Trial of Nebulized CF Candidate Therapy Completes Single-ascending Dosing

The RESTORE-CF clinical trial investigating Translate Bio’s candidate therapy MRT5005 has completed the single-ascending dose regimen in patients with cystic fibrosis (CF), the company announced.

The ongoing Phase 1/2 trial (NCT03375047) is testing the safety and efficacy of single and multiple escalating doses of nebulized MRT5005, compared with each other and a placebo, in 32 adults with CF who have class I or II genetic mutations in the CFTR gene (the gene that is defective in CF patients).

The trial, being conducted in collaboration with the Cystic Fibrosis Foundation Therapeutics Development Network, is now moving into the multiple ascending dose phase.

“We are excited to share that we have completed dosing in the single-ascending dose portion of the ongoing Phase 1/2 clinical trial for MRT5005 in patients with cystic fibrosis, and anticipate reporting interim data from this trial in the third quarter of this year,” Ronald Renaud, chief executive officer of Translate Bio, said in a press release.

The single-ascending dose of the trial included 12 CF patients who were randomized to receive a single administration of increasing doses of MRT5005 — 8, 16, or 24 mg — or a placebo. Another 12 patients will be included in the multiple escalating doses portion, where they will receive weekly administrations of the treatment or a placebo for five weeks.

After this dose testing, the trial will include eight patients who will receive one of the two highest, well-tolerated MRT5005 doses for five weeks.

Researchers will evaluate MRT5005’s safety and tolerability, as well as its impact on lung tissue and CFTR protein production through biopsy analysis. They will also analyze early signs of efficacy by looking at lung function, specifically changes in forced expiratory volume in one second (FEV1).

Translate Bio expects to announce results of the RESTORE-CF trial by the end of 2019.

MRT5005 is a messenger RNA product designed to deliver the correct sequence of the CFTR gene to lung cells so that they can produce a fully functional CFTR protein. MRT5005 is the first potential mRNA approach to specifically target the lungs.

Previous preclinical studies showed that nebulized MRT5005 can effectively reach lung cells and cross the mucus barrier in mice and rats with CF.