Jerry Vockley, MD, PhD1; Barbara Burton, MD2; Gerard Berry, MD3; Nicola Longo, MD, PhD4; John A. Phillips, MD5; Amarilis Sanchez-Valle, MD6; Kimberly Chapman, MD7; Pranoot Tanpaiboon, MD7; Stephanie Grunewald, MD, PhD8; Elaine Murphy, MD9; Alexandra Bowden, PhD10; Yunming Mu, PhD10; Jason Cataldo, DO10
1University of Pittsburgh, Pittsburgh, PA, USA; 2Ann & Robert H. Lurie Children’s Hospital, Chicago, Illinois, USA; 3Boston Children’s Hospital, Boston, MA, USA; 4University of Utah, Salt Lake City, UT, USA; 5Vanderbilt University Medical Center, Nashville, TN, USA; 6USF Health, Morsani College of Medicine, Tampa, FL, USA; 7Children’s National Health System, Washington DC, USA; 8Great Ormond St, UCL Institute of Child Health, London, UK; 9National Hosp for Neurology & Neurosurgery, London, UK; 10Ultragenyx Pharmaceutical Inc., Novato, CA, USA
Background: Long-chain fatty acid oxidation disorders (LC-FAOD) are autosomal recessive conditions that impair conversion of long-chain fatty acids into energy, resulting in major clinical events (MCEs). Triheptanoin (trihep) is a highly purified, 7-carbon chain triglyceride being investigated for LC-FAOD treatment.
Methods: An open-label, long-term extension study (NCT02214160) is evaluating safety and efficacy of trihep in patients (pts) with LC-FAOD who participated in prior clinical trials or investigator-sponsored trials (ISTs) or expanded access; pts not previously treated with trihep also are enrolled.
Results: In total, 75 pts enrolled as of June 1, 2018; 24 rolled over from the Phase 2 study. Prior to trihep, these 24 pts had a median annualized event rate (AER) of 1.5 events/yr. Following an additional 78 wks of trihep (≥3 yrs of total treatment), pts had a 67% reduction in median AER (0.5 events/yr, overall; 0.7 events/yr, Phase 2; 0 events/yr, extension). Twenty pts not previously treated with trihep had a pre-treatment median AER of 2.3 events/yr. In these pts, a median of 63 wks of trihep treatment resulted in a 70% reduction in median AER (0.7 events/yr), consistent with results seen in the 24 rollover pts. In 31 pts from ISTs or expanded access, pre-treatment data were not available for comparison. The most common related adverse events (AEs) among all 75 pts were diarrhea, abdominal pain/discomfort, and vomiting, with most mild to moderate in severity. Three pts had AEs classified as serious due to hospitalization (diverticulitis, ileus, rhabdomyolysis) considered possibly related to drug by the investigator; all resolved. Two pts had AEs leading to death; neither was deemed related to drug. Most pts (87%) are continuing treatment.
Discussion: Trihep showed sustained clinical benefit in reducing the rate and duration of MCEs in 2 distinct patient cohorts. Additionally, safety was consistent with previous observations during this long-term treatment.
JV, BB, GB, NL, JP, ASV, KC, PT, SG, and EM are clinical investigators for this study sponsored by Ultragenyx Pharmaceutical Inc. YM and JC are employees of Ultragenyx Pharmaceutical Inc. AB is a former employee of Ultragenyx Pharmaceutical Inc.
Corresponding author contact information:
Jerry Vockley, M.D., Ph.D.
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