 10003 1 0 0 0 0001757940 Perceptive Xontogeny Venture Fund, LP 51 ASTOR PLACE, 10TH FLOOR NEW YORK NY 10003 1 0 0 0 0001164426 EDELMAN JOSEPH C/O PERCEPTIVE ADVISORS LLC 51 ASTOR PLACE, 10TH FLOOR NEW YORK NY 10003 1 0 0 0 Stock Option (Right to Buy) 14.18 2021-08-27 4 A 0 25291 0.00 A 2031-08-26 Common stock 25291 25291 I See Footnotes The shares of common stock underlying this option will vest and become exercisable in 36 equal monthly installments beginning on August 27, 2021, subject to the Fred Callori's continuous service with the Issuer on each such date. Consists of a proportionate interest in stock options awarded to Mr. Callori in connection with his role as a member of the Issuer's Board of Directors. Mr. Callori serves as a partner of Perceptive Xontogeny Venture Funds. Perceptive Advisors LLC may be deemed to have an indirect pecuniary interest in the securities reported herein because the Advisor has the right to receive the director compensation provided in respect of Mr. Callori's board service through a partial management fee offset. Each of the Reporting Persons disclaims, for purposes of Section 16 of the Securities Exchange Act of 1934, beneficial ownership of such securities, except to the extent of his/its indirect pecuniary interest therein, and this report shall not be deemed an admission that any of the Reporting Persons is the beneficial owner of such securities for purposes of Section 16 or for any other purposes. /s/ Joseph Edelman for Perceptive Advisors LLC, By: Joseph Edelman, its managing member 2021-08-31 /s/ Joseph Edelman for Perceptive Life Sciences Master Fund LTD, By: Perceptive Advisors LLC, its investment manager, by Joseph Edelman, its managing member 2021-08-31 /s/ Joseph Edelman for Perceptive Xontogeny Venture Fund L.P., By: Perceptive Xontogeny Ventures GP, LLC, its general partner, By: Joseph Edelman, its managing member 2021-08-31 /s/ Joseph Edelman 2021-08-31