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. We have completed enrollment in this study.

Who was included in the Study?

Doctors assessed patients who presented to the emergency room at one of the participating hospitals with a TBI. Patients were 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 happened on the Study?

Everyone who was entered into the study received the same standard medical care as any other patient treated at the hospital for TBI. Study patients also received 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 received was determined by chance, like flipping a coin or rolling dice. This is called random assignment, and no one knew which of the drugs the patient received However, they had a 2 in 3 (66.6%) chance of getting the NNZ-2566 drug. The most common side-effects reported during previous 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).

Now that the study is over, we will work with our participating hospitals to evaluate the study data. The data evaluation will focus on learning as much as we can about the safety and effectiveness of Intrepid-2566.  All of the data that was collected in the study will be confirmed by research staff and the data will be analyzed. We anticipate that this process with take up to one year.

Where was the INTREPID-2566 Study Conducted?

The INTREPID-2566 study was conducted at up to 30 centers in the United States. The following hospitals recruited 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.

When can I find out my treatment assignment if I participated in the study?

We will notify you of your treatment assignment (Intrepid-2566 or placebo) after all study participants have completed their follow up period and the data has been analyzed. This process may take up to one year after completion. The point of contact for updates on this process will be your enrolling hospital.

Where can I find out more about the study results?

The study results will be released in several ways. They will be released to the participating hospitals and to the medical community through publication in peer review journals. 


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