FDA Grants Fast Track Designation to 4D Molecular Therapeutics for Retinitis Pigmentosa Therapy

The U.S. Food and Drug Administration granted Fast Track designation to 4D Molecular Therapeutics’ 4D-125 for treatment of patients with inherited retinal dystrophies due to defects in the RPGR gene, including X-linked retinitis pigmentosa.

X-linked retinitis pigmentosa (XLRP) is a rare inherited X-linked recessive genetic disorder that causes progressive vision loss and blindness in boys and young men. There are currently no approved therapies for XLRP. Seventy percent of cases are caused by mutations in the retinitis pigmentosa GTPase regulator (“RPGR”) gene. The estimated worldwide prevalence of XLRP due to RPGR variants is approximately one in 25,600 people, which represents approximately 24,000 patients in the United States, and France, Germany, Italy, Spain, and the United Kingdom (together, EU-5). It is characterized by dysfunction and degeneration of photoreceptors in the retina. Symptoms of XLRP are initially characterized by night blindness, followed by loss of peripheral visual field, decreasing visual acuity, and eventually blindness.

4D-125 is a targeted and evolved R100-based product candidate, which was invented at 4DMT for efficient intravitreal delivery, and is designed to deliver a functional copy of the RPGR gene to photoreceptors in the retina.

4DMT is currently enrolling patients in an on-going phase 1/2 clinical trial. The study employs a standard 3+3 dose-escalation design, followed by dose expansion. In dose-escalation, patients were enrolled in one of two dose cohorts: 3E11 vg/eye and 1E12 vg/eye. The dose expansion phase of the study is enrolling patients at the 1E12 vg/eye dose. The primary objectives of this trial are to evaluate the safety and maximum tolerated dose of 4D-125. Secondary endpoints include assessments of clinical activity, including both visual function and anatomical endpoints.

The FDA’s Fast Track process is designed to accelerate the development and review of treatments for serious and life-threatening diseases where no treatment exists or where the treatment in discovery may provide advantages over what is currently available. A drug candidate that receives Fast Track designation is eligible for more frequent communication with the FDA throughout the drug development process and a rolling and/or priority review of its marketing application if relevant criteria are met.

“Patients living with XLRP currently have no approved treatments, and they suffer from progressive vision loss and blindness that reduces their quality of life and independence,” said Robert Kim, senior vice president and Ophthalmology Therapeutic Area head of 4DMT. “Fast Track designation is a landmark event for the program and underscores the potential of 4D-125 to address a significant unmet need for those living with XLRP.”

Photo: Robert Kim, senior vice president and Ophthalmology Therapeutic Area head of 4DMT

Author: Rare Daily Staff