Andreas Argyrides

Eliana Merle

Joseph Schwartz

Kyuwon Choi

Laura Chico

Olivia Brayer

Patrick Trucchio

Vamil Divan

Yasmeen Rahimi

- Gossamer Bio has entered into an **option agreement to acquire Respira Therapeutics**, including its lead product candidate **RT234**, an investigational inhaled dry-powder therapy designed for on-demand treatment of pulmonary hypertension.  **[1728117_0d4a3798d21646559314475be6f7ab2b]** 
- The deal includes an initial issuance of **2.5 million shares** of Gossamer common stock upon signing, with an additional **1.5 million shares** upon exercising the acquisition option, along with milestone payments and high single-digit royalties on potential net sales of RT234.  **[1728117_0d4a3798d21646559314475be6f7ab2b]** 
- During an anticipated **two-year option period**, Gossamer will fund specific development activities to advance RT234's readiness for clinical trials.  **[1728117_0d4a3798d21646559314475be6f7ab2b]** 
- This acquisition is expected to **expand Gossamer’s pulmonary hypertension portfolio**, complementing its existing product Seralutinib, despite Gossamer’s current financial challenges including negative margins.  **[1728117_0d4a3798d21646559314475be6f7ab2b]**

Gossamer Bio Enters Option Agreement to Acquire Respira Therapeutics

- **Gossamer Bio** has entered into an agreement with Respira Therapeutics, Inc., granting Gossamer an option to acquire the company.  **[1728117_20250925NE83261:0]** 
- The transaction is designed to accelerate the development of **RT234**, an investigational first-in-class, as-needed treatment for pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD).  **[1728117_20250925NE83261:0]** 
- In connection with the signing, Gossamer is issuing **2.5 million shares of common stock**, and will issue an additional **1.5 million shares** upon exercise of the acquisition option.  **[1728117_20250925NE83261:0]** 
- The acquisition agreement also provides for success-based clinical, regulatory, and commercial milestone payments, and a royalty on potential net sales of RT234.  **[1728117_20250925NE83261:0]**

Gossamer Bio Enters Agreement for Option to Acquire Respira Therapeutics

- Gossamer Bio is transitioning into a commercialization company, preparing for the launch of **seralutinib** for Pulmonary Arterial Hypertension (PAH) in the **first half of 2027**, with commercial approval anticipated between **March and May 2027**.  **[1728117_tx_381226_0]** **[1728117_tx_381226_5]** 
- The company expects a significant Phase 3 data readout for the ProSera study of seralutinib in PAH in **February 2026**, targeting a clinically meaningful **20 to 25 meter improvement** in the six-minute walk test.  **[1728117_tx_381226_0]** **[1728117_tx_381226_2]** **[1728117_tx_381226_5]** 
- Gossamer Bio plans to deploy approximately **60 sales representatives** for the U.S. launch of seralutinib, with the company booking sales domestically and receiving mid to high teens royalties from ex-U.S. sales by a partner.  **[1728117_tx_381226_6]** 
- A second Phase 3 study, Serenata, for seralutinib in PH-ILD is expected to enroll its first patient by the **end of 2025**, leveraging significant operational synergies with the ProSera study, including **60% site overlap**.  **[1728117_tx_381226_0]** **[1728117_tx_381226_7]**

Gossamer Bio Prepares for Seralutinib Commercialization and Key Data Readouts

Gossamer Bio (GOSS)