About the INTREPID-2566 Study

INTREPID-2566 is a research study to assess the safety of an investigational drug – NNZ-2566. A second purpose of the study is to assess the drug’s effectiveness to reduce the effects of brain injury and improve recovery in patients with TBI. The study will find out if NNZ-2566 given with standard medical care is safe and works better than standard medical care alone.

Who will be Included in the Study?

Doctors will assess patients who come into the emergency room at one of the participating hospitals with a TBI. Patients may be entered into the study if they:

  • Are between 16 and 75 years of age
  • Have a blunt closed head injury (i.e. nothing entering the brain);
  • The doctors determine that the severity of the TBI is moderate or severe;
  • Do not have other serious injuries and have not lost too much blood;
  • Are able to read and write English;
  • Are not pregnant.

What will Happen on the Study?

Everyone who is entered into the study will get the same standard medical care as any other patient treated at the hospital for TBI. Study patients will also get either NNZ-2566 in normal saline or normal saline alone (called a placebo) delivered into their vein by intravenous (IV) infusion.

Whichever of these two infusions the patient gets will be determined by chance, like flipping a coin or rolling dice. This is called random assignment, and no one will know which of the drugs the patient was randomly assigned to receive until after the study has finished. However, they will have a 2 in 3 (66.6%) chance of getting the NNZ-2566 drug.

The study drug (NNZ-2566 or placebo) must be started within 8 hours of the patient’s TBI. This is because the earlier the study drug is given the better the chance of preventing further bruising, swelling, inflammation and damage. The study drug will be given to the patient for 3 days.

Safety and efficacy will be evaluated using physical observations, blood tests, monitoring of amnesia and memory, heart monitoring (ECG), and continuous electroencephalogram (cEEG) monitoring for signs of brain seizures. The patient’s recovery will be assessed at 1 and 3 months after their injury to see how well they are coping medically, emotionally, and socially using standardized tests and questionnaires. They will also be asked how well they are doing in their work, school, or at home, and what kinds of problems they might be having.

What are the Risks?

NNZ-2566 has been tested for safety in the laboratory and animal studies required by the FDA. It has also been tested in 95 healthy volunteers (Phase I Clinical Trial) and has not shown any serious side-effects. It has also been given to more than 90 patients with TBI in this study. The most common side-effects reported during these studies that may have been related to NNZ-2566 were:

  • Infusion site reactions such as bruising and irritation of the vein (27% of patients)
  • Mild headache (11% of patients)
  • Dizziness (7% of patients)
  • Back pain (4% of patients)
  • Bruising or irritation at the blood sampling site (4% of patients)
  • Sleepiness (3%)
  • Nausea (3%)
  • Mild changes in heart rhythm or ECG (< 3% of patients)

Less frequently reported side effects that may have been related to NNZ-2566, occurring in less than 3% of study patients, were palpitations, nosebleed, decreased appetite, irritation or swelling in throat (sore throat), flu-like symptoms, fainting, nausea, lack of energy, sleepiness, numbness around the drug infusion site, abdominal pain, rash, itchy skin, diarrhea, sweating, muscular pain, low blood pressure, and reversible changes in a blood laboratory tests (raised amylase, related to the digestive system and raised ALT, a liver function test).

What are the Benefits?

There may be no benefit to patients from participating in the INTREPID-2566 study. In animal studies, NNZ-2566 was shown to reduce brain damage and seizures, and to improve recovery after TBI. Patients in the study may get the same benefit if they receive NNZ-2566.

All patients in the study may benefit from cEEG monitoring, regardless of whether they get NNZ-2566 or placebo. Seizures often occur after TBI and may indicate that the patient’s condition is getting worse. Doctors treat seizures as part of standard medical care because this improves the patient’s condition. However, some seizures can only be identified by doctors if the patient is being monitored with cEEG. Therefore, cEEG monitoring as part of the INTREPID-2566 study may help doctors see some seizures that would otherwise be missed and go untreated.

Where is the INTREPID-2566 Study Being Conducted?

The INTREPID-2566 study is being conducted at up to 30 centers in the United States. The following hospitals will recruit subjects under the EFIC protocol for this study:

In the United States

  • Arrowhead Regional Medical Center, Colton, CA.
  • UC Davis Medical Center, Sacramento, CA.
  • Detroit Receiving Hospital, Detroit, MI.
  • Sinai-Grace Hospital, Detroit, MI.
  • University of Pittsburgh Medical Center, Pittsburgh, PA.
  • The Queens Medical Center, Honolulu, HI.



The INTREPID-2566 study is sponsored by Neuren Pharmaceuticals and funded in part by grants from the US Army Medical Research and Materiel Command.