IPO · Health Care · Proposed listing on Nasdaq
Windward Bio IPO: how the business makes money
Windward Bio is developing long-acting antibody medicines for asthma, COPD and eczema. It has no product revenue, and its net loss was $42.6 million in the six months to Jun 30, 2026.
By Hardik Bhandare · Checked against filings:
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Windward Bio Group AG · Basel, Switzerland · Founded 2024
Based on the amended registration statement (Form F-1/A) dated .
Figures: from the preliminary prospectus (F-1), subject to change.
The company has publicly filed its registration statement (Form S-1 or F-1) with the SEC. No price range is set yet.
Last updated
- Revenue, six months to Jun 30, 2026
- $0
- Net loss, six months to Jun 30, 2026
- $42.6M
- Cash, cash equivalents and marketable securities, Jun 30, 2026
- $207.3M
- Officers and directors as a group before the IPO, Sep 30, 2026
- 46.6%
- Proposed listing
- Nasdaq: WWB
The short version
The Windward Bio IPO in 5 points
1 · What it sells
Windward Bio sells nothing yet and had $0 of revenue in the six months to Jun 30, 2026; it is developing two antibody medicines, WIN378 and WIN027, for asthma, COPD and eczema.
2 · Who pays it
No customer pays Windward Bio, so there is no revenue split to show; investors had put in $310.0 million of gross cash by Jun 30, 2026.
3 · What it keeps from $100
With no revenue, Windward Bio keeps nothing from sales: in the six months to Jun 30, 2026 its operating loss was $44.7 million and its net loss $42.6 million, after $2.2 million of financial income.
4 · Where the operating profit comes from
Windward Bio has no operating profit: in the six months to Jun 30, 2026, research and development cost $30.1 million and general and administrative costs $14.5 million, including $8.8 million of share-based pay.
5 · The one thing to watch
Windward Bio's F-1/A of Oct 30, 2026 leaves the price range and shares offered blank, and says it expects WIN378's week-24 asthma results in the first half of 2027.
Sources: From Windward Bio's F-1/A dated Oct 30, 2026 · checked
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01The business in one line
What does Windward Bio do?
Windward Bio licenses experimental antibody medicines and pays for the trials needed to seek approval; nobody pays it yet, so investors' money funds the work.
- It has no product on sale and no revenue. Research and overhead led to a net loss of $42.6 million in the six months to Jun 30, 2026.
- Investors had put in $310.0 million of cash by Jun 30, 2026. It held $207.3 million of cash, cash equivalents and marketable securities that day.
02The offer
What is the Windward Bio IPO?
- New shares sold by the company
- Not yet in the filing
- To list on
- Nasdaq
- Proposed ticker
- WWB
- Lock-up on existing holders
- 180 days
- New shares: Windward Bio sells all the shares, so the money, after underwriting costs, goes to the company. No selling shareholder is named.
- The underwriters get a 30-day option to buy extra shares from the company. The F-1/A leaves that number blank.
- The price range, shares offered, money raised, share count after the offering and offering dates are all blank. A later amendment would add them.
- A reverse split is coming, but its ratio is blank. Every share count and per-share figure on this page is from before that split.
- At Sep 30, 2026 there were 68,920,723 shares (Cityfort calculation from F-1/A filed Oct 30, 2026): 15,491,686 common plus 53,429,037 preferred, which convert one-for-one. Up to 397,495 more come from Series B warrants settled just before the offering, the number depending on the price.
- Investors also agreed to a second Series B tranche of $55.0 million (Cityfort calculation from F-1/A filed Oct 30, 2026: $165.0 million round minus $110.0 million first tranche). It closes by Jun 30, 2027, or with the IPO if that comes first.
- If it closes with the IPO, its share number is set at the IPO price. The F-1/A does not say how those shares enter the post-offering count.
- Windward Bio is a Swiss company and a foreign private issuer. It proposes to list on the Nasdaq Global Market under the ticker WWB.
