TRex Bio (TRXB) is preparing to offer 8,333,334 shares on the Nasdaq Global Select Market at $14–$16 per share. At the $15 midpoint, the offering would raise approximately $125 million before expenses and value the company at approximately $411.7 million, based on 27.45 million shares outstanding after the offering, excluding the underwriters’ option. J.P. Morgan, Evercore ISI, Cantor, Stifel and Wedbush PacGrow are underwriting the transaction. The South San Francisco company is developing medicines designed to restore immune balance and promote tissue repair in autoimmune and inflammatory diseases.
TRex’s approach centers on regulatory T cells, or Tregs, which help control immune responses and maintain healthy tissue. Rather than simply blocking inflammatory signals, the company aims to strengthen the immune system’s own regulatory mechanisms in affected tissues. Its Deep Biology platform uses human tissue samples and functional testing to identify drug targets and guide development. The approach offers a potentially differentiated path in immunology, although its ability to deliver meaningful and durable benefits in patients remains to be established.
The lead wholly owned candidate, TRB-061, is a TNFR2 agonist designed to expand and activate Tregs in inflamed tissues. TRex began a Phase 1a trial in healthy volunteers in June 2025 and initiated the Phase 1b portion in patients with moderate-to-severe atopic dermatitis in April 2026. Topline Phase 1b data are expected in mid-2027. The study evaluates safety, drug exposure and biological activity, alongside exploratory measures of clinical efficacy. Atopic dermatitis is a substantial market, but TRex will need to demonstrate a compelling benefit in a field that already includes established biologic and oral treatments.
A second wholly owned candidate, TRB-071, targets CD30 and is intended to augment tissue Tregs while blocking inflammatory signaling. The program is being developed initially with inflammatory bowel disease in mind and remains in studies needed to support an application to begin human testing. Subject to regulatory clearance, TRex expects to initiate a Phase 1 trial in the first half of 2027. The company also sees opportunities for its pipeline in additional indications, including alopecia areata.
Eli Lilly is both an investor and a development partner. A separate candidate discovered through TRex’s platform, TRB-051, is being advanced by Lilly. The prospectus states that Lilly intends to move that program into a Phase 2a trial in lupus with cutaneous involvement in the second half of 2026. Lilly has also indicated interest in purchasing IPO shares, subject to its combined ownership not exceeding 19.9% following the offering. That indication is nonbinding. The relationship provides external support for the platform, but does not establish clinical success for TRex’s wholly owned programs.
TRex has no approved products and has not generated product-sales revenue. It recognized $39.1 million of collaboration revenue in 2024, but none in 2025 or the first half of 2026. Net losses increased from $3.1 million in 2024 to $34.8 million in 2025. For the first six months of 2026, the company reported a $29.3 million net loss, compared with $17.7 million a year earlier. Research and development spending rose to $26.0 million from $15.0 million over those same six-month periods, reflecting the expanding development effort. The earlier collaboration revenue should therefore be viewed separately from any future recurring commercial revenue.
As of June 30, 2026, TRex held approximately $90.9 million in cash, cash equivalents and marketable securities. At the midpoint, estimated IPO net proceeds are $111.3 million, increasing to $128.7 million if the underwriters fully exercise their option to purchase 1.25 million additional shares. Management expects existing resources and offering proceeds to fund operations into the second half of 2029, based on its current plan. Proceeds are intended to support TRB-061 development, including Phase 2 trials in atopic dermatitis and alopecia areata through topline results, and TRB-071 development through a Phase 1 healthy-volunteer trial, alongside working capital and general corporate purposes.
TRex offers exposure to a distinctive immunology platform, a Lilly relationship and several anticipated clinical milestones. The principal uncertainty is whether encouraging biological activity can translate into meaningful patient outcomes with an acceptable safety profile. Its wholly owned pipeline remains early, losses are increasing, and additional financing may eventually be required. At the proposed valuation, the investment case depends primarily on future clinical execution rather than current revenue or profitability.