United States securities and exchange commission logo April 27, 2023 Douglas Onsi Chief Executive Officer LEAP THERAPEUTICS, INC. 47 Thorndike Street, Suite B1-1 Cambridge, MA 02141 Re: LEAP THERAPEUTICS, INC. Registration Statement on Form S-3 Filed April 21, 2023 File No. 333-271399 Dear Douglas Onsi : This is to advise you that we have not reviewed and will not review your registration statement. Please refer to Rules 460 and 461 regarding requests for acceleration. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Please contact Lauren Hamill at 303-844-1008 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Julio Vega