Directors, executive officers and certain shareholders agree not to sell for 180 days from the prospectus date. Jefferies, TD Securities and Piper Sandler can release them, per the F-1/A.
Share classes and votes
- Underwriters
- 4 named in the S-1 (lead: Jefferies LLC, TD Securities (USA) LLC (TD Cowen on the cover), Piper Sandler & Co., UBS Securities LLC (UBS Investment Bank on the cover))
- Controlled company
- The F-1/A does not say Windward Bio will be a controlled company under Nasdaq rules.
- Lead underwriters
- Jefferies LLC, TD Securities (USA) LLC (TD Cowen on the cover), Piper Sandler & Co., UBS Securities LLC (UBS Investment Bank on the cover)
- Transfer agent
- Computershare Trust Company, N.A.
Learn: How to read an S-1: Anthropic's IPO registration statement · IPO lock-up agreements: what they are and when they end
03Where the new money goes
What will Windward Bio do with the money it raises?
- WIN378: complete the POLARIS-1 Phase 2/3 and confirmatory POLARIS-2 Phase 3 asthma trials and the SIRIUS Phase 2 COPD trial, plus related research and developmentThe F-1/A names this use first; the amount is blank.Amount not fixed
- WIN027: complete the planned global Phase 2b COPD trial and the planned global Phase 2 atopic dermatitis trial, plus related research and developmentThe amount is blank in the F-1/A.Amount not fixed
- Other bispecific antibody programs: the lab and safety studies needed before a first human trial (IND-enabling studies)The amount is blank in the F-1/A.Amount not fixed
- Working capital and general corporate purposesThe remainder, per the F-1/A. Part may go to licensing or buying other assets; the company says it has no agreements to do so now.Amount not fixed
No amounts are in the filing yet. The company says it expects to need more funds to fully carry out these plans. No proceeds are stated as going to an affiliate.
Only the shares the company sells raise money for it; money from shares sold by existing stockholders goes to them.
04Key dates
What are the key dates for the Windward Bio IPO?
Learn: IPO lock-up agreements: what they are and when they end
05What it sells
What does Windward Bio sell?
WIN378 (also HBM9378 and SKB378)
An antibody against TSLP, a signaling protein that starts a chain of inflammation. The company aims for an injection twice a year. It is in a Phase 2/3 severe asthma trial (POLARIS-1) and a Phase 2 COPD trial (SIRIUS).
WIN378's early results, as the company states them
The company says in its F-1/A (Oct 30, 2026) that a Phase 2 interim look showed a half-life of up to 75 days. A key lung measure, FEV1, rose up to 174 mL at week 24. It reports no treatment-related serious adverse events. It warns these results may not carry over to later trials.
WIN027 (also QX027N)
A bispecific antibody: one medicine built to block two signals, TSLP and IL-13. It is in a Phase 1 study in healthy volunteers. The company says a blinded interim look as of June 2026 showed a 62-day half-life.
Other bispecific antibodies
Earlier programs at the lead optimization stage, when scientists choose the best molecule. Part of the money raised would take them through the studies needed before a first human trial, the company said in its F-1/A (Oct 30, 2026).
What it does
- Does: Licenses drug candidates from other companies and pays for trials
- Does: Runs trials and manufacturing through outside firms
- Does: Holds global rights outside Greater China for WIN027, and outside Greater China and certain Asian countries for WIN378
What it does not do
- Does not: Sell any product: neither candidate is approved
- Does not: Own a manufacturing plant or have a sales force
- Does not: Have Phase 3 results for either candidate
06Who pays it
Who pays Windward Bio?
No customers yet
Not disclosed
Windward Bio has no product on sale and reported no revenue in any period in its F-1/A, through Jun 30, 2026.
Investors (funding, not revenue)
Not disclosed
Share sales brought in $310.0 million of gross cash by Jun 30, 2026: $200.0 million of Series A and $110.0 million of Series B. Including the second Series B tranche, the F-1/A says up to $365.0 million.
