Eli Lilly-backed TRex Bio and hypertension-focused Retension Pharmaceuticals are the latest biotechs to set out plans to go public this year, while ADARx is eyeing up to $446 million from its own listing.
Neither TRex nor Retension have suggested how many shares they are likely to offer—or at what price—but their respective Securities and Exchange Commission filings on Friday gave a sense of how they would use their IPO proceeds.
Top of the list of spending priorities for TRex is bankrolling phase 2 trials for its tumor necrosis factor receptor 2 (TNFR2) agonist TRB-061 in atopic dermatitis. Topline data from an ongoing phase 1 trial is due to read out in mid-2027.
The company also has plans to expand development of the Fc-fusion protein into other autoimmune and inflammatory diseases, including alopecia areata, it explained in the filing.
The other key priority is TRB-071, a CD30 agonist that TRex plans to take into the clinic in a phase 1 trial of healthy volunteers. By triggering both the activation and expansion of regulatory T cells (Tregs), the biotech believes TRB-071 has the potential to address underlying immune dysregulation in immune-mediated diseases such as inflammatory bowel disease, according to the filing.
Since TRex broke cover in 2021 with a $59 million series A, the South San Francisco-based biotech has attracted attention on the strength of a platform for discovering ways to modulate Tregs, a subset of T cells that play a key role in tissue inflammation. The biotech penned a collaboration with Johnson & Johnson a year later, and in 2023 Lilly paid $55 million to take up its option to license an immune effector cell modulator that has since entered the clinic.
Lilly has already expressed an interest in participating in the IPO, TRex explained in Friday's filing.
TRex’s history with the Indianapolis Big Pharma goes way back, with the biotech’s CEO Johnston Erwin being a long-time Lilly veteran. Erwin currently oversees a workforce of 60 full-time employees, with around $91 million sitting in the bank following on from an $84 million series B in 2024 and $50 million financing at the start of this year.
Meanwhile, Retension has one candidate in mind when it thinks of how to spend the proceeds of its own planned IPO. The first priority will be completing a phase 2b study of RTN-001 in patients with uncontrolled hypertension (uHTN). The biotech has been testing the once-daily, oral, small molecule phosphodiesterase-5 (PDE-5) inhibitor as a way to reduce blood pressure by potentiating nitric oxide signaling.
Retension is hoping that RTN-001 will differentiate itself from first-generation PDE-5 inhibitors like Viagra—which never lived up to their early promise to reduce blood pressure—because the next-gen drug has been engineered to have increased bioavailability and an increased distribution to the muscular arteries.
RTN-001 has already demonstrated a clinically meaningful reduction in systolic blood pressure and diastolic blood pressure in pilot phase 2 studies, the biotech noted in its own SEC filing.
Part of the IPO proceeds will also be used to launch a phase 3 study in uHTN, Retension added.
Retension’s Chief Scientific Officer Paul Sweetnam, Ph.D., and three other members of the biotech’s development team were involved with the invention of RTN-001 while working together at Surface Logix. Retension’s CEO Eric Keller entered the story when the company he helmed at the time, Nano Terra, bought out Surface Logix.
Through various licensing deals and company acquisitions, RTN-001 has come under the overall ownership of companies like Kadmon and Sanofi, before Retension was created and granted the license to the drug.
The small company currently only numbers 12 full-time professionals, with $13.5 million sitting in the bank as of the end of June.
The interest from Retension and TRex in joining the Nasdaq comes during a bumper run of IPOs in 2026 that has included record-breaking listings from the likes of Parabilis Medicines and Kailera Therapeutics.
Another drug developer already in the IPO queue is small interfering RNA (siRNA) biotech ADARx Pharmaceuticals. The AbbVie-backed company said it is hoping to raise $397.1 million from an IPO—rising to $445.9 million if underwriters fully take up their option to buy additional shares. The money would fund the development of three clinical-stage medicines.