Clearside Biomedical : 2024 Proxy Statement

CLEARSIDE BIOMEDICAL, INC.

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To Be Held On June 20, 2024

Dear Stockholder:

The Annual Meeting of Stockholders of Clearside Biomedical, Inc. (the "Company") will be held at the offices of the Company at 900 North Point Parkway, Suite 200, Alpharetta, Georgia 30005, on Thursday, June 20, 2024 at 8:00 a.m. local time for the following purposes:

1. To elect the Board's nominees, Richard Croarkin, William D. Humphries and Nancy J. Hutson, to the Board of Directors to hold office until the 2027 Annual Meeting of Stockholders.
2. To approve, on an advisory basis, the compensation of the Company's named executive officers, as disclosed in the proxy statement accompanying this Notice.
3. To ratify the selection by the Audit Committee of the Board of Directors of Ernst & Young LLP as independent registered public accounting firm, or auditors, for the year ending December 31, 2024.
4. To conduct any other business properly brought before the meeting, including any adjournments or postponements of the meeting.

These items of business are more fully described in the Proxy Statement accompanying this Notice. All stockholders are invited to attend the meeting in person. The record date for the Annual Meeting is April 22, 2024. Only stockholders of record at the close of business on that date are entitled to notice of and to vote at the meeting or any adjournment thereof.

	By Order of the Board of Directors,
	/s/ Charles Deignan
Alpharetta, Georgia	Charles Deignan
April 26, 2024	Chief Financial Officer

We are primarily providing access to our proxy materials over the internet pursuant to the Securities and Exchange Commission's notice and access rules. On or about April 26, 2024, we expect to mail to our stockholders a Notice of Internet Availability of Proxy Materials that will indicate how to access our 2024 Proxy Statement and 2023 Annual Report on the internet and will include instructions on how you can receive a paper copy of the annual meeting materials, including the notice of annual meeting, proxy statement and proxy card.

Whether or not you expect to attend the meeting in person, please submit voting instructions for your shares promptly using the directions on your Notice, or, if you elected to receive printed proxy materials by mail, your proxy card, to vote by one of the following methods: 1) over the internet at www.proxypush.com/CLSD, 2) by telephone by calling the toll-free number [phone], or 3) if you elected to receive printed proxy materials by mail, by marking, dating and signing your proxy card and returning it in the accompanying postage-paid envelope. Even if you have voted by proxy, you may still vote in person if you attend the meeting. Please note, however, that if your shares are held of record by a broker, bank or other nominee and you wish to vote at the meeting, you must obtain a proxy issued in your name from that record holder.

April 26, 2024

Dear Stockholders:

As we near the midpoint of 2024, I am excited to highlight our significant progress which has positioned Clearside for an important year. We believe the work we are doing has the potential to change the treatment paradigm for serious retinal diseases and leave a lasting positive impact for patients, physicians, and for you, our stockholders.

Leadership in Suprachoroidal Delivery

The increasing acceptance and adoption of suprachoroidal delivery over the last several years has been truly transformative for the ophthalmic industry. As the original pioneers in this space, we are proud that Clearside's technology has led the way for this important and innovative approach for delivery of drugs to the back of the eye, where various sight-threatening diseases occur.

Our suprachoroidal injection technology platform utilizes our patented SCS Microinjector®, combined with specialized drug formulations, to easily and safely deliver therapeutic agents to the suprachoroidal space ("SCS"). SCS administration provides targeted drug delivery to potentially improve efficacy and compartmentalization of medication to reduce or eliminate the possibility of unwanted effects on non-diseased cells. Our SCS Microinjector has been used in thousands of patient injections as a method for reliable, repeatable, in-officenon-surgical drug delivery. Most importantly, our SCS Microinjector has demonstrated a positive safety profile to date.

