Daphne Zohar, the chief executive who co-founded Karuna Therapeutics and saw it sold to Bristol-Myers Squibb for $14bn in 2024, is taking another biotech public. Seaport Therapeutics, a Boston clinical-stage company, has filed to raise $212.4m in an initial public offering and plans to sell 11.8 million shares at $16 to $18 each. The company expects phase 2 results for its lead antidepressant in the first half of 2027 and has reported positive early-stage data for an oral anxiety treatment, giving the IPO a near-£1bn valuation at the top end.
Offer details and valuation
Seaport Therapeutics is seeking $212.4m from public investors. It plans to market 11.8 million shares with a $16 to $18 range. At $18 a share, the filing values the company at about $912m on the outstanding share count it provided.
The filing lists the company as Boston-based and clinical-stage. Proceeds from the offering are aimed at advancing its drug candidates through later trials. That role for IPO proceeds is common among early-stage biotechs that face expensive clinical timelines.
Pipeline and near-term milestones
Seaport's lead programme targets major depressive disorder. The company said phase 2 results are due in the first half of 2027. That readout is the next material milestone for investors. The filing also notes positive data from an early-stage study of a second candidate, an oral therapy for generalized anxiety disorder.
Seaport plans to move the anxiety programme into two parallel trials. Advancing a candidate directly into parallel trials suggests the company sees a clear development path. It also raises near-term spending needs, which the IPO would help cover.
Backers, ownership and financials
The filing shows Seaport has deep backing from established life-science investors. PureTech Health Plc, which is listed on both Nasdaq and the London Stock Exchange, owns nearly half the company after bringing in outside investors. Affiliates of Arch Venture Partners hold roughly 13.4 percent.
General Atlantic is shown with about 8.6 percent.
Those shareholders joined previous funding rounds that, the filing says, have raised $325m since Seaport was spun out in 2024. The company reported a net loss of $74.9m last year, up from $46.9m a year earlier. Losses at this stage reflect increased spending on trials and development.
Daphne Zohar is listed as chief executive officer. Zohar co-founded Karuna Therapeutics, which was acquired by Bristol-Myers Squibb for $14bn in 2024. Her track record and the backing from large investors are likely to be central to how underwriters market the deal.
Why Seaport is asking for public capital now
Seaport is clinical-stage and needs capital to pay for trials. The phase 2 readout for the lead antidepressant and the planned paired trials for the anxiety drug create defined spending profiles. Public markets can supply larger sums than private rounds. They also let existing backers realise some liquidity while retaining stakes.
The filing implies the company wants to line up funding ahead of its 2027 readout. For drug developers, having cash before key trial results reduces financing risk. It also gives management room to run multiple programmes in parallel if the data allow.
Investors often view a clear near-term milestone as attractive. Seaport offers a concrete event in the first half of 2027. That can make the IPO easier to pitch. The anxiety drug's positive early-stage data adds a second potential value driver.
At the same time, clinical-stage biotechs carry binary risks tied to trial outcomes. The filing shows rising losses year-over-year.
That will factor into valuation discussions. Underwriters and institutional investors will balance the upside of trial success against the need for continued cash.
PureTech's near-50 percent stake means the company will remain a dominant shareholder. That concentration can reassure some public investors about stability. It can also limit the float and influence trading dynamics after the IPO.
The presence of Arch affiliates and General Atlantic signals institutional confidence. Those investors typically back later-stage development or commercial-scale opportunities. Their holdings suggest they see a credible path for Seaport's assets.
Seaport is entering public markets at a time when biotech listings are carefully scrutinised. Investors have grown choosier about trial risk and cash burn. That has raised the bar for companies seeking to go public without late-stage data.
Still, Seaport brings both a near-term clinical milestone and biopharma pedigree. Its CEO's previous role in a company acquired for $14bn will be highlighted in marketing materials. That background helps when selling a story of technical execution plus commercial upside.
The $16 to $18 range determines initial dilution for existing shareholders. At the top of the range, the implied market value is close to $912m. That gives PureTech and other early backers a large paper valuation soon after listing.
Public investors will watch the use of proceeds closely. The filing ties the money to trial work and development. That means investor returns will be driven mainly by clinical progress rather than near-term revenue.
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The next material milestone is the phase 2 readout for its lead antidepressant, due in the first half of 2027.
This article was created with AI assistance.
