Viridian Therapeutics Highlights Recent Progress and Reports Fourth Quarter and Full Year 2023 Financial Results - VRDN-001 Phase 3 THRIVE and THRIVE-2 topline clinical data readouts are expected for mid-year 2024 and ye

Viridian Therapeutics Highlights Recent Progress and Reports Fourth Quarter and Full Year 2023 Financial

- VRDN-001 Phase 3 THRIVE and THRIVE-2

topline clinical data readouts are expected for mid-year 2024 and year-end 2024, respectively -

- Subcutaneous VRDN-003 pivotal program in thyroid eye disease expected to start mid-year 2024 pending regulatory authority alignment, as previously shared -

- Fc receptor (FcRn)

inhibitors are on track with VRDN-006 Investigational New Drug Application (IND) submission anticipated by year-end 2024 and

VRDN-008 non-human primate data expected in the second half of 2024 -

- Year-end 2023 cash balance of approximately $477.4 million; in January 2024, raised

approximately $150 million in gross proceeds from a public offering which extended the company s operating runway into the second half of 2026 -

WALTHAM, Mass., February 27, 2024 Viridian Therapeutics, Inc. (NASDAQ: VRDN), a biotechnology company focused on discovering and

developing potential best-in-class medicines for serious and rare diseases, today reported recent business highlights and financial results for the fourth quarter and

full year ended December 31, 2023.

Throughout 2023, we delivered important clinical results across our TED portfolio, marking significant

progress for the company, said Steve Mahoney, Viridian President and Chief Executive Officer. We also unveiled our FcRn inhibitor portfolio in October 2023. I would like to thank the Viridian team for their commitment throughout this

past year as we work towards our mission of delivering potential best-in-class medicines for patients with serious rare and autoimmune diseases. The momentum we

generated throughout 2023 has placed us in a strong position to execute on our upcoming 2024 milestones across our TED and FcRn inhibitor portfolios.

Thyroid Eye Disease Portfolio: VRDN-001 and VRDN-003

FcRn Inhibitor Portfolio: VRDN-006 and VRDN-008

In October 2023, Viridian unveiled its development of a portfolio of engineered FcRn inhibitors, including VRDN-006 and VRDN-008. FcRn inhibitors have the potential to treat a broad array of autoimmune diseases. Viridian s multi-pronged engineering approach has resulted in a

portfolio of FcRn-targeting molecules that leverage the clinically and commercially validated mechanism of FcRn inhibition while potentially addressing the limitations of current agents.

Recent Financing Activity & Runway Extension

UPCOMING PRESENTATIONS AT

Viridian plans to present encore VRDN-001 Phase 2 clinical data and Phase 3 clinical trial designs via

two abstracts at the 50th Annual Meeting of the North American Neuro-Ophthalmology Society (NANOS) to be held March 2-7, 2024 in Honolulu, Hawaii. Following

NANOS, the presentations will be available at www.viridiantherapeutics.com/pipeline/scientific-presentations.

CORPORATE HIGHLIGHTS

About Viridian Therapeutics

Viridian is a biopharmaceutical company focused on engineering and developing potential best-in-class medicines for patients with serious and rare diseases. Viridian s expertise in antibody discovery and protein engineering enables the development of differentiated therapeutic candidates

for previously validated drug targets in commercially established disease areas.

Viridian is advancing multiple candidates in the clinic for the

treatment of patients with thyroid eye disease (TED). The company is conducting two global Phase 3 clinical trials (THRIVE and THRIVE-2) to evaluate the safety and efficacy of

VRDN-001 in patients with active and chronic TED. Viridian s goal is to advance VRDN-001 as a potential best-in-class intravenous therapy followed by VRDN-003 as a potential first- and

best-in-class subcutaneous therapy for the treatment of TED.

to its TED portfolio, Viridian is advancing a novel portfolio of neonatal Fc receptor (FcRn) inhibitors, including VRDN-006 and VRDN-008, which has the potential to be

developed in multiple autoimmune diseases.

Viridian is based in Waltham, Massachusetts. For more information, please visit

www.viridiantherapeutics.com. Follow Viridian on LinkedIn and X.

Forward Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements may be

identified by the use of words such as, but not limited to, anticipate, believe, continue, could, estimate, expect, intend, may, might,

plan, potential, predict, project, should, target, will, or would or other similar terms or expressions that concern our expectations, plans and

intentions. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on our current beliefs, expectations, and assumptions. Forward-looking statements include, without limitation,

statements regarding: preclinical and clinical development of Viridian s product candidates VRDN-001, VRDN-003, VRDN-006 and

VRDN-008; anticipated start dates of studies, including those related to the VRDN-003 pivotal program; alignment with regulatory authorities and anticipated regulatory

submissions; enrollment in Viridian s clinical studies, including the THRIVE and THRIVE-2 Phase 3 clinical studies; upcoming milestones and anticipated data results, including topline results; the

potential utility, efficacy, potency, safety, clinical benefits, clinical response and convenience of VRDN-001, VRDN-003,

VRDN-006 and VRDN-008; Viridian s product candidates potentially being

best-in-class; that pharmacokinetic modeling predicts that convenient dosing regimens of VRDN-003 (e.g., a subcutaneous injection

once every two, four, or eight weeks) could achieve exposure levels of VRDN-003 that are equivalent to the exposure levels of VRDN-001 that produced clinically

meaningful results in TED; potential dosing schedules and trial designs; the Company s expected cash, cash equivalents and short-term investments of $645.7 million as of January 31, 2024; and that the company s cash, cash

equivalents and short-term investments will be sufficient to fund its operations into the second half of 2026. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. No

representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. Such forward-looking statements are subject to a number of material risks and uncertainties including but not limited to:

potential utility, efficacy, potency, safety, clinical benefits, clinical response and convenience of Viridian s product candidates; the relationship between the results from the positive data from completed or ongoing clinical trials and the

results of ongoing or future clinical trials; that preliminary data may not be representative of final data; the timing, progress and plans for our ongoing or future research, preclinical and clinical development programs; trial protocols for

ongoing clinical trials; expectations regarding the timing for regulatory filings; expectations regarding the timing for enrollment and data; uncertainty and potential delays related to clinical drug development; the duration and impact of

regulatory delays in our clinical programs; the timing of and our ability to obtain and maintain regulatory approvals for our therapeutic candidates; manufacturing risks; competition from other therapies or products; estimates of market size; other

matters that could affect the sufficiency of existing cash, cash equivalents and short-term investments to fund operations; our financial position and projected cash runway; our future operating results and financial performance; Viridian s

intellectual property position; the timing of preclinical and clinical trial activities and reporting results from same, including those risks set forth under the caption Risk Factors in our most recent quarterly report on Form 10-Q

filed with the Securities and Exchange Commission (SEC) on November 13, 2023 and other subsequent disclosure documents filed with the SEC. Any forward-looking statement speaks only as of the date on which it was made. Neither the company, nor

its affiliates, advisors, or representatives, undertake any obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by law. These forward-looking

statements should not be relied upon as representing the company s views as of any date subsequent to the date hereof.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(amounts in thousands, except share and per share data)

Viridian Therapeutics, Inc.

Selected Financial Information

Condensed Condolidated Balance Sheets

(amounts in thousands)

Louisa Stone, 617-272-4604

Manager, Investor Relations