Calliditas Therapeutics has initiated a Phase II trial to evaluate setanaxib as a treatment for Alport syndrome.

The randomised, placebo-controlled Phase II trial is expected to enrol approximately 20 patients with a confirmed genetic diagnosis of Alport syndrome. Another inclusion criterion for the trial is the presence of significant proteinuria despite treatment with a renin-angiotensin system (RAS) blocker, as per a 30 November press release.

The trial will evaluate the safety and tolerability of setanaxib over 24 weeks. The study will also evaluate kidney function by measuring the urine protein-creatinine ratio (UPCR) and estimated glomerular filtration rate (eGFR) compared to placebo.

Setanaxib is a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) enzyme inhibitor. NOX enzymes are responsible for the production of reactive oxygen species, which, in turn, regulates cell proliferation and differentiation and modulates innate immune response, inflammation, and fibrosis.

The drug was granted an orphan drug designation by the European Medicines Agency (EMA) Committee for Orphan Medicinal Products (COMP) for the treatment of Alport syndrome.

Alport syndrome is a rare genetic disorder which is characterised by progressive kidney disease. The disease is caused by the mutations in type 4 collagen genes. The disease symptoms vary from person to person due, in part, to the different possible subtypes and gene variants of the disease. As per the US National Organization for Rare Disorders (NORD), approximately 30,000-60,000 people in the US have Alport syndrome.

Setanaxib development programme

Setanaxib is also being evaluated as a treatment for primary biliary cholangitis (PBC), squamous cell carcinoma of the head and neck (SCCHN), and idiopathic pulmonary fibrosis (IPF).

The placebo-controlled Phase IIb/III trial (NCT05014672) investigating setanaxib as an add-on therapy in PBC patients is estimated to be completed in September 2025, as per ClinicalTrial.gov. The primary endpoint is the reduction in alkaline phosphatase (ALP) level. Key secondary endpoints include changes in liver stiffness score and the effect on pruritus (itching) and fatigue. PBC is a progressive, chronic, autoimmune liver disease.

The Phase II trial (NCT05323656) investigating setanaxib as a combination therapy with Merck’s Keytruda (pembrolizumab) has enrolled 55 patients with recurrent or metastatic SCCHN. The trial compared the setanaxib combination therapy with placebo and Keytruda. The trial is estimated to be completed in June 2024, as per ClinicalTrial.gov.

Another drug in Calliditas’ pipeline includes Nefecon (targeted-release budesonide formulation), marketed in the US under the brand name Tarpeyo and as Kinpeygo in the EU. The drug met its primary endpoint in the Phase III NefIgArd trial (NCT03643965) in patients with primary IgA nephropathy (IgAN). The prescription Drug User Fee Act (PDUFA) date for Nefecon’s supplemental new drug application (sNDA) application is set for 20 December.