Gossamer Bio has entered into an option agreement to acquire Respira Therapeutics and its lead product candidate RT234, an investigational inhaled vardenafil dry-powder therapy designed for as-needed use in pulmonary hypertension. The deal positions Gossamer to potentially expand its pulmonary hypertension franchise with the first on-demand treatment option for patients with pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD).
Addressing Critical Unmet Medical Need
Despite existing treatment options, the majority of pulmonary hypertension patients continue to struggle with debilitating symptoms that disrupt daily life and limit their independence, as no approved PRN therapies exist in PAH or PH-ILD. RT234 represents a novel treatment approach designed to provide rapid, on-demand relief of exertional symptoms such as breathlessness on top of background therapy.
"There is a clear unmet need for an 'as needed' therapy in PAH and PH-ILD, where patients lack an option for rapid symptom management," said Faheem Hasnain, Co-Founder, Chairman, and CEO of Gossamer Bio. "Supported by positive clinical data, RT234, an investigational inhaled, as needed therapy, is intended to address this gap and supplement chronic treatments."
Clinical Evidence and Development Pathway
RT234 is an inhaled, PRN formulation of vardenafil delivered via a dry-powder inhaler. Vardenafil is an FDA-approved phosphodiesterase type 5 (PDE5) inhibitor for a non-PH indication. While PDE5 inhibitors sildenafil and tadalafil are FDA-approved for chronic treatment of PAH, on-demand use in PAH and PH-ILD represents a novel treatment approach.
In two completed open-label Phase 2 studies in PAH patients, RT234 demonstrated rapid and clinically meaningful improvements in both hemodynamic and functional measures. Hemodynamic benefits included reductions in pulmonary vascular resistance and favorable changes in mean pulmonary arterial pressure and cardiac output. Acute functional gains were also observed, such as improvements in six-minute walk distance and encouraging signals during cardiopulmonary exercise testing. No major safety issues have been observed to date.
Positive FDA interactions support a clear clinical development path. If the option is exercised, Gossamer intends to pursue a 505(b)(2) regulatory pathway for inhaled RT234 in the United States, which could simplify the approval process by referencing existing data.
Strategic and Financial Structure
The capital-efficient transaction structure requires no upfront cash and no cash upon exercise of the option. Gossamer will issue 2.5 million shares in connection with signing, equating to about 1% of Gossamer's common shares outstanding, with an additional 1.5 million shares due upon exercise of the option. Current and former shareholders of Respira will be eligible for certain success-based clinical, regulatory, and commercial milestone payments and a high single-digit royalty on potential net sales of RT234.
During the option period, Gossamer will fund certain pre-agreed development expenses for up to approximately 2 years, focused on CMC and device readiness. This structure is designed to minimize near-term cash burn and preserve Gossamer's financial position, while allowing for the continued preparation of RT234 for subsequent clinical development.
Complementary Portfolio Strategy
RT234's on-demand profile is potentially synergistic to Gossamer's existing PH programs and consistent with the company's plan to build a PH-focused commercial enterprise. The therapy is intended to be part of a complete PH toolkit for physicians and patients, complementing Gossamer's lead candidate seralutinib for chronic treatment of PAH and PH-ILD.
"RT234 would be an excellent complement to seralutinib as we look to expand our pulmonary hypertension franchise and deepen our engagement with PH clinicians and patients," Hasnain noted. "The option transaction structure gives us flexibility in decision making as we approach key corporate milestones, keeping our attention squarely on near-term seralutinib priorities in PAH and PH-ILD."
If the option is exercised, Gossamer does not expect to commence clinical trials of RT234 until at least 2027. Respira Therapeutics is backed by Samsara BioCapital, a leading life sciences investment firm focused on advancing innovative therapies for patients with high unmet needs.
