In short
99mTc-NTP15-5 is an investigational imaging agent being studied to detect joint damage in rheumatoid arthritis and finger osteoarthritis. It is a radioactive tracer given by intravenous infusion, and its current clinical development is a single authorised Phase 2 trial with 80 planned participants. The trial measures whether the tracer can correctly identify abnormal hand joints when compared with standard radiological and clinical assessment.
Key points
- Phase 2 trial authorised in the EU for imaging hand joints in arthritis
- 80 participants planned for enrolment
- Studied in rheumatoid arthritis and finger osteoarthritis
- Given as an intravenous infusion at 15 MBq/kg
- Main measure is diagnostic accuracy in detecting abnormal joints
- Trial status: Authorised, not yet reporting results
What is 99mTc-NTP15-5?
99mTc-NTP15-5 is an investigational imaging agent, also called a radiotracer, being developed for use in nuclear medicine. The full chemical name of the underlying substance is TRIETHYL-[3-(1,4,7,10,13-PENTAZACYCLOPENTADEC-1-YL)PROPYL]AZANIUM CHLORIDE. In the trial, this substance is labelled with technetium-99m (99mTc), a radioactive isotope commonly used in medical imaging, to form the product 99mTc-NTP15-5.
99mTc-NTP15-5 has no marketing authorisation and remains an investigational substance. Its development is currently limited to a single Phase 2 clinical trial authorised in the European Union.
How does 99mTc-NTP15-5 work?
99mTc-NTP15-5 is designed to bind to structures found in damaged or inflamed joints. When injected into the bloodstream, the radioactive technetium-99m label emits gamma rays that can be detected by a special camera used in nuclear medicine, producing images of the joints. Areas where the tracer accumulates more than in healthy tissue appear as abnormal uptake on the scan, which may indicate a pathological joint.
The precise molecular target of NTP15-5 is not described in the available trial record. The trial is designed to test whether the visual pattern of tracer uptake can distinguish abnormal joints from joints with physiological uptake, without specifying the exact biological mechanism of binding.
Which conditions is 99mTc-NTP15-5 studied for?
- Rheumatoid arthritis — a long-term autoimmune condition that causes pain, swelling and damage in joints, including those of the hands.
- Finger osteoarthritis — a degenerative joint disease affecting the finger joints, leading to pain, stiffness and loss of function.
Both conditions are studied together in the same Phase 2 trial, which compares imaging results between the two patient groups.
How is 99mTc-NTP15-5 given?
99mTc-NTP15-5 is given as an intravenous infusion. In the authorised trial, the dose is reported as 15 MBq/kg (megabecquerels per kilogram of body weight). The product is prepared as a solution for infusion and administered in a nuclear medicine setting, where the subsequent imaging is also performed.
What do the clinical trials show?
One clinical trial of 99mTc-NTP15-5 is registered in the EU Clinical Trials Information System (CTIS). The trial is a Phase 2 interventional study that has been authorised but has not yet reported results.
The trial plans to enrol 80 participants, divided into two groups: one with finger osteoarthritis and one with rheumatoid arthritis. The purpose is to evaluate the performance of 99mTc-NTP15-5 in identifying a pathological hand joint in each of the two groups.
The main outcome measure is the diagnostic accuracy of 99mTc-NTP15-5 imaging in detecting an abnormal joint among the 15 joints of the hands. The scintigraphic analysis of the joints will be visual, blinded to the pathology, and binary in nature. A joint will be considered pathological on 99mTc-NTP15-5 imaging if there is abnormal tracer uptake compared with joints showing physiological uptake. The diagnosis of a pathological joint, used as the gold standard, will be based on a composite radiological-clinical analysis.
What side effects are known?
No side effect data for 99mTc-NTP15-5 are provided in the available trial record. The trial is in an early phase of investigation, and safety information has not yet been published in the registry entry.