{"id":2967,"date":"2026-09-08T08:00:00","date_gmt":"2026-09-08T12:00:00","guid":{"rendered":"https:\/\/www.insilens.com\/?p=2967"},"modified":"2026-09-08T20:40:31","modified_gmt":"2026-09-09T00:40:31","slug":"win378-shows-six-month-pharmacology-as-phase-iii-begins","status":"publish","type":"post","link":"https:\/\/www.insilens.com\/?p=2967","title":{"rendered":"WIN378 Shows Six-Month Pharmacology as Phase III Begins"},"content":{"rendered":"

Evidence<\/strong> Source-gap catch-up · Published<\/strong> September 8, 2026 · Discovery<\/strong> September 8, 2026 · Importance<\/strong> 4\/5 · Direction<\/strong> Positive<\/p>\n

\"WIN378<\/p>\n

Summary<\/h4>\n

Windward Bio reported interim results from the randomized, double-blind Phase II portion of POLARIS-1 in uncontrolled moderate-to-severe asthma and initiated the seamless Phase III portion. Among the first 98 of 147 Phase II participants, a single WIN378 dose produced dose-dependent Week-24 FEV1 increases up to 174 mL and placebo-adjusted increases up to 256 mL, alongside sustained reductions in fractional exhaled nitric oxide and blood eosinophils. A half-life up to 75 days supports infrequent dosing. The result validates durable pharmacology but not yet exacerbation reduction, clinical superiority or twice-yearly adherence benefit.<\/p>\n

What Happened<\/h4>\n

POLARIS-1 evaluated three WIN378 dose levels against placebo over 48 weeks. At Week 24, reported effects included FEV1 improvement up to 174 mL, a placebo-adjusted difference up to 256 mL with p=0.033, FeNO reduction up to 24 parts per billion or 43% with p=0.006, and eosinophil reduction up to 200 cells per microliter or 51% with p below 0.0001. Near-maximal effects were reported by Week 2 and persisted through Week 24 after one dose.<\/p>\n

The company reported no treatment-related serious adverse events, withdrawals or discontinuations; overall adverse events were described as balanced, with low injection-site reaction and anti-drug-antibody rates. Dose-specific counts, confidence intervals and full safety tables were not disclosed. Two twice-yearly doses were selected for Phase III, whose primary endpoint is annualized severe-asthma exacerbation rate. POLARIS-2 is planned for the first half of 2027.<\/p>\n

Deep Analysis<\/h4>\n

Durable TSLP blockade can reduce treatment burden:<\/strong> The long half-life, rapid biomarker suppression and sustained lung-function effect form a coherent exposure-pharmacodynamic package. If maintained over annual dosing cycles, twice-yearly administration could reduce injection frequency relative to current biologics. Adherence improvement has not been measured, and a long pharmacologic tail can complicate management of rare toxicity, pregnancy or immunogenicity. The observed pharmacology does not prove superior exacerbation control.<\/p>\n

Biomarkers and FEV1 may not predict pivotal success:<\/strong> TSLP is clinically validated, making biomarker suppression credible, but asthma approvals and differentiation depend heavily on exacerbations, steroid reduction, symptoms and safety across phenotypes. The interim analysis includes only 98 participants, uses maxima across dose levels and has not disclosed a full multiplicity framework. The randomized, blinded design and alignment across FEV1, FeNO and eosinophils reduce the likelihood that the signal is solely measurement noise.<\/p>\n

Signal Extraction<\/h4>\n

Verified facts: same-day primary company update; randomized double-blind Phase II; first 98 of 147 participants; quantitative Week-24 lung-function and biomarker effects; half-life up to 75 days; Phase III initiation. Company claims: best-in-disease potential and twice-yearly suitability. Missing facts: baseline strata, dose-level denominators, full confidence intervals, exacerbations, symptoms, rescue medication, oral-corticosteroid effects, anti-drug-antibody detail and long-tail safety.<\/p>\n

Company and Product Background<\/h4>\n

Windward Bio is a Basel-based clinical-stage company founded in 2024 to develop long-acting biologics for respiratory and dermatologic diseases. It holds global WIN378 rights outside China and selected Asian markets. The antibody originated from Harbour BioMed’s fully human antibody platform and is also known as HBM9378 and SKB378 through Harbour and Kelun-Biotech. Windward’s portfolio also includes WIN027, a TSLP and IL-13 bispecific antibody.<\/p>\n

WIN378 is a fully human monoclonal antibody engineered with silenced effector function and an extended half-life. It binds two distinct sites on thymic stromal lymphopoietin, interfering with TSLP engagement of its receptor complex. Tezepelumab clinically validates the target, so the development question is whether WIN378 can preserve efficacy and safety with substantially less frequent dosing.<\/p>\n

InSilens Take<\/h4>\n

WIN378 has moved beyond a convenience hypothesis: one dose produced measurable pharmacology through six months, and the Phase III program is now testing whether that durability translates into fewer severe exacerbations. The signal is positive but still intermediate. Biomarkers and FEV1 establish activity, not a best-in-class profile, and the maxima reported across doses require a full dataset. Pivotal exacerbation reduction, end-of-interval coverage, immunogenicity and long-term safety will determine whether the dosing proposition becomes clinically meaningful.<\/p>\n

Signal Assessment<\/h4>\n\n\n\n\n\n
Signal Importance<\/strong><\/td>\n4 \/ 5 — the update combines sustained six-month pharmacology with a pivotal transition for a global long-acting immunology asset<\/td>\n<\/tr>\n
Signal Direction<\/strong><\/td>\nPositive — lung function and inflammatory biomarkers moved favorably versus placebo, with no material treatment-related safety imbalance reported<\/td>\n<\/tr>\n
Confidence in Facts<\/strong><\/td>\nHigh — quantitative results disclosed by Windward and independently mirrored by Harbour BioMed and Kelun-Biotech, with a registered study<\/td>\n<\/tr>\n
Confidence in Interpretation<\/strong><\/td>\nModerate-low — interim dataset is incomplete, and the pivotal clinical endpoint, severe exacerbations, has not been read out<\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Windward Bio reported interim results from the randomized, double-blind Phase II portion of POLARIS-1 in uncontrolled moderate-to-severe asthma and initiated the seamless Phase III portion. Among the first 98 of 147 Phase II participants,…<\/p>\n","protected":false},"author":1,"featured_media":2968,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11,3],"tags":[505,630,629,628],"class_list":["post-2967","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-clinical","category-therapeutic-indication","tag-severe-asthma","tag-tslp","tag-win378","tag-windward-bio"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2967","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2967"}],"version-history":[{"count":1,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2967\/revisions"}],"predecessor-version":[{"id":2999,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2967\/revisions\/2999"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/media\/2968"}],"wp:attachment":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2967"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2967"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2967"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}