X0202 SCHEDULE 13G 0001940272 XXXXXXXX LIVE Common Stock, $0.0001 par value per share 03/31/2026 0001620463 LeonaBio, Inc. 04746L203 18706 North Creek Parkway Suite 104 Bothell WA 98011 Rule 13d-1(b) ADAR1 Capital Management, LLC b TX 0.00 727481.00 0.00 727481.00 727481.00 N 7.7 IA OO Includes (i) 568,234 shares of common stock, $0.0001 par value per share ("Common Stock") held by ADAR1 Partners, LP, (ii) 77,371 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 81,876 shares of Common Stock held by other separately managed accounts as of March 31, 2026. Excludes 1,230,315 shares of Common Stock underlying common warrants held by ADAR1 Partners, LP and Spearhead Insurance Solutions IDF, LLC, the exchange and exercise of which are subject to 4.99% beneficial ownership limitations. As the investment manager of ADAR1 Partners, LP and as the sub-advisor of Spearhead Insurance Solutions IDF, LLC and the separately managed accounts referenced above, ADAR1 Capital Management, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC and the separately managed accounts. Based on 9,393,514 shares of Common Stock of LeonaBio, Inc. (the "Issuer") outstanding as of March 31, 2026, reported in the Issuer's Form 10-Q for the quarterly period ended March 31, 2026, filed with the Securities and Exchange Commission on May 7, 2026. Daniel Schneeberger b V8 0.00 727481.00 0.00 727481.00 727481.00 N 7.7 HC IN Includes (i) 568,234 shares of common stock, $0.0001 par value per share ("Common Stock") held by ADAR1 Partners, LP, (ii) 77,371 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 81,876 shares of Common Stock held by other separately managed accounts as of March 31, 2026. Excludes 1,230,315 shares of Common Stock underlying common warrants held by ADAR1 Partners, LP and Spearhead Insurance Solutions IDF, LLC, the exchange and exercise of which are subject to 4.99% beneficial ownership limitations. As the manager of ADAR1 Capital Management, LLC, Mr. Schneeberger may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC and the separately managed accounts referenced above. Based on 9,393,514 shares of Common Stock of LeonaBio, Inc. (the "Issuer") outstanding as of March 31, 2026, reported in the Issuer's Form 10-Q for the quarterly period ended March 31, 2026, filed with the Securities and Exchange Commission on May 7, 2026. LeonaBio, Inc. 18706 North Creek Parkway Suite 104 Bothell, WA, 98011 This Schedule is being filed on behalf of each of the following persons (each, a "Reporting Person" and collectively, the "Reporting Persons"): (i) ADAR1 Capital Management, LLC ("ADAR1 Capital Management"); and (ii) Daniel Schneeberger ("Mr. Schneeberger"). The address of the principal business office of each of the Reporting Persons is 3503 Wild Cherry Drive, Building 9, Austin, Texas 78738. (i) ADAR1 Capital Management is a Texas limited liability company; and (ii) Mr. Schneeberger is a citizen of Switzerland. N IA HC The information contained on the cover pages of this Schedule 13G is incorporated herein by reference. The information contained on the cover pages of this Schedule 13G is incorporated herein by reference. The information contained on the cover pages of this Schedule 13G is incorporated herein by reference. The information contained on the cover pages of this Schedule 13G is incorporated herein by reference. The information contained on the cover pages of this Schedule 13G is incorporated herein by reference. The information contained on the cover pages of this Schedule 13G is incorporated herein by reference. Y Y N Mr. Schneeberger is filing this Schedule 13G as a control person in respect of shares beneficially owned by ADAR1 Capital Management, an investment adviser as described in SS 240.13d-1(b)(1)(ii)(E). 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 A: Joint Filing Agreement ADAR1 Capital Management, LLC /s/ Daniel Schneeberger 05/15/2026 Daniel Schneeberger /s/ Daniel Schneeberger 05/15/2026