Organization, Basis of Presentation and Summary of Significant Accounting Policies	6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Basis of Presentation and Summary of Significant Accounting Policies	1. Organization, Basis of Presentation and Summary of Significant Accounting Policies Organization Phathom Pharmaceuticals, Inc., or the Company or Phathom, was incorporated in the state of Delaware in January 2018. The Company is a commercial-stage biopharmaceutical company focused on commercializing and developing novel treatments for gastrointestinal, or GI, diseases. The Company’s financial statements are prepared in accordance with U.S. generally accepted accounting principles, or GAAP. In May 2022, the U.S. Food and Drug Administration, or FDA, approved the Company's new drug applications, or NDAs for vonoprazan triple therapy, under the brand name VOQUEZNA TRIPLE PAK, and vonoprazan dual therapy, under the brand name VOQUEZNA DUAL PAK for the treatment of Helicobacter pylori, or H. pylori, infection. On November 1, 2023, the FDA approved the Company's NDA for VOQUEZNA 10mg and 20mg tablets for the treatment of erosive gastroesophageal reflux disease, or Erosive GERD. The Company initiated commercial launch of VOQUEZNA in the U.S. for both the Erosive GERD and H. pylori indications, and VOQUEZNA TRIPLE PAK and VOQUEZNA DUAL PAK for treatment of H. pylori infection in the fourth quarter of 2023. Additionally, on July 17, 2024, the FDA approved VOQUEZNA 10 mg tablets for the relief of heartburn associated with non-erosive gastroesophageal reflux disease or Non-Erosive GERD. Liquidity and Capital Resources From inception to June 30, 2026, the Company has devoted substantially all of its efforts to organizing and staffing the Company, business planning, raising capital, in-licensing vonoprazan, meeting with regulatory authorities, managing the clinical trials of vonoprazan, preparing for commercialization of its initial products containing vonoprazan, commercially launching its approved products in the U.S., and providing other selling, general and administrative support for these operations. The Company has a limited operating history as a commercial company. Although the Company has generated product revenue to date, the amount of future sales and income potential from its business remains uncertain. The Company has incurred net losses and negative cash flows from operating activities since its inception and despite the Company's plans and expectations, could continue to incur additional net losses in the future. The Company has funded its operations primarily through commercial bank debt, the revenue interest financing debt and various equity offerings, including the Company's at-the-market, or ATM, offerings. From inception through June 30, 2026, the Company sold 41,612,032 shares of common stock and 3,859,000 pre-funded warrants, generating net proceeds of approximately $665.3 million, after deducting underwriting discounts, commissions and offering costs. The accompanying unaudited interim condensed financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities in accordance with GAAP. Management is required to perform a two-step analysis over the Company’s ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (Step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (Step 2). Management believes that it has sufficient working capital on hand to fund operations through at least the next twelve months from the date these unaudited interim condensed financial statements were issued. There can be no assurance that the Company’s projections of its future working capital needs will prove accurate, that the Company will be successful in acquiring additional funding, if needed, or that any additional funding, if needed, would be sufficient to continue operations in future years. Basis of Presentation The unaudited interim condensed financial statements included herein have been prepared by the Company in accordance with GAAP, and pursuant to the rules and regulations of the Securities and Exchange Commission, or the SEC. In the opinion of management, the accompanying unaudited interim condensed financial statements include all adjustments, consisting of normal recurring adjustments, which are necessary to present fairly the Company’s financial position, results of operations, and cash flows. The interim results of operations are not necessarily indicative of the results that may occur for the full fiscal year. Certain information in the footnote disclosures of the financial statements has been condensed or omitted where it substantially duplicates information provided in the Company’s latest audited financial statements, in accordance with the rules and regulations of the SEC. These unaudited interim condensed financial statements should be read in conjunction with the Company’s audited financial statements and footnotes included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2025, or the 2025 Form 10-K, filed with the SEC on February 26, 2026. During the six months ended June 30, 2026, there were no significant changes to the Company’s summary of significant accounting policies contained in the Company’s 2025 Form 10-K. The Company’s complete listing of significant accounting policies is set forth in Note 1 of the notes to the audited financial statements in the Company's 2025 Form 10-K. Selected significant accounting policies are discussed in detail below. Use of Estimates The preparation of the Company’s unaudited condensed interim financial statements requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities in the Company’s unaudited condensed interim financial statements and accompanying notes. The most significant estimates in the Company’s unaudited condensed interim financial statements relate to accruals for net product revenues and the valuation for the revenue interest financing liability. In addition, management’s assessment of the Company’s ability to continue as a going concern involves the estimation of the amount and timing of future cash inflows and outflows. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results could differ materially from those estimates and assumptions. Fair Value Measurements The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets. Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, are classified within the Level 1 designation discussed above, while accounts receivable, prepaid and other current assets, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. The Company has no financial assets measured at fair value on a recurring basis. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. As of June 30, 2026 and December 31, 2025, the estimated fair value of the Company’s long-term debt approximated the carrying amount given its floating interest rate basis. The fair value of the Company’s long-term debt was estimated for disclosure purposes only and was determined based on quoted market data for valuation, and thus categorized as Level 2 in the fair value hierarchy. Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held. The Company is also subject to credit risk from our accounts receivable related to our product sales. The Company monitors exposure within accounts receivable and records an allowance for credit losses as necessary. The Company extends credit primarily to wholesale distributors. Customer creditworthiness is monitored and collateral is not required. The allowance for credit losses reflects the best estimate of expected credit losses of the accounts receivable portfolio determined on the basis of historical experience, current information, and forecasts of future economic conditions. The Company determines its allowance methodology by pooling receivable balances at the customer level. The Company considers various factors, including its previous loss history, individual credit risk associated with each customer, and the current and future conditions of the general economy. These credit risk factors are monitored on a quarterly basis and updated as necessary. To the extent that any individual debtor is identified whose credit quality has deteriorated, the Company establishes allowances based on the individual risk characteristics of such customer. The Company makes concerted efforts to collect all outstanding balances due from customers; however, account balances are charged off against the allowance when management believes it is probable the receivable will not be recovered. The Company does not have any off-balance-sheet credit exposure related to customers. As of June 30, 2026, three customers accounted for 81% of the accounts receivable balance, with each of these individual customers ranging from 24% to 29% of the accounts receivable balance. As of December 31, 2025, three customers accounted for 78% of the accounts receivable balance, with each of these individual customers ranging from 19% to 30% of the accounts receivable balance. For the three and six months ended June 30, 2026, three customers accounted for 67% and 68% of product sales in each period, with each of these individual customers ranging from 20% to 24% of product sales. For the three and six months ended June 30, 2025, three customers accounted for 69% and 72% of product sales in each period, with each of these individual customers ranging from 22% to 24% of product sales in both periods. Net Loss Per Share Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding and pre-funded warrants outstanding for the period, without consideration for other potentially dilutive securities. For the three and six months ended June 30, 2026 and 2025, basic shares outstanding includes the weighted average effect of the Company’s outstanding pre-funded warrants, the exercise of which requires little or no consideration for the delivery of shares of common stock. For the three and six months ended June 30, 2026 and 2025, the Company had no weighted-average unvested shares to exclude from the weighted-average number of common shares outstanding. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Dilutive common stock equivalents are comprised of unvested common stock, options and warrants. For the periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as inclusion of the potentially dilutive securities (warrants, stock options, and restricted stock units) would be antidilutive. Recently Adopted Accounting Standards There were no recently adopted accounting standards which would have a material impact on the Company's unaudited interim condensed financial statements. Recently Issued Accounting Pronouncements In November 2024, the FASB issued ASU 2024-03 - Disaggregation of Income Statement Expenses, which requires more detailed disclosures about specified categories of expenses (including employee compensation, depreciation, and amortization) included in certain expense captions presented on the face of the income statement. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027, may be applied prospectively or retrospectively, and allows for early adoption. This standard is not expected to have an impact on any amounts recognized in our financial statements, but will result in more detailed disclosures addressing the categorization of expenses. The Company assesses the adoption impact of recently issued accounting standards by the Financial Accounting Standards Board or other standard setting bodies on the Company's financial statements as well as material updates to previous assessments, if any, from the Company’s 2025 Form 10-K. There were no new accounting standards issued in the second quarter of 2026 that are expected to materially impact the Company.

