Bambusa, Aspen, and Tang added to IPO pipeline

2026's sizeable haul of biotech IPOs shows no signs of letting up, with three more companies – Bambusa, Aspen, and blank cheque firm Tang – joining the queue.

Boston, Massachusetts-based immunology and inflammation (I&I) specialist Bambusa Therapeutics, which was set up in 2024 by former BioNTech executives Shanshan Xu and Helmut Jeggle, filed its intention to list on the Nasdaq under the BBTX ticker. It is developing a pipeline of drugs licensed from BioNTech's Chinese subsidiary Biotheus.

Leading the charge is BBT001, billed as a next-generation bispecific antibody directed against IL-4Rα and IL-31, two targets shared with Sanofi/Regeneron's blockbuster type 2 inflammatory skin disease therapy Dupixent (dupilumab). BBT001 is in a phase 2a trial in China in chronic spontaneous urticaria (CSU), while Bambusa is running a phase 1 study in atopic dermatitis.

Following after in Bambusa's clinical pipeline is BBT002, which targets IL-4Rα and IL-5 and is in early-stage clinical trials for chronic obstructive pulmonary disease (COPD), chronic rhinosinusitis with nasal polyps (CRSwNP), and asthma. The company also has a pair of preclinical-stage candidates, namely TL1A and IL-23p19-targeting BBT003 for inflammatory bowel disease and BBT004, a B-cell-depleting bispecific antibody for autoimmune diseases.

Aspen Neuroscience, which is developing stem cell therapies for Parkinson's disease, has filed an IPO to raise additional funding for its one-off, autologous candidate, sasineprocel (formerly ANPD001), which is derived from patient skin cells and is currently in the phase 1/2a ASPIRO study.

The eight-year-old San Diego, California, biotech is developing cell therapies based on an induced pluripotent stem cell (iPSC) derived cell therapy platform that creates therapies that are based on a patient's own cells, eliminating the need for immunosuppressive therapy. As of mid-August, 15 Parkinson's patients have been dosed with sasineprocel, which has shown encouraging preliminary efficacy results, including symptom improvements. A phase 3 trial is due to start next year.

Aspen plans to list on the Nasdaq under the symbol ASPE. It has raised $340 million in venture capital funding to date, most recently closing a $115 million Series C a year ago.

The third new IPO, filed by Tang Capital Acquisition, is a slightly different proposition as it involves a special purpose acquisition company (SPAC) set up to provide a Nasdaq listing to an established biotech company via a merger.

The San Diego start-up is planning to raise up to $75 million in its IPO, according to a Renaissance Capital report, which notes that one backer (Tang Capital Management) has already signed up to buy $50 million in shares. The SPAC, which plans to list under the TCAA symbol, will target private, development-stage biopharmaceutical companies for merger after the IPO completes.

TRex Bio launches, and City prices

In other recent IPO developments, South San Francisco-based TRex Bio raised $117 million on its debut, but was notable for pricing below the midpoint of its expected range, an unusually modest return among this year's listings. TRex's lead candidate TRB-061, a TNFR2 agonist, is in a phase 1b trial in moderate-to-severe atopic dermatitis with data expected in mid-2027.

Meanwhile, RNAi-focused biotech City Therapeutics priced its IPO at a range of $17 to $19, offering 9.72 million shares that could generate up to $185 million and give it a valuation above $1 billion. The funds will go towards its lead programme, CITY-FXI, an RNAi candidate for the treatment of thromboembolic diseases, which has just started clinical testing.

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