Use these links to rapidly review the document TABLE OF CONTENTS PART IV INDEX TO CONSOLIDATED FINANCIAL STATEMENTS Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2019 Or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001 ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington D.C. 20549 FORM 10-Q (Mark One) x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2019 OR o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-37990 LEAP THERAPEUTICS, INC. (Exact name of registrant as specified in its charter) Delaware 27-4412575 S ...

PART I — FINANCIAL INFORMATION [Financial Statements](index=6&type=section&id=Item%201.%20Financial%20Statements) Unaudited financial statements as of June 30, 2019, report a $17.0 million net loss for H1 2019, $15.7 million cash, and substantial doubt about going concern [Condensed Consolidated Balance Sheets](index=6&type=section&id=Condensed%20Consolidated%20Balance%20Sheets) As of June 30, 2019, total assets were $20.1 million, with $15.7 million in cash, and total stockholders' equity at $10.9 million Condensed Consolidated Balance Sheet Data (in thousands) | Account | June 30, 2019 (Unaudited) | December 31, 2018 | | :--- | :--- | :--- | | Cash and cash equivalents | $15,747 | $16,284 | | Total current assets | $16,794 | $17,322 | | Total assets | $20,137 | $19,074 | | Total current liabilities | $8,456 | $6,451 | | Total liabilities | $9,198 | $9,899 | | Total stockholders' equity | $10,939 | $9,175 | [Condensed Consolidated Statements of Operations](index=7&type=section&id=Condensed%20Consolidated%20Statements%20of%20Operations) Net loss for Q2 2019 increased to $8.4 million, while H1 2019 net loss decreased to $17.0 million due to non-recurring warrant liability loss in prior year Operating Results (in thousands, except per share data) | Metric | Q2 2019 | Q2 2018 | H1 2019 | H1 2018 | | :--- | :--- | :--- | :--- | :--- | | Research and development | $6,136 | $4,234 | $12,926 | $8,465 | | General and administrative | $2,325 | $2,603 | $4,330 | $4,716 | | Loss from operations | $(8,461) | $(6,837) | $(17,256) | $(13,181) | | Net loss | $(8,366) | $(7,364) | $(16,969) | $(17,986) | | Net loss per share | $(0.37) | $(0.50) | $(0.82) | $(1.32) | [Condensed Consolidated Statements of Cash Flows](index=11&type=section&id=Condensed%20Consolidated%20Statements%20of%20Cash%20Flows) Net cash used in operating activities increased to $14.1 million in H1 2019, with financing activities providing $13.6 million Cash Flow Summary for Six Months Ended June 30 (in thousands) | Activity | 2019 | 2018 | | :--- | :--- | :--- | | Net cash used in operating activities | $(14,051) | $(11,531) | | Net cash used in investing activities | $(100) | $0 | | Net cash provided by financing activities | $13,582 | $16,013 | | Net (decrease) increase in cash | $(537) | $4,744 | [Notes to Condensed Consolidated Financial Statements](index=12&type=section&id=Notes%20to%20Condensed%20Consolidated%20Financial%20Statements) Notes detail the company's pre-revenue status, going concern doubt, adoption of new lease and financial instrument accounting standards, and recent financing activities - The company is a biopharmaceutical firm focused on developing cancer therapeutics and has not yet generated any revenue or achieved profitable operations[39](index=39&type=chunk)[42](index=42&type=chunk) - Management has concluded that **substantial doubt exists** about the company's ability to continue as a going concern for one year, given its need for additional capital to fund operations[44](index=44&type=chunk) - On January 1, 2019, the company adopted ASU 2017-11, reclassifying its **$3.448 million** 2017 Warrant liability to additional paid-in capital[58](index=58&type=chunk)[87](index=87&type=chunk) - The company adopted new lease accounting standard ASU 2016-02 on January 1, 2019, recording a right-of-use asset of **$1.755 million** and a lease liability of **$1.720 million**[83](index=83&type=chunk) - In February 2019, the company completed a public offering, raising net proceeds of approximately **$12.1 million**[93](index=93&type=chunk) - Subsequent to the quarter end, in July 2019, the company entered into an agreement with Lincoln Park Capital for the right to sell up to **$20.0 million** in common stock and completed an initial sale of **$1.0 million**[117](index=117&type=chunk)[118](index=118&type=chunk) - The company is involved in patent opposition proceedings at the European Patent Office (EPO) regarding its TRX518 antibody patents[110](index=110&type=chunk)[112](index=112&type=chunk) [Management's Discussion and Analysis of Financial Condition and Results of Operations](index=29&type=section&id=Item%202.