1. Organization, Basis of Presentation and Summary of Significant Accounting Policies

Organization

Phathom Pharmaceuticals, Inc., or the Company or Phathom, was incorporated in the state of Delaware in January 2018. The Company is a commercial-stage biopharmaceutical company focused on commercializing and developing novel treatments for gastrointestinal, or GI, diseases. The Company’s financial statements are prepared in accordance with U.S. generally accepted accounting principles, or GAAP.

In May 2022, the U.S. Food and Drug Administration, or FDA, approved the Company's new drug applications, or NDAs for vonoprazan triple therapy, under the brand name VOQUEZNA TRIPLE PAK, and vonoprazan dual therapy, under the brand name VOQUEZNA DUAL PAK for the treatment of Helicobacter pylori, or H. pylori, infection. On November 1, 2023, the FDA approved the Company's NDA for VOQUEZNA 10mg and 20mg tablets for the treatment of erosive gastroesophageal reflux disease, or Erosive GERD. The Company initiated commercial launch of VOQUEZNA in the U.S. for both the Erosive GERD and H. pylori indications, and VOQUEZNA TRIPLE PAK and VOQUEZNA DUAL PAK for treatment of H. pylori infection in the fourth quarter of 2023. Additionally, on July 17, 2024, the FDA approved VOQUEZNA 10 mg tablets for the relief of heartburn associated with non-erosive gastroesophageal reflux disease or Non-Erosive GERD.

Liquidity and Capital Resources

From inception to June 30, 2026, the Company has devoted substantially all of its efforts to organizing and staffing the Company, business planning, raising capital, in-licensing vonoprazan, meeting with regulatory authorities, managing the clinical trials of vonoprazan, preparing for commercialization of its initial products containing vonoprazan, commercially launching its approved products in the U.S., and providing other selling, general and administrative support for these operations. The Company has a limited operating history as a commercial company. Although the Company has generated product revenue to date, the amount of future sales and income potential from its business remains uncertain. The Company has incurred net losses and negative cash flows from operating activities since its inception and despite the Company's plans and expectations, could continue to incur additional net losses in the future. The Company has funded its operations primarily through commercial bank debt, the revenue interest financing debt and various equity offerings, including the Company's at-the-market, or ATM, offerings. From inception through June 30, 2026, the Company sold 41,612,032 shares of common stock and 3,859,000 pre-funded warrants, generating net proceeds of approximately $665.3 million, after deducting underwriting discounts, commissions and offering costs.

The accompanying unaudited interim condensed financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities in accordance with GAAP. Management is required to perform a two-step analysis over the Company’s ability to continue as a going concern. Management must first evaluate whether there are conditions and events that raise substantial doubt about the Company’s ability to continue as a going concern (Step 1). If management concludes that substantial doubt is raised, management is also required to consider whether its plans alleviate that doubt (Step 2).

Management believes that it has sufficient working capital on hand to fund operations through at least the next twelve months from the date these unaudited interim condensed financial statements were issued. There can be no assurance that the Company’s projections of its future working capital needs will prove accurate, that the Company will be successful in acquiring additional funding, if needed, or that any additional funding, if needed, would be sufficient to continue operations in future years.

Basis of Presentation

The unaudited interim condensed financial statements included herein have been prepared by the Company in accordance with GAAP, and pursuant to the rules and regulations of the Securities and Exchange Commission, or the SEC. In the opinion of management, the accompanying unaudited interim condensed financial statements include all adjustments, consisting of normal recurring adjustments, which are necessary to present fairly the Company’s financial position, results of operations, and cash flows. The interim results of operations are not necessarily indicative of the results that may occur for the full fiscal year. Certain information in the footnote disclosures of the financial statements has been condensed or omitted where it substantially duplicates information provided in the Company’s latest audited financial statements, in accordance with the rules and regulations of the SEC. These unaudited interim

condensed financial statements should be read in conjunction with the Company’s audited financial statements and footnotes included in its Annual Report on Form 10-K for the fiscal year ended December 31, 2025, or the 2025 Form 10-K, filed with the SEC on February 26, 2026.

During the six months ended June 30, 2026, there were no significant changes to the Company’s summary of significant accounting policies contained in the Company’s 2025 Form 10-K. The Company’s complete listing of significant accounting policies is set forth in Note 1 of the notes to the audited financial statements in the Company's 2025 Form 10-K. Selected significant accounting policies are discussed in detail below.

