IPO
TRex Bio raises $117M IPO; Retension Pharmaceuticals lists with $45M IPO
Biotech
IPO
Key Facts
Signal Type
IPO
Industry
Biotech
Companies
TRex Bio, Retension Pharmaceuticals, City Therapeutics, Eli Lilly, Johnson & Johnson
Date
TRex Bio went public on the Nasdaq under the ticker “TRXB,” raising $116.7 million in gross proceeds by offering 8.3 million shares at $14 each—the bottom end of its predicted range. Eli Lilly, a prior collaborator, expressed interest in participating in the IPO. The biotech had previously broken cover with a $59 million Series A in 2021 and secured an $84 million Series B in 2024, leaving it with ~$91 million in the bank before this offering.
CEO Johnston Erwin, a long-time Lilly veteran, oversees 60 full-time employees at TRex Bio’s South San Francisco headquarters. The company’s clinical-stage pipeline includes a TNFR2 agonist (TRB-061) in Phase 1 for atopic dermatitis with topline data expected in mid-2027, and a CD30 agonist (TRB-071) slated for a Phase 1 trial in healthy volunteers. On the investor side, Eli Lilly (backer of the 2023 license option) and Johnson & Johnson (2022 collaboration partner) are key stakeholders.
The IPO signals continued capital market appetite for Treg-modulating therapies and autoimmune disease targets. However, TRex’s pricing at the low end of the range suggests cautious investor sentiment. The $116.7M proceeds will primarily fund:
If underwriters fully exercise their option to purchase an additional 1.3 million shares, net proceeds could rise to $128.7 million. This liquidity positions TRex for aggressive execution over the next 12–18 months.
Topline Phase 1 data for TRB-061 in atopic dermatitis is expected by mid-2027—a key pipeline de-risking event. The company’s ability to hire additional clinical staff or contract with CROs will be a direct signal of spend velocity. Additionally, the IPO filing mentions plans to move TRB-061 into Phase 2 for autoimmune diseases beyond AD; watch for specific trial site selection and investigator contracts.
Source:
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