A critical difference between SCS delivery and intravitreal delivery is that SCS administration does not involve putting any drug, physical inserts, or gels into the vitreous. The suprachoroidal injection is potentially a safer mode of drug delivery, as it allows for drug to flow to the posterior segment of the eye, behind the patient's visual field. This limits the risk of vitreous floaters, vitreal or anterior chamber toxicity, or possibly impairing or interfering with a patient's vision. Recently published clinical research data indicates intravitreal drug delivery is a leading cause of endophthalmitis, a serious eye infection that can cause blindness. With SCS administration, there is potentially a much lower risk of endophthalmitis. To date, no cases of endophthalmitis have been reported related to the use of our SCS Microinjector.

Further, SCS delivery using our SCS Microinjector was validated with the FDA approval and subsequent commercial launch by Bausch & Lomb in the U.S. of our first product, XIPERE® (triamcinolone acetonide injectable suspension) for suprachoroidal use, for the treatment of macular edema associated with uveitis. Finally, I am pleased to report that as of January 1, 2024, our proprietary suprachoroidal injection procedure now has a permanent Category 1 CPT code assignment, which we believe facilitates better access, insurance coverage, and physician adoption for products using our injection procedure.

Differentiated Clinical Program in Wet AMD

Our lead clinical program, CLS-AX(axitinib-a tyrosine kinase inhibitor), is targeting the multi-billion-dollar market for wet AMD. This market continues to grow as a result of the aging population, particularly in the U.S. With higher demand, there is room for new treatments that may provide significant improvement over current therapies. While the currently approved therapies, including faricimab and high dose aflibercept, are effective, they are delivered intravitreally and only offer the potential of lasting up to four months in most patients. We believe suprachoroidal CLS-AX may extend the time between doses to meaningfully reduce the treatment burden for patients, caregivers and payors.

The data readout from our CLS-AX Phase 2b ODYSSEY clinical trial remains on track for the third quarter of this year. We expect the data to show that we can maintain visual acuity and allow the majority of participants to remain supplemental treatment-free for at least 4 months and potentially up to 6 months on CLS-AX. Notably, our 36-week study was designed to re-dose patients with CLS-AX at 6 months, which we anticipate will provide valuable data on patients treated with more than one dose of CLS-AX. We intend to leverage this data on the flexibility to repeat treatment for patients in a chronic disease, as we begin planning our CLS-AX Phase 3 clinical development program.

Value-Driving Collaborations

In addition to our two commercial and development partners for XIPERE, we have established multiple partnerships with leading biopharma companies who are utilizing our SCS Microinjector to deliver their therapeutics. During 2023, each of our SCS Microinjector licensing partners reported excellent progress in their later-stage clinical development programs. We are proud of the fact that there are now five different therapeutic assets in development, including gene-based therapy, utilizing our SCS Microinjector for suprachoroidal delivery for five different ophthalmic indications. These collaborations provide external validation of the utility and adaptability of our proprietary SCS injection technology platform and the significant contribution of suprachoroidal delivery to the treatment paradigm for retinal disorders.

Strong and Experienced Team

We have an outstanding team at Clearside that we have strategically added to over the past several months. In March of this year, we were excited to welcome Dr. Victor Chong as our Chief Medical Officer. Victor is a well- respected, board-certified retinal specialist with more than 25 years of experience advancing drug candidates through all stages of drug development, including the development of ranibizumab and aflibercept for wet AMD. Victor's extensive major pharmaceutical company experience, most recently as Vice President, Global Head of Retina at Johnson & Johnson, is extremely valuable as he spearheads our product development activities led by the upcoming ODYSSEY data analysis and the planning for our Phase 3 program.

In April, we added seasoned biotechnology executive, Tony Gibney, to our Board of Directors. Tony has a deep understanding of the biotechnology business, combined with recent and relevant ophthalmology experience at Iveric Bio. With broad expertise in business strategy, collaborations, finance, and M&A, Tony will provide critical insights and guidance for our strategic and business development initiatives as Clearside enters this next pivotal growth phase and explores value creating opportunities, including possible suprachoroidal pipeline expansion.

Looking Ahead

We expect 2024 will be a transformational year for Clearside. We believe that the data readout from the Phase 2b ODYSSEY trial will demonstrate that CLS-AX could be a valuable addition to the treatment regimen for patients with wet AMD. We are committed to maintaining our leadership role in the suprachoroidal space as we and our partners generate additional data demonstrating the benefits of drug delivery with our SCS Microinjector.

