aibioLeonaBio Series A warrants become exercisable at $6.35 a share
Tickers LONA
LeonaBio said its Series A common warrants became exercisable on September 18, 2026 and remain exercisable until October 19, 2026, with about $146.2 million of cash if fully exercised.
Key facts
- Company
- LeonaBio, Inc. (NASDAQ: LONA)
- News type
- Financings
- Primary source
- LeonaBio, Inc. 8-K (2026-09-22)
LeonaBio, Inc. (NASDAQ: LONA) said in a Form 8-K dated September 18, 2026 that its Series A common warrants became exercisable that day and will remain exercisable until October 19, 2026. The warrants cover 23,031,494 shares of common stock at an exercise price of $6.35 per share. If they are exercised in full for cash, the company says they would provide approximately $146.2 million of additional capital.
The warrant terms
The warrants were issued in December 2025 as part of a private placement. The filing says that if the resale registration statement covering the shares issuable on exercise is not effective at the time of exercise, the warrants may be exercised on a cashless net exercise basis, which would provide the company with less or no cash proceeds. It also says some or all of the warrants may expire unexercised.
The filing names no underwriter, placement agent or financial advisor for the warrants or for the December 2025 private placement.
The lasofoxifene program
LeonaBio describes itself as a clinical-stage biopharmaceutical company developing novel therapeutics for high unmet medical needs, including treatment-resistant metastatic breast cancer and amyotrophic lateral sclerosis (ALS). Its lead drug candidate, lasofoxifene, is a selective estrogen receptor modulator that is being evaluated in ELAINE-3, a registrational Phase 3 trial for metastatic breast cancer with ESR1 mutations. The annual report says the company acquired rights to lasofoxifene in December 2025 and in-licensed it globally, excluding Asia and certain countries in the Middle East.
The annual report says estrogen receptor-positive breast cancer accounts for roughly 70% of all breast cancer cases. Endocrine therapies remain the standard of care, but most patients with metastatic disease eventually develop resistance, often through mutations in the ESR1 gene. The company says tumors with these mutations show diminished sensitivity to standard agents such as fulvestrant.
The company is amending the ELAINE-3 protocol to increase the sample size from 500 participants to up to 600 participants. The stated goal is to make sure the trial has the appropriate number of disease progression events. The primary analysis will be performed after 285 progression-free survival events are observed by blinded independent central review. The FDA granted lasofoxifene Fast Track Designation in May 2019.
The company's second program, ATH-1105, is a small-molecule positive modulator of the neurotrophic HGF system. According to the annual report, it has completed a first-in-human Phase 1 trial, and planning for a Phase 2 trial in ALS is underway.
Financial position
The annual report figures in SEC XBRL data show research and development expense of $17.5 million for 2025, compared with $70.7 million for 2024. The net loss was $105.6 million for 2025 and $96.9 million for 2024. Operations used $45.7 million of cash in 2025 and $97.2 million in 2024.
Year-end cash and cash equivalents were $69.3 million at December 31, 2025, against $48.4 million a year earlier. Short-term investments were $19.1 million at year-end 2025, compared with $2.8 million at year-end 2024. The quarterly report gives cash and cash equivalents of $32.3 million at June 30, 2026, and short-term investments of $18.7 million at the same date.
What is unproven and what could go wrong
LeonaBio has no approved product. The annual report says Pfizer's US applications for lasofoxifene in other indications drew no approvals, Pfizer chose not to launch it in Europe, and the drug is not authorized for marketing anywhere in the world. Its breast cancer case rests on a pivotal trial still being enlarged from 500 participants to up to 600, with topline data expected in the second half of 2027. ATH-1105 has only completed a first-in-human trial, and an ALS Phase 2 is still being planned.
The company lost $105.6 million in 2025, with operations using $45.7 million of cash, and held $32.3 million in cash and $18.7 million in short-term investments at June 30, 2026. The $146.2 million of warrant proceeds depends on holders exercising for cash by October 19, 2026, and the filing says some or all may expire unexercised. If holders do exercise, they would receive up to 23,031,494 new shares at $6.35, adding to the share count.