How spread out the customers are
With no revenue, Windward Bio has no customer split to report. Its F-1/A also says it has never commercialized a product and has no sales organization.
07How the money flows · FY2025
How does money flow through Windward Bio?
Money in
- Revenue (none in FY2025)$0M
- Financial income, mainly from cash and securities$3.6M
The company
Windward Bio
$3.6M came in
Money out
- Research and development$32.6M
- General and administrative$19.2M
- Financial expense, currency differences and income tax$0.1M
- Net loss−$48.3M
- No customers paid Windward Bio in FY2025: revenue was zero.
- Financial income on its cash and securities brought in $3.6 million.
- Research and development took $32.6 million, of which outside services and materials were $23.5 million. General and administrative costs took $19.2 million. Those lines include $9.9 million of share-based pay.
- That left an operating loss of $51.8 million and a net loss of $48.3 million.
- License payments are not in these costs. Windward Bio paid $25.0 million for licenses in FY2025 and recorded them as assets. Selling shares brought in $200.0 million.
08What it needs to run
What does Windward Bio need to run?
Licensed drug rights
WIN378 comes from Kelun and Harbour BioMed, signed Dec 31, 2024, with $40.0 million of up-front terms. WIN027 comes from Qyuns, signed Dec 19, 2025, with $30.0 million. Each deal was half cash, half equity, and carries further milestones and royalties.
Outside manufacturers
WIN378 supply has come from Kelun; the company said in its F-1/A (Oct 30, 2026) that it expects a transfer to US contract manufacturers by the end of 2026. WIN027 is made in Taizhou, China, by a Qyuns subsidiary; the company also expects a US transfer before pivotal trials.
Trial money
Research and development cost $30.1 million in the six months to Jun 30, 2026, up from $13.3 million a year earlier. The company does not track this spending by program.
People
38 employees at Sep 30, 2026, of whom 24 work in research and development; 25 are in Switzerland. 17 hold a Ph.D. or M.D.
09Why it makes money
Why does Windward Bio make money?
Windward Bio does not make money yet: share sales pay for trials, and its licenses carry more payments as drugs advance.
Money comes in from investors and goes out to trials, license payments and staff. Costs grow with no revenue to offset them. The operating loss rose from $23.3 million in the first half of 2025 to $44.7 million in the first half of 2026.
Operating loss, first half of the year (US$ million)
−$23.3−$44.7
Six months to Jun 30, 2025 to Six months to Jun 30, 2026
- Investors buy shares: $310.0 million of gross cash by Jun 30, 2026
- License candidates: $40.0 million up front for WIN378, $30.0 million for WIN027
- Pay outside firms for trials and supply: $22.2 million in the first half of 2026
- Trials reach set points, which can trigger more license payments
- Approval would be needed before any sale; neither candidate has it
- Any future sales would carry royalties and sales milestones owed to the licensors
↺ Step 6 feeds back into step 1.
10Competitors and what protects it
Who does Windward Bio compete with?
Amgen and AstraZeneca
The F-1/A cites their reported sales of Tezspire, an approved TSLP antibody: nearly $2 billion in asthma sales in 2025.
Generate Biomedicines
GB-0895, named in the F-1/A as an ultra-long-acting TSLP rival.
GSK
GSK5784283, named in the F-1/A as an ultra-long-acting TSLP rival.
Keymed and Belenos
CM512/BEL512, a long-acting TSLP and IL-13 candidate in Phase 2, per the F-1/A.
Apogee, Upstream Bio, Johnson & Johnson, Eli Lilly, Pfizer and Sanofi
Also named as competitors in the F-1/A, which notes Apogee's pending acquisition by AbbVie.
What protects the business
Each strength is scored 1 (weak) to 5 (strong) for the business, with the reason. It is not a rating of the share.
- Dosing interval2 of 5
The company says a half-life of up to 75 days supports twice-yearly dosing, but this rests on interim data. No Phase 3 results exist, and the F-1/A names ultra-long-acting rivals.