All of our stakeholders are vital to Clearside's success. We are grateful for the commitment and support of our stockholders as we navigate clinical, regulatory and market dynamics. In addition, I would like to express my deep appreciation to the physician investigators, study participants, and especially to our dedicated Clearside employees. Our substantial progress over the past several years in advancing the acceptance of suprachoroidal drug delivery demonstrates what is possible when we believe in our mission and our technology and remain steadfastly committed to developing innovative treatments that have the potential to improve outcomes for individuals living with sight-threatening diseases.

Sincerely,

George Lasezkay, Pharm.D., J.D.

President and Chief Executive Officer

TABLE OF CONTENTS
	Page
QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING	1
PROPOSAL NO. 1 - ELECTION OF DIRECTORS	6
NOMINEES FOR ELECTION FOR A THREE-YEARTERM EXPIRING AT THE 2027 ANNUAL
MEETING	6
DIRECTORS CONTINUING IN OFFICE UNTIL THE 2025 ANNUAL MEETING	8
DIRECTORS CONTINUING IN OFFICE UNTIL THE 2026 ANNUAL MEETING	9
INFORMATION REGARDING THE BOARD OF DIRECTORS AND CORPORATE
GOVERNANCE	10
INDEPENDENCE OF THE BOARD OF DIRECTORS	10
BOARD LEADERSHIP STRUCTURE	10
BOARD DIVERSITY	11
ROLE OF THE BOARD IN RISK OVERSIGHT	11
MEETINGS OF THE BOARD OF DIRECTORS	12
INFORMATION REGARDING COMMITTEES OF THE BOARD OF DIRECTORS	12
AUDIT COMMITTEE	12
Report of the Audit Committee of the Board of Directors	13
COMPENSATION COMMITTEE	13
NOMINATING AND CORPORATE GOVERNANCE COMMITTEE	15
STOCKHOLDER COMMUNICATIONS WITH THE BOARD OF DIRECTORS	16
CODE OF ETHICS	17
HEDGING POLICY	17
CLAWBACKS	17
PROPOSAL NO.2 - ADVISORY VOTE ON EXECUTIVE COMPENSATION	18
PROPOSAL NO.3 - RATIFICATION OF SELECTION OF INDEPENDENT AUDITORS	19
PRINCIPAL ACCOUNTANT FEES AND SERVICES	19
PRE-APPROVAL POLICIES AND PROCEDURES	19
INFORMATION ABOUT OUR EXECUTIVE OFFICERS	20
EXECUTIVE OFFICERS WHO ARE NOT DIRECTORS	20
SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT	21
EXECUTIVE COMPENSATION	23
SUMMARY COMPENSATION TABLE	23
NARRATIVE TO SUMMARY COMPENSATION TABLE	24
OUTSTANDING EQUITY AWARDS AS OF DECEMBER 31, 2023	27
EMPLOYMENT AGREEMENTS AND POTENTIAL PAYMENTS UPON TERMINATION OR CHANGE IN
CONTROL	28
PAY VERSUS PERFORMANCE	31
NON-EMPLOYEEDIRECTOR COMPENSATION	34
DIRECTOR COMPENSATION TABLE	34
NARRATIVE TO DIRECTOR COMPENSATION TABLE	34
SECURITIES AUTHORIZED FOR ISSUANCE UNDER EQUITY COMPENSATION PLANS . . . .	36
TRANSACTIONS WITH RELATED PERSONS	37
RELATED-PERSON TRANSACTIONS POLICY AND PROCEDURES	37
CERTAIN RELATED PERSON TRANSACTIONS	37
INDEMNIFICATION	38
HOUSEHOLDING OF PROXY MATERIALS	39
OTHER MATTERS	39

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Cautionary Note Regarding Forward-Looking Statements

This proxy statement contains forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements may be identified by words such as "believe", "expect", "may", "plan", "potential", "will", and similar expressions, and are based on Clearside's current beliefs and expectations. These forward-looking statements include statements regarding the clinical development of CLS-AX, the expected timing of topline results from the ODYSSEY clinical trial, Clearside's expectations regarding the results of the ODYSSEY clinical trial and the potential benefits of CLS-AX and other product candidates using Clearside's SCS Microinjector®. These statements involve risks and uncertainties that could cause actual results to differ materially from those reflected in such statements. Risks and uncertainties that may cause actual results to differ materially include uncertainties inherent in the conduct of clinical trials, Clearside's reliance on third parties over which it may not always have full control and other risks and uncertainties that are described in Clearside's Annual Report on Form 10-K for the year ended December 31, 2023, filed with the U.S. Securities and Exchange Commission ("SEC") on March 12, 2024 and Clearside's other Periodic Reports filed with the SEC.

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CLEARSIDE BIOMEDICAL, INC.

900 North Point Parkway, Suite 200

Alpharetta, Georgia 30005

PROXY STATEMENT

FOR THE 2024 ANNUAL MEETING OF STOCKHOLDERS

To Be Held on June 20, 2024

QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING

Why did I receive a notice regarding the availability of proxy materials on the internet?

Pursuant to rules adopted by the SEC, we have elected to provide access to our proxy materials over the internet. Accordingly, we have sent you a Notice of Internet Availability of Proxy Materials (the "Notice") because the Board of Directors (the "Board" or "Board of Directors") of Clearside Biomedical, Inc. (sometimes referred to as the "Company" or "Clearside") is soliciting your proxy to vote at the 2024 Annual Meeting of Stockholders, including at any adjournments or postponements of the meeting. All stockholders will have the ability to access the proxy materials on the website referred to in the Notice or request to receive a printed set of the proxy materials. Instructions on how to access the proxy materials over the internet or to request a printed copy may be found in the Notice.

We intend to mail the Notice on or about April 26, 2024 to all stockholders of record entitled to vote at the annual meeting.

How do I attend the annual meeting?

The meeting will be held on Thursday, June 20, 2024 at 8:00 a.m. local time at the offices of the Company at 900 North Point Parkway, Suite 200, Alpharetta, Georgia 30005. Information on how to vote in person at the annual meeting is discussed below.

Who can vote at the annual meeting?

Only stockholders of record at the close of business on April 22, 2024 will be entitled to vote at the annual meeting. On this record date, there were 74,731,139 shares of common stock outstanding and entitled to vote.

Stockholder of Record: Shares Registered in Your Name

If on April 22, 2024 your shares were registered directly in your name with Clearside's transfer agent, Equiniti Trust Company, LLC (formerly American Stock Transfer & Trust Company, LLC), then you are a stockholder of record. As a stockholder of record, you may vote in person at the meeting or vote by proxy. Whether or not you plan to attend the meeting, we urge you to fill out and return the enclosed proxy card or vote by proxy over the telephone or on the internet as instructed below to ensure your vote is counted.

Beneficial Owner: Shares Registered in the Name of a Broker or Bank

If on April 22, 2024 your shares were held, not in your name, but rather in an account at a brokerage firm, bank or other similar organization, then you are the beneficial owner of shares held in "street name" and the Notice is being forwarded to you by that organization. The organization holding your account is considered to be the stockholder of record for purposes of voting at the annual meeting. As a beneficial owner, you have the right to direct your broker, bank or other agent regarding how to vote the shares in your account. You are also invited to attend the annual meeting. However, because you are not the stockholder of record, you may not vote your shares in person at the meeting unless you request and obtain a valid proxy from your broker, bank or other agent.

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What am I voting on?

There are three matters scheduled for a vote:

• Proposal No. 1- Election of three directors;
• Proposal No. 2- Approval, on an advisory basis, of the compensation of our named executive officers, as disclosed in this proxy statement; and
• Proposal No. 3- Ratification of selection by the Audit Committee of the Board of Directors of Ernst & Young LLP as our independent registered public accounting firm for our year ending December 31, 2024.

