FDA relaxes clinical hold on Translate Bio’s cystic fibrosis drug

RNA specialist Translate Bio is just weeks away from dosing the first patients in its phase 1/2 trial in cystic fibrosis patients after a green light from the FDA.

Lexington-based Translate Bio, which is trying to develop messenger RNA-based therapeutics for CF, said its lead MRT5005 candidate has the potential to treat all patients with the disease, regardless of the underlying mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

In CF, mutations in the CFTR gene disrupt ion transport across epithelial cells, leading to the production of thick mucus, particularly in the lungs and pancreas.

Translate Bio’s mRNA drug could represent an improvement over approved CF medicines like Vertex Kalydeco and two-drug follow-ups Orkambi and Symdeko, which target specific mutations and are only suitable for use in around 30,000 of the 70,000 patients with CF worldwide. Vertex is, however, working on three-drug combinations that could bring more patients into scope.

Translate Bio—which was formerly known as RaNA Therapeutics—acquired MRT5005 as part of a deal to take control of Shire’s mRNA assets last year.

The drug will be the “first mRNA therapeutic to enter the clinic with targeted delivery to the lung,” according to Translate Bio’s CEO Ronald Renaud. Once delivered via a nebulizer, the drug is designed to serve as a template for the production of functional CFTR in cells of the lung, bypassing the mutated form.

The trial (RESTORE-CF), which is being supported by the Cystic Fibrosis Foundation, will enroll at least 32 patients and look at the effectiveness of delivery and lung function, as well as the safety and tolerability of the drug. Its due to complete in the middle of 2019.

The approval to start the trial is a relief for Translate Bio, coming after a delay of a few months caused by an FDA request. The FDA asked for additional chemistry, manufacturing and controls (CMC) information for the drug, which placed the program under a temporary clinical hold. It now says it intends to start dosing patients in mid-2018.

“As our first IND submission and the first clinical trial to evaluate a product candidate derived from our mRNA technology (MRT) platform, this is a significant milestone for the company,” said Renaud.

Vertex is also developing RNA-based drugs for CF via a partnership with Moderna Therapeutics agreed in 2016, while others active in this area include Arcturus and ProQR Therapeutics.