Long-term Outcome of N-Carbamylglutamate Treatment in Propionic Acidemia and Methylmalonic Acidemia

• Neurodevelopment [ Time Frame: Intake through 7 days or discharge ] [ Designated as safety issue: No ]
  Neurodevelopmental outcome as measured by Cognitive Composite (Bayley III), Motor Composite (Bayley III) and Functional Status Scale and safety of NCG treatment as measured by adverse events and laboratory blood tests
  
  

• Safety and Efficacy [ Time Frame: Intake through 7 days or discharge ] [ Designated as safety issue: Yes ]
  Safety as measured by adverse events. Efficacy as measured by resolution of hypoammonemia.
  
  

Drug: N-carbamylglutamate

Chemical Composition: N-carbamyl-L-glutamic acid (NCG) The daily dose will be 100 mg/kg/ day. The doses are to be divided into 2 equal doses and administered orally or enterally by nasogastric or gastrostomy tube (standard of care will prevail when choosing the mode of drug administration).

The tablets must be dispersed in a minimum of 2.5-10 ml of water and ingested immediately or administered by fast push through a syringe via a nasogastric or gastrostomy tube. The suspension has a slightly acidic taste.

This drug will be administered for 7 days after admission or until discharge (whichever is sooner).

Other Names:
• Carbaglu
• NCG

Methods/Design This 5-year, Phase II, double-blind study aims to recruit and enroll 34 PA and MMA patients during acute episodes of hyperammonemia.

The primary aim is to circumvent the long-term neurodevelopmental decline due to having a prolonged levels of ammonia during crisis in the blood and urine. After treatment and crisis resolution with Carbaglu or placebo and standard of care therapy, measures of neurodevelopmental outcomes (Bayley II and Functional Status Scale) are being measured at 9, 15,21 and 30 months post-discharge from the hospital. Safety of NCG treatment will also be monitored as measured by close examination of adverse events and laboratory blood tests. To test for the effectiveness of NCG, longitudinal models to evaluate the groupwise difference (NCG vs. Placebo) in the trajectory of change in neurodevelopmental outcomes and safety analyses between drug and placebo patients.

Subsequent Episodes At any time after the initial episode, participants may present to the hospital with PA- or MMA-associated symptoms. If the plasma ammonia level verified as a bonafide episode of HA (plasma ammonia is ≥ 100 µmol/l), that participant will receive the same study medication that they received during their initial episode in a double-blinded fashion, (i.e. If the participant received NCG at the time of initial randomization, he/she will continue to receive NCG at each subsequent HA episode. If the participant received PLBO at the time of initial randomization, he/she will continue to receive PLBO at each subsequent HA episode). Only the pharmacist will know if the participant receives NCG or PLBO. The same study assessments (previously stated) will be conducted at each qualifying HSA episode.