Table of Contents As filed with the Securities and Exchange Commission on September 18, 2025. Registration No. 333-289532 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 Amendment No. 1 to FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TUHURA BIOSCIENCES, INC. 10500 University Center Drive, Suite 110 Tampa, Florida 33612 (813) 875-6600 (Address, including zip code, and telephone number, including area code, of registrant's principal executive offices) James Bianco C ...

Table of Contents As filed with the Securities and Exchange Commission on September 18, 2025. Registration No. 333-289532 UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 Amendment No. 1 to FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TUHURA BIOSCIENCES, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Nevada 2834 99-0360497 (Primary Standard Industrial Classification Code Number) (I.R.S. Emp ...

Core Insights - TuHURA Biosciences has completed the acquisition of Kineta, Inc. and its VISTA inhibiting monoclonal antibody, now named TBS-2025, with plans to initiate a Phase 2 trial in relapsed/refractory NPM1-mutated Acute Myeloid Leukemia (AML) in the second half of 2025 [1][4] - The company has initiated a Phase 3 accelerated approval trial of IFx-2.0 as an adjunctive therapy with Keytruda® for advanced and metastatic Merkel cell carcinoma (MCC), under a Special Protocol Assessment (SPA) agreement with the FDA [1][3] Corporate Highlights - TuHURA completed a $12.5 million equity financing transaction and received an additional $3 million from warrant exercise proceeds [2][5] - The company was included in the Russell 3000® and Russell 2000® Indexes as of June 27, 2025 [4] Clinical Development - The Phase 3 trial of IFx-2.0 is a single randomized placebo-controlled trial that could potentially meet the requirements for both accelerated and full approval without the need for a post-accelerated approval confirmatory trial [3] - A Phase 1b/2a trial has been initiated for IFx-2.0 as an adjunctive therapy in first-line treatment of checkpoint-naïve patients with MCC of unknown primary origin, targeting newly diagnosed patients with metastatic tumors [3] Financial Performance - Research and development expenses for the second quarter of 2025 were $4.9 million, compared to $2.8 million for the same period in 2024 [7] - Net cash outflows from operating activities for the first half of 2025 were ($10.9) million, compared to ($8.9) million for the same period in 2024 [7] Upcoming Milestones - The company plans to advance TBS-2025 into a randomized Phase 2 trial in the second half of 2025 [6] - TuHURA anticipates providing updates on enrollment progress in its Phase 3 trial of IFx-2.0 by the end of 2025 and topline results from the Phase 1b/2a trial in Q1 2026 [12]

Table of Contents As filed with the Securities and Exchange Commission on [ ], 2025. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TUHURA BIOSCIENCES, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Nevada 2834 99-0360497 (Primary Standard Industrial Classification Code Number) (I.R.S. Employer Identification No.) 10500 Un ...

Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-1 REGISTRATION STATEMENT Table of Contents As filed with the Securities and Exchange Commission on [ ], 2025. UNDER THE SECURITIES ACT OF 1933 TUHURA BIOSCIENCES, INC. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Nevada 2834 99-0360497 (Primary Standard Industrial Classification Code Number) (I.R.S. Employer Identification No.) 10500 Un ...

Core Points - TuHURA Biosciences, Inc. has been added to the Russell 3000® Index and automatically included in the Russell 2000® Index as part of the 2025 annual reconstitution, effective June 27, 2025 [1][2] - The inclusion in the Russell indexes signifies the company's progress in its first year as a publicly traded entity and reflects its potential for continued development [2] - TuHURA is currently enrolling patients in a Phase 3 accelerated approval trial of its lead product IFx-2.0, which is being tested as an adjunctive therapy to Keytruda® for advanced or metastatic Merkel cell carcinoma [2][11] - The company has also acquired a novel anti-VISTA antibody from Kineta, Inc. and plans to advance it into a Phase 2 clinical trial for treating NMPL1-mutated Acute Myeloid Leukemia [2] Company Overview - TuHURA Biosciences, Inc. is focused on developing novel technologies to overcome resistance to cancer immunotherapy, addressing both primary and acquired resistance [10] - The company's lead product, IFx-2.0, is designed to enhance the effectiveness of checkpoint inhibitors [11] - TuHURA is also leveraging its Delta Opioid Receptor technology to create bi-specific antibody drug conjugates aimed at inhibiting immune suppression in the tumor microenvironment [12]

