Eli Lilly Discontinues Mid-Stage Relaxin Study in Chronic Kidney Disease

Eli Lilly has terminated a Phase II trial of its investigational relaxin analog volenrelaxin in chronic kidney disease (CKD), citing a "lack of foreseeable clinical benefit" in the target population. The decision, announced last week, comes on the heels of a similar discontinuation in a related heart failure study that showed no benefit in an overlapping patient group.

Study Termination and Its Implications

The pharmaceutical giant updated the study's clinicaltrials.gov webpage to reflect the termination of the trial. While details about the related heart failure study remain unclear, another Phase II trial of volenrelaxin in chronic heart failure with preserved ejection fraction is still listed as active but not recruiting.

Volenrelaxin, a synthetic analog of the human relaxin protein, was designed to activate the relaxin receptor. Previous animal studies had shown promising results, including increased renal blood flow in rats. A Phase I trial had also demonstrated the drug's safety and suitability for subcutaneous dosing, with encouraging signs of efficacy in improving kidney perfusion upon repeated dosing.

Impact on Industry Partners

The news of Lilly's decision had immediate repercussions beyond the company itself. Massachusetts-based Tectonic Therapeutics, which is developing a similar compound, saw its stock price plummet by as much as 40% following the announcement.

Tectonic's candidate, TX45, is a relaxin fusion molecule that activates the RXFP1 receptor, similar to volenrelaxin. The biotech company is proposing TX45 as a treatment for pulmonary hypertension in the presence of heart failure with preserved ejection fraction.

Analysts at Leerink Partners initially expressed concern about the likelihood of success for TX45 in light of Lilly's decision. However, in a follow-up note, they reiterated confidence in Tectonic, pointing out several key differences between TX45 and volenrelaxin, including distinct approaches, indications, and endpoints.

Looking Ahead

As the pharmaceutical industry digests this setback in relaxin-based therapies, attention will likely turn to Tectonic's ongoing efforts. The company is preparing for a Phase Ib readout in the first quarter of 2025, which may provide further insights into the potential of relaxin receptor activation in treating cardiovascular and renal conditions.

Eli Lilly is scheduled to hold its fourth-quarter and full-year earnings call on February 6, where more details about the volenrelaxin program and its future may be disclosed. The industry will be watching closely to see how this development affects Lilly's pipeline and strategy in the chronic kidney disease and heart failure therapeutic areas.