Gossamer looks to acquire Respira, its PH treatment candidate, RT234
Two companies have entered into an option agreement
Gossamer Bio is moving toward acquiring Respira Therapeutics and its lead treatment candidate, RT234, an inhaled therapy being developed for the on-demand treatment of pulmonary hypertension (PH).
The two companies entered into an option agreement that gives Gossamer the exclusive right to this acquisition within an agreed-upon time frame.
Gossamer plans to develop RT234 for pulmonary arterial hypertension (PAH) and PH associated with interstitial lung disease (PH-ILD), the same two indications for which it is already developing its own inhaled treatment candidate, seralutinib.
“RT234 would be an excellent complement to seralutinib as we look to … deepen our engagement with PH clinicians and patients and to reinforce our long-term commitment to those living with pulmonary hypertension,” Faheem Hasnain, co-founder, chairman, and CEO of Gossamer, said in a company press release.
Through the option agreement, Gossamer can acquire Respira and RT234 in exchange for company shares. Respira shareholders will be eligible for payments should certain developmental milestones for RT234 be met, as well as royalty payments for any future sales.
During the option period, Gossamer will fund certain development expenses for up to two years, focusing primarily on issues related to drug manufacturing and development of RT234’s inhalation device.
The structure is intended to help Gossamer focus funding on its existing projects while still preparing RT234 for clinical development. Hasnain indicated that this gives the company “flexibility in [decision-making],” and allows its focus to remain “on near-term seralutinib priorities.”
RT234 is inhaled formulation of vardenafil
All forms of PH are characterized by increased pressure in the pulmonary arteries that carry blood from the heart to the lungs. In PAH, this is caused by various factors that result in pulmonary artery narrowing, while in PH-ILD, it’s due to an underlying lung disease.
Symptoms include shortness of breath, fatigue, dizziness, and abnormal heartbeats, which make daily activities more difficult.
Even with available PH treatments, symptoms can still get acutely worse, especially with exercise or exertion. As a result, there’s a need for on-demand therapies that can be used in such cases to yield quick relief.
RT234 is an inhaled formulation of vardenafil, a medication designed to help blood vessels relax and widen, thus lowering pressure in the pulmonary arteries and improving blood flow. Vardenafil is currently approved in the U.S. as an oral formulation for treating erectile dysfunction.
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. Supported by positive clinical data, RT234 … is intended to address this gap and supplement chronic treatments.
Vardenafil is a phosphodiesterase-5 inhibitor, the same class of medications to which the approved oral PAH therapies Revatio (sildenafil) and Adcirca (tadalafil) belong. In contrast to these therapies, which are taken once daily, RT234 is designed to be delivered directly to the lungs via a dry-powder inhaler and used as needed for quick symptom relief.
“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,” Hasnain said. “Supported by positive clinical data, RT234 … is intended to address this gap and supplement chronic treatments.”
Gossamer intends to pursue regulatory approval in US if deal goes through
The inhaled therapy has been evaluated in PAH patients in two open-label Phase 2 clinical trials — a Phase 2a study (NCT05343637) and a Phase 2b study (NCT04266197).
In those studies, a single dose of RT234 led to rapid and clinically meaningful improvements for patients without any major safety issues, according to Gossamer. The treatment was associated with increased exercise capacity and reduced breathlessness. It also improved measures of blood flow.
There are no ongoing clinical trials of RT234. If Gossamer does acquire RT234, it ultimately intends to pursue regulatory approval in the U.S. through the 505(b)(2) pathway, which allows it to leverage existing data on vardenafil in its approved indication to expedite the process. If the option is exercised, the company does not expect to begin new clinical trials until at least 2027.
Gossamer will continue developing seralutinib, a daily inhaled therapy designed to block the activity of signaling molecules that contribute to the abnormal cell growth that drives pulmonary artery narrowing in PH. Gossamer is developing seralutinib in collaboration with Chiesi Farmaceutici.
The fully enrolled Phase 3 PROSERA trial (NCT05934526) is testing the treatment candidate’s ability to improve exercise capacity in adults with PAH. Top-line results are due early next year, and if positive, could support an application for regulatory approval in PAH.
Gossamer also expects to launch a global Phase 3 trial called SERANATA (NCT07181382) by year’s end that will primarily evaluate seralutinib’s ability to improve exercise abilities in people with PH-ILD.
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