FDA paves way for Phase 2 study of TX45 in PH-HFpEF patients
Experimental injection treatment aims to relax and widen blood vessels
The U.S. Food and Drug Administration has given Tectonic Therapeutic the go-ahead to start a Phase 2 clinical trial of TX45, the company’s experimental treatment for pulmonary hypertension and heart failure with preserved ejection fraction (PH-HFpEF).
“We remain enthusiastic about the potential of TX45 to address the unmet needs of patients living with PH-HFpEF for whom there is no approved therapy,” Alise Reicin, MD, president and CEO of Tectonic, said in a company press release.
Reicin noted that the planned launch of the Phase 2 trial is supported by available safety and pharmacological data from an ongoing Phase 1 study of TX45 in healthy adults as well as individuals with PH-HFpEF.
“We expect to report topline results from our Phase 1a single dose healthy volunteer trial this September and topline results from our Phase 1b single dose patient trial in mid-2025,” Reicin said.
Global Phase 2 clinical trial to enroll broad range of PH-HFpEF patients
In PH-HFpEF, the heart is able to pump a normal or near-normal amount of blood with each heartbeat, but the heart muscle is abnormally stiff. As a result, the left ventricle — the part of the heart normally responsible for pumping oxygen-rich blood out to the body — isn’t able to keep up with demands. This leads to pulmonary hypertension, or high blood pressure in the lungs’ vessels.
TX45 contains a version of relaxin — a naturally occurring hormone that can prompt blood vessels to widen and relax, among other functions — that’s fused to part of an antibody, called an Fc domain, intended to prolong the hormone’s stability in the body.
“We believe our novel Fc-relaxin fusion protein has been engineered to optimize the pharmacology of TX45,” Reicin said.
The upcoming Phase 2 trial will take place at sites worldwide and is expected to launch in the next month, according to Tectonic. It is designed to enroll up to 180 people with PH-HFpEF, who will be randomly assigned to one of two doses of TX45 or a placebo, given by subcutaneous (under-the-skin) injection for 24 weeks (about six months), with an eight-week follow-up period after treatment ends.
Aiming to enroll a broad range of PH-HFpEF patients, the trial will include a group with combined post and precapillary pulmonary hypertension, a severe form of PH-HFpEF marked by especially high pulmonary vascular resistance (PVR, a measure of the resistance of blood vessels to blood flow through the lungs), the company reported.
A main study goal will be to assess the impact of TX45 on PVR and other measures of blood flow in the lungs. Six-minute walk distance, a standardized assessment used to track exercise capacity in ambulatory individuals, also will be assessed.
Top-line trial results are expected in 2026.
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