Parkinson’s disease cell therapy-focused Aspen Neuroscience and bispecific biotech Bambusa Therapeutics are each hoping to raise around $134 million from their respective IPOs.
Both companies announced earlier this month that they were mulling a public listing, but they’ve now put some figures onto those plans in documents filed with the Securities and Exchange Commission Monday.
Aspen is aiming to offer 9.4 million shares priced between $15 and $17 apiece, according to its filing. Assuming the final price falls in the middle of this range, the biotech expects to bring in $134.5 million in net proceeds—rising to $155.4 million if underwriters buy an additional 1.4 million shares at the same price.
Aspen’s move comes off the back of promising phase 1/2a data for its Parkinson’s disease asset. The autologous therapy, called sasineprocel, is designed to turn skin cells from patients into stem cells that are then prompted to become new neurons to be implanted into the brain.
Around $8 million of the IPO funds is needed for an ongoing phase 1/2a trial in patients with sporadic and genetic Parkinson's, with $110 million to be set aside for a phase 3 program, according to the filing.
Should the phase 3 succeed and sasineprocel gain approval, Aspen CEO Damien McDevitt, Ph.D., has previously told Fierce that he thinks the biotech can commercialize the therapy itself and use it as a springboard to take the company’s stem cell platform to the next level.
Aspen is also planning to spend $4 million on its autologous microglia cell replacement therapies. These will initially be aimed at a group of rare, genetically defined neurological disorders called leukodystrophies with a target of beginning human trials in the second half of 2027.
The San Diego-based biotech launched in 2019 with $6.5 million and a mission to develop the first autologous cell therapies for Parkinson's. The company’s approach has its origins in the lab of Aspen’s co-founder Jeanne Loring, Ph.D., the founding director of the Center for Regenerative Medicine at The Scripps Research Institute.
By 2020, Aspen had raised a $70 million series A—whose investors included Open AI CEO Sam Altman—followed by a $147.5 million series B in 2022, and a $115 million series C in November 2025. That most recent round saw Gilead Sciences' cell therapy unit Kite Pharma pitch in.
As of the end of June, the company numbered 120 full-time employees and had $72.4 million in the bank.
Bambusa has a similar plan
Bambusa is also aiming for the same ballpark with its own IPO. Like Aspen, the idea is to offer 9.4 million shares priced between $15 and $17, according to Bambusa’s own filing.
The company estimates this will bring net proceeds of $134.9 million—boosted to $155.8 million if underwriters buy up an additional 1.4 million shares at the same price.
While the two IPO outlines may be almost identical, Bambusa’s pipeline is very different to Aspen.
Around $90 million of the IPO haul is due to be spent on launching a phase 2b study of BBT001 for atopic dermatitis (AD). BBT001 is a next-generation, long-acting bispecific antibody targeting both interleukin-4 receptor alpha (IL-4Rα) and IL-31.
BBT001 is already undergoing a global phase 1 trial for AD, as well as a phase 2 study in chronic spontaneous urticaria in China.
In July, the company touted “potentially transformative” preliminary data of 17 patients from the phase 1 study that showed that 82% of those who received BBT001 achieved a more than 50% improvement in eczema area and severity by Week 6 when adjusted for placebo.
A further $40 million is needed to develop BBT002, a long-acting bispecific antibody targeting IL-4/13 and IL-5. Bambusa has already taken BBT002 into a global phase 1 study for chronic obstructive pulmonary disease (COPD), as well as a phase 1/2a and a phase 2a trial in China for COPD and chronic rhinosinusitis with nasal polyps, respectively. Next up is a phase 2b study for one of these respiratory indications.
The company is led by founder and CEO Shanshan Xu, M.D., Ph.D., who previously held leadership roles at BioNTech and Berenberg Capital Markets. Xu oversees a workforce of 30 full-time employees, and Bambusa had $71.5 million on hand by the end of June.