%20Management%27s%20Discussion%20and%20Analysis%20of%20Financial%20Condition%20and%20Results%20of%20Operations) Management discusses increased R&D expenses, critical liquidity with $15.7 million cash, and substantial doubt about going concern, mitigated by a $20 million equity commitment [Company Overview and Recent Developments](index=29&type=section&id=Company%20Overview%20and%20Recent%20Developments) The company focuses on developing DKN-01 and TRX518, with recent positive clinical data for DKN-01 and a new $21 million equity commitment facility - Presented positive data for DKN-01 in combination with KEYTRUDA for esophagogastric cancer, showing a **50% overall response rate** and **31.6 weeks median overall survival** in DKK1-high patients[124](index=124&type=chunk) - Initiated a clinical trial evaluating TRX518 in a triple combination with cyclophosphamide chemotherapy and BAVENCIO (avelumab)[125](index=125&type=chunk) - Entered into a purchase agreement with Lincoln Park Capital for an initial **$1 million** stock purchase and the option to sell up to an additional **$20 million** in common stock[127](index=127&type=chunk) [Results of Operations](index=33&type=section&id=Results%20of%20Operations) R&D expenses increased to $6.1 million in Q2 2019 and $12.9 million in H1 2019, while H1 net loss decreased to $17.0 million due to non-recurring items R&D Expenses by Program (in thousands) | Program | Q2 2019 | Q2 2018 | H1 2019 | H1 2018 | | :--- | :--- | :--- | :--- | :--- | | DKN-01 program | $3,247 | $3,652 | $8,622 | $6,845 | | TRX518 program | $2,889 | $582 | $4,304 | $1,620 | | **Total R&D Expenses** | **$6,136** | **$4,234** | **$12,926** | **$8,465** | - The increase in R&D expenses for H1 2019 was primarily due to a **$4.7 million** increase in clinical trial costs from higher patient enrollment, partially offset by a **$1.2 million** decrease in manufacturing costs[156](index=156&type=chunk) - General and administrative expenses for H1 2019 decreased by **$0.4 million** compared to H1 2018, mainly due to lower bonus expense and reduced legal and consulting fees[158](index=158&type=chunk) [Financial Position, Liquidity and Capital Resources](index=38&type=section&id=Financial%20Position%2C%20Liquidity%20and%20Capital%20Resources) The company ended Q2 2019 with $15.7 million cash, faces substantial doubt about going concern, and relies on a July 2019 Lincoln Park agreement for future capital - As of June 30, 2019, the company had cash and cash equivalents of **$15.7 million**[166](index=166&type=chunk) - Due to the need for additional capital and uncertainties in raising it, management determined there is **substantial doubt** about the company's ability to continue as a going concern[166](index=166&type=chunk)[188](index=188&type=chunk) - In July 2019, the company secured access to up to **$20.0 million** in capital through a purchase agreement with Lincoln Park[167](index=167&type=chunk) Cash Flow Summary for Six Months Ended June 30 (in thousands) | Activity | 2019 | 2018 | | :--- | :--- | :--- | | Cash used in operating activities | $(14,051) | $(11,531) | | Cash provided by financing activities | $13,582 | $16,013 | [Quantitative and Qualitative Disclosures About Market Risk](index=40&type=section&id=Item%203.%20Quantitative%20and%20Qualitative%20Disclosures%20About%20Market%20Risk) This section is not applicable for the reporting period - Not Applicable[177](index=177&type=chunk) [Controls and Procedures](index=40&type=section&id=Item%204.