What if another matter is properly brought before the meeting?

The Board of Directors knows of no other matters that will be presented for consideration at the Annual Meeting. If any other matters are properly brought before the meeting, it is the intention of the persons named in the accompanying proxy to vote on those matters in accordance with their best judgment.

How do I vote?

You may either vote "For" all of the nominees to the Board of Directors or you may "Withhold" your vote for any nominee you specify. For the other matters to be voted on, you may vote "For" or "Against" or abstain from voting.

The procedures for voting are:

Stockholder of Record: Shares Registered in Your Name

If you are a stockholder of record, you may vote in person at the Annual Meeting or vote by proxy in one of three ways: online, by telephone or using a proxy card that you may request or that we may elect to deliver at a later time. Whether or not you plan to attend the meeting, we urge you to vote by proxy to ensure your vote is counted. You may still attend the Annual Meeting and vote in person even if you have already voted by proxy.

• To vote online, go to www.proxypush.com/CLSD. You will be asked to provide the Company number and control number from the Notice. Your vote must be received by 5:00 p.m. Eastern Time on June 19, 2024 to be counted.
• To vote over the telephone, dial toll-free [phone]. You will be asked to provide the Company number and control number from the Notice. Your vote must be received by 5:00 p.m. Eastern Time on June 19, 2024 to be counted.
• To vote by mail if you requested printed proxy materials, you can vote by promptly completing and returning your signed proxy card in the envelope provided. You should mail your signed proxy card sufficiently in advance for it to be received by June 19, 2024.
• To vote in person, come to the Annual Meeting, and we will give you a ballot when you arrive.

Beneficial Owner: Shares Registered in the Name of Broker or Bank

If you are a beneficial owner of shares registered in the name of your broker, bank or other agent, you should have received a Notice containing voting instructions from that organization rather than from us. Please follow the voting instructions in the Notice to ensure that your vote is counted. To vote in person at the Annual Meeting, you must obtain a valid proxy from your broker, bank or other agent. Follow the instructions from your broker, bank or other agent included with the proxy materials, or contact that organization to request a proxy form.

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How many votes do I have?

On each matter to be voted upon, you have one vote for each share of common stock you own as of April 22, 2024.

If I am a stockholder of record and I do not vote, or if I return a proxy card or otherwise vote without giving specific voting instructions, what happens?

If you are a stockholder of record and do not vote by completing your proxy card, by telephone, through the internet or in person at the annual meeting, your shares will not be voted.

If you return a signed and dated proxy card or otherwise vote without marking voting selections, your shares will be voted, as applicable, "For" the election of each of the nominees for director, "For" the approval, on an advisory basis, of the compensation of our named executive officers, as disclosed in this proxy statement and "For" the ratification of Ernst & Young LLP as independent auditors for the year ending December 31, 2024. If any other matter is properly presented at the meeting, your proxyholder (one of the individuals named on your proxy card) will vote your shares using his or her best judgment.

If I am a beneficial owner of shares held in street name and I do not provide my broker or bank with voting instructions, what happens?

If you are a beneficial owner of shares held in street name and you do not instruct your broker, bank or other agent how to vote your shares, your broker, bank or other agent may still be able to vote your shares in its discretion. In this regard, under the rules of the New York Stock Exchange ("NYSE"), brokers, banks and other securities intermediaries that are subject to NYSE rules may use their discretion to vote your "uninstructed" shares with respect to matters considered to be "routine" under NYSE rules, but not with respect to "non-routine" matters. In this regard, Proposals No. 1 and No. 2 are considered to be "non-routine" under NYSE rules, meaning that your broker may not vote your shares on that proposal in the absence of your voting instructions. However, Proposal No. 3 is considered to be a "routine" matter under NYSE rules meaning that if you do not return voting instructions to your broker, bank or other agent by its deadline, your shares may be voted by your broker, bank or other agent in its discretion on Proposal No. 3.

If you are a beneficial owner of shares held in street name, in order to ensure your shares are voted in the way you would prefer, you must provide voting instructions to your broker, bank or other agent by the deadline provided in the materials you receive from your broker, bank or other agent.

