With a $165 million cash tailwind, Windward Bio is advancing its TSLP challengers to Amgen and AstraZeneca\'s Tezspire.\n Windward Bio is in full sail with a $165 million crossover financing to push its long-acting anti-TSLP antibody into phase 3, betting that a twice-yearly dosing schedule will be a key differentiator in an increasingly crowded respiratory market. The upsized round was led by OrbiMed and drew several other heavy hitters, including RA Capital Management, Janus Henderson Investors and Sanofi Ventures as new investors, plus existing backers like Novo Holdings.The cash infusion is meant to accelerate the development of the company’s lead candidate, a twice-yearly anti-TSLP agent dubbed WIN378, which is currently nearing an initial readout from a phase 2 dose-ranging portion of the phase 2/3 Polaris trial in asthma. The company now expects to launch the first phase 3 study in the fourth quarter of 2026, with another phase 2 in chronic obstructive pulmonary disease scheduled to start before the end of June. With the new funds, Windward also aims to push its long-acting TSLPxIL-13 bispecific candidate, WIN027, into “multiple proof-of-concept studies across respiratory and dermatology indications” starting in the coming fourth quarter, the Swiss biotech said in a May 4 release.Windward’s ascent has been rapid, emerging in January 2025 with a $200 million series A and former Roche veteran Luca Santarelli, M.D., as CEO. Before founding Windward, Santarelli had successfully steered the buyouts of VectivBio and Therachon, which he cofounded, by Ironwood Pharmaceuticals and Pfizer, respectively.“This financing further strengthens our balance sheet and allows us to advance our programs of next-generation therapies for patients living with serious respiratory and dermatological diseases.” Santarelli, who also serves as Windward’s board chair, said in a May 4 statement. A “NewCo” built on drug candidates licensed from Chinese biotechs, Windward got ex-China rights to WIN387 from Kelun-Biotech and Harbour BioMed and to WIN027 from Qyuns Therapeutics.By targeting TSLP, Windward is entering a high-stakes arena. Full name thymic stromal lymphopoietin, TSLP has become a hot target in immunology, acting as an upstream master switch for the inflammatory cascade.Amgen and AstraZeneca broke into the field in 2021 with the FDA’s approval for Tezspire, a once-monthly subcutaneous injection, for the add-on maintenance treatment of severe asthma.One of Windward’s closest rivals is Upstream Bio, which is developing verekitug. Recently released phase 2 data suggested a 12-week regimen of verekitug achieved Tezspire-like efficacy in asthma, although a 24-week dose—which would be a more direct competitor to Windward’s WIN378—fell short of expectations. About a month ago, Sanofi’s TSLPxIL-13 bispecific nanobody candidate, lunsekimig, hit goals in a pair of midstage studies for moderate-to-severe asthma and chronic rhinosinusitis but failed on the primary endpoint of a phase 2b atopic dermatitis study.GSK entered the arena in 2024 through its $1 billion upfront deal to acquire Aiolos Bio, which got its long-acting anti-TSLP antibody from China’s Jiangsu Hengrui Pharmaceuticals. Other companies, such as Teva and Blackstone-backed Uniquity Bio, are also in the mix with their own anti-TSLP candidates.
