Novel. Simple. Hopeful.


Ocera in-licensed OCR-002 (ornithine phenylacetate) from University College London. OCR-002 is an ammonia scavenger designed to rapidly lower abnormally elevated systemic ammonia levels (hyperammonemia) and treat hepatic encephalopathy (HE) in patients with liver cirrhosis and acute liver failure.

With severe liver impairment, toxic substances that are normally removed by the liver, such as ammonia, accumulate in the blood. Elevated ammonia levels can cause swelling of the brain. Signs and symptoms of HE include impaired cognition, confusion, and a decreased level of consciousness which can progress to coma and ultimately death. Patients are currently treated with laxatives that help eliminate ammonia in the gut and antibiotics that target ammonia production.

Unlike currently approved therapies for HE, OCR-002 is unique in that it directly lowers circulating blood levels of ammonia through pathways that do not require liver function.

OCR-002 is in development as both an intravenous formulation which is well suited for the hospitalized population with acute HE, and as an oral formulation to provide a chronic use option to maintain remission of HE in patients with liver cirrhosis.

Product Formulation Indication Preclinical Phase 1 Phase 2 Phase 3
OCR-002 IV Acute Hepatic
Encephalopathy (HE)*
Cirrhosis and GI
Acute Liver Failure
Oral Chronic HE

*FDA Orphan drug and Fast Track Status      **Investigator-sponsored

STOP-HE: Phase 2b Trial in Acute HE

Ocera is currently enrolling patients in a Phase 2b placebo-controlled, randomized, double-blind trial, STOP-HE, designed to evaluate the Safety, Tolerability, pharmacokinetics and efficacy of intravenously-administered OCR-002 (Ornithine Phenylacetate) in resolving neurocognitive symptoms of acute Hepatic Encephalopathy in hospitalized patients with elevated ammonia. For more trial-related information, please see our Resources page.

STOP-ALF: Phase 2a Trial for Acute Liver Failure/Injury

In September 2016, enrollment was completed in STOP-ALF, a Phase 2a clinical trial to evaluate the Safety and Tolerability of Ornithine Phenylacetate in patients with Acute Liver Failure. The study was conducted by the Acute Liver Failure Study Group, an NIH-sponsored network of university tertiary care liver transplant sites, with support and supply of study medication from Ocera. The study was a multi-center, open label, dose-ranging study to assess the safety and pharmacokinetics of OCR-002 IV in patients with acute liver failure or injury. For more trial-related information, please see our Resources page.

Phase 2a Trial in Cirrhosis and Upper GI Bleed

In February 2015, an investigator-sponsored Phase 2a study of OCR-002 IV was completed. Part A, designed as an open-label safety and tolerability study in patients with cirrhosis and upper gastrointestinal (GI) bleeding, demonstrated rapid ammonia lowering in 24 hours in the active cohort. Part B, a placebo-controlled study in patients with decompensated cirrhosis showed rapid reduction in the OCR-002 arm in the first 12-24 hours and a statistically significant difference in urinary excretion of ammonia.

Phase 1 Trial in Patients with Cirrhosis for Chronic HE

Ocera initiated dosing in September 2016 in a Phase 1 study of orally available OCR-002 in patients with cirrhosis for the prevention of hepatic encephalopathy. The Phase 1 trial is a two-part, open-label, crossover study to understand the pharmacokinetics, PAGN formation and the absolute bioavailability of oral immediate-release doses of OCR-002. Data from Part One is expected by the end of 2016.


Part Two, also in patients with cirrhosis, will evaluate a multi-dose solid form regimen and resultant steady-state pharmacokinetics, and data is expected by the end of the first half of 2017.


Phase 2 development will begin following satisfactory results from both parts of the Phase 1 trial.