Europe Grants Orphan Drug Status to JR-441, ERT for Sanfilippo A

Marta Figueiredo, PhD avatar

by Marta Figueiredo, PhD |

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The European Commission has granted an orphan drug designation to JR-441, JCR Pharmaceuticals’ brain-penetrating experimental enzyme replacement therapy (ERT) for Sanfilippo syndrome type A, the company has announced.

The designation is given to investigative therapies with the potential to be safe and effective for rare, life-threatening, or chronically debilitating conditions that have no approved treatments, or where the potential therapy is showing significant benefit over existing treatments.

It is meant to accelerate JR-441’s clinical development and review by providing regulatory support and financial benefits. It also provides a 10-year marketing exclusivity period in Europe upon regulatory approval, if granted.

JCR is planning to launch a global clinical trial testing the therapy in the first half of 2023.

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Sanfilippo syndrome type A, also known as mucopolysaccharidosis type IIIA, is caused by the absence or reduced activity of the heparan N-sulfatase enzyme due to mutations in the SGSH gene. Heparan N-sulfatase deficiency leads to the toxic accumulation of heparan sulfate, a complex sugar molecule, inside cells.

While this toxic buildup occurs throughout the body, nerve cells in the central nervous system (CNS; the brain and spinal cord) are particularly sensitive to heparan sulfate accumulation, dying as a consequence.

Enzyme replacement therapy for Sanfilippo type A involves the delivery of the faulty of missing enzyme, heparan N-sulfatase, to patients. This type of therapeutic approach is expected to slow or prevent further neurodegeneration.

While enzymes cannot naturally cross the blood-brain barrier (BBB) — a protective membrane that prevents microbes and large molecules in circulation from entering the CNS — JR-441 comprises a heparan N-sulfatase fused to an antibody that binds to a BBB transporter called the transferrin receptor.

As such, JR-441 is designed to effectively cross the BBB and increase the levels and activity of heparan N-sulfatase in the brain and spinal cord.

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JCR also used this strategy, based on its proprietary J-Brain Cargo BBB-penetrating technology, to develop ERTs for other mucopolysaccharidoses (MPS), a group of inherited diseases caused by the toxic accumulation of glycosaminoglycans, long and complex sugar molecules, due to deficiencies in enzymes that break them down.

Among the ERTs are Izcargo (pabinafusp alfa), approved for MPS type II (Hunter syndrome) in Japan, and JR-171, a therapy candidate for MPS type I that is currently being tested in early clinical trials.

Other J-Brain Cargo-based ERTs are being tested in preclinical studies, and include JR-446 for Sanfilippo type B, and JR-443 for MPS type VII (Sly syndrome).

“JCR, as a specialty pharma in the rare disease arena, will continue to proactively engage in research and development of transformative treatment options for patients with rare diseases,” the company stated in the press release.