Organization and Basis of Presentation	6 Months Ended
Jun. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation Viracta Therapeutics, Inc. (“Viracta,” the “Company,” or the “combined company”), formerly known as Sunesis Pharmaceuticals, Inc., was incorporated in the state of Delaware in February 1998 and is based in San Diego, California. Viracta is a clinical-stage, precision oncology company focused on the treatment and prevention of virus-associated cancers that impact patients worldwide. Viracta’s lead product candidate is an all-oral combination therapy of its proprietary investigational drug, nanatinostat and the antiviral agent valganciclovir (collectively referred to as “Nana-val”). Nana-val is currently being investigated in multiple ongoing clinical trials, including NAVAL-1, a pivotal, global, multicenter, open-label Phase 2 basket trial for the treatment of multiple subtypes of relapsed/refractory (“R/R”) Epstein-Barr virus-positive (“EBV+”) lymphoma, as well as a multinational, open-label Phase 1b/2 trial for the treatment of EBV+ recurrent or metastatic nasopharyngeal carcinoma (“R/M NPC”) and other EBV+ solid tumors. In August 2024, Viracta announced it plans to pause the EBV+ solid tumor program to focus resources on the more advanced EBV+ lymphoma program. Merger Transaction between Private Viracta Therapeutics, Inc. and Sunesis Pharmaceuticals, Inc. and Name Change On November 29, 2020, the Company, then operating as Sunesis Pharmaceuticals, Inc., entered into an agreement and plan of merger and reorganization (the “Merger Agreement”) with privately held Viracta Therapeutics, Inc. (“Private Viracta”) and Sol Merger Sub, Inc., a wholly owned subsidiary of the Company (“Merger Sub”). On February 24, 2021, the transactions contemplated by the Merger Agreement were completed, and Merger Sub merged into Private Viracta, with Private Viracta surviving the merger as a wholly owned subsidiary of the Company (the “Merger”). Sunesis changed its name to Viracta Therapeutics, Inc. On February 25, 2021, the combined company’s common stock began trading on The Nasdaq Global Select Market under the ticker symbol “VIRX”. Except as otherwise indicated, references herein to “Viracta,” the “Company,” or the “combined company,” refer to Viracta Therapeutics, Inc. on a post-Merger basis, and the term “Private Viracta” refers to the business of privately held Viracta Therapeutics, Inc., prior to the completion of the Merger. References to “Sunesis” refer to Sunesis Pharmaceuticals, Inc. prior to completion of the Merger. Liquidity and Capital Resources As of June 30, 2024, the Company has devoted substantially all its efforts to product development and has not realized product sales revenues from its planned principal operations. The Company has a limited operating history, and the sales and income potential of the Company’s business and market are unproven. The Company has experienced net losses since its inception and, as of June 30, 2024, had an accumulated deficit of $284.9 million. The Company expects to continue to incur net losses and operating cash outflows for at least the next several years. A successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. Based on the Company's current financial position and business plan, the Company will need to raise additional capital through the issuance of its common stock, through other equity or debt financings or through collaborations or partnerships with other companies, to fund its continued operations. The Company may be unable to raise additional funds or to enter into such agreements or arrangements on favorable terms, or at all. If the Company is unable to raise capital or enter into such agreements as and when needed, it may have to significantly delay, scale back, or discontinue the development or commercialization of one or more of its product candidates. As of June 30, 2024, the Company had cash, cash equivalents, and short-term investments of $30.0 million and working capital of $2.4 million. On November 4, 2021, the Company entered into a loan and security agreement with Silicon Valley Bank, now a division of First-Citizens Bank and Trust Company (“SVB”), and Oxford Finance LLC (“Oxford”), collectively referred to as “Lenders,” for up to $50.0 million, with $5.0 million refinanced at the time of entering into the agreement and $45.0 million available under certain circumstances, as amended August 26, 2022. The second tranche of $20.0 million was drawn by the Company on December 29, 2022. The availability of the additional tranche of $25.0 million, previously available under certain conditions, expired on December 31, 2023. Pursuant to the terms of the Second Amendment, the Company remitted a prepayment of $5.0 million toward the outstanding principal in March 2024 (see Note 5). Based on the Company’s current financial position and business plan, management believes that its existing cash, cash equivalents and short-term investments may not be sufficient to fund the Company’s planned operations for at least twelve months from the issuance date of these condensed consolidated financial statements. The Company’s current liquidity position, recurring net losses from operations and negative cash flows from operating activities raise substantial doubt about its ability to continue as a going concern. Because management’s equity and/or debt financing plans, along with collaborative or other funding arrangements have not yet been executed and are not fully within the Company’s control, such plans cannot be considered probable of being achieved. As a result, the Company has concluded that its plans do not alleviate substantial doubt about the Company’s ability to continue as a going concern. Due to these circumstances and based on the Company's assessment that the material adverse change clause under the SVB-Oxford Loan Facility (see Note 5) is not within the Company's control, all amounts due under the SVB-Oxford Loan Facility have been classified as a current liability as of June 30, 2024. The accompanying condensed consolidated financial statements have been prepared on a basis which assumes the Company will be able to continue as a going concern, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from any uncertainty related to its ability to continue as a going concern.

