Additional investment in Windward Bio

LEI: 549300Q7EXQQH6KF7Z84

8 May 2026

RTW Biotech Opportunities Ltd

Additional investment in Windward Bio

· $165 million crossover financing to advance clinical studies in asthma and COPD

· RTW Bio investing $1.7 million as part of the financing round

· As at 31 March 2026, Windward Bio represented 0.6% of the Company's NAV

RTW Biotech Opportunities Ltd ("the Company"), the London Stock Exchange-listed investment company focused on identifying transformative assets with high growth potential across the life sciences sector, is pleased to the note an additional investment in the $165 million crossover financing of private portfolio company Windward Bio ("Windward"). Windward is a private, clinical-stage biotechnology company committed to improving outcomes for people living with serious immunological diseases. RTW Bio first invested in Windward's Series A launch in January 2025 and is investing $1.7 million as part of this financing.

Lead program WIN378 is an antibody designed to treat asthma and chronic obstructive pulmonary disease (COPD). The drug has been engineered for an extended half-life, enabling twice-yearly subcutaneous dosing, a meaningful step forward from the monthly administration required by most current biologics. It is currently being evaluated in a Phase 2/3 asthma study, with initial readouts expected in the second half of 2026. If approved, WIN378 would be the first ultra long-acting anti-TSLP antibody available to patients.

As at 31 March 2026, Windward represented 0.6% of the Company's NAV.

Rod Wong, CIO of RTW Investments, said, "We are pleased to further support Windward Bio as it advances a differentiated portfolio of long‑acting immunology therapies with the potential to meaningfully improve outcomes for patients. WIN378 has the profile we look for in a best-in-class asset: a well-validated target, a clear durability advantage over existing treatments, and compelling clinical trial data. This financing round will position the Windward team well to set a new standard of care for patients with asthma and COPD."

The announcement can be found here.

Enquiries:

About RTW Biotech Opportunities Ltd:

RTW Biotech Opportunities Ltd (LSE: RTW) is an investment fund focused on identifying transformative assets with high growth potential across the biopharmaceutical and medical technology sectors. Driven by a long-term approach to support innovative businesses, RTW Biotech Opportunities Ltd invests in companies developing next-generation therapies and technologies that can significantly improve patients' lives. RTW Biotech Opportunities Ltd is managed by RTW Investments, LP, a leading healthcare-focused entrepreneurial investment firm with deep scientific expertise and a strong track record of supporting companies developing life-changing therapies.

Visit the website at www.rtwbio.com for more information.

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The information in this announcement may include forward-looking statements, which are based on the current expectations and projections about future events, and in certain cases can be identified by the use of terms such as "may", "will", "should", "expect", "anticipate", "project", "estimate", "intend", "continue", "target", "believe" (or the negatives thereon) or other variations thereon or comparable terminology. These forward-looking statements, as well as those included in any related materials, are subject to risks, uncertainties and assumptions about the Company and/or its underlying investments, including, among other things, the development of the applicable entity's business, trends in its operating industry, expected use of financing proceeds and future capital expenditures and acquisitions. In light of these risks, uncertainties and assumptions, the events in the forward-looking statements may not occur.