EXPLANATORY NOTE
Viridian Therapeutics, Inc. (the “Registrant” or “we”) registered, pursuant to a Registration Statement on Form
S-8 filed on November 24, 2020 (Registration No. 333-250906) (the “2020 Plan Registration Statement”), 1,810,948 shares of our Common Stock, par
value $0.01 per share (“Common Stock”), under the Viridian Therapeutics, Inc. 2020 Stock Incentive Plan (the “2020 Plan”).
We also registered, pursuant to a Registration Statement on Form
S-8 filed on February 16, 2017 (Registration No. 333-216112) (the “2008 Plan Registration Statement”), 2,311,015 shares of our Common Stock, par
value $0.01 per share (“Common Stock”), under the Miragen Therapeutics, Inc. 2008 Equity Incentive Plan (the “2008 Plan” and together with the 2020 Plan, the “Prior Plans”).
Our board of directors approved the Viridian Therapeutics, Inc. Amended and Restated 2016 Equity Incentive Plan (the “2016 Plan”) on
April 18, 2022 and such plan was subsequently approved by our stockholders on June 8, 2022. Pursuant to the terms of the 2016 Plan, the following shares of Common Stock will be issuable under the 2016 Plan: (i) any shares of Common
Stock that remain available for grant under the 2020 Plan as of June 8, 2022 and (ii) any shares of Common Stock subject to outstanding awards under the Prior Plans as of June 8, 2022 that on or after June 8, 2022 are forfeited,
terminated, expire or otherwise lapse without being exercised (to the extent applicable), or are settled in cash.
Pursuant to the
undertakings in Item 9 of the 2020 Plan Registration Statement and Item 9 of the 2008 Plan Registration Statement , we are filing this Post-Effective Amendment No. 1 to the 2020 Plan Registration Statement and 2008 Plan Registration Statement
to provide that such registration statements shall also cover the 928,205 shares of Common Stock representing (i) the 928,049 shares of Common Stock that remain available for grant under the 2020 Plan as of June 8, 2022; (ii) the 0 shares
of Common Stock subject to outstanding awards under the 2020 Plan as of June 8, 2022 that on or after June 8, 2022 are forfeited, terminated, expire or otherwise lapse without being exercised (to the extent applicable), or are settled in
cash and that thus are or become issuable under the 2016 Plan; and (iii) the 156 shares of Common Stock subject to outstanding awards under the 2008 Plan as of June 8, 2022 that on or after June 8, 2022 are forfeited, terminated,
expire or otherwise lapse without being exercised (to the extent applicable), or are settled in cash and that thus are or become issuable under the 2016 Plan.