D Molecular Therapeutics Reports Financial Results for the Year Ended

4D Molecular Therapeutics Reports Financial Results for the Year Ended December 31, 2020

and Provides Operational Highlights

- First patient dosed in the 4D-310 Phase 1/2 clinical trial in Fabry disease

- Intravitreal product candidates, 4D-125 for the treatment of XLRP and 4D-110 for the treatment

of choroideremia, completed dose escalation portion of Phase 1/2 clinical

trials (n=12 patients)

- Intravitreal product candidate 4D-150 for the treatment of wet AMD

initiate clinical trial in the second half of 2021

- Cash and cash equivalents of approximately $277M as of Dec 31, 2020

Emeryville, CA March 25, 2021 4D Molecular Therapeutics (Nasdaq: FDMT), a clinical-stage gene therapy company harnessing the power of

directed evolution for targeted gene therapies, announced financial results for the year ended December 31, 2020 and provided operational highlights.

2020 was a transformational year for 4D Molecular Therapeutics, said David Kirn, M.D., Co-founder and

Chief Executive Officer of 4DMT. We transitioned into a clinical-stage company, with three product candidates currently in clinical development: 4D-125 for

X-linked retinitis pigmentosa, 4D-110 for choroideremia, and 4D-310 for Fabry disease. In addition, we strengthened our

leadership team and corporate governance, with the addition of key clinical development executives and four experienced board members, including our Executive Chairman John Milligan, Ph.D. With the proceeds from our IPO, we raised the capital

necessary to expand our vision for developing transformative next-generation gene therapies in multiple therapeutic areas for both rare and large market diseases.

Recent Operational Highlights

Expected Upcoming Milestones

Financial Results for the Year Ended December 31, 2020

Cash and Cash Equivalents: Cash and cash equivalents was $276.7 million as of December 31, 2020, as compared to $49.7 million as of

December 31, 2019. The increase in cash and cash equivalents was primarily a result of the proceeds received from the December 2020 initial public offering and the issuance of our Series C redeemable convertible preferred stock in the second

quarter of 2020, which was partially offset by cash used in operations. We expect cash and cash equivalents to be sufficient to fund operations into mid-2023.

Revenue: Total revenue was $13.6 million for the year ended December 31, 2020, as compared to $7.0 million for the year ended

December 31, 2019. The increase was primarily driven by the recognition of revenue under the Roche collaboration agreement entered into in 2017.

R&D Expenses: Research and development expenses were $53.0 million for the year ended December 31, 2020, as compared to

$38.7 million for the year ended December 31, 2019. This increase was primarily due to higher external costs incurred to advance our clinical and preclinical programs and higher payroll and stock-based compensation expenses.

G&A Expenses: General and administrative expenses were $17.2 million for the year ended

December 31, 2020, as compared to $13.9 million for the year ended December 31, 2019. This increase was primarily due to higher payroll and stock-based compensation expenses and higher professional service expenses.

Net Loss: Net loss was $56.7 million for the year ended December 31, 2020, as compared to $49.3 million for the year ended

clinical-stage company harnessing the power of directed evolution for targeted gene therapies. 4DMT seeks to unlock the full potential of gene therapy using its platform, Therapeutic Vector Evolution, which combines the power of directed evolution

with approximately one billion synthetic capsid sequences to invent evolved vectors for use in targeted gene therapy products. The company is initially focused in three therapeutic areas: ophthalmology, cardiology, and pulmonology. The 4DMT targeted

and evolved vectors are invented with the goal of being delivered through clinically routine, well-tolerated and minimally invasive routes of administration, transducing diseased cells in target tissues efficiently, having reduced immunogenicity

and, where relevant, having resistance to pre-existing antibodies. 4DMT is currently conducting three clinical trials: 4D-125 is in a Phase 1/2 clinical trial for XLRP

patients, 4D-110 is in a Phase 1 clinical trial for choroideremia patients and 4D-310 is in a Phase 1/2 clinical trial for Fabry disease patients.

4D Molecular Therapeutics , 4DMT ,

Therapeutic Vector Evolution , and the 4DMT logo are trademarks of 4DMT.

Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation

Reform Act of 1995, as amended, including, without limitation, implied and express statements regarding plans and timelines for the clinical development of 4D-310,

4D-125, 4D-110, 4D-150 and 4D-710, including the therapeutic potential and clinical

benefits thereof; the estimated timing of clinical data being available for 4D-125 s Phase 1/2 clinical trial and 4D-310 s Phase 1/2 clinical trial; the

estimated timing of initiating the clinical trials for 4D-150 and 4D-710; expectations on how long our cash and cash equivalents can fund operations; expectations

regarding current and future interactions with the U.S. Food and Drug Administration (FDA); and 4D Molecular Therapeutics strategy, business plans and focus. The words may, might, will, could,

would, should, expect, plan,

anticipate, intend, believe, expect, estimate, seek, predict, future, project,

potential, continue, target and similar words or expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking

statements in this press release are based on management s current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those

expressed or implied by any forward-looking statements contained in this press release, including, without limitation, risks associated with: the impact of COVID-19 on countries or regions in which we have

operations or do business, as well as on the timing and anticipated results of our clinical trials, strategy and future operations; the delay of any current or planned clinical trials for the development of 4D Molecular Therapeutics drug

candidates, the risk that the results of our clinical trials may not be predictive of future results in connection with future clinical trials; 4D Molecular Therapeutics ability to successfully demonstrate the safety and efficacy of its drug

candidates; the timing and outcome of our planned interactions with regulatory authorities; and obtaining, maintaining and protecting our intellectual property. These and other risks and uncertainties are described in greater detail in the section

entitled Risk Factors in 4D Molecular Therapeutics most recent Annual Report on Form 10-K to be filed on the date hereof, as well as any subsequent filings with the Securities and Exchange

Commission. In addition, any forward-looking statements represent 4D Molecular Therapeutics views only as of today and should not be relied upon as representing its views as of any subsequent date. 4D Molecular Therapeutics explicitly

disclaims any obligation to update any forward-looking statements. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements.

4D-310, 4D-125 and 4D-110 are our

product candidates in clinical trials and have not yet been approved for marketing by the US FDA or any other regulatory authority. No representation is made as to the safety or effectiveness of 4D-310, 4D-125, or 4D-110 for the therapeutic use for which they are being studied.

4D Molecular Therapeutics, Inc.

Condensed Statements of Operations and Comprehensive Loss

(in thousands, except share and per share amounts)

4D Molecular Therapeutics, Inc.

Condensed Balance Sheet Data