PEPG

SEC.gov | Request Rate Threshold Exceeded

U.S. Securities and Exchange Commission

You’ve Exceeded the SEC’s Traffic Limit

Your request rate has exceeded the SEC’s maximum allowable requests per second. Your access to SEC.gov will be limited for 10 minutes.

Current guidelines limit each user to a total of no more than 10 requests per second, regardless of the number of machines used to submit requests. To ensure that SEC.gov remains available to all users, we reserve the right to block IP addresses that submit excessive requests.

The block will be lifted automatically by waiting 10 minutes. Continuing to exceed the SEC’s maximum allowable request rate during the time-out period will extend the duration of the time-out period. To ensure fair access for all users, please reduce the rate of your requests and visit SEC.gov again after the 10 minute time-out period has passed.

For best practices on efficiently downloading information from SEC.gov, including the latest EDGAR filings, visit sec.gov/developer. You can also sign up for email updates on the SEC open data program, including best practices that make it more efficient to download data, and SEC.gov enhancements that may impact scripted downloading processes. For more information, contact opendata@sec.gov.

For more information, please see the SEC’s Web Site Privacy and Security Policy. Thank you for your interest in the U.S. Securities and Exchange Commission.

Reference ID: 0.e618d017.1786388795.cf9c9574

More Information

Internet Security Policy

By using this site, you are agreeing to security monitoring and auditing. For security purposes, and to ensure that the public service remains available to users, this government computer system employs programs to monitor network traffic to identify unauthorized attempts to upload or change information or to otherwise cause damage, including attempts to deny service to users.

Unauthorized attempts to upload information and/or change information on any portion of this site are strictly prohibited and are subject to prosecution under the Computer Fraud and Abuse Act of 1986 and the National Information Infrastructure Protection Act of 1996 (see Title 18 U.S.C. §§ 1001 and 1030).

To ensure our website performs well for all users, the SEC monitors the frequency of requests for SEC.gov content to ensure automated searches do not impact the ability of others to access SEC.gov content. We reserve the right to block IP addresses that submit excessive requests. Current guidelines limit users to a total of no more than 10 requests per second, regardless of the number of machines used to submit requests.

If a user or application submits more than 10 requests per second, further requests from the IP address(es) may be limited for a brief period. Once the rate of requests has dropped below the threshold for 10 minutes, the user may resume accessing content on SEC.gov. This SEC practice is designed to limit excessive automated searches on SEC.gov and is not intended or expected to impact individuals browsing the SEC.gov website.

Note that this policy may change as the SEC manages SEC.gov to ensure that the website performs efficiently and remains available to all users.

Note: We do not offer technical support for developing or debugging scripted downloading processes.

EX-99.1

2 pepg-ex99_1.htm

EX-99.1

EX-99.1

PepGen Reports First Quarter 2026 Financial Results and Recent Corporate Highlights

– FREEDOM2-DM1 5 mg/kg cohort demonstrated favorable safety, splicing and vHOT data, with the totality of results supporting the potential of the ongoing 10 mg/kg dose cohort –

– The FREEDOM2 10 mg/kg cohort is fully enrolled, with data on track for 2H 2026 –

– Well-funded with $132.3M of cash as of March 31, 2026, sufficient to fund operations through FREEDOM2 12.5 mg/kg MAD readout and into 2H 2027 –

BOSTON— May 12, 2026-- PepGen Inc. (Nasdaq: PEPG), a clinical-stage biotechnology company advancing the next generation of oligonucleotide therapies with the goal of transforming the treatment of severe neuromuscular and neurological diseases, today reported financial results and recent corporate highlights for the quarter ended March 31, 2026, and recent corporate highlights.

"We made encouraging progress during the first quarter of 2026 in our FREEDOM2-DM1 trial. The 5 mg/kg cohort — the initial dose cohort — demonstrated a favorable tolerability profile and promising efficacy trends, reinforcing our confidence in PGN-EDODM1's potential at higher doses," said James McArthur, PhD, President and Chief Executive Officer of PepGen. "Enrollment in the 10 mg/kg cohort is now complete and we remain on track to report data in the second half of this year. With funding in place through the 10 and 12.5 mg/kg cohorts, we are well positioned to continue dose escalating and deliver on the promise of this program for the DM1 community."

