New Drug Application on Track for LCFAOD A Rare Autosomal Recessive Disease

A recent article in the publication CheckOrphan announced encouraging results of a long term extension study sponsored by Ultragenyx involving UX007 (triheptanoin) in patients with long-chain fatty acid oxidation disorders (LC-FAOD).


Fatty acids are important components of dietary fats or triglycerides serving various purposes in the body. They are composed of carbon atom chains with hydrogen atoms that are joined at one end with an acid group attached to the other.

The fatty acids are responsible for building cell membrane structure, producing energy or forming nerve cells. Long-chain fatty acids contain over twenty carbon atoms.

LCFAODs are inherited conditions in which the body cannot convert long-chain fatty acids into energy. This malfunction may lead to glucose deficiency causing liver, muscle and heart disease. LCFAOD may begin at a very young age, in teenage years, or in adulthood. Patients with the disorder may experience severe energy deficiency that leads to complications such as:

  • Rhabdomyolysis (breakdown of muscle fibers into the blood)
  • Hypoglycemia (low blood sugar)
  • Hypotonia (decrease in muscle tone; weakness)
  • Cardiomyopathy (weakness of heart muscles)

Six genetic diseases are associated with LCFAOD disorders that affect several thousand people in the US. The common denominator in these disorders is a defective enzyme or it may also be enzymes that are missing entirely.

Due to the nature of this inherited disorder infants in the US are now screened for it routinely.

 About the Long Term Extension Study

The trial prior to the extension study, the Phase II trial (NCT01886378) was designed to analyze the safety and clinical effects of UX007 (triheptanoin). Subjects as young as six months were accepted into the study. After four weeks on their own therapy, the subjects began taking UX007 for approximately twenty-four weeks at which time the UX007 therapy was extended for another fifty-four weeks.

Patients who had participated in the Phase II Ultragenyx sponsored study were then moved into the extension study. As a result, these twenty-four patients received UX007 for seventy-eight weeks making a combined total of three years.

About the Results

The researchers analyzed the subjects over the entire treatment period. They found a reduction in hospital admissions (excluding emergency room visits) as well as a reduction in the duration and frequency of these events.

Examining a second group of twenty patients who had not received UX007 prior to the extension study showed a seventy percent decrease in hospital admissions as well as an eighty percent decrease in the duration of these events.

With regard to safety, the results of the long-term extension study were comparable to the results found in the Phase II study.

New Drug Application

Ultragenyx is on target to submit a New Drug Application in mid-2019 which will include findings from the following:

  • the long-term efficacy and safety extension study (75 patients)
  • the Phase II study of UX007 (29 patients)
  • Medical records from patients who received the drug through compassionate use (no suitable drugs available) (20 patients)
  • Data from expanded access (also compassionate use; severe or life-threatening disease)  (70 patients)
  • A study showing the effect of UX007 on cardiac function (32 patients)

The company feels confident that these findings will be a strong and positive component of its New Drug Application submission.


Rose Duesterwald

Rose Duesterwald

Rose became acquainted with Patient Worthy after her husband was diagnosed with Acute Myeloid Leukemia (AML) six years ago. During this period of partial remission, Rose researched investigational drugs to be prepared in the event of a relapse. Her husband died February 12, 2021 with a rare and unexplained occurrence of liver cancer possibly unrelated to AML.

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