--- title: "TRex Bio files for IPO as Eli Lilly signals interest in buying shares" url: "https://aibio.space/news/trex-bio-files-ipo-eli-lilly-signals-interest-buying-shares/" publisher: "aibio.space (Biotech Investor Relations News)" date: "2026-09-18" section: "Financings" tickers: "NASDAQ:TRXB" source: "https://www.sec.gov/Archives/edgar/data/2139097/000119312526395671/ck0002139097-20260918.htm" summary: "TRex Bio filed for a Nasdaq IPO on September 18, 2026. Eli Lilly, which signed a research collaboration with the company in 2023, has indicated interest in" --- By the aibio.space news desk. Sources - [TRex Bio, Inc. S-1 (2026-09-18)](https://www.sec.gov/Archives/edgar/data/2139097/000119312526395671/ck0002139097-20260918.htm) [TRXB](https://aibio.space/companies/trex-bio/) 2026-09-18 # TRex Bio files for IPO as Eli Lilly signals interest in buying shares Tickers [TRXB](https://aibio.space/companies/trex-bio/) TRex Bio filed for a Nasdaq IPO on September 18, 2026. Eli Lilly, which signed a research collaboration with the company in 2023, has indicated interest in buying shares, but the indication is not binding and the price range and share count are still blank. ## Key facts - **Company**: TRex Bio, Inc. (NASDAQ: TRXB) - **News type**: Financings - **Primary source**: [TRex Bio, Inc. S-1 (2026-09-18)](https://www.sec.gov/Archives/edgar/data/2139097/000119312526395671/ck0002139097-20260918.htm) *The lower Manhattan skyline. CC0, via rawpixel. The picture shows the field, not the companies named.* ## The filing TRex Bio, Inc. filed a Form S-1 registration statement on September 18, 2026 for an initial public offering of its common stock. The South San Francisco company has applied to list on The Nasdaq Global Select Market under the symbol TRXB, and the offering depends on that listing. The preliminary prospectus leaves the number of shares, the expected price range and the underwriting figures blank. ## Lilly's indication Eli Lilly and Company has indicated an interest in buying shares at the IPO price. The indication is capped so that Lilly's total stake, including shares it already owns, will not exceed 19.9% of the shares outstanding after the offering. The prospectus says the indication is not a binding agreement. Lilly may buy more, fewer or no shares, and the underwriters may sell more, fewer or none to Lilly. Any Lilly purchase reduces the number of shares left for public buyers. Lilly has a history with the company. In 2023 the two signed a research collaboration and license agreement, and Lilly paid a one-time upfront of $55.0 million. The company recognized total collaboration revenue of $41.9 million that year across its collaboration agreements. Its chief executive, M. Johnston Erwin, Jr., spent 36 years at Eli Lilly and Company before joining TRexBio. He has been chief executive and a director since May 2021, and chair since 2026. ## The company and its pipeline TRex describes itself as a clinical-stage biopharmaceutical company focused on regulatory T cells in tissue. Its most advanced wholly owned candidate, TRB-061, is a TNFR2 agonist. It is in a Phase 1a/b trial in healthy volunteers and in patients with moderate-to-severe atopic dermatitis, with topline data from the patient portion expected in mid-2027. The company says its Phase 1a trial in healthy participants showed expansion of a tissue Treg subpopulation. That is a finding in volunteers, and the company's first topline data in patients are not due until mid-2027. The second candidate, TRB-071, is a CD30 agonist aimed at inflammatory bowel disease. It is in IND-enabling studies and, subject to regulatory allowance, is expected to enter a Phase 1 trial in the first half of 2027. The company's platform, which it calls Deep Biology, is built on a proprietary database of healthy and diseased tissue samples. The S-1 presents the platform's value as a belief, not a demonstrated result. ## Losses and cash TRex reported a net loss of $3.1 million for 2024 and $34.8 million for 2025. Net cash used in operating activities was $25.6 million in 2024 and $41.4 million in 2025. It has had net losses and negative operating cash flow every year since its founding except 2023, when the Lilly upfront produced net income. As of December 31, 2025, the company had cash, cash equivalents and marketable securities of $67.7 million and an accumulated deficit of $94.3 million. In January 2026 it sold 16,182,795 shares of Series B preferred stock in an extension of its Series B financing, for about $50.0 million. The company believes its year-end cash plus the extension proceeds will fund operations for at least twelve months from the date the financial statements were issued. ## Underwriters and counsel J.P. Morgan, Evercore ISI, Cantor, Stifel, Wedbush and PacGrow are named as underwriters. They have a 30-day option to buy additional shares from the company. The cover page lists Ropes & Gray LLP and Latham & Watkins LLP as copies to, without saying which firm represents the company and which the underwriters. ## What the filing leaves open The S-1 gives 73,867,448 shares outstanding as of June 30, 2026, after a preferred stock conversion, and excludes 11,518,123 shares issuable on exercise of options at a weighted average exercise price of $0.31. It leaves blank the number of shares offered, the price and the net proceeds. Part of the proceeds is earmarked for TRB-061 trials in atopic dermatitis and alopecia areata, part for a Phase 1 trial of TRB-071, and the rest for working capital. A directed share program, run by J.P. Morgan Securities LLC, would reserve a blank percentage of the shares for directors, officers, employees and others. [Report an error](https://aibio.space/reputation/#correction) ## Companies in this story TRXB TRex Bio, Inc. 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Cite as: aibio.space, "TRex Bio files for IPO as Eli Lilly signals interest in buying shares", 2026-09-18, https://aibio.space/news/trex-bio-files-ipo-eli-lilly-signals-interest-buying-shares/