LeonaBio, Inc. SEC filings document the company’s status as a Delaware clinical-stage biopharmaceutical issuer listed on The Nasdaq Capital Market under the LONA ticker. Its 8-K reports furnish financial results, business updates, Regulation FD disclosures, board matters, and material events tied to its product candidates and corporate development activity.
Registration statement amendments cover delayed or continuous securities offerings, while amended material-event filings document the completed Sermonix license transaction, related securities issuance, and SEC accounting disclosures under Regulation S-X. The filing record also reflects the company’s transition from Athira Pharma to LeonaBio and the capital-structure disclosures associated with its common stock and warrants.
LeonaBio, Inc. (LONA) reported a common-stock purchase and a warrant disposition dated October 26, 2026. The common-stock transaction row records an indirect purchase of 3,149,470 shares, with 3,149,470 shares reported afterward; the row’s reported price is not usable. No Rule 10b5-1 plan is reported.
A separate row reports disposition of a warrant covering 5,502,402 common shares, with an exercise price of $0.0010 per share. Its footnotes attribute the warrant to Sermonix Pharmaceuticals, Inc., whose CEO is reporting person David J. Portman. The footnote says the securities are reported to reflect his voting control and that his personal indirect beneficial ownership does not exceed 10%. It says the warrant was partly exercised into 3,149,740 shares and the remaining rights assigned to Perceptive Xentogeny Venture Fund II, LP as a distribution-in-kind; Sermonix then held 3,149,740 shares.
LeonaBio, Inc. (LONA) reported that Sermonix Pharmaceuticals, Inc. exercised a prefunded warrant on October 26, 2026, for the purchase and issuance of 3,149,470 common shares. Sermonix and its CEO David Portman reported shared voting and dispositive power over 3,149,470 shares, or 25.1% of the class. The stated percentage uses 9,421,663 shares outstanding disclosed in LeonaBio’s Form 10-Q filed August 14, 2026, and gives effect to the warrant exercise.
On October 26, 2026, Sermonix completed an assignment to Perceptive Xontogeny Venture Fund 11, LP (PXV II) of a newly issued prefunded warrant for 2,352,932 shares. Sermonix also declared a distribution in kind with respect to 4,725,754 common shares, including 2,352,932 assigned to PXV II; distribution to other Sermonix equity owners was contemplated but had not occurred. Sermonix agreed to assign 170,940 shares to a creditor in satisfaction of amounts owed, with remittance on or shortly after October 26, 2026.
LeonaBio, Inc. (LONA) reports that Sermonix Pharmaceuticals, Inc. exercised pre-funded warrants for 776,648 common shares on October 26, 2026, at an exercise price of $0.0010 per share.
Perceptive Advisors LLC, Joseph Edelman (a director and ten-percent owner), and Perceptive Life Sciences Master Fund Ltd. are the reporting persons; each is identified as a director and ten-percent owner. They reported Sermonix’s entire interest, not a proportionate amount, and disclaim beneficial ownership except to the extent of any indirect pecuniary interest. Holding entries list warrants exercisable for 457,645 shares held by Perceptive Xontogeny Venture Fund II, LP (PXV II), 1,372,935 shares held by the Master Fund, and 2,352,932 shares distributed by Sermonix to PXV II. The 19.99% beneficial-ownership limitation did not permit the Master Fund or PXV II to exercise any warrants as of the report date.
LeonaBio, Inc.'s amended ownership disclosure reports that PXV II received Sermonix Pre-Funded Warrants exercisable for 2,352,932 common shares on October 26, 2026, pursuant to a previously disclosed distribution of securities to owners of Sermonix common stock. The warrants are not exercisable to the extent exercise would result in beneficial ownership above 19.99% of LeonaBio's outstanding common stock.
The cover pages list Perceptive Advisors LLC and Joseph Edelman as each beneficially owning 1,889,403 shares (19.99%); Perceptive Life Sciences Master Fund, Ltd. as beneficially owning 1,559,647 shares (16.5%); and PXV II as beneficially owning 359,837 shares (3.8%).
LeonaBio, Inc. (LONA) reports that a large warrant issue has become exercisable. As part of a December 2025 private placement, the company issued Series A Common Warrants covering 23,031,494 shares of common stock at an exercise price of $6.35 per share. These warrants became exercisable on September 18, 2026 and will remain exercisable until October 19, 2026.