%20Controls%20and%20Procedures) Management concluded that disclosure controls and procedures were effective as of June 30, 2019, with no material changes in internal control - The Principal Executive Officer and Principal Financial Officer concluded that as of June 30, 2019, the company's disclosure controls and procedures were effective[179](index=179&type=chunk) - There were no changes in internal control over financial reporting during the quarter that materially affected, or are reasonably likely to affect, internal control[180](index=180&type=chunk) PART II — OTHER INFORMATION [Legal Proceedings](index=42&type=section&id=Item%201.%20Legal%20Proceedings) The company reported no legal proceedings for the period - None[182](index=182&type=chunk) [Risk Factors](index=42&type=section&id=Item%201A.%20Risk%20Factors) The company faces significant risks including substantial financial losses, a $17.0 million net loss for H1 2019, and substantial doubt about its ability to continue as a going concern - The company has a history of significant losses, reporting a net loss of **$17.0 million** for the six months ended June 30, 2019, and an accumulated deficit of **$179.2 million**[186](index=186&type=chunk) - Management has concluded that **substantial doubt exists** as to the company's ability to continue as a going concern due to its need for additional capital[188](index=188&type=chunk) - The company will require substantial additional capital to fund operations and advance its clinical programs; failure to obtain this financing could force delays or elimination of R&D programs[191](index=191&type=chunk) - Raising additional capital may cause significant dilution to existing stockholders or require the company to relinquish valuable rights to its product candidates[193](index=193&type=chunk) [Unregistered Sales of Equity Securities and Use of Proceeds](index=43&type=section&id=Item%202.%20Unregistered%20Sales%20of%20Equity%20Securities%20and%20Use%20of%20Proceeds) The company reported no unregistered sales of equity securities for the period - None[194](index=194&type=chunk) [Other Information](index=45&type=section&id=Item%205.%20Other%20Information) The company reported no other information for the period - None[197](index=197&type=chunk) [Exhibits](index=45&type=section&id=Item%206.%20Exhibits) This section lists exhibits filed with the Quarterly Report on Form 10-Q, including officer certifications and XBRL data files - The Exhibit Index lists certifications from the Principal Executive Officer and Principal Financial Officer (Exhibits 31.1, 31.2, 32.1) and the company's financial statements formatted in XBRL (Exhibit 101)[198](index=198&type=chunk)[201](index=201&type=chunk)

Financial Performance - Net loss for Q1 2019 was $8,603,000, an improvement of 18.9% compared to a net loss of $10,622,000 in Q1 2018[25]. - For the three months ended March 31, 2019, the company reported a net loss of $8.6 million, increasing the accumulated deficit to $170.9 million[166]. - The basic and diluted net loss per share for the three months ended March 31, 2019, was $(0.47), compared to $(0.85) for the same period in 2018, indicating a 44.7% reduction in loss per share[99]. - The company incurred a net loss of $23.1 million for the year ended December 31, 2018, reflecting ongoing financial challenges[166]. - The company expects significant increases in expenses as it advances clinical trials and preclinical activities for its product candidates[147]. - The company anticipates continued significant operating losses as it advances the clinical development of its product candidates DKN-01 and TRX518[167]. - Management has expressed substantial doubt regarding the company's ability to continue as a going concern due to the need for additional capital[168]. Assets and Equity - Total current assets increased to $22,712,000 as of March 31, 2019, up from $17,322,000 as of December 31, 2018, representing a growth of 31.8%[19]. - Total stockholders' equity increased to $17,064,000 as of March 31, 2019, compared to $9,175,000 as of December 31, 2018, reflecting an increase of 85.8%[19]. - Cash and cash equivalents at the end of Q1 2019 were $21,709,000, a decrease of 38.5% from $35,376,000 at the end of Q1 2018[31]. - The company had cash and cash equivalents of $21.7 million as of March 31, 2019, indicating a need for additional capital to