- Patents2 of 5
WIN378's patent families would expire in 2040, 2044 and 2047, and are mostly pending. WIN027's would expire in 2040, 2045 and 2046, per the F-1/A.
- Rights to the drugs2 of 5
Windward Bio licenses both candidates rather than owning them from the start. The F-1/A says missing milestone, royalty or payment duties can cost it the rights.
- Sales reach1 of 5
Windward Bio has no sales organization and has never commercialized a product, per its F-1/A.
Weak spot
Two licensed candidates, neither approved
The F-1/A says Windward Bio's prospects depend on WIN378 and WIN027. A delay or failure in trials or approval would hit that directly.
11Where growth could come from
Where could Windward Bio's growth come from?
Windward Bio says in its F-1/A (Oct 30, 2026) that it expects WIN378's Phase 2 week-24 asthma results in the first half of 2027. It expects Phase 3 results in the first half of 2029.
WIN378 in severe asthma
EarlyPhase 2 part enrolled 147 patients against a target of 120 (F-1/A)
The Phase 3 part started in September 2026, with about 600 more patients. POLARIS-2, also about 600 patients, plans to start recruiting in the first half of 2027, the company said in its F-1/A (Oct 30, 2026).
Status: Early, too early to judge.
WIN378 in COPD
EarlySIRIUS Phase 2 trial started in June 2026 (F-1/A)
The company said in its F-1/A (Oct 30, 2026) that it expects results in the second half of 2027.
Status: Early, too early to judge.
WIN027 in COPD and atopic dermatitis
New62-day half-life in a blinded Phase 1 interim look as of June 2026, per the company (F-1/A)
Start-up work on both later trials began in September 2026. The company said in its F-1/A (Oct 30, 2026) that it plans recruiting in the first half of 2027 and expects atopic dermatitis results in the second half of 2028 and COPD results in the first half of 2029.
Status: New, recently announced.
Patients not on biologics
Early$60 billion peak opportunity and more than 8 million eligible patients, management's estimates (F-1/A)
Management estimates about 20% of eligible severe asthma, 1% of COPD and 15% of atopic dermatitis patients get biologics. The F-1/A says the research has not been independently verified.
Status: Early, too early to judge.
Status compares progress with what the company itself said it would do: Working = on track against what the company said; Mixed = partly on track; Behind = behind the company's own plan; New = recently announced; Early = too early to judge.
12The numbers · Consolidated · US$
How has Windward Bio done?
Revenue
$0MFY2025
Windward Bio had no revenue in any period; figures follow IFRS, not US GAAP, and FY2024 covers only Jul 5 to Dec 31, 2024.
US$
See the numbers
Net profit
−$48.3MFY2025
Net loss was $42.6 million in the first half of 2026, up from $22.8 million a year earlier; per-share losses predate the coming reverse split.
US$
See the numbers
Free cash flow
−$33.8MFY2025
Free cash flow (Cityfort calculation from F-1/A filed Oct 30, 2026) was an outflow of $33.8 million in FY2025; it leaves out $25.0 million of license payments.
US$ · cash from operations minus spending on plants and equipment
See the numbers
See all yearly numbers
EBITDA here = operating income plus depreciation and amortization (from the cash flow statement). Fiscal years are the company's own (December 31). Net profit is the share belonging to the company's owners.
Windward Bio says in its F-1/A that it is an emerging growth company, so the filing gives two audited years instead of three.
Latest part-year · Six months ended Jun 30, 2026 (6 months to Jun 30, 2026)
- Revenue
- $0M
- EBITDA
- −$44.3M
- Net profit
- −$42.6M
- EPS (not annualised)
- −$5.28
A part-year can't be compared with a full year. Audited figures from the F-1/A (interim period unaudited), converted from US$ thousands to US$ million.
Learn: Stock-based compensation and dilution: pay that becomes shares
13Financial strength · Jun 30, 2026
How much debt does Windward Bio have?
