Nature of Business and Basis of Presentation	3 Months Ended
Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation PepGen Inc., or the Company or PepGen, headquartered in Boston, Massachusetts, is a biopharmaceutical company developing a transformative oligonucleotide delivery technology and pipeline of product candidates to treat neuromuscular and neurologic diseases with a high unmet medical need. Initial Public Offering On May 10, 2022, the Company closed its initial public offering (IPO) in which the Company sold an aggregate of 9,000,000 shares at a public offering price of $12.00 per share for gross proceeds of $108.0 million. In connection with the IPO, the Company granted the underwriters a 30-day option to purchase 1,350,000 additional shares of common stock. On May 16, 2022, the underwriters exercised the option in part and the Company issued 1,238,951 shares of common stock for gross proceeds of $14.9 million. From the IPO and option exercise by the underwriters, the Company received approximately $122.9 million in gross proceeds and $110.2 million in net proceeds, after deducting underwriting discounts and offering expenses payable by the Company. Immediately prior to consummation of the IPO, all 12,546,805 outstanding shares of the Company’s redeemable convertible preferred stock, and 35,529 preferred stock warrants that were exercised on May 4, 2022 (see Note 3), converted into 12,359,856 shares of the Company’s common stock. As a result of this conversion, the Company's net loss per share, basic and diluted, will be significantly different from future filings. Liquidity and Capital Resources Since inception, the Company has not generated any revenue from product sales or other sources and has incurred significant operating losses and negative cash flows from operations. The Company’s primary uses of cash and cash equivalents to date have been to fund research and development activities, business planning, establishing and maintaining the Company’s intellectual property portfolio, hiring personnel, leasing premises and associated capital expenditures, raising capital, and providing general and administrative support for these operations. As of March 31, 2023, the Company had an accumulated deficit of $119.2 million. To date, the Company has funded operations primarily through private placements of convertible preferred stock and its IPO. As of March 31, 2023, the Company had cash and cash equivalents of $165.4 million. Based on its current operating plans, the Company believes that its cash and cash equivalents as of March 31, 2023, will be sufficient to fund its currently planned operations for at least the next 12 months from the filing of these condensed consolidated financial statements. As the Company continues to pursue its business plan to successfully develop and obtain regulatory approval for the Company’s product candidates, it expects to finance its operations through the sale of equity, debt financings or other capital resources, which could include income from collaborations, strategic partnerships or marketing, distribution, licensing or other strategic arrangements with third parties, or from grants. However, there can be no assurance that any additional financing or strategic transactions will be available to the Company on acceptable terms, if at all. If events or circumstances occur such that the Company does not obtain additional funding, it may need to delay, reduce or eliminate its product development or future commercialization efforts, which could have a material adverse effect on the Company’s business, results of operations or financial condition. Basis of Presentation and Consolidation The accompanying condensed consolidated financial statements are unaudited and have been prepared in conformity with generally accepted accounting principles in the United States of America (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). The condensed consolidated financial statements have been prepared on the same basis as the audited annual financial statements. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position as of March 31, 2023, and results of operations for the interim periods ended March 31, 2023 and March 31, 2022. The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These condensed consolidated financial statements should be read in conjunction with the audited financial statements as of and for the years ended December 31, 2022 and 2021, and the notes thereto, included in the Company’s Annual Report, filed with the Securities and Exchange Commission (the SEC) on March 23, 2023, or Form 10-K.

Nature of Business and Basis of Presentation

3 Months Ended

Mar. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Nature of Business and Basis of Presentation

1. Nature of Business and Basis of Presentation

PepGen Inc., or the Company or PepGen, headquartered in Boston, Massachusetts, is a biopharmaceutical company developing a transformative oligonucleotide delivery technology and pipeline of product candidates to treat neuromuscular and neurologic diseases with a high unmet medical need.

Initial Public Offering

On May 10, 2022, the Company closed its initial public offering (IPO) in which the Company sold an aggregate of 9,000,000 shares at a public offering price of $12.00 per share for gross proceeds of $108.0 million. In connection with the IPO, the Company granted the underwriters a 30-day option to purchase 1,350,000 additional shares of common stock. On May 16, 2022, the underwriters exercised the option in part and the Company issued 1,238,951 shares of common stock for gross proceeds of $14.9 million. From the IPO and option exercise by the underwriters, the Company received approximately $122.9 million in gross proceeds and $110.2 million in net proceeds, after deducting underwriting discounts and offering expenses payable by the Company.

Immediately prior to consummation of the IPO, all 12,546,805 outstanding shares of the Company’s redeemable convertible preferred stock, and 35,529 preferred stock warrants that were exercised on May 4, 2022 (see Note 3), converted into 12,359,856 shares of the Company’s common stock. As a result of this conversion, the Company's net loss per share, basic and diluted, will be significantly different from future filings.

Liquidity and Capital Resources

Since inception, the Company has not generated any revenue from product sales or other sources and has incurred significant operating losses and negative cash flows from operations. The Company’s primary uses of cash and cash equivalents to date have been to fund research and development activities, business planning, establishing and maintaining the Company’s intellectual property portfolio, hiring personnel, leasing premises and associated capital expenditures, raising capital, and providing general and administrative support for these operations. As of March 31, 2023, the Company had an accumulated deficit of $119.2 million. To date, the Company has funded operations primarily through private placements of convertible preferred stock and its IPO. As of March 31, 2023, the Company had cash and cash equivalents of $165.4 million. Based on its current operating plans, the Company believes that its cash and cash equivalents as of March 31, 2023, will be sufficient to fund its currently planned operations for at least the next 12 months from the filing of these condensed consolidated financial statements.

As the Company continues to pursue its business plan to successfully develop and obtain regulatory approval for the Company’s product candidates, it expects to finance its operations through the sale of equity, debt financings or other capital resources, which could include income from collaborations, strategic partnerships or marketing, distribution, licensing or other strategic arrangements with third parties, or from grants. However, there can be no assurance that any additional financing or strategic transactions will be available to the Company on acceptable terms, if at all. If events or circumstances occur such that the Company does not obtain additional funding, it may need to delay, reduce or eliminate its product development or future commercialization efforts, which could have a material adverse effect on the Company’s business, results of operations or financial condition.

Basis of Presentation and Consolidation

The accompanying condensed consolidated financial statements are unaudited and have been prepared in conformity with generally accepted accounting principles in the United States of America (GAAP). Any reference in these notes to applicable guidance is meant to refer to the authoritative GAAP as found in the Accounting Standards Codification (ASC) and Accounting Standards Update (ASU) of the Financial Accounting Standards Board (FASB). The condensed consolidated financial statements have been prepared on the same basis as the audited annual financial statements. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position as of March 31, 2023, and results of operations for the interim periods ended March 31, 2023 and March 31, 2022.

The results of operations for the interim periods are not necessarily indicative of the results of operations to be expected for the full year. These condensed consolidated financial statements should be read in conjunction with the audited financial statements as of and for the years ended December 31, 2022 and 2021, and the notes thereto, included in the Company’s Annual Report, filed with the Securities and Exchange Commission (the SEC) on March 23, 2023, or Form 10-K.