X0202 SCHEDULE 13G 0002147397 XXXXXXXX LIVE Common stock, par value $0.0001 07/27/2026 0001566044 Yarrow Bioscience, Inc. 92941V407 470 James Street, Suite 007 New Haven CT 06513 Rule 13d-1(b) RTW Fund Group GP, LLC DE 0.00 266307.00 0.00 266307.00 266307.00 Y 9.99 IA HC Excludes shares of Common Stock issuable upon the exercise of pre-funded warrants held by the Reporting Persons in excess of a beneficial ownership limitation of 9.99%. Roderick Wong X1 0.00 266307.00 0.00 266307.00 266307.00 Y 9.99 HC IN Excludes shares of Common Stock issuable upon the exercise of pre-funded warrants held by the Reporting Persons in excess of a beneficial ownership limitation of 9.99%. Yarrow Bioscience, Inc. 470 James Street, Suite 007, New Haven, CT 06513 This statement is filed by: (i) RTW Fund Group GP, LLC ("RTW Fund Group"), a Delaware limited liability company and the manager of a certain entity ("RTW Entity"), with respect to shares of Common Stock, par value $0.0001 per share (the "Shares") of Yarrow Bioscience, Inc. (the "Company") directly held by RTW Entity; and (ii) Roderick Wong, M.D. ("Dr. Wong"), the Managing Member of RTW Fund Group, with respect to the Shares directly held by RTW Entity. The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." The filing of this statement should not be construed as an admission that any of the foregoing persons or any Reporting Person is, for the purposes of Section 13 of the Securities Exchange Act of 1934, as amended, the beneficial owner of the Shares reported herein. The address of the business office of each of the Reporting Persons is 40 10th Avenue, Floor 7, New York, New York 10014. RTW Fund Group is a Delaware limited liability company. Dr. Wong is a citizen of the United States. N IA HC The information required by Item 4(a) is set forth in Rows 5 - 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The percentages set forth in Row 11 of the cover pages are calculated based upon 2,669,788 Shares outstanding as of July 29, 2026, as reported in the Company's Current Report on Form 8-K filed with the Securities and Exchange Commission on July 30, 2026. RTW Fund Group: 9.99% Dr. Wong: 9.99% RTW Fund Group: 0 Dr. Wong: 0 RTW Fund Group: 266,307 Dr. Wong: 266,307 RTW Fund Group: 0 Dr. Wong: 0 RTW Fund Group: 266,307 Dr. Wong: 266,307 Y N See Item 2. RTW Entity has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Shares reported herein. Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11. Exhibit 99.1 Joint Filing Agreement RTW Fund Group GP, LLC /s/ Roderick Wong, M.D. 07/30/2026 Roderick Wong /s/ Roderick Wong, M.D. 07/30/2026