Use of Estimates

The preparation of the Company’s unaudited condensed interim financial statements requires management to make estimates and assumptions that impact the reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities in the Company’s unaudited condensed interim financial statements and accompanying notes. The most significant estimates in the Company’s unaudited condensed interim financial statements relate to accruals for net product revenues and the valuation for the revenue interest financing liability. In addition, management’s assessment of the Company’s ability to continue as a going concern involves the estimation of the amount and timing of future cash inflows and outflows. Although these estimates are based on the Company’s knowledge of current events and actions it may undertake in the future, actual results could differ materially from those estimates and assumptions.

Fair Value Measurements

The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or non-recurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

Level 1: Observable inputs such as quoted prices in active markets.

Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly.

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, are classified within the Level 1 designation discussed above, while accounts receivable, prepaid and other current assets, accounts payable, and accrued liabilities, approximate fair value due to their short maturities.

The Company has no financial assets measured at fair value on a recurring basis. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented.

As of June 30, 2026 and December 31, 2025, the estimated fair value of the Company’s long-term debt approximated the carrying amount given its floating interest rate basis. The fair value of the Company’s long-term debt was estimated for disclosure purposes only and was determined based on quoted market data for valuation, and thus categorized as Level 2 in the fair value hierarchy.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.

The Company is also subject to credit risk from our accounts receivable related to our product sales. The Company monitors exposure within accounts receivable and records an allowance for credit losses as necessary. The Company extends credit primarily to wholesale distributors. Customer creditworthiness is monitored and collateral is not required. The allowance for credit losses reflects the best estimate of expected credit losses of the accounts receivable portfolio determined on the basis of historical experience, current

information, and forecasts of future economic conditions. The Company determines its allowance methodology by pooling receivable balances at the customer level. The Company considers various factors, including its previous loss history, individual credit risk associated with each customer, and the current and future conditions of the general economy. These credit risk factors are monitored on a quarterly basis and updated as necessary. To the extent that any individual debtor is identified whose credit quality has deteriorated, the Company establishes allowances based on the individual risk characteristics of such customer. The Company makes concerted efforts to collect all outstanding balances due from customers; however, account balances are charged off against the allowance when management believes it is probable the receivable will not be recovered. The Company does not have any off-balance-sheet credit exposure related to customers.

As of June 30, 2026, three customers accounted for 81% of the accounts receivable balance, with each of these individual customers ranging from 24% to 29% of the accounts receivable balance. As of December 31, 2025, three customers accounted for 78% of the accounts receivable balance, with each of these individual customers ranging from 19% to 30% of the accounts receivable balance. For the three and six months ended June 30, 2026, three customers accounted for 67% and 68% of product sales in each period, with each of these individual customers ranging from 20% to 24% of product sales. For the three and six months ended June 30, 2025, three customers accounted for 69% and 72% of product sales in each period, with each of these individual customers ranging from 22% to 24% of product sales in both periods.

Net Loss Per Share

Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding and pre-funded warrants outstanding for the period, without consideration for other potentially dilutive securities. For the three and six months ended June 30, 2026 and 2025, basic shares outstanding includes the weighted average effect of the Company’s outstanding pre-funded warrants, the exercise of which requires little or no consideration for the delivery of shares of common stock. For the three and six months ended June 30, 2026 and 2025, the Company had no weighted-average unvested shares to exclude from the weighted-average number of common shares outstanding. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Dilutive common stock equivalents are comprised of unvested common stock, options and warrants. For the periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding as inclusion of the potentially dilutive securities (warrants, stock options, and restricted stock units) would be antidilutive.

Recently Adopted Accounting Standards

There were no recently adopted accounting standards which would have a material impact on the Company's unaudited interim condensed financial statements.

Recently Issued Accounting Pronouncements

In November 2024, the FASB issued ASU 2024-03 - Disaggregation of Income Statement Expenses, which requires more detailed disclosures about specified categories of expenses (including employee compensation, depreciation, and amortization) included in certain expense captions presented on the face of the income statement. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027, may be applied prospectively or retrospectively, and allows for early adoption. This standard is not expected to have an impact on any amounts recognized in our financial statements, but will result in more detailed disclosures addressing the categorization of expenses.

The Company assesses the adoption impact of recently issued accounting standards by the Financial Accounting Standards Board or other standard setting bodies on the Company's financial statements as well as material updates to previous assessments, if any, from the Company’s 2025 Form 10-K. There were no new accounting standards issued in the second quarter of 2026 that are expected to materially impact the Company.