12:00 AM
Jun 05, 2014
 |  BC Innovations  |  Cover Story

Alas, porphyria

For over two decades, treatment of acute porphyrias has relied on hemin infusions that restore heme levels, but the therapy is slow to work, has side effects and is expensive. Now, a team led by Alnylam Pharmaceuticals Inc. has created an siRNA therapeutic that reduces disease symptoms in mice.1

However, to really improve patient care, the company will also need a strategy to raise awareness and combat misdiagnosis of these rare disorders.

Alnylam is completing IND-enabling toxicity studies. The company expects to submit an IND in 2014 and start clinical trials in 2015.

Acute hepatic porphyrias are orphan diseases caused by enzyme deficiencies that disrupt heme biosynthesis and ultimately result in misregulation of aminolevulinate synthase-1 (ALAS-1), the first enzyme in the heme biosynthetic pathway. These inherited disorders are characterized by life-threatening acute attacks that include severe abdominal pain, muscle weakness, seizures and paralysis.

According to Karl Anderson, the prevalence of acute porphyrias is unknown. "It is estimated at about 5 per 100,000. We usually see only those who are sick and not the many others who have not yet developed symptoms," he said.

Anderson is director of the Porphyria Laboratory & Center and a professor in the Department of Preventative Medicine and Community Health at The University of Texas Medical Branch.

There are three known triggers of acute attacks: drugs that induce heme-dependent cytochrome P450 enzyme activity in the liver, hormonal changes, and starvation or extreme dieting.

Robert Desnick told SciBX that during an acute attack, patients often experience a prodromal period with brain fog and fatigue. Then, he said, "All hell breaks loose. They get excruciating abdominal pain that takes them to the emergency room."

However, the disease is often undiagnosed or misdiagnosed in the emergency...

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