The University of Colorado (CU) has signed exclusive, worldwide licensing and collaboration agreements with rare-disease research-and-development firm Orphan Technologies Ltd to develop an enzyme replacement therapy for Cystathionine Beta-Synthase (CBS) -deficient homocystinuria, a rare, inherited metabolic disease that is often fatal at a young age. The collaboration was initiated in 2010 and includes sponsored-research funding by OT to continue development of the treatment approach pioneered by Jan P. Kraus, a professor of pediatrics at the CU School of Medicine. Orphan Technologies plans to begin first-in-human trials in 2014.
CBS-deficient homocystinuria is a rare genetic disorder caused by low levels of active CBS enzyme. Individuals with this disease are unable to fully metabolize the amino acid methionine, which is found in nearly all foods. That leads to the accumulation of toxic levels of related metabolites (molecules that are the product of metabolism), and deficits in others.
Patients with homocystinuria suffer major multi-systemic disorder, including mental retardation, dislocation of the lens of the eye (leading to blindness if not treated), seizures, osteoporosis and stroke. Taken together, these lead to a significantly shorter life expectancy; almost one fourth of untreated patients die before the age of 30.
About 40% of patients with homocystinuria benefit from vitamin B6 supplementation. But for the rest, treatment is limited to a methionine-restricted (low protein) diet and supplementation with cystine, folate, and betaine (Cystadane) which partially restore metabolic balance; however, these treatment approaches do not repair the broken methionine metabolic cycle and don't resolve all metabolic abnormalities, so patients still suffer from severe, life-threating symptoms.
Professor Kraus has devised an enzyme replacement therapy to correct the underlying cause of the disease. This approach has the potential to restore the normal metabolism of methionine, which could avoid the accumulation of toxic levels of metabolites, prevent the appearance or worsening of symptoms, normalize life expectancy, and eliminate the need for diet restrictions.
"Today the therapy for homocystinuria concentrates on lowering the concentration of a single metabolite, homocysteine, while metabolites further downstream are unaffected by the available treatment," said Professor Kraus. "However, these downstream metabolites may be of considerable clinical significance, and our approach has the potential to restore all the affected metabolites to their normal level, and as such reduce or prevent symptoms and enable a return to a normal diet."