Respira Reacquires Full Rights Over RT234 for As-Needed PAH Symptom Relief

Alice Melão, MSc avatar

by Alice Melão, MSc |

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Respira Therapeutics has regained full worldwide research, development, and licensing rights over its inhaled medicine-device combination product, called RT234, for the treatment of pulmonary arterial hypertension (PAH).

This follows the decision of its partner United Therapeutics to terminate the collaboration with Respira, which was established in April 2017.

RT234 is an inhaled therapy being developed to provide symptom relief in people with PAH. It is thought to help improve exercise tolerance and reduce breathlessness and fatigue related to PAH.

The therapeutic combo combines the potent vasodilator vardenafil — available in the United States in an oral form for the treatment of erectile dysfunction — with Respira’s dry-powder inhaler technology AOS-DPI. In contrast to available PAH therapies that are administrated under a specific treatment regimen, RT234 was designed to be taken when necessary (on-demand use).

In April, RT234 received orphan drug designation by the U.S. Food and Drug Administration for the treatment of PAH.

Preclinical studies and a Phase 1 clinical trial (ACTRN12618001077257) in healthy volunteers demonstrated that RT234 is well-tolerated and in general safe.

Respira Therapeutics is exploring the safety and potential of RT234 as a treatment for PAH in an open-label Phase 2a trial (ACTRN12619001178134). The trial, currently recruiting participants in Australia, is expected to enroll approximately 15 adults with PAH.

Participants will be assigned to one of three groups taking increasing doses of RT234 (up to 2,400 micrograms per dose). The treatment’s safety will be assessed through a patient self-report by phone at day three and day 30 after the first administration.

The impact of RT234 on exercise capacity will be measured through changes in blood pressure during a cycle ergometer aerobic fitness test. Exercise measurements will be obtained prior to RT234 dosing, and immediately after the second dose.

“The positive data from our non-clinical and Phase 1 studies in healthy volunteers represent significant milestones for the development of RT234 as the first as-needed therapy for symptomatic relief in PAH patients,” Bob Curtis, president and CEO of Respira, said in a press release.

“We are proud of the progress the Respira team has made to advance RT234 from a product concept into Phase 2 development in a very short time. As a result, we are well-positioned and excited to move RT234 through Phase 2 clinical trials for pulmonary arterial hypertension and explore additional product indications to maximize the value of our RT234 program.”

Respira also plans to explore the use of RT234 in other groups of patients with pulmonary hypertension.

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