If all Series A Common Warrants are exercised for cash, LeonaBio states that it would receive approximately $146.2 million in additional capital. The company cautions that some or all of the warrants may expire unexercised or be exercised on a cashless net exercise basis, which would result in reduced or no cash proceeds.
LeonaBio, Inc. (LONA) reports that David J. Portman is a ten percent owner and discloses his indirect control over a large warrant position. The filing lists an indirectly held warrant for 5,502,402 shares of LeonaBio common stock, exercisable at $0.001 per share with no expiration.
The warrant is held by Sermonix Pharmaceuticals, Inc., where Mr. Portman is Chief Executive Officer, and the filing states it is being made to report his voting control over these securities. It also states that his personal indirect beneficial ownership does not exceed ten percent of LeonaBio’s stock.
LeonaBio, Inc. (LONA) is the subject of a Schedule 13D reporting that Sermonix Pharmaceuticals, Inc. and its CEO, David Portman, beneficially own 5,502,402 shares of LeonaBio common stock, or 36.9% of the class on an as-converted basis, through prefunded warrants received in a strategic collaboration.
The warrants were issued as partial consideration under a Securities Purchase Agreement and a License Agreement granting LeonaBio an exclusive license to develop and commercialize lasofoxifene, in exchange for royalties, milestones and the prefunded warrants. On August 24, 2026, Sermonix became eligible to exercise the prefunded warrants for 5,502,402 shares, subject to transactions effective October 26, 2026, including an assignment of 2,352,932 warrant shares to Perceptive Xontogeny, planned exercises for 3,149,470 shares, distributions-in-kind totaling 4,725,754 shares, and an assignment of 170,940 shares to a creditor.
LeonaBio, Inc. (LONA) reported enrollment of the 500th subject in its ongoing Phase 3 ELAINE-3 clinical trial of lasofoxifene in combination with abemaciclib for ER-positive, HER2-negative, ESR1-mutated metastatic breast cancer after progression on aromatase inhibitors and CDK4/6 inhibitors.
LeonaBio previously issued 23,031,494 Series A Common Warrants in a December 2025 private placement, each with an exercise price of $6.35 per share, generally payable in cash unless a resale registration statement is unavailable, in which case they may be exercised on a cashless net basis. The warrants become exercisable at each holder’s option after the earlier of (1) the latest of June 30, 2026, the publicly announced ELAINE-3 Enrollment Date, and specified FDA action on Eli Lilly’s imlunestrant plus abemaciclib application, and (2) October 31, 2026, and remain exercisable for 30 days, no later than November 30, 2026. If exercised in full for cash, they would provide approximately $146.2 million of additional capital.
LeonaBio, Inc. (LONA) received an amended Schedule 13D (Amendment No. 8) from Perceptive Advisors LLC and affiliated reporting persons updating their ownership and warrant arrangements. Perceptive entities report beneficial ownership of 1,889,403 shares of common stock, representing 19.99% of the class, based on 9,421,663 shares outstanding and giving effect to warrants for 30,081 shares that may be exercised within existing limits.
Perceptive Life Sciences Master Fund, Ltd. holds 1,559,647 shares (16.5%), and Perceptive Xontogeny Venture Fund II holds 359,837 shares (3.8%), all with shared voting and dispositive power. Sermonix plans to distribute pre-funded warrants exercisable for 2,352,932 additional shares to PXV II effective October 26, 2026, but these and other warrants are subject to a 19.99% Beneficial Ownership Limitation, capping how many shares may be acquired. The reporting persons state they have made no transactions in LeonaBio common stock in the past sixty days, and certain director stock options are excluded from beneficial ownership because they cannot be exercised above the same 19.99% threshold without advance notice.
LeonaBio, Inc. (symbol LONA) reports that investment entities associated with Acorn Bioventures have filed Amendment No. 2 to a Schedule 13G disclosing significant ownership of its common stock. Based on 9,421,663 shares outstanding as of August 12, 2026, Acorn Bioventures, L.P. and its general partner Acorn Capital Advisors GP, LLC report beneficial ownership of 480,653 shares, or 5.1% of the common stock, with shared voting power over these shares. Acorn Bioventures 2, L.P. and its general partner Acorn Capital Advisors GP 2, LLC report beneficial ownership of 663,763 shares, or 7.0% of the common stock, also with shared voting power. Anders Hove, as Manager of both general partners, may be deemed to beneficially own an aggregate 1,492,521 shares, representing 12.1% of LeonaBio’s common stock, with shared voting power over those shares.