- Total debt$0M
- Cash and investments$207M
- Net cash (cash minus debt)$207M
- Net worth (shareholders' money)$266M
- Debt to equity
- 0×
- $ of debt for every $1 of shareholders' money
- Net cash of $207.3 million is a Cityfort calculation from F-1/A filed Oct 30, 2026: cash, cash equivalents and marketable securities as stated, with no borrowings. Lease liabilities are not counted as debt here.
- The F-1/A gives about $181.8 million of cash, cash equivalents and marketable securities at Sep 30, 2026. That is a preliminary, unaudited management estimate, and the auditor has not reviewed it.
- The board says cash suffices through the next 12 months from Jun 30, 2026. The company's cash runway date with the offering is blank.
- $80.0 million of the $290.7 million of total assets is licenses recorded as intangible assets. Accumulated losses were $93.2 million.
- $5.0 million of license amounts were still owed at Jun 30, 2026, shown as other payables.
14Who owns it before the IPO · Sep 30, 2026
Who owns Windward Bio before the IPO?
- Officers and directors (as a group), shares
- 46.6%
Largest stockholders before the IPO
From the prospectus table of principal stockholders. Holdings fall after the IPO when new shares are sold; the prospectus also shows the holding after the offering.
15Who runs it
Who runs Windward Bio, and did they deliver?
Luca Santarelli
Founder, Chief Executive Officer and Chair · since 2025
Earlier founder and CEO of VectivBio, acquired by Ironwood, and co-founder and CEO of Therachon, acquired by Pfizer. Chair since January 2025; holds 10.0% before the offering.
Claudia D'Augusta
Chief Financial Officer · since 2025
Omar Khwaja
Chief Medical Officer · since 2025
Kevin Harris
Chief Operating Officer · since 2025
Earlier Chief Commercial Officer of VectivBio.
Scott Applebaum
Chief Legal and Corporate Development Officer · since 2025
David P. Bonita
Director · since 2025
A Member at OrbiMed Advisors; OrbiMed holds 14.3% before the offering.
Otello Stampacchia
Director · since 2025
Founder of Omega Fund Management; Omega holds 8.9% before the offering.
Iqbal Mufti
Director · since 2025
Operating Partner of SR One Capital Management.
Sandip Kapadia
Director · since 2026
Chief Financial Officer of Harmony Biosciences from March 2021 to April 2026.
Timothy Anderson
Director, resigning on the IPO's effective date · since 2025
A Managing Director at Blue Owl Capital.
Naveed I. Siddiqi
Director, resigning on the IPO's effective date · since 2025
Senior Partner at Novo Holdings.
16Governance signals
What do Windward Bio's governance filings show?
- Auditor
- Ernst & Young AG, since 2025
- Auditor changes
- None in the period covered
- Audit qualifications
- None reported
- Related-party dealings
- Five director-linked investors bought in both the Series A and Series B rounds. Four executives contributed Windward Bio 27 AG, which holds the Qyuns license, for 3,399,466 common shares in March 2026. The company believes the terms were comparable to arm's length.
- Credit rating
- No public credit rating found
Flags to know about
disclosure
Foreign private issuer reporting
As a foreign private issuer, Windward Bio has no duty to file 10-Qs or 8-Ks and reports annually on Form 20-F. It may also use exemptions on Section 16(b), share-issuance approvals and board committee oversight, per the F-1/A.
disclosure
IFRS, not US GAAP
The numbers follow IFRS, with no reconciliation to US GAAP. Licenses are recorded as intangible assets and paid through investing cash flow, so research and development expense leaves them out.
other
Internal controls not yet tested by an auditor
The audit report gives no opinion on internal control over financial reporting. As an emerging growth company, Windward Bio can defer an auditor's report on those controls, per the F-1/A.
other
Board independence as stated
The board found every director other than Luca Santarelli independent. Five of the other six are linked to investors, or employed by one, per the F-1/A.
related party
Related-party policy only from the underwriting agreement
The company said in its F-1/A (Oct 30, 2026) that it expects to adopt a formal related-party policy, effective when the underwriting agreement is signed.
