PepGen : Corporate Deck – May 2024

Company Presentation

May 2024

Disclaimers

This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. These statements may be identified by words such as "aims," "anticipates," "believes," "could," "estimates," "expects," "forecasts," "goal," "intends," "may," "plans," "possible," "potential," "seeks," "will," and variations of these words or similar expressions that are intended to identify forward-looking statements. Any such statements in this presentation that are not statements of historical fact may be deemed to be forward-looking statements. These forward-looking statements include, without limitation, statements about our EDO technology, our preclinical studies and results, clinical programs, including study designs and regulatory timelines, product candidates, including their planned development, safety profile and therapeutic potential, plans for future development, expected timing for achievement of milestones, corporate strategies, and our financial resources and expected cash runway.

Any forward-looking statements in this presentation are based on current expectations, estimates and projections only as of the date of this presentation and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in or implied by such forward- looking statements. These risks and uncertainties include, but are not limited to: delays or failure to successfully initiate or complete our ongoing and planned development activities for our product candidates, including PGN-EDO51,PGN-EDODM1 and PGN-EDO53; our ability to enroll patients in our clinical trials, including CONNECT1-EDO51,CONNECT2-EDO51,FREEDOM-DM1andFREEDOM2-DM1; that our interpretation of clinical and preclinical study results may be incorrect, or that we may not observe the levels of therapeutic activity in clinical testing that we anticipate based on prior clinical or preclinical results; our product candidates, including PGN-EDO51 and PGN-EDODM1, may not be safe and effective or otherwise demonstrate safety and efficacy in our clinical trials; adverse outcomes from our regulatory interactions, including delays in regulatory review, clearance to proceed or approval by regulatory authorities with respect to our programs, including clearance to commence planned clinical studies of our product candidates, including CONNECT2-EDO51 or FREEDOM2-DM1, or other regulatory feedback requiring modifications to our development programs; changes in regulatory framework that are out of our control; our ability to obtain, maintain and protect our intellectual property; our ability to enforce our patents against infringers and defend our patent portfolio against challenges from third parties; competition from others developing therapies for the indications we are pursuing; unexpected increases in the expenses associated with our development activities or other events that adversely impact our financial resources and cash runway; and our dependence on third parties for some or all aspects of our product manufacturing, research and preclinical and clinical testing. Additional risks concerning PepGen's programs and operations are described in our most recent annual report on Form 10-K and quarterly report on Form 10-Q that are filed with the SEC. PepGen explicitly disclaims any obligation to update any forward-looking statements except to the extent required by law.

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PepGen: Who We Are

				Clinical stage pipeline:
Our mission	Proprietary delivery platform patient read outs in 2024

• Transforming the lives of patients	• Enhanced Delivery
with severe neuromuscular and	oligonucleotide (EDO) platform
neurological diseases	−	Increased cellular uptake
	−	Increased nuclear uptake
	−	Enhanced potency at
		tolerable doses

• Duchenne Muscular Dystrophy (DMD): Initial patient read out from multiple ascending dose study (Phase 2) expected mid- 2024
• Myotonic dystrophy type 1 (DM1): Initial patient read out from single ascending dose study (Phase 1) expected 2H:2024

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The Challenge of Oligonucleotides

Naked Oligo (PMO)

Naked oligonucleotides are not efficiently taken up into the muscle cells and the nucleus

Red= oligo

Note: 1. In vitro staining image is shown with 10µMconc. of PMO23 (naked oligonucleotide); 2. C2C12 mouse cells were differentiated for 4 days into

myotubes and treated with fluorescentlytagged compounds for 24h. PMO: phosphorodiamidate morpholino oligonucleotide

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PepGen's EDO platform has been designed and developed to solve this

decades long problem

PepGen's EDO: Up to 25-fold higher nuclear uptake of oligo

EDO platform results in nuclear delivery of oligonucleotide therapeutics

Red= oligo

Note: 1. In vitro staining image is shown with 10µMconc. of EDO23; 2. C2C12 mouse cells were differentiated for 4 days into myotubes and treated with fluorescentlytagged compounds for 24h.

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PepGen's advanced pipeline enabled by EDO technology

	PROGRAM	INDICATION	PRECLINICAL	PHASE 1	PHASE 2	PIVOTAL
		Duchenne muscular
	PGN-EDO51	dystrophy
		Exon 51
	PGN-EDODM1	Myotonic dystrophy type 1
	DMPK
		Duchenne muscular
	PGN-EDO53	dystrophy
		Exon 53

	•	DMD Exon 45, Exon 44	• Neurological Diseases
Research	•	Additional neuromuscular
		diseases

Note: Clinical plans are subject to alignment with regulatoryauthorities

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Latest milestones achieved and upcoming for 2024

Achieved

Upcoming

• CONNECT1 Phase 2 initiated and 5 mg/kg dose cohort fully enrolled

DMD • CONNECT2 Phase 2 open in UK

• FREEDOM Phase 1 open in US, Canada and UK

DM1

• Preliminary data from CONNECT1 5 mg/kg dose cohort expected in mid-2024
• Dosing of first patient in CONNECT2 expected in 2H:2024
• Preliminary data from at least the 5 mg/kg dose cohort of FREEDOM expected in 2H:2024
• FREEDOM2 initiation expected in 2H:2024

Q1 2024: Completed $80 million follow-on common stock offering; cash runway into 20261

1. Based on current operating plan

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PGN-EDO51 for Duchenne muscular dystrophy (DMD)

DMD presents with a significant unmet medical need

Disease overview

• Caused by mutation in dystrophin gene resulting in progressive muscle damage

• Onset of symptoms in early childhood

- Loss of ambulation by early adolescence

- Loss of respiratory and cardiac function resulting in early adulthood mortality

Market opportunity

• US and EU ~40,000 patients
• ~21% patients amenable to:
• • PGN-EDO51:Phase 2 (exon 51)
  • PGN-EDO53:CTA/IND enabling studies advancing in 2024 (exon 53)
• Novel therapies needed to restore functional dystrophin and prevent loss of muscle function and early mortality

Source:https://www.cureduchenne.org/cure/exon-skipping/.

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EDO technology resulted in significant increase in exon skipping and dystrophin in mdx mice that was uniformly distributed across muscle

PGN-EDO23

(murine analogue of PGN-EDO51)

EXON SKIPPING	DYSTROPHIN (WESTERN BLOT)

Biceps, 30 mg/kg, Q4W

DYSTROPHIN (IF) and

% POSITIVE FIBERS

WT control

mdx

Week:

0 4 8 12 16

Tissue

analysis

PGN-EDO23

Tissue analysis

91.5%

52.5%

0%

82.3%

3.7X

22.5%

0%

>99%

mdx control

<0.1%

mdx, PGN-EDO23 4x30 mg/kg

97.1%

PGN-EDO23

PGN-EDO23

Protocol: mdx mice received up to 4 doses of PGN-EDO23, w ith 4-week intervals between doses. Tissue samples w ere collected 4 w eeks post-each dose. Exon skipping w as

evaluated by RT-PCR and dystrophin protein w as evaluated by w estern blot and immunofluorescence (IF). IF scale bar = 200 µM. Graph is presented as mean ± SD; n = 4-5 per cohort; grey band is dystrophin LLOQ (2.5%).

Dystrophin / Nucleus

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