fund operations[170]. - The accumulated deficit as of March 31, 2019, was $(170,871,000), compared to $(153,535,000) as of December 31, 2018, reflecting an increase in the deficit of 11.3%[19]. Research and Development - Research and development expenses for Q1 2019 were $6,790,000, a 60.3% increase compared to $4,231,000 in Q1 2018[21]. - The DKN-01 program accounted for $5.375 million in research and development expenses, up from $3.193 million in 2018, a 68% increase[135]. - The company plans to increase research and development expenses to support the ongoing development of DKN-01 and TRX518, subject to funding availability[118]. - Research and development expenses increased to $6.79 million for the three months ended March 31, 2019, compared to $4.23 million in the same period of 2018, representing a 61% increase[135]. - The company recorded Australian research and development incentive income of $75,000 in Q1 2019, down from $646,000 in Q1 2018, a decrease of 88%[139]. - The percentage of eligible research and development expenses reimbursed under the Australian incentive program was 43.5% for both the year ended December 31, 2018, and the three months ended March 31, 2019[46]. Capital Raising and Financing - The company raised $12,331,000 from the issuance of common stock in Q1 2019, compared to $15,033,000 in Q1 2018, showing a decrease of 17.9%[31]. - The Company completed a public offering on February 5, 2019, issuing 7,557,142 shares at $1.75 per share, resulting in net proceeds of approximately $12,122,000[111]. - The company expects to seek additional capital through a combination of private and public equity offerings, debt financings, and strategic collaborations[172]. - The company plans to seek additional funding through public or private equity financings or government programs to support its operations and development programs[41]. Operational Activities - The company reported a net cash used in operating activities of $6,868,000 for Q1 2019, compared to $5,478,000 for Q1 2018, indicating a 25.3% increase in cash outflow[31]. - There were no investing activities reported during the three months ended March 31, 2019 and 2018[154]. - The company has not yet generated any revenues and continues to rely on raising capital for its operations[40]. - The company has incurred significant losses since its inception in 2011, with losses reported in every reporting period[166]. Clinical Trials and Product Development - DKN-01 is currently being studied in multiple ongoing clinical trials for various cancers, with significant clinical benefits reported in several patient populations[115]. - TRX518 is undergoing clinical trials in combination with gemcitabine chemotherapy and PD-1 antagonists, with positive responses observed in patients with advanced solid tumors[115]. - The company plans to pursue the clinical development of its advanced product candidates, DKN-01 and TRX518, and expand its intellectual property portfolio[151]. Expenses - General and administrative expenses for the three months ended March 31, 2019, were $771,000, compared to $611,000 in the same period of 2018, marking a 26.2% increase[98]. - General and administrative expenses decreased slightly to $2.005 million in Q1 2019 from $2.113 million in Q1 2018, a reduction of 5%[137]. - As of March 31, 2019, accrued expenses totaled $4,150,000, an increase from $2,872,000 as of December 31, 2018, with clinical trials accounting for $3,597,000[75].

.. . leaptherapeutics LEAP THERAPEUT Patient Number / Patienten Sponsor Trial Code / Drug name: DKN-01 for inte DKN-01 zur intravenösen Potency / Dosisstärke: 200 Sponsor/CRO: Universität Langenbeckstr. 1 5E4 . Company Overview| April 2019 Leap Therapeutics | | Forward Looking Statements This presentation contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this presentation, including statements regardi ...

Use these links to rapidly review the document TABLE OF CONTENTS PART IV INDEX TO CONSOLIDATED FINANCIAL STATEMENTS Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ý ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 Or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to (Exact name of registrant ...