Business Description

1. Nature of the Business and Basis of Presentation Background and Basis of Presentation Oruka Therapeutics, Inc., together with its subsidiary (collectively, the “Company”), formerly known as ARCA biopharma, Inc. (“ARCA”), is a clinical-stage biopharmaceutical company that is the result of the reverse recapitalization discussed below. Prior to the reverse recapitalization, the private company Oruka Therapeutics, Inc. (“Pre-Merger Oruka”) was established and incorporated under the laws of the state of Delaware on February 6, 2024 (referred to in the Notes as the inception of the Company). The Company is headquartered in Menlo Park, California. The Company is focused on developing novel monoclonal antibody therapeutics for psoriasis (“PsO”) and other inflammatory and immunology (“I&I”) indications. The accompanying consolidated financial statements reflect the operations of the Company and its wholly-owned subsidiary. Intercompany balances and transactions have been eliminated in consolidation. The accompanying consolidated financial statements have been prepared in conformity with United States (“U.S.”) generally accepted accounting principles (“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 Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). Reverse Recapitalization and Pre-Closing Financing, and Reverse Stock Split On August 29, 2024 (the “Closing”), the Company completed the acquisition (the “Merger”) of Pre-Merger Oruka pursuant to an Agreement and Plan of Merger and Reorganization, dated as of April 3, 2024 (the “Merger Agreement”). Following the transactions contemplated by the Merger Agreement, Pre-Merger Oruka merged with and into Atlas Merger Sub Corp., a wholly owned subsidiary of ARCA and following that, Pre-Merger Oruka then merged with and into Atlas Merger Sub II, LLC (“Second Merger Sub”), with Second Merger Sub being the surviving entity. Second Merger Sub changed its corporate name to “Oruka Therapeutics Operating Company, LLC”. On August 29, 2024, the Company changed its name from “ARCA biopharma, Inc.” to “Oruka Therapeutics, Inc.” and the Company effected a 1-for-12 reverse stock split (the “Reverse Stock Split”) of its common stock, par value $0.001 per share (“Company Common Stock”), which became effective on September 3, 2024. All references to common stock, options to purchase common stock, outstanding common stock warrants, common stock share data, per share data, Company Common Stock, and related information contained in the consolidated financial statements have been retrospectively adjusted to reflect the effect of the Reverse Stock Split for all periods presented, unless otherwise specifically indicated or the context otherwise requires. Immediately prior to the execution and delivery of the Merger Agreement, certain new and existing investors of Pre-Merger Oruka entered into a subscription agreement with Pre-Merger Oruka (that was subsequently amended and restated in July 2024, the “Subscription Agreement”), pursuant to which, and on the terms and subject to the conditions of which, immediately prior to the Closing, those investors purchased shares of common stock of Pre-Merger Oruka (“Pre-Merger Oruka Common Stock”) and Pre-Merger Oruka pre-funded warrants for gross proceeds of approximately $275.0 million (which includes $25.0 million of proceeds previously received from the issuance of the Convertible Note (as defined in Note 9) and accrued interest on such note which converted to shares of Pre-Merger Oruka Common Stock) (the “Pre-Closing Financing”). The Company incurred transaction costs of $20.5 million, which were recorded as a reduction to additional paid-in capital in the consolidated financial statements. In connection with the Closing, the shares of Pre-Merger Oruka Common Stock were converted into shares of Company Common Stock and pre-funded warrants of Company Common Stock in accordance with the Exchange Ratio (as defined below and determined by the terms of the Merger Agreement).…