17Group and related parties
How much does Windward Bio rely on related parties?
- Kelun and Harbour BioMed licensed WIN378. Deal terms: $40.0 million up front, half in equity, and $10.0 million of milestones paid so far. Up to $320.0 million of development milestones and up to $600.0 million of sales milestones per product remain.
- Up to 50% of the remaining first seven WIN378 development milestones, up to $73.75 million, may be paid in shares after the IPO. A 20% holding cap applies.
- Qyuns licensed WIN027 for $30.0 million up front, half in equity to its affiliate Linkbio. Up to $100.0 million of development milestones and up to $570.0 million of sales milestones remain.
- Royalties run from low single digits to low double digits for WIN378, and mid to high single digits for WIN027. They last at least 10 years from first sale in each country.
- Four executives owned Windward Bio 27 AG, holder of the Qyuns license, and the company controlled it through contracts. They contributed it in March 2026 for 3,399,466 common shares.
- The shareholders' agreement among investors ends at the IPO, except for registration rights, per the F-1/A.
18Legal cases · as of Oct 30, 2026
What legal cases does the Windward Bio offer document list?
Cases are listed as the offer document describes them. A pending case is an allegation until a court or regulator decides it.
19What could go wrong
What could go wrong for Windward Bio?
- Execution
Two candidates carry the whole company
Windward Bio's prospects depend on WIN378 and WIN027, per its F-1/A. Delay or failure in trials or approval is its central risk. No Phase 3 results exist yet.
Watch WIN378's Phase 2 week-24 results, which the company said in its F-1/A (Oct 30, 2026) it expects in the first half of 2027.
- Cash and liquidity
Losses and no revenue
The net loss was $42.6 million in the six months to Jun 30, 2026, and accumulated losses reached $93.2 million. The F-1/A says losses are not expected to end soon.
Watch Operating loss and operating cash flow in the next filing.
- Cash and liquidity
More funding needed even after the offering
Cash, cash equivalents and marketable securities fell from $207.3 million at Jun 30, 2026 to about $181.8 million at Sep 30, 2026, on a preliminary, unaudited estimate. The company said in its F-1/A (Oct 30, 2026) that it expects to need more funds.
Watch The cash runway date, blank in the F-1/A.
- Concentration
License duties can cost it the drugs
Missing milestone, royalty or payment duties can cost Windward Bio its rights to both candidates, per the F-1/A. Up to $320.0 million and up to $100.0 million of development milestones remain.
Watch Milestone payments and any share payments to Kelun and Harbour BioMed.
- Regulation
China links
Both licensors are based or operate in China, and transfers of technology and supply may be restricted. In its F-1/A (Oct 30, 2026), the company says a US list under the BIOSECURE Act is due by mid-December 2026, and flags the effect if Kelun or Qyuns were designated.
Watch The BIOSECURE Act list, and the transfer of supply to US manufacturers.
- Execution
Outside firms run the work
Trials and manufacturing are outsourced, and the company relies on data its licensors produced earlier. It has no plant of its own.
Watch Whether WIN378's manufacturing transfer finishes by the end of 2026, as the company said in its F-1/A (Oct 30, 2026) it expects.
- Competition
Rivals with similar long-acting candidates
The F-1/A names ultra-long-acting TSLP rivals from Generate Biomedicines and GSK, and a TSLP and IL-13 rival in Phase 2 from Keymed and Belenos. Tezspire is already approved.
Watch Rivals' trial results and approvals.
- Other
A young company with no sales experience
Windward Bio was formed in July 2024 and began operating in January 2025. It has 38 employees and has never commercialized a product. The F-1/A lists dependence on key people, including Luca Santarelli.
Watch Changes in the senior team.
20Risks of the offer
What risks does the Windward Bio offer document flag?
Size and price not yet set
The F-1/A leaves the price range, shares offered, money raised, dilution and ownership after the offering blank. A later amendment would state them.