Who is paying for this proxy solicitation?

We will pay for the entire cost of soliciting proxies. In addition to these proxy materials, our directors and employees may also solicit proxies in person, by telephone or by other means of communication. Directors and employees will not be paid any additional compensation for soliciting proxies. We will also reimburse brokerage firms, banks and other agents for the cost of forwarding proxy materials to beneficial owners.

What does it mean if I receive more than one Notice?

If you receive more than one Notice, your shares may be registered in more than one name or in different accounts. Please follow the voting instructions on the Notices to ensure that all of your shares are voted.

Can I change my vote after submitting my proxy?

Stockholder of Record: Shares Registered in Your Name

Yes. You can revoke your proxy at any time before the final vote at the meeting. If you are the record holder of your shares, you may revoke your proxy in any one of the following ways:

• You may submit another properly completed proxy card with a later date.

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• You may grant a subsequent proxy by telephone or through the internet.
• You may send a timely written notice that you are revoking your proxy to Clearside's Corporate Secretary at 900 North Point Parkway, Suite 200, Alpharetta, Georgia 30005.
• You may attend the annual meeting and vote in person. Simply attending the meeting will not, by itself, revoke your proxy.

Your most current proxy card or telephone or internet proxy is the one that is counted.

Beneficial Owner: Shares Registered in the Name of Broker or Bank

If your shares are held by your broker, bank or other agent, you should follow the instructions provided by that organization.

When are stockholder proposals and director nominations due for next year's Annual Meeting?

To be considered for inclusion in next year's proxy materials, your proposal must be submitted in writing by December 27, 2024 to our Corporate Secretary at 900 North Point Parkway, Suite 200, Alpharetta,

Georgia 30005. If you wish to submit a proposal (including a director nomination) at the meeting that is not to be included in next year's proxy materials, you must deliver your notice to our Corporate Secretary at the address above between February 20, 2025 and March 22, 2025. Your notice to the Corporate Secretary must set forth information specified in our bylaws, including your name and address and the class and number of shares of our stock that you beneficially own. In addition to satisfying the foregoing requirements under our Bylaws, to comply with the universal proxy rules, stockholders who intend to solicit proxies in support of director nominees other than our nominees must provide notice that sets forth the information required by Rule 14a-19 under the Securities Exchange Act of 1934, as amended (the "Exchange Act").

If you propose to bring business before an annual meeting other than a director nomination, your notice must also include, as to each matter proposed, the following: (a) a brief description of the business desired to be brought before the annual meeting and the reasons for conducting that business at the annual meeting and (b) any material interest you have in that business. If you propose to nominate an individual for election as a director, your notice must also include, as to each person you propose to nominate for election as a director, the following: (1) the name, age, business address and residence address of the person; (2) the principal occupation or employment of the person; (3) the class and number of shares of our stock that are owned of record and beneficially owned by the person; (4) the date or dates on which the shares were acquired and the investment intent of the acquisition; and (5) any other information concerning the person as would be required to be disclosed in a proxy statement soliciting proxies for the election of that person as a director in an election contest (even if an election contest is not involved), or that is otherwise required to be disclosed pursuant to Section 14 of the Exchange Act, and the rules and regulations promulgated under the Exchange Act, including the person's written consent to being named as a nominee and to serving as a director if elected. We may require any proposed nominee to furnish other information as we may reasonably require to determine the eligibility of the proposed nominee to serve as an independent director or that could be material to a reasonable stockholder's understanding of the independence, or lack of independence, of the proposed nominee.

For more information, and for more detailed requirements, please refer to our Amended and Restated Bylaws, filed as an exhibit to our most recent Annual Report on Form 10-K, filed with the SEC on March 12, 2024.

What are "broker non-votes"?

As discussed above, when a beneficial owner of shares held in "street name" does not give voting instructions to his or her broker, bank or other securities intermediary holding his or her shares as to how to vote on matters deemed to be "non-routine" under NYSE rules, the broker, bank or other such agent cannot vote the shares.

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