Recent Program Updates

PGN-EDODM1: Myotonic Dystrophy Type 1 (DM1)

• FREEDOM2 Phase 2 Multiple Ascending Dose (MAD) Randomized, Placebo-Controlled Clinical Trial of PGN-EDODM1:

o PepGen reported promising topline results from the 5 mg/kg MAD cohort, demonstrating favorable safety, splicing and vHOT data. The Company believes the totality of safety and efficacy results support the potential of PGN-EDODM1 in the ongoing 10 mg/kg dose cohort. Read the full release here.

o The Company has fully enrolled the 10 mg/kg MAD cohort of FREEDOM2. PepGen expects to report data from this cohort in the second half of 2026, with data from the 12.5 mg/kg cohort anticipated in 2027.

o PepGen has currently enrolled 13 patients in the open label extension (OLE) at 5 mg/kg, including 6 patients from FREEDOM2, with no patient discontinuations.

o The Company has received regulatory clearance to initiate the FREEDOM2 trial in South Korea, Australia, and New Zealand. Sites are currently open and active in Canada, the UK and South Korea, with plans to open sites in New Zealand and Australia.

o The U.S. Food and Drug Administration (FDA) placed a partial clinical hold on the FREEDOM2 study. The partial clinical hold questions raised by the FDA relate to previously submitted preclinical pharmacology and toxicology studies. The timing of the

ongoing FREEDOM2 clinical study has not been impacted. The Company continues to work with the FDA to address the Agency’s questions as quickly as possible.

Financial Results for the Three Months Ended March 31, 2026

• Cash, Cash Equivalents and Marketable Securities were $132.3 million as of March 31, 2026. Based on currently planned operations, the Company believes that its existing cash, cash equivalents, and marketable securities will be sufficient to fund its operations into the second half of 2027.

• Research and Development Expenses were $13.0 million for the three months ended March 31, 2026, compared to $25.4 million for the same period in 2025.

• General and Administrative Expenses were $5.9 million for the three months ended March 31, 2026, compared to $5.9 million for the same period in 2025.

• Net Loss was $17.8 million, or $(0.26) basic and diluted net loss per share, for the three months ended March 31, 2026, compared to $30.2 million, or $(0.92) basic and diluted net loss per share, for the same period in 2025. PepGen had approximately 69.2 million shares outstanding on March 31, 2026.

About PGN-EDODM1

PGN-EDODM1, PepGen's investigational candidate in development for the treatment of DM1, utilizes the Company's proprietary EDO technology to deliver a therapeutic oligonucleotide that is designed to restore the normal splicing function of MBNL1, a key RNA splicing protein. PGN-EDODM1 addresses the deleterious effects of cytosine-uracil-guanine (CUG) repeat expansion in the dystrophia myotonica protein kinase (DMPK) transcripts which sequester MBNL1, by binding to the pathogenic CUG trinucleotide repeat expansion present in the DMPK transcripts, and disrupting the binding between the CUG repeat expansion and MBNL1. PepGen believes this innovative therapeutic approach may have considerable advantages over oligonucleotide modalities that rely on knockdown or degradation of the DMPK transcripts as it will allow the DMPK transcripts to continue to perform their normal function within the cell, while also liberating MBNL1 to

8-K

false000183559700018355972026-03-042026-03-04

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 04, 2026

PepGen Inc. (Exact name of Registrant as Specified in Its Charter)

Delaware

001-41374

85-3819886

(State or Other Jurisdiction of Incorporation)

(Commission File Number)

(IRS Employer Identification No.)

321 Harrison Avenue 8th Floor

Boston, Massachusetts

02118

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s Telephone Number, Including Area Code: (781) 797-0979

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common stock, par value $0.0001 per share

PEPG

Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter). Emerging growth company ☒ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02 Results of Operations and Financial Condition. On March 4, 2026, PepGen Inc. (the "Company") announced its financial results for the year ended December 31, 2025 and issued a press release titled "PepGen Reports Fourth Quarter and Year-End 2025 Financial Results and Recent Corporate Highlights". A copy of the press release is furnished as Exhibit 99.1.

The information provided in this Current Report on Form 8-K (this “Form 8-K”), including Exhibit 99.1, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any of the Company’s filings under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, except as expressly set forth by specific reference in such filing. Item 8.01 Other Events. On March 4, 2026, the Company announced that it received a partial clinical hold notice from the U.S. Food and Drug Administration on the FREEDOM2-DM1 Phase 2 multiple ascending dose ("MAD"), randomized, placebo-controlled clinical trial of PGN-EDODM1 in patients with myotonic dystrophy type 1 ("DM1"). A copy of the press release issued in connection with the announcement is attached as Exhibit 99.2 to this form 8-K and incorporated herein by reference. Item 9.01 Financial Statements and Exhibits. (d) Exhibits

Exhibit Number

Description

99.1

Press Release issued by PepGen Inc. on March 4, 2026 titled "PepGen Reports Fourth Quarter and Year-End 2025 Financial Results and Recent Corporate Highlights"

99.2

Press Release issued by PepGen Inc. on March 4, 2026 titled "PepGen Announces Regulatory Updates on FREEDOM2"

104

Cover Page Interactive Data File (embedded within Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

PepGen Inc.

Date:

March 4, 2026

By:

/s/ Noel Donnelly

Noel Donnelly, Chief Financial Officer