Per-share figures will change
The F-1/A says a reverse split is coming but leaves the ratio blank. Share counts and loss per share in the filing are from before it.
Second Series B tranche
The second tranche can close with the IPO, in a share number set at the IPO price. The F-1/A's post-offering share count does not say how these shares enter it.
Discretion over the money
Management has broad discretion over the proceeds. The company said in its F-1/A (Oct 30, 2026) that it expects to need more funds to fully carry out its planned uses.
No prior market
The shares have no public market yet, and the F-1/A warns the price may be volatile. Holders' shares can be sold after the 180-day lock-upA period after an IPO when insiders agree not to sell their shares. Learn more.
Swiss company, foreign issuer rules
Shareholder rights follow Swiss law, and foreign-issuer reporting differs from a US company's. The articles also cap votes for holders above a percentage that is blank in the F-1/A.
Tax rules for US holders
The F-1/A says Windward Bio may be a passive foreign investment company (PFIC), which can change the tax treatment for US holders.
21How it got here
How did Windward Bio get here?
2024
Milestone
Company formed
Windward Bio Group AG was incorporated in Switzerland on Jul 5, 2024.
2024
Business-model change
WIN378 license signed
On Dec 31, 2024 it licensed WIN378 from Kelun and Harbour BioMed, for $40.0 million up front in cash and equity.
2025
Milestone
Operations and Series A
It began operating in January 2025 and raised $200.0 million in Series A shares across January and July 2025.
2025
Business-model change
WIN027 license signed
On Dec 19, 2025 it licensed WIN027 from Qyuns, for $30.0 million up front in cash and equity.
2026
Milestone
Series B first tranche
It closed $110.0 million of a $165.0 million Series B round on May 12, 2026.
2026
Milestone
Phase 3 asthma work begins
The Phase 3 part of POLARIS-1 started in September 2026, after the company picked two twice-yearly doses from the Phase 2 interim look.
2026
Milestone
F-1 filed
After confidential drafts from Jul 24, 2026, Windward Bio publicly filed its F-1 on Oct 23, 2026, and an amendment on Oct 30, 2026.
22Both sides
What do supporters and critics point to?
What supporters point to
- The company says an interim look at WIN378 showed a half-life of up to 75 days, and no treatment-related serious adverse events (F-1/A, Oct 30, 2026).
- Windward Bio had $207.3 million of cash, cash equivalents and marketable securities, and no borrowings, at Jun 30, 2026.
- CEO Luca Santarelli founded VectivBio, acquired by Ironwood, and co-founded Therachon, acquired by Pfizer, per the F-1/A.
- Management estimates that about 20% of eligible severe asthma patients and about 1% of eligible COPD patients get biologics.
- The F-1/A says Tezspire, an approved TSLP antibody, had nearly $2 billion in asthma sales in 2025.
What critics point to
- Windward Bio has no revenue, a $42.6 million net loss for the six months to Jun 30, 2026, and $93.2 million of accumulated losses.
- In its F-1/A (Oct 30, 2026), the company warns interim results may not carry over to later trials; no Phase 3 results exist, and it expects them in the first half of 2029.
- Both candidates come from licensors based or operating in China, and the F-1/A flags possible limits on technology transfer and supply.
- Remaining license terms include up to $320.0 million of development milestones for WIN378 and up to $100.0 million for WIN027.
- The company said in its F-1/A (Oct 30, 2026) that it expects to need more funds even after the offering.
23What to watch next
What should you watch next for Windward Bio?
Next event
Amended F-1 (F-1/A) with a price range and share count
Date not announced yet.
Price range, share count and reverse split
A later amendment would state the shares offered, the price range, the money raised and the split ratio.
Series B second tranche
The $55.0 million tranche (Cityfort calculation from F-1/A filed Oct 30, 2026) can close with the IPO. A later filing may show how it enters the share count.
WIN378's next results
The company says in its F-1/A (Oct 30, 2026) that it expects Phase 2 week-24 results in the first half of 2027. Week-48 results would follow in the second half.
