By Don Tracy, Associate Editor

The Fast Track designation for INZ-701 was based nonclinical pharmacology data and preliminary safety and efficacy data from the ongoing Phase I/II trial of INZ-701 in adults with ABCC6 Deficiency.
The FDA has granted Fast Track Designation for Inozyme Pharma’s INZ-701, aimed to treat patients with ABCC6 Deficiency. According to the company, the Fast Track designation was based on preliminary safety and efficacy data from its ongoing Phase I/II trial of INZ-701 in adults with ABCC6 Deficiency, as well as nonclinical pharmacology data. Inozyme believes that INZ-701’s development process will benefit from more frequent engagement with the FDA and expedited regulatory review.1
“Through Fast Track designation, the FDA recognizes the potential of INZ-701 in ABCC6 Deficiency. We plan to work closely with the agency to establish an efficient path to approval. Receipt of Fast Track designation underscores our belief that INZ-701 could serve as an important therapy for patients living with ABCC6 Deficiency, notably for pediatric patients in whom this condition increases the risk of major clinical events such as stroke and severe neurological and cardiovascular disease,” said Douglas A. Treco, PhD, CEO, chairman, Inozyme Pharma, in a press release. “We look forward to presenting our development plans to regulatory agencies and reaching agreement on a pivotal study in pediatric patients with ABCC6 Deficiency by year-end 2024.”
The ongoing trial enrolled 10 patients with heavy disease burden, as evidenced by serious cardiovascular disease and retinal disease. As part of the trial, patients were divided into three dose cohorts of INZ-701: 0.2 mg/kg (n=3), 0.6 mg/kg (n=3), and 1.8 mg/kg (n=4) for 32 days. Doses were selected based on preclinical studies and PK/PD modeling. The primary endpoint of the study was safety and tolerability of INZ-701 in adult patients with ABCC6 Deficiency.
Results found a reduction in or stabilization of carotid intima-media thickness (cIMT), a marker for cardiovascular disease and stroke, and an increase in choroidal thickness, indicating potential benefits in vascular and retinal health. Further, four patients were found to have an improvement in visual function scores (VFQ-25) and nine patients experienced an improved global impression of change (GIC) score. Lastly, PK and PD data revealed a sustained increase in plasma pyrophosphate (PPi) levels at the 1.8 mg/kg dose.2
No severe adverse events (SAEs) were found in patients treated with INZ-701, with the medication being generally well tolerated. Minor AEs included discoloration, discomfort, erythema, induration, pain, pruritus, warmth, fatigue, night sweats and urticaria.2,3
“We are excited by the excellent safety and preliminary efficacy profile of INZ-701 in adults with ABCC6 Deficiency,” said Treco, in a press release. “Our investigations into the natural history of this disease have identified a substantial and previously overlooked pediatric population with a high risk of stroke. We believe these patients represent a critical unmet need in this genetic disease and that changes observed in adults treated with INZ-701 will translate to clinical benefits in a future trial in children.”
Currently, there are no therapies approved to treat ABCC6 Deficiency. It is caused by mutations in the ABCC6 gene, resulting in a reduction of systemic adenosine triphosphate (ATP) levels and low levels of pyrophosphate (PPi) and adenosine in the blood.4
“The high risk of ischemic stroke in pediatric patients with ABCC6 Deficiency and its devastating consequences represents a serious unmet need in this population,” commented Professor Zulf Mughal, MD, consultant in pediatric bone disorders, Al Jalila Children's Specialty Hospital, Dubai, UAE, in a press release. “I am very encouraged to see that INZ-701 may improve vascular pathology and believe that this effect may translate to clinical benefits in patients of all ages.”