With FDA hold lifted, IPF clinical trial of LTI-03 begins dosing patients
Enrollment ongoing; goal is to assess inhaled therapy's safety, tolerability
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Following the lifting of a regulatory hold late last year, a U.S. clinical trial testing LTI-03, an inhaled therapy for people with idiopathic pulmonary fibrosis (IPF), is now fully underway.
Treatment developer Rein Therapeutics announced that dosing has started in the Phase 2 clinical trial, which aims to assess the safety and tolerability of the drug candidate.
“Dosing the first patient in this Phase 2 trial marks an important step forward for Rein and, more importantly, for patients living with IPF,” Brian Windsor, PhD, CEO of Rein, said in a company press release, which noted that interim data are expected before the end of the year.
“This milestone reflects our team’s focus on execution and brings us closer to understanding the potential impact of LTI-03 for patients,” Windsor said.
The clinical trial, dubbed RENEW (NCT06968845), initially began recruiting patients last year. However, a subsequent full clinical hold from the U.S. Food and Drug Administration stopped its progress. According to the developer, the hold was lifted later in 2025 after Rein addressed the regulatory agency’s concerns. No details were provided on what those concerns were, with the company at the time noting only that they were “fully resolved.”
Now back on track, the study aims to enroll approximately 120 people with IPF, ages 40 and older. Eligible participants may be on stable IPF treatment or have discontinued such treatment at least eight weeks before the study, and also meet certain minimum requirements for lung function measures.
Recruitment is ongoing at five study locations in the U.S., and Rein said more sites are expected to open in the coming months.
Secondary goal of IPF trial is assessing effects on lung function
Participants in the study will be randomly assigned to take LTI-03 or a placebo, administered twice daily via a dry powder inhaler, for about six months.
The study’s main goal is to assess whether the therapy is safe and well tolerated in adults with IPF. Secondary goals include evaluating LTI-03’s effects on measures of lung function.
Rein said it expects enrollment to continue through the middle of 2027, though the company hopes to announce interim findings in the second half of this year.
IPF is marked by inflammation and fibrosis,or scarring, in the lungs. The active agent in LTI-03 is a portion of the protein caveolin-1 (Cav1). This protein normally helps to regulate wound healing and scar formation. Studies have shown that IPF is marked by reduced Cav1 protein levels in the lungs.
By restoring activity of the Cav 1 protein, LTI-03 aims to modulate the activity of several fibrosis-associated molecular pathways to help preserve lung function.
Current [IPF] therapies offer limited benefit and often come with significant side effects. Our goal with LTI-03 is to go beyond slowing disease progression and help preserve lung function by addressing the underlying biology of fibrosis.
The therapy has shown promising effects in preclinical studies. In an earlier Phase 1b trial (NCT05954988), its use was shown to reduce fibrosis markers in newly-diagnosed IPF patients.
“Current [IPF] therapies offer limited benefit and often come with significant side effects. Our goal with LTI-03 is to go beyond slowing disease progression and help preserve lung function by addressing the underlying biology of fibrosis,” Rein said.
Regulators in the U.S. and the European Union have granted LTI-03 orphan drug designation as a potential treatment for IPF. This designation aims to offer extra incentives for companies developing medicines to treat rare diseases.
