Potential Cystic Fibrosis Therapy Gets FDA Fast Track Approval, Clinical Tests to Follow

Proteostasis Therapeutics, Inc., announced that it recently received Fast Track Designation from the U.S. Food and Drug Administration (FDA) for PTI-428, an investigational oral treatment for cystic fibrosis (CF).

CF is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, resulting in a disruption of ion flow within cells and the progressive buildup of thick mucus in organs that include the lungs.

PTI-428 is an oral modulator in the amplifier class. Amplifiers are CFTR modulators that selectively increase the amount of an immature form of the CFTR protein, providing additional substrate for other CFTR modulators (e.g., correctors or potentiators) to act upon.

The company also recently received FDA authorization to start clinical trials of PTI-428 in CF patients. A Phase 1 trial, expected to start by spring 2016, will assess the drug’s pharmacokinetics, preliminary pharmacodynamics, and safety profile. Final data is expected by the close of the year.

“We are very pleased to receive this Fast Track designation from the FDA for PTI-428 for the treatment of CF,” Meenu Chhabra, Proteostasis’ president and CEO,  said in a company news release. “PTI-428 is a unique CFTR amplifier that when used in combination with existing treatments and therapies presently in clinical development, has shown a consistent positive effect on CFTR protein activity in vitro, nearly doubling activity in patient derived human bronchial epithelial [HBE] cells not only for the most common gene mutation found in CF, but across multiple gene mutations. We have also demonstrated that a novel combination of PTI-428, together with a proprietary corrector and a proprietary potentiator, can restore in vitro CFTR protein activity to approximately 97% of normal in patient-derived HBE cells homozygous for F508del.”

Fast Track designation is given to facilitate the development and expedite the review of novel drugs intending to treat serious or life-threatening diseases, and which have shown a potential to address unmet medical needs. The designation allows for direct and frequent communication between the company and the FDA regarding the development plan or clinical trial design, and may make the drug eligible for priority review later on.

Proteostasis Therapeutics, with headquarters in Cambridge, Massachusetts, specializes in disease-modifying therapies for diseases of protein processing, like CF. The company uses a phenotypic screening approach, called the DRT platform, to identify drug candidates that modulate the proteostasis imbalance in cells.