UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-38800 Harpoon Therapeutics, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-38800 Harpoon Therapeutics, Inc. (Exact name of registrant as specified in its charter) Delaware 47-3458693 (State or other jurisdiction of ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Securities registered pursuant to Section 12(b) of the Act: | Title of each class | Trading Symbol(s) | Name of each exchange on which registered | | --- | --- | ...

Financial Performance - The company reported net losses of $67.7 million, $116.8 million, and $49.9 million for the years ended December 31, 2022, 2021, and 2020, respectively, with an accumulated deficit of $352.5 million as of December 31, 2022[445]. - The company has incurred significant net operating losses since inception and expects to continue incurring losses for the foreseeable future, with research and development expenses anticipated to increase[446]. - Net loss narrowed by $48.9 million, or 42%, to $67.7 million in 2022 from $116.7 million in 2021[490]. - The net cash used in operating activities was $89.2 million in 2022, compared to $122.2 million in 2021, indicating improved cash flow management[490]. - In 2022, cash used in operating activities was $89.2 million, consisting of a net loss of $67.7 million and a net change of $33.6 million in net operating assets and liabilities, partially offset by $12.1 million in non-cash charges[491]. - In 2021, cash used in operating activities was $122.2 million, with a net loss of $116.7 million and a net change of $19.9 million in net operating assets and liabilities, partially offset by $14.5 million in non-cash charges[492]. - Cash provided by financing activities in 2022 was $6.4 million, mainly from $5.4 million in net proceeds from the sale of common stock[494]. - Cash provided by financing activities in 2021 was $111.5 million, primarily from $107.6 million in net proceeds from a follow-on offering[495]. Research and Development - HPN217 demonstrated an overall response rate (ORR) of 77% (10/13) at the highest step doses (12 and 24 mg), with 86% (18/21) of responders remaining on study treatment[426]. - The Phase 1 clinical trial of HPN217 included 62 patients treated with doses up to 24 mg/week, with the most frequent treatment-emergent adverse events being anemia (44%), fatigue (32%), and transient cytokine release syndrome (CRS) (27%)[425]. - HPN328 is currently enrolling patients in a Phase 1/2 clinical trial, with 39% of enrolled patients showing a decrease in sum of target lesion diameters[432]. - The company plans to present interim data for HPN328 in the second half of 2023 and aims to identify a recommended Phase 2 dose by the end of 2023[435]. - Research and development expenses are expected to increase substantially as the company advances its product candidates through clinical trials and regulatory approval processes[464]. - Research and development expenses rose by $9.3 million, or 13%, to $81.4 million in 2022, driven by a $7.2 million increase in product and clinical development expenses[471]. - Research and development expenses consist of personnel costs and non-personnel costs, with significant judgments made in estimating accrued liabilities[513]. Corporate Actions - A corporate restructuring in November 2022 resulted in a workforce reduction of approximately 45%, with estimated costs of up to $1.8 million for termination benefits[444]. - The company implemented a corporate restructuring in November 2022, reducing workforce by approximately 45% to focus on its clinical pipeline[481]. - In November 2022, the company announced a corporate restructuring expected to incur cash payments of up to approximately $1.1 million for termination benefits in the first half of 2023[497]. Revenue and Collaboration - The company has a global Development and Option Agreement with AbbVie for HPN217, which includes potential future payments totaling up to $430 million upon achievement of certain milestones[429]. - AbbVie made an upfront payment of $30.0 million and a development milestone payment of $50.0 million related to the HPN217 program[453]. - If AbbVie exercises its option for the HPN217 program, it will pay an option exercise fee of $200.0 million and up to $230.0 million in further milestone payments[453]. - The company recognized $24.4 million and $18.4 million of revenue from the Development and Option Agreement for the years ended 2022 and 2021, respectively[455]. - Under the Restated Collaboration Agreement, the company received an upfront payment of $20.0 million, with $7.5 million and $0.9 million recognized as revenue in 2022 and 2021, respectively[459]. - Collaboration and license revenue increased by $8.3 million, or 35%, to $31.9 million in 2022 compared to $23.7 million in 2021[470]. - The company has entered into collaboration and license agreements with AbbVie and Werewolf Therapeutics, generating revenue from non-refundable upfront license fees, milestone payments, and royalties on net sales[504]. Financial Position - As of December 31, 2022, the company had $53.1 million in cash and cash equivalents, with an accumulated deficit of $352.5 million[476]. - The company received approximately $11.2 million in net proceeds from the sale of common stock from October 2020 to December 31, 2022, and an additional $1.5 million in 2023[448]. - In March 2023, the company sold 25,000 shares of Series A Preferred Stock and warrants for a total gross proceeds of approximately $25.0 million[449]. - Deferred revenue under the Development and Option Agreement was $21.7 million as of December 31, 2022[455]. - Total operating expenses decreased by $40.2 million, or 29%, to $100.2 million in 2022 from $140.4 million in 2021, primarily due to a $50.0 million decrease in litigation settlement[474]. - Interest income surged by $0.5 million, or 223%, to $0.8 million in 2022, attributed to higher interest yields on cash and marketable securities[475]. Accounting and Compliance - The company is classified as an emerging growth company under the JOBS Act, allowing it to delay adopting new accounting standards until certain conditions are met[520]. - The company expects to utilize the extended transition period for any new or revised accounting standards while remaining an emerging growth company[521]. - The company will maintain its status as an emerging growth company until it reaches total annual gross revenues of at least $1.235 billion or the market value of its common stock held by non-affiliates exceeds $700 million[522]. - Stock-based compensation expense for all awards is recognized based on estimated fair values on the grant date, using the Black-Scholes model[515].

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-38800 Harpoon Therapeutics, Inc. (Exact name of registrant as specified in its charter) Delaware 47-3458693 (State or other jurisdicti ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-38800 Harpoon Therapeutics, Inc. (Exact name of registrant as specified in its charter) Delaware 47-3458693 (State or other jurisdiction of ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 131 Oyster Point Blvd, Suite 300 South San Francisco, CA 94080 (Address of principal executive offices) Registrant's telephone number, including area code: (650) 443-7400 Securities registered pursuant to Section 12(b) of the Act: | Title of each class | Trading Symbol(s) | Name of ea ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-38800 Harpoon Therapeutics, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or org ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-38800 Harpoon Therapeutics, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File No. 001-38800 Harpoon Therapeutics, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) Delaware 47-3458693 (I.R.S. Employer Identification No.) (Mark One) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECUR ...