Jnana Therapeutics has dosed the first subject in a Phase Ib clinical trial of JNT-517 to treat phenylketonuria (PKU), a rare genetic metabolic disease.

The placebo-controlled, double-blind, randomised trial will assess the pharmacokinetics, tolerability, and safety of the phenylalanine (Phe) transporter SLC6A19 inhibitor JNT-517 in individuals with PKU.

It will also evaluate the effect of JNT-517 on plasma and urinary Phe.

A total of 28 participants aged 18 to 65 diagnosed with PKU will receive JNT-517 orally over a period of four weeks. They are expected to be enrolled at clinical sites in Australia and the US.

Jnana Therapeutics Development head and senior vice-president John Throup said: “JNT-517 offers a promising new approach, with the potential to reduce elevated plasma Phe levels across all levels of disease severity, and has demonstrated positive results with compelling proof of mechanism in a Phase Ia study.

“I’d like to thank the PKU community and clinical investigators for their partnership in initiating this study.”

A total of 64 healthy individuals participated in the Phase Ia portion of the study. The single and multiple ascending dose cohorts in the study showed an increase in urinary Phe​.

JNT-517 was found to be safe and well tolerated at all dose levels examined.

It acts at a cryptic allosteric site and blocks kidney reabsorption of Phe, thereby reducing blood Phe levels.

Last year, JNT-517 received a rare pediatric disease designation from the US Food and Drug Administration (FDA).

The company is also engaged in developing various therapies for treating cancer and immune-mediated diseases.