Acquisition Overview - TuHURA Biosciences has successfully completed the acquisition of Kineta, Inc., which includes a novel VISTA inhibiting monoclonal antibody (mAb) now named TBS-2025, enhancing TuHURA's late-stage immuno-oncology pipeline [1][2] - The acquisition allows TuHURA to initiate a Phase 2 randomized trial for TBS-2025 in the second half of 2025 [1] Financial Details - The completion of the acquisition unlocks the fourth tranche of funds from a $12.5 million aggregate PIPE financing announced on June 3, 2025 [1] - Each share of Kineta common stock was converted into the right to receive 0.185298 shares of TuHURA common stock, totaling 2,868,169 shares [3] Product Development - TBS-2025 is positioned to overcome acquired resistance to cancer immunotherapy, particularly in patients with NPM1 mutated acute myeloid leukemia (AML) [2] - The drug is being investigated in combination with a menin inhibitor, aiming to improve response rates and reduce relapse in AML patients [2] Mechanism of Action - VISTA is a significant immune checkpoint expressed on myeloid cells, contributing to immunosuppression in the tumor microenvironment [5] - TBS-2025 is designed to block VISTA, potentially enhancing T cell function and improving treatment outcomes in cancer therapy [5][6] Clinical Trials - TBS-2025 has shown promising results in a Phase 1/2 trial, demonstrating good tolerance and over 90% receptor occupancy [7] - The drug is administered intravenously every two weeks and has been tested both as a monotherapy and in combination with pembrolizumab [6][7] Company Background - TuHURA Biosciences focuses on developing technologies to address primary and acquired resistance to cancer immunotherapy [8] - The company is also working on bi-specific antibody drug conjugates targeting myeloid derived suppressor cells to enhance immune response [10]

Core Viewpoint - TuHURA Biosciences and Kineta have successfully completed stockholder meetings, approving a merger and key proposals, including an increase in authorized shares and reincorporation in Delaware [1][2]. Company Overview - TuHURA Biosciences, Inc. is a Phase 3 immuno-oncology company focused on developing technologies to overcome resistance to cancer immunotherapy [4]. - Kineta, Inc. is a clinical-stage biotechnology company dedicated to creating next-generation immunotherapies to address challenges in current cancer treatments [8]. Merger Details - TuHURA stockholders approved all proposals at the TuHURA Special Meeting, including increasing authorized shares to 200 million [1]. - Kineta stockholders also approved the merger with TuHURA at their Special Meeting [2]. - The merger is expected to close soon after satisfying remaining conditions [2]. Product Development - TuHURA's lead product, IFx-2.0, aims to overcome primary resistance to checkpoint inhibitors and is preparing for a Phase 3 trial in advanced Merkel Cell Carcinoma [5]. - TuHURA is also developing bi-specific antibody drug conjugates targeting Myeloid Derived Suppressor Cells to enhance immune response [6]. - Kineta's pipeline includes KVA12123, a VISTA blocking immunotherapy in Phase 1/2 trials, showing strong tumor growth inhibition in preclinical models [9]. Financial and Strategic Context - Kineta underwent a corporate restructuring in February 2024 to reduce expenses and preserve cash, including workforce reductions and halting new patient enrollment in trials [10]. - The merger aims to maximize stockholder value and enhance the combined company's capabilities in immunotherapy [10].

Core Insights - TuHURA Biosciences, Inc. is focused on developing novel technologies to address resistance to cancer immunotherapy, with a particular emphasis on its Phase 3 programs and innovative antibody drug conjugates [4][5][6] Group 1: Company Overview - TuHURA is a Phase 3 immune-oncology company that aims to overcome both primary and acquired resistance to cancer immunotherapy, which are common reasons for treatment failure [4] - The company is preparing to initiate a randomized placebo-controlled Phase 3 trial of its lead product, IFx-2.0, in combination with Keytruda® for advanced Merkel Cell Carcinoma [5] - TuHURA's acquisition of Kineta, Inc. is expected to enhance its portfolio, including the rights to Kineta's KVA12123 antibody, with the merger targeted to close in Q2 2025 [3] Group 2: Upcoming Events - James A. Bianco, M.D., CEO of TuHURA, will present at the 3rd Annual H.C. Wainwright BioConnect Investor Conference on May 20, 2025, highlighting the company's Phase 3 program and its bi-specific immune modulating antibody drug [1][2] - Management will also be available for one-on-one meetings with qualified investors during the conference [2] Group 3: Research and Development - TuHURA is leveraging its Delta Opioid Receptor technology to develop bi-specific immune modulating antibody drug conjugates targeting Myeloid Derived Suppressor Cells, aiming to prevent T cell exhaustion [7] - The company plans to initiate a randomized trial in Q3 2025 for a menin inhibitor combined with a VISTA inhibiting antibody in relapsed or refractory Acute Myeloid Leukemia (AML) [6]

Core Insights - TuHURA Biosciences, Inc. is advancing its Phase 3 immune-oncology initiatives, focusing on overcoming resistance to cancer immunotherapy [5][6] - The company announced that abstracts from Kineta Inc. and Moffitt Cancer Center will be presented at the AACR Annual Meeting 2025, showcasing novel therapies for advanced melanoma [1][2] Group 1: Company Developments - TuHURA is set to present initial results from a Phase 1 study of KVA12123, an anti-VISTA antibody, in combination with pembrolizumab for advanced solid tumors [2] - The company is preparing to initiate a Phase 3 trial for its lead product, IFx-2.0, as an adjunctive therapy to Keytruda® for advanced Merkel Cell Carcinoma [6] - TuHURA has entered into a merger agreement with Kineta, Inc. to acquire the rights to KVA12123, with the merger expected to close in Q2 2025 [4] Group 2: Research and Presentations - The accepted abstracts for the AACR Annual Meeting include mechanistic insights into IFx-Hu2.0 responses after prior anti-PD-1 therapy failure [2] - Presentations will take place on April 28, 2025, with specific sessions dedicated to experimental therapeutics and immunology [2][3]