Organization and Basis of Presentation

6 Months Ended

Jun. 30, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

1. Organization and Basis of Presentation

Viracta Therapeutics, Inc. (“Viracta,” the “Company,” or the “combined company”), formerly known as Sunesis Pharmaceuticals, Inc., was incorporated in the state of Delaware in February 1998 and is based in San Diego, California. Viracta is a clinical-stage, precision oncology company focused on the treatment and prevention of virus-associated cancers that impact patients worldwide. Viracta’s lead product candidate is an all-oral combination therapy of its proprietary investigational drug, nanatinostat and the antiviral agent valganciclovir (collectively referred to as “Nana-val”). Nana-val is currently being investigated in multiple ongoing clinical trials, including NAVAL-1, a pivotal, global, multicenter, open-label Phase 2 basket trial for the treatment of multiple subtypes of relapsed/refractory (“R/R”) Epstein-Barr virus-positive (“EBV+”) lymphoma, as well as a multinational, open-label Phase 1b/2 trial for the treatment of EBV+ recurrent or metastatic nasopharyngeal carcinoma (“R/M NPC”) and other EBV+ solid tumors. In August 2024, Viracta announced it plans to pause the EBV+ solid tumor program to focus resources on the more advanced EBV+ lymphoma program.

Merger Transaction between Private Viracta Therapeutics, Inc. and Sunesis Pharmaceuticals, Inc. and Name Change

On November 29, 2020, the Company, then operating as Sunesis Pharmaceuticals, Inc., entered into an agreement and plan of merger and reorganization (the “Merger Agreement”) with privately held Viracta Therapeutics, Inc. (“Private Viracta”) and Sol Merger Sub, Inc., a wholly owned subsidiary of the Company (“Merger Sub”). On February 24, 2021, the transactions contemplated by the Merger Agreement were completed, and Merger Sub merged into Private Viracta, with Private Viracta surviving the merger as a wholly owned subsidiary of the Company (the “Merger”). Sunesis changed its name to Viracta Therapeutics, Inc. On February 25, 2021, the combined company’s common stock began trading on The Nasdaq Global Select Market under the ticker symbol “VIRX”.

Except as otherwise indicated, references herein to “Viracta,” the “Company,” or the “combined company,” refer to Viracta Therapeutics, Inc. on a post-Merger basis, and the term “Private Viracta” refers to the business of privately held Viracta Therapeutics, Inc., prior to the completion of the Merger. References to “Sunesis” refer to Sunesis Pharmaceuticals, Inc. prior to completion of the Merger.

Liquidity and Capital Resources

As of June 30, 2024, the Company has devoted substantially all its efforts to product development and has not realized product sales revenues from its planned principal operations. The Company has a limited operating history, and the sales and income potential of the Company’s business and market are unproven. The Company has experienced net losses since its inception and, as of June 30, 2024, had an accumulated deficit of $284.9 million. The Company expects to continue to incur net losses and operating cash outflows for at least the next several years. A successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. Based on the Company's current financial position and business plan, the Company will need to raise additional capital through the issuance of its common stock, through other equity or debt financings or through collaborations or partnerships with other companies, to fund its continued operations. The Company may be unable to raise additional funds or to enter into such agreements or arrangements on favorable terms, or at all. If the Company is unable to raise capital or enter into such agreements as and when needed, it may have to significantly delay, scale back, or discontinue the development or commercialization of one or more of its product candidates. As of June 30, 2024, the Company had cash, cash equivalents, and short-term investments of $30.0 million and working capital of $2.4 million.

On November 4, 2021, the Company entered into a loan and security agreement with Silicon Valley Bank, now a division of First-Citizens Bank and Trust Company (“SVB”), and Oxford Finance LLC (“Oxford”), collectively referred to as “Lenders,” for up to $50.0 million, with $5.0 million refinanced at the time of entering into the agreement and $45.0 million available under certain circumstances, as amended August 26, 2022. The second tranche of $20.0 million was drawn by the Company on December 29, 2022. The availability of the additional tranche of $25.0 million, previously available under certain conditions, expired on December 31, 2023. Pursuant to the terms of the Second Amendment, the Company remitted a prepayment of $5.0 million toward the outstanding principal in March 2024 (see Note 5).

Based on the Company’s current financial position and business plan, management believes that its existing cash, cash equivalents and short-term investments may not be sufficient to fund the Company’s planned operations for at least twelve months from the issuance date of these condensed consolidated financial statements. The Company’s current liquidity position, recurring net losses from operations and negative cash flows from operating activities raise substantial doubt about its ability to continue as a going concern. Because management’s equity and/or debt financing plans, along with collaborative or other funding arrangements have not yet been executed and are not fully within the Company’s control, such plans cannot be considered probable of being achieved. As a result, the

Company has concluded that its plans do not alleviate substantial doubt about the Company’s ability to continue as a going concern. Due to these circumstances and based on the Company's assessment that the material adverse change clause under the SVB-Oxford Loan Facility (see Note 5) is not within the Company's control, all amounts due under the SVB-Oxford Loan Facility have been classified as a current liability as of June 30, 2024. The accompanying condensed consolidated financial statements have been prepared on a basis which assumes the Company will be able to continue as a going concern, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classifications of liabilities that may result from any uncertainty related to its ability to continue as a going concern.