Cash
The F-1/A's preliminary, unaudited estimate is about $181.8 million at Sep 30, 2026. The runway date is blank.
The BIOSECURE Act list
In its F-1/A (Oct 30, 2026), the company says the list is due by mid-December 2026, and flags the effect if Kelun or Qyuns were designated.
24Key facts
Key facts about Windward Bio
- What does Windward Bio do?
- Windward Bio Group AG, based in Basel, Switzerland, develops long-acting antibody medicines for asthma, COPD and atopic dermatitis. As of its F-1/A dated Oct 30, 2026, it had no product on sale and two candidates in human trials, WIN378 and WIN027.
- How does Windward Bio make money?
- Windward Bio does not make money yet: its revenue was $0 in FY2025 and in the six months to Jun 30, 2026. Its business model is to license drug candidates and fund trials with investors' money. Share sales brought in $310.0 million of gross cash by Jun 30, 2026.
- Who are Windward Bio's customers?
- Windward Bio had no customers as of its F-1/A dated Oct 30, 2026, because it has no product on sale. It also has no sales organization. Its licensed rights exclude Greater China for both candidates, and certain other Asian countries for WIN378.
- Is Windward Bio profitable?
- No. Windward Bio's net loss was $48.3 million in FY2025 and $42.6 million in the six months to Jun 30, 2026. In those six months, research and development cost $30.1 million and general and administrative costs $14.5 million, including $8.8 million of share-based pay. Financial income was $2.2 million.
- What is Windward Bio's revenue by segment?
- Windward Bio reports one segment and had no revenue in FY2025 or in the six months to Jun 30, 2026, per its F-1/A dated Oct 30, 2026. There is no split by segment, product or region.
- What is WIN378?
- WIN378 is Windward Bio's antibody against TSLP, a signaling protein that starts a chain of inflammation. At Oct 30, 2026 it was in a Phase 2/3 severe asthma trial and a Phase 2 COPD trial. The Phase 2 part of the asthma trial enrolled 147 patients.
- What is WIN027?
- WIN027 is Windward Bio's bispecific antibody, built to block both TSLP and IL-13, two inflammation signals. At Oct 30, 2026 it was in a Phase 1 study in healthy volunteers. Windward Bio's up-front license terms for it were $30.0 million, half in cash and half in equity.
- How much cash does Windward Bio have?
- Windward Bio reported $207.3 million of cash, cash equivalents and marketable securities at Jun 30, 2026, and no borrowings. Its F-1/A also gives a preliminary, unaudited management estimate of about $181.8 million at Sep 30, 2026.
- Who owns Windward Bio before the IPO?
- At Sep 30, 2026, Novo Holdings held 14.5% of Windward Bio, OrbiMed 14.3%, CEO Luca Santarelli 10.0%, SR One 9.5% and Omega Funds 8.9%, per its F-1/A. Officers and directors as a group held 46.6%. Ownership after the offering is blank.
- What is the Windward Bio IPO?
- Windward Bio filed a Form F-1 with the SEC on Oct 23, 2026, and an amendment on Oct 30, 2026, to list on the Nasdaq Global Market as WWB. Only the company sells shares; the price range and share count are not yet in the filing.
25Sources and changes
Where every number on this page comes from
Sources (2 documents)
- S1Windward Bio Group AG Form F-1/A (Amendment No. 1) registration statement, preliminary prospectus (price range and share count blank) · SEC EDGAR (filed by Windward Bio Group AG) · Tier 1: company or exchange filing · Oct 30, 2026
- S3Windward Bio Group AG EDGAR filing list (CIK 0002145089), read 5 Nov 2026 · SEC EDGAR · Tier 1: company or exchange filing · Nov 5, 2026
Changes to this page (v1 · Nov 5, 2026)
- v1 · Nov 5, 2026First version, based on the F-1/A dated Oct 30, 2026. (first version, based on the F-1/A)
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