Welcome to our dedicated page for LeonaBio SEC filings (Ticker: LONA), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
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) 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.
LeonaBio, Inc. is a clinical-stage biopharmaceutical company developing lasofoxifene for ESR1-mutated metastatic breast cancer and brelgometon for ALS. For the six months ended June 30, 2026, it reported a net loss of $51.9 million, significantly higher than $16.1 million a year earlier, driven by much higher research and development and general and administrative spending.
Cash, cash equivalents and investments totaled $51.1 million at June 30, 2026, down from $69.9 million at year-end, with $37.9 million used in operating activities in the first half. The company states that existing liquidity may not fund operations for at least 12 months, raising substantial doubt about its ability to continue as a going concern.
LeonaBio raised $90.0 million in a December 2025 PIPE, issuing common stock and multiple warrant classes, including 23.0 million Series A Common Warrants that, if fully exercised, could provide an additional $146.2 million. A 5.5 million-share Sermonix pre-funded warrant was reclassified from liability to equity after stockholder approval, eliminating a large fair value liability from the balance sheet.
LeonaBio reported results for the quarter ended June 30, 2026 and highlighted progress across its oncology and neurodegeneration pipeline. The company’s lead program, lasofoxifene, is being evaluated in the Phase 3 ELAINE-3 trial in ER-positive, HER2-negative, ESR1‑mutated metastatic breast cancer in combination with abemaciclib. Enrollment has reached 495 patients, and LeonaBio expects to complete enrollment of approximately 600 participants in 4Q 2026, with topline data expected in the second half of 2027.
Lasofoxifene previously showed encouraging activity in the Phase 2 ELAINE‑1 and ELAINE‑2 studies, and LeonaBio is investing in CMC, regulatory and commercial readiness ahead of potential approval. The company also advanced brelgometon (ATH‑1105), which completed a first‑in‑human Phase 1 trial in 80 healthy volunteers, demonstrating favorable safety, tolerability and CNS penetration, supporting a planned Phase 2 proof‑of‑concept trial in ALS.
Cash, cash equivalents and investments were $51.1 million as of June 30, 2026. Net cash used in operations was $37.9 million for the quarter. Research and development expenses rose to $12.9 million, general and administrative expenses to $6.6 million, and net loss to $19.0 million, or $0.80 per share. The company points to up to an additional $146 million in potential proceeds from cash‑exercisable warrants issued in its December 2025 financing as a key funding source for upcoming milestones.
LeonaBio, Inc. reported a Form 4 showing a grant of stock options covering 28,000 shares of common stock to a board designee associated with Perceptive Advisors. The options have an exercise price of $9.54 per share and expire on April 8, 2036, vesting monthly over 24 months while the optionee continues as a Service Provider.
LeonaBio, Inc. reported a Form 4 showing an option grant related to director compensation. Entities associated with director Joseph Edelman received a stock option covering 28,000 shares of common stock at an exercise price of $8.35 per share. The option vests on the earlier of June 23, 2027 or the day before the next annual stockholder meeting after June 22, 2026, and expires on June 22, 2036. The grant was made under LeonaBio’s Outside Director Compensation Policy, with Perceptive entities having an indirect pecuniary interest through a management fee offset and disclaiming beneficial ownership except to that extent.
LeonaBio, Inc. director Fred Callori received a grant of stock options covering 2,333 shares of common stock at an exercise price of $8.35 per share. These options vest on the earlier of June 23, 2027 or just before the next annual stockholder meeting after June 22, 2026 and expire on June 22, 2036.