Both Seaport Therapeutics and Hemab Therapeutics are hoping to bring in around $180 million each from their public listings this week, in the latest sign that biotech IPOs are regaining their momentum.
Boston-based Seaport is planning to offer 11.8 million shares priced between $16 and $18 apiece, according to an April 27 Securities and Exchange Commission filing. Should the final share price fall in the middle of this range, the biotech expects the IPO to bring in $183.5 million in net proceeds—rising to $211.4 million if underwriters fully take up their 30-day offer to buy an additional 1.77 million shares at the same price.
Seaport is captained by CEO Daphne Zohar, a co-founder of Karuna, the biotech behind Bristol Myers Squibb’s approved schizophrenia drug Cobenfy. Karuna’s former CEO Steven Paul, M.D., serves as the chair of Seaport’s board of directors.
The biotech employs 58 people and was originally assembled by PureTech Health—where Zohar was previously CEO—and supplied with $100 million when it launched in the spring of 2024. Seaport followed that up with a $225 million series B a few months later.
Out of the $325 million raised to date, Seaport entered 2026 with a hefty chunk of funds—$233.7 million, to be precise—still intact. When combining these funds with the IPO proceeds, Seaport said today that it has earmarked $121 million to advance its lead depression candidate SPT-300, also known as GlyphAllo.
SPT-300 is a prodrug of allopregnanolone—a naturally occurring neurosteroid that is marketed in a synthetic form as Zulresso for postpartum depression. The asset has been developed leveraging Seaport’s Glyph platform, which is designed to enhance the bioavailability of oral drugs by reducing their metabolism in the body before they reach their intended target. The idea is that this should, in turn, reduce hepatotoxicity and other side effects.
The $121 million will be used to fund an ongoing phase 2b study of SPT-300 in major depressive disorder (MDD) through to a topline readout next year, as well as launch a phase 3 study, Seaport said in the filing.
Meanwhile, $97 million will be needed complete phase 2 studies of SPT-320, also known as GlyphAgo, a prodrug of agomelatine—an antidepressant available in Europe as Valdoxan but not approved by the FDA. Seaport has been banking on the ability of its Glyph platform to lower the dose required for effectiveness by reducing its metabolism in the liver and therefore removing the need for liver function monitoring.
More cash will also be required for SPT-348, a prodrug of a non-hallucinogenic analog of LSD, as well as for general R&D activities and working capital.
Hemab heads for $180 million
Hemab is aiming for the same ballpark as Seaport, setting out plans today to offer 11.76 million shares at a price of between $16 and $18. Assuming a final price of $17, the biotech anticipates net proceeds of $180.3 million —rising to $208.2 million if underwriters buy the additional 1.76 million shares on offer.
The Cambridge, Massachusetts- and Copenhagen, Denmark-based biotech has previously touted an ambition to become “the ultimate clotting company” and disclosed in its own SEC filing that it expects to spend between $120 million and $130 million to develop its lead bispecific antibody sutacimig.
The biotech has already tested sutacimig in Glanzmann thrombasthenia, a rare genetic bleeding disorder caused by a deficiency of the platelet integrin alpha IIb beta3, which prevents blood from properly clotting. Hemab has previously pointed to phase 2 study as demonstrating that sutacimig achieved clinically meaningful bleeding reduction in these patients.
The IPO funds would help finance a phase 3 study in Glanzmann thrombasthenia, as well as an ongoing phase 2 trial in another bleeding disorder called Factor VII deficiency.
Meanwhile, Hemab expects it will need $60 million to $70 million to fund its monovalent antibody HMB-002 through a phase 1/2 study for von Willebrand disease, another genetic disorder that impacts blood clotting.
Beyond that, $25 million to $35 million will likely be required for “additional discovery, preclinical, and clinical activities for current and future programs,” Hemab said in the filing.
The company employs 72 people full-time, split across the U.S. and Denmark. They are led by Benny Sorensen, M.D., Ph.D., who previously served at the likes of Codiak Biosciences and Alnylam Pharmaceuticals.
Hemab’s strategy of using “targeted solutions rather than generic approaches” to clotting disorders has secured a steady stream of financings, from a $55 million series A haul in 2021 to a $135 million series B in 2023 and a $157 million series C last year. By the end of 2025, Hemab still had $185.5 million in the bank, according to the filing.
Biotech IPO levels have fluctuated in the early months of 2026. An early boom in February petered out, before obesity-focused Kailera Therapeutics reinvigorated the sector